vendor/github.com/go-logr/logr/CHANGELOG.md

+# CHANGELOG
+
+## v1.0.0-rc1
+
+This is the first logged release.  Major changes (including breaking changes)
+have occurred since earlier tags.

vendor/github.com/go-logr/logr/CONTRIBUTING.md

+# Contributing
+
+Logr is open to pull-requests, provided they fit within the intended scope of
+the project.  Specifically, this library aims to be VERY small and minimalist,
+with no external dependencies.
+
+## Compatibility
+
+This project intends to follow [semantic versioning](http://semver.org) and
+is very strict about compatibility.  Any proposed changes MUST follow those
+rules.
+
+## Performance
+
+As a logging library, logr must be as light-weight as possible.  Any proposed
+code change must include results of running the [benchmark](./benchmark)
+before and after the change.

vendor/github.com/go-logr/logr/README.md

+# A minimal logging API for Go
+
+[![Go Reference](https://pkg.go.dev/badge/github.com/go-logr/logr.svg)](https://pkg.go.dev/github.com/go-logr/logr)
+
+logr offers an(other) opinion on how Go programs and libraries can do logging
+without becoming coupled to a particular logging implementation.  This is not
+an implementation of logging - it is an API.  In fact it is two APIs with two
+different sets of users.
+
+The `Logger` type is intended for application and library authors.  It provides
+a relatively small API which can be used everywhere you want to emit logs.  It
+defers the actual act of writing logs (to files, to stdout, or whatever) to the
+`LogSink` interface.
+
+The `LogSink` interface is intended for logging library implementers.  It is a
+pure interface which can be implemented by logging frameworks to provide the actual logging
+functionality.
+
+This decoupling allows application and library developers to write code in
+terms of `logr.Logger` (which has very low dependency fan-out) while the
+implementation of logging is managed "up stack" (e.g. in or near `main()`.)
+Application developers can then switch out implementations as necessary.
+
+Many people assert that libraries should not be logging, and as such efforts
+like this are pointless.  Those people are welcome to convince the authors of
+the tens-of-thousands of libraries that *DO* write logs that they are all
+wrong.  In the meantime, logr takes a more practical approach.
+
+## Typical usage
+
+Somewhere, early in an application's life, it will make a decision about which
+logging library (implementation) it actually wants to use.  Something like:
+
+```
+    func main() {
+        // ... other setup code ...
+
+        // Create the "root" logger.  We have chosen the "logimpl" implementation,
+        // which takes some initial parameters and returns a logr.Logger.
+        logger := logimpl.New(param1, param2)
+
+        // ... other setup code ...
+```
+
+Most apps will call into other libraries, create structures to govern the flow,
+etc.  The `logr.Logger` object can be passed to these other libraries, stored
+in structs, or even used as a package-global variable, if needed.  For example:
+
+```
+    app := createTheAppObject(logger)
+    app.Run()
+```
+
+Outside of this early setup, no other packages need to know about the choice of
+implementation.  They write logs in terms of the `logr.Logger` that they
+received:
+
+```
+    type appObject struct {
+        // ... other fields ...
+        logger logr.Logger
+        // ... other fields ...
+    }
+
+    func (app *appObject) Run() {
+        app.logger.Info("starting up", "timestamp", time.Now())
+
+        // ... app code ...
+```
+
+## Background
+
+If the Go standard library had defined an interface for logging, this project
+probably would not be needed.  Alas, here we are.
+
+### Inspiration
+
+Before you consider this package, please read [this blog post by the
+inimitable Dave Cheney][warning-makes-no-sense].  We really appreciate what
+he has to say, and it largely aligns with our own experiences.
+
+### Differences from Dave's ideas
+
+The main differences are:
+
+1. Dave basically proposes doing away with the notion of a logging API in favor
+of `fmt.Printf()`.  We disagree, especially when you consider things like output
+locations, timestamps, file and line decorations, and structured logging.  This
+package restricts the logging API to just 2 types of logs: info and error.
+
+Info logs are things you want to tell the user which are not errors.  Error
+logs are, well, errors.  If your code receives an `error` from a subordinate
+function call and is logging that `error` *and not returning it*, use error
+logs.
+
+2. Verbosity-levels on info logs.  This gives developers a chance to indicate
+arbitrary grades of importance for info logs, without assigning names with
+semantic meaning such as "warning", "trace", and "debug."  Superficially this
+may feel very similar, but the primary difference is the lack of semantics.
+Because verbosity is a numerical value, it's safe to assume that an app running
+with higher verbosity means more (and less important) logs will be generated.
+
+## Implementations (non-exhaustive)
+
+There are implementations for the following logging libraries:
+
+- **a function** (can bridge to non-structured libraries): [funcr](https://github.com/go-logr/logr/tree/master/funcr)
+- **a testing.T** (for use in Go tests, with JSON-like output): [testr](https://github.com/go-logr/logr/tree/master/testr)
+- **github.com/google/glog**: [glogr](https://github.com/go-logr/glogr)
+- **k8s.io/klog** (for Kubernetes): [klogr](https://git.k8s.io/klog/klogr)
+- **a testing.T** (with klog-like text output): [ktesting](https://git.k8s.io/klog/ktesting)
+- **go.uber.org/zap**: [zapr](https://github.com/go-logr/zapr)
+- **log** (the Go standard library logger): [stdr](https://github.com/go-logr/stdr)
+- **github.com/sirupsen/logrus**: [logrusr](https://github.com/bombsimon/logrusr)
+- **github.com/wojas/genericr**: [genericr](https://github.com/wojas/genericr) (makes it easy to implement your own backend)
+- **logfmt** (Heroku style [logging](https://www.brandur.org/logfmt)): [logfmtr](https://github.com/iand/logfmtr)
+- **github.com/rs/zerolog**: [zerologr](https://github.com/go-logr/zerologr)
+- **github.com/go-kit/log**: [gokitlogr](https://github.com/tonglil/gokitlogr) (also compatible with github.com/go-kit/kit/log since v0.12.0)
+- **bytes.Buffer** (writing to a buffer): [bufrlogr](https://github.com/tonglil/buflogr) (useful for ensuring values were logged, like during testing)
+
+## FAQ
+
+### Conceptual
+
+#### Why structured logging?
+
+- **Structured logs are more easily queryable**: Since you've got
+  key-value pairs, it's much easier to query your structured logs for
+  particular values by filtering on the contents of a particular key --
+  think searching request logs for error codes, Kubernetes reconcilers for
+  the name and namespace of the reconciled object, etc.
+
+- **Structured logging makes it easier to have cross-referenceable logs**:
+  Similarly to searchability, if you maintain conventions around your
+  keys, it becomes easy to gather all log lines related to a particular
+  concept.
+
+- **Structured logs allow better dimensions of filtering**: if you have
+  structure to your logs, you've got more precise control over how much
+  information is logged -- you might choose in a particular configuration
+  to log certain keys but not others, only log lines where a certain key
+  matches a certain value, etc., instead of just having v-levels and names
+  to key off of.
+
+- **Structured logs better represent structured data**: sometimes, the
+  data that you want to log is inherently structured (think tuple-link
+  objects.)  Structured logs allow you to preserve that structure when
+  outputting.
+
+#### Why V-levels?
+
+**V-levels give operators an easy way to control the chattiness of log
+operations**.  V-levels provide a way for a given package to distinguish
+the relative importance or verbosity of a given log message.  Then, if
+a particular logger or package is logging too many messages, the user
+of the package can simply change the v-levels for that library.
+
+#### Why not named levels, like Info/Warning/Error?
+
+Read [Dave Cheney's post][warning-makes-no-sense].  Then read [Differences
+from Dave's ideas](#differences-from-daves-ideas).
+
+#### Why not allow format strings, too?
+
+**Format strings negate many of the benefits of structured logs**:
+
+- They're not easily searchable without resorting to fuzzy searching,
+  regular expressions, etc.
+
+- They don't store structured data well, since contents are flattened into
+  a string.
+
+- They're not cross-referenceable.
+
+- They don't compress easily, since the message is not constant.
+
+(Unless you turn positional parameters into key-value pairs with numerical
+keys, at which point you've gotten key-value logging with meaningless
+keys.)
+
+### Practical
+
+#### Why key-value pairs, and not a map?
+
+Key-value pairs are *much* easier to optimize, especially around
+allocations.  Zap (a structured logger that inspired logr's interface) has
+[performance measurements](https://github.com/uber-go/zap#performance)
+that show this quite nicely.
+
+While the interface ends up being a little less obvious, you get
+potentially better performance, plus avoid making users type
+`map[string]string{}` every time they want to log.
+
+#### What if my V-levels differ between libraries?
+
+That's fine.  Control your V-levels on a per-logger basis, and use the
+`WithName` method to pass different loggers to different libraries.
+
+Generally, you should take care to ensure that you have relatively
+consistent V-levels within a given logger, however, as this makes deciding
+on what verbosity of logs to request easier.
+
+#### But I really want to use a format string!
+
+That's not actually a question.  Assuming your question is "how do
+I convert my mental model of logging with format strings to logging with
+constant messages":
+
+1. Figure out what the error actually is, as you'd write in a TL;DR style,
+   and use that as a message.
+
+2. For every place you'd write a format specifier, look to the word before
+   it, and add that as a key value pair.
+
+For instance, consider the following examples (all taken from spots in the
+Kubernetes codebase):
+
+- `klog.V(4).Infof("Client is returning errors: code %v, error %v",
+  responseCode, err)` becomes `logger.Error(err, "client returned an
+  error", "code", responseCode)`
+
+- `klog.V(4).Infof("Got a Retry-After %ds response for attempt %d to %v",
+  seconds, retries, url)` becomes `logger.V(4).Info("got a retry-after
+  response when requesting url", "attempt", retries, "after
+  seconds", seconds, "url", url)`
+
+If you *really* must use a format string, use it in a key's value, and
+call `fmt.Sprintf` yourself.  For instance: `log.Printf("unable to
+reflect over type %T")` becomes `logger.Info("unable to reflect over
+type", "type", fmt.Sprintf("%T"))`.  In general though, the cases where
+this is necessary should be few and far between.
+
+#### How do I choose my V-levels?
+
+This is basically the only hard constraint: increase V-levels to denote
+more verbose or more debug-y logs.
+
+Otherwise, you can start out with `0` as "you always want to see this",
+`1` as "common logging that you might *possibly* want to turn off", and
+`10` as "I would like to performance-test your log collection stack."
+
+Then gradually choose levels in between as you need them, working your way
+down from 10 (for debug and trace style logs) and up from 1 (for chattier
+info-type logs.)
+
+#### How do I choose my keys?
+
+Keys are fairly flexible, and can hold more or less any string
+value. For best compatibility with implementations and consistency
+with existing code in other projects, there are a few conventions you
+should consider.
+
+- Make your keys human-readable.
+- Constant keys are generally a good idea.
+- Be consistent across your codebase.
+- Keys should naturally match parts of the message string.
+- Use lower case for simple keys and
+  [lowerCamelCase](https://en.wiktionary.org/wiki/lowerCamelCase) for
+  more complex ones. Kubernetes is one example of a project that has
+  [adopted that
+  convention](https://github.com/kubernetes/community/blob/HEAD/contributors/devel/sig-instrumentation/migration-to-structured-logging.md#name-arguments).
+
+While key names are mostly unrestricted (and spaces are acceptable),
+it's generally a good idea to stick to printable ascii characters, or at
+least match the general character set of your log lines.
+
+#### Why should keys be constant values?
+
+The point of structured logging is to make later log processing easier.  Your
+keys are, effectively, the schema of each log message.  If you use different
+keys across instances of the same log line, you will make your structured logs
+much harder to use.  `Sprintf()` is for values, not for keys!
+
+#### Why is this not a pure interface?
+
+The Logger type is implemented as a struct in order to allow the Go compiler to
+optimize things like high-V `Info` logs that are not triggered.  Not all of
+these implementations are implemented yet, but this structure was suggested as
+a way to ensure they *can* be implemented.  All of the real work is behind the
+`LogSink` interface.
+
+[warning-makes-no-sense]: http://dave.cheney.net/2015/11/05/lets-talk-about-logging

vendor/github.com/go-logr/logr/discard.go

+/*
+Copyright 2020 The logr Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package logr
+
+// Discard returns a Logger that discards all messages logged to it.  It can be
+// used whenever the caller is not interested in the logs.  Logger instances
+// produced by this function always compare as equal.
+func Discard() Logger {
+	return Logger{
+		level: 0,
+		sink:  discardLogSink{},
+	}
+}
+
+// discardLogSink is a LogSink that discards all messages.
+type discardLogSink struct{}
+
+// Verify that it actually implements the interface
+var _ LogSink = discardLogSink{}
+
+func (l discardLogSink) Init(RuntimeInfo) {
+}
+
+func (l discardLogSink) Enabled(int) bool {
+	return false
+}
+
+func (l discardLogSink) Info(int, string, ...interface{}) {
+}
+
+func (l discardLogSink) Error(error, string, ...interface{}) {
+}
+
+func (l discardLogSink) WithValues(...interface{}) LogSink {
+	return l
+}
+
+func (l discardLogSink) WithName(string) LogSink {
+	return l
+}

vendor/github.com/go-logr/logr/funcr/funcr.go

+/*
+Copyright 2021 The logr Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package funcr implements formatting of structured log messages and
+// optionally captures the call site and timestamp.
+//
+// The simplest way to use it is via its implementation of a
+// github.com/go-logr/logr.LogSink with output through an arbitrary
+// "write" function.  See New and NewJSON for details.
+//
+// Custom LogSinks
+//
+// For users who need more control, a funcr.Formatter can be embedded inside
+// your own custom LogSink implementation. This is useful when the LogSink
+// needs to implement additional methods, for example.
+//
+// Formatting
+//
+// This will respect logr.Marshaler, fmt.Stringer, and error interfaces for
+// values which are being logged.  When rendering a struct, funcr will use Go's
+// standard JSON tags (all except "string").
+package funcr
+
+import (
+	"bytes"
+	"encoding"
+	"fmt"
+	"path/filepath"
+	"reflect"
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/go-logr/logr"
+)
+
+// New returns a logr.Logger which is implemented by an arbitrary function.
+func New(fn func(prefix, args string), opts Options) logr.Logger {
+	return logr.New(newSink(fn, NewFormatter(opts)))
+}
+
+// NewJSON returns a logr.Logger which is implemented by an arbitrary function
+// and produces JSON output.
+func NewJSON(fn func(obj string), opts Options) logr.Logger {
+	fnWrapper := func(_, obj string) {
+		fn(obj)
+	}
+	return logr.New(newSink(fnWrapper, NewFormatterJSON(opts)))
+}
+
+// Underlier exposes access to the underlying logging function. Since
+// callers only have a logr.Logger, they have to know which
+// implementation is in use, so this interface is less of an
+// abstraction and more of a way to test type conversion.
+type Underlier interface {
+	GetUnderlying() func(prefix, args string)
+}
+
+func newSink(fn func(prefix, args string), formatter Formatter) logr.LogSink {
+	l := &fnlogger{
+		Formatter: formatter,
+		write:     fn,
+	}
+	// For skipping fnlogger.Info and fnlogger.Error.
+	l.Formatter.AddCallDepth(1)
+	return l
+}
+
+// Options carries parameters which influence the way logs are generated.
+type Options struct {
+	// LogCaller tells funcr to add a "caller" key to some or all log lines.
+	// This has some overhead, so some users might not want it.
+	LogCaller MessageClass
+
+	// LogCallerFunc tells funcr to also log the calling function name.  This
+	// has no effect if caller logging is not enabled (see Options.LogCaller).
+	LogCallerFunc bool
+
+	// LogTimestamp tells funcr to add a "ts" key to log lines.  This has some
+	// overhead, so some users might not want it.
+	LogTimestamp bool
+
+	// TimestampFormat tells funcr how to render timestamps when LogTimestamp
+	// is enabled.  If not specified, a default format will be used.  For more
+	// details, see docs for Go's time.Layout.
+	TimestampFormat string
+
+	// Verbosity tells funcr which V logs to produce.  Higher values enable
+	// more logs.  Info logs at or below this level will be written, while logs
+	// above this level will be discarded.
+	Verbosity int
+
+	// RenderBuiltinsHook allows users to mutate the list of key-value pairs
+	// while a log line is being rendered.  The kvList argument follows logr
+	// conventions - each pair of slice elements is comprised of a string key
+	// and an arbitrary value (verified and sanitized before calling this
+	// hook).  The value returned must follow the same conventions.  This hook
+	// can be used to audit or modify logged data.  For example, you might want
+	// to prefix all of funcr's built-in keys with some string.  This hook is
+	// only called for built-in (provided by funcr itself) key-value pairs.
+	// Equivalent hooks are offered for key-value pairs saved via
+	// logr.Logger.WithValues or Formatter.AddValues (see RenderValuesHook) and
+	// for user-provided pairs (see RenderArgsHook).
+	RenderBuiltinsHook func(kvList []interface{}) []interface{}
+
+	// RenderValuesHook is the same as RenderBuiltinsHook, except that it is
+	// only called for key-value pairs saved via logr.Logger.WithValues.  See
+	// RenderBuiltinsHook for more details.
+	RenderValuesHook func(kvList []interface{}) []interface{}
+
+	// RenderArgsHook is the same as RenderBuiltinsHook, except that it is only
+	// called for key-value pairs passed directly to Info and Error.  See
+	// RenderBuiltinsHook for more details.
+	RenderArgsHook func(kvList []interface{}) []interface{}
+
+	// MaxLogDepth tells funcr how many levels of nested fields (e.g. a struct
+	// that contains a struct, etc.) it may log.  Every time it finds a struct,
+	// slice, array, or map the depth is increased by one.  When the maximum is
+	// reached, the value will be converted to a string indicating that the max
+	// depth has been exceeded.  If this field is not specified, a default
+	// value will be used.
+	MaxLogDepth int
+}
+
+// MessageClass indicates which category or categories of messages to consider.
+type MessageClass int
+
+const (
+	// None ignores all message classes.
+	None MessageClass = iota
+	// All considers all message classes.
+	All
+	// Info only considers info messages.
+	Info
+	// Error only considers error messages.
+	Error
+)
+
+// fnlogger inherits some of its LogSink implementation from Formatter
+// and just needs to add some glue code.
+type fnlogger struct {
+	Formatter
+	write func(prefix, args string)
+}
+
+func (l fnlogger) WithName(name string) logr.LogSink {
+	l.Formatter.AddName(name)
+	return &l
+}
+
+func (l fnlogger) WithValues(kvList ...interface{}) logr.LogSink {
+	l.Formatter.AddValues(kvList)
+	return &l
+}
+
+func (l fnlogger) WithCallDepth(depth int) logr.LogSink {
+	l.Formatter.AddCallDepth(depth)
+	return &l
+}
+
+func (l fnlogger) Info(level int, msg string, kvList ...interface{}) {
+	prefix, args := l.FormatInfo(level, msg, kvList)
+	l.write(prefix, args)
+}
+
+func (l fnlogger) Error(err error, msg string, kvList ...interface{}) {
+	prefix, args := l.FormatError(err, msg, kvList)
+	l.write(prefix, args)
+}
+
+func (l fnlogger) GetUnderlying() func(prefix, args string) {
+	return l.write
+}
+
+// Assert conformance to the interfaces.
+var _ logr.LogSink = &fnlogger{}
+var _ logr.CallDepthLogSink = &fnlogger{}
+var _ Underlier = &fnlogger{}
+
+// NewFormatter constructs a Formatter which emits a JSON-like key=value format.
+func NewFormatter(opts Options) Formatter {
+	return newFormatter(opts, outputKeyValue)
+}
+
+// NewFormatterJSON constructs a Formatter which emits strict JSON.
+func NewFormatterJSON(opts Options) Formatter {
+	return newFormatter(opts, outputJSON)
+}
+
+// Defaults for Options.
+const defaultTimestampFormat = "2006-01-02 15:04:05.000000"
+const defaultMaxLogDepth = 16
+
+func newFormatter(opts Options, outfmt outputFormat) Formatter {
+	if opts.TimestampFormat == "" {
+		opts.TimestampFormat = defaultTimestampFormat
+	}
+	if opts.MaxLogDepth == 0 {
+		opts.MaxLogDepth = defaultMaxLogDepth
+	}
+	f := Formatter{
+		outputFormat: outfmt,
+		prefix:       "",
+		values:       nil,
+		depth:        0,
+		opts:         opts,
+	}
+	return f
+}
+
+// Formatter is an opaque struct which can be embedded in a LogSink
+// implementation. It should be constructed with NewFormatter. Some of
+// its methods directly implement logr.LogSink.
+type Formatter struct {
+	outputFormat outputFormat
+	prefix       string
+	values       []interface{}
+	valuesStr    string
+	depth        int
+	opts         Options
+}
+
+// outputFormat indicates which outputFormat to use.
+type outputFormat int
+
+const (
+	// outputKeyValue emits a JSON-like key=value format, but not strict JSON.
+	outputKeyValue outputFormat = iota
+	// outputJSON emits strict JSON.
+	outputJSON
+)
+
+// PseudoStruct is a list of key-value pairs that gets logged as a struct.
+type PseudoStruct []interface{}
+
+// render produces a log line, ready to use.
+func (f Formatter) render(builtins, args []interface{}) string {
+	// Empirically bytes.Buffer is faster than strings.Builder for this.
+	buf := bytes.NewBuffer(make([]byte, 0, 1024))
+	if f.outputFormat == outputJSON {
+		buf.WriteByte('{')
+	}
+	vals := builtins
+	if hook := f.opts.RenderBuiltinsHook; hook != nil {
+		vals = hook(f.sanitize(vals))
+	}
+	f.flatten(buf, vals, false, false) // keys are ours, no need to escape
+	continuing := len(builtins) > 0
+	if len(f.valuesStr) > 0 {
+		if continuing {
+			if f.outputFormat == outputJSON {
+				buf.WriteByte(',')
+			} else {
+				buf.WriteByte(' ')
+			}
+		}
+		continuing = true
+		buf.WriteString(f.valuesStr)
+	}
+	vals = args
+	if hook := f.opts.RenderArgsHook; hook != nil {
+		vals = hook(f.sanitize(vals))
+	}
+	f.flatten(buf, vals, continuing, true) // escape user-provided keys
+	if f.outputFormat == outputJSON {
+		buf.WriteByte('}')
+	}
+	return buf.String()
+}
+
+// flatten renders a list of key-value pairs into a buffer.  If continuing is
+// true, it assumes that the buffer has previous values and will emit a
+// separator (which depends on the output format) before the first pair it
+// writes.  If escapeKeys is true, the keys are assumed to have
+// non-JSON-compatible characters in them and must be evaluated for escapes.
+//
+// This function returns a potentially modified version of kvList, which
+// ensures that there is a value for every key (adding a value if needed) and
+// that each key is a string (substituting a key if needed).
+func (f Formatter) flatten(buf *bytes.Buffer, kvList []interface{}, continuing bool, escapeKeys bool) []interface{} {
+	// This logic overlaps with sanitize() but saves one type-cast per key,
+	// which can be measurable.
+	if len(kvList)%2 != 0 {
+		kvList = append(kvList, noValue)
+	}
+	for i := 0; i < len(kvList); i += 2 {
+		k, ok := kvList[i].(string)
+		if !ok {
+			k = f.nonStringKey(kvList[i])
+			kvList[i] = k
+		}
+		v := kvList[i+1]
+
+		if i > 0 || continuing {
+			if f.outputFormat == outputJSON {
+				buf.WriteByte(',')
+			} else {
+				// In theory the format could be something we don't understand.  In
+				// practice, we control it, so it won't be.
+				buf.WriteByte(' ')
+			}
+		}
+
+		if escapeKeys {
+			buf.WriteString(prettyString(k))
+		} else {
+			// this is faster
+			buf.WriteByte('"')
+			buf.WriteString(k)
+			buf.WriteByte('"')
+		}
+		if f.outputFormat == outputJSON {
+			buf.WriteByte(':')
+		} else {
+			buf.WriteByte('=')
+		}
+		buf.WriteString(f.pretty(v))
+	}
+	return kvList
+}
+
+func (f Formatter) pretty(value interface{}) string {
+	return f.prettyWithFlags(value, 0, 0)
+}
+
+const (
+	flagRawStruct = 0x1 // do not print braces on structs
+)
+
+// TODO: This is not fast. Most of the overhead goes here.
+func (f Formatter) prettyWithFlags(value interface{}, flags uint32, depth int) string {
+	if depth > f.opts.MaxLogDepth {
+		return `"<max-log-depth-exceeded>"`
+	}
+
+	// Handle types that take full control of logging.
+	if v, ok := value.(logr.Marshaler); ok {
+		// Replace the value with what the type wants to get logged.
+		// That then gets handled below via reflection.
+		value = invokeMarshaler(v)
+	}
+
+	// Handle types that want to format themselves.
+	switch v := value.(type) {
+	case fmt.Stringer:
+		value = invokeStringer(v)
+	case error:
+		value = invokeError(v)
+	}
+
+	// Handling the most common types without reflect is a small perf win.
+	switch v := value.(type) {
+	case bool:
+		return strconv.FormatBool(v)
+	case string:
+		return prettyString(v)
+	case int:
+		return strconv.FormatInt(int64(v), 10)
+	case int8:
+		return strconv.FormatInt(int64(v), 10)
+	case int16:
+		return strconv.FormatInt(int64(v), 10)
+	case int32:
+		return strconv.FormatInt(int64(v), 10)
+	case int64:
+		return strconv.FormatInt(int64(v), 10)
+	case uint:
+		return strconv.FormatUint(uint64(v), 10)
+	case uint8:
+		return strconv.FormatUint(uint64(v), 10)
+	case uint16:
+		return strconv.FormatUint(uint64(v), 10)
+	case uint32:
+		return strconv.FormatUint(uint64(v), 10)
+	case uint64:
+		return strconv.FormatUint(v, 10)
+	case uintptr:
+		return strconv.FormatUint(uint64(v), 10)
+	case float32:
+		return strconv.FormatFloat(float64(v), 'f', -1, 32)
+	case float64:
+		return strconv.FormatFloat(v, 'f', -1, 64)
+	case complex64:
+		return `"` + strconv.FormatComplex(complex128(v), 'f', -1, 64) + `"`
+	case complex128:
+		return `"` + strconv.FormatComplex(v, 'f', -1, 128) + `"`
+	case PseudoStruct:
+		buf := bytes.NewBuffer(make([]byte, 0, 1024))
+		v = f.sanitize(v)
+		if flags&flagRawStruct == 0 {
+			buf.WriteByte('{')
+		}
+		for i := 0; i < len(v); i += 2 {
+			if i > 0 {
+				buf.WriteByte(',')
+			}
+			k, _ := v[i].(string) // sanitize() above means no need to check success
+			// arbitrary keys might need escaping
+			buf.WriteString(prettyString(k))
+			buf.WriteByte(':')
+			buf.WriteString(f.prettyWithFlags(v[i+1], 0, depth+1))
+		}
+		if flags&flagRawStruct == 0 {
+			buf.WriteByte('}')
+		}
+		return buf.String()
+	}
+
+	buf := bytes.NewBuffer(make([]byte, 0, 256))
+	t := reflect.TypeOf(value)
+	if t == nil {
+		return "null"
+	}
+	v := reflect.ValueOf(value)
+	switch t.Kind() {
+	case reflect.Bool:
+		return strconv.FormatBool(v.Bool())
+	case reflect.String:
+		return prettyString(v.String())
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return strconv.FormatInt(int64(v.Int()), 10)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return strconv.FormatUint(uint64(v.Uint()), 10)
+	case reflect.Float32:
+		return strconv.FormatFloat(float64(v.Float()), 'f', -1, 32)
+	case reflect.Float64:
+		return strconv.FormatFloat(v.Float(), 'f', -1, 64)
+	case reflect.Complex64:
+		return `"` + strconv.FormatComplex(complex128(v.Complex()), 'f', -1, 64) + `"`
+	case reflect.Complex128:
+		return `"` + strconv.FormatComplex(v.Complex(), 'f', -1, 128) + `"`
+	case reflect.Struct:
+		if flags&flagRawStruct == 0 {
+			buf.WriteByte('{')
+		}
+		for i := 0; i < t.NumField(); i++ {
+			fld := t.Field(i)
+			if fld.PkgPath != "" {
+				// reflect says this field is only defined for non-exported fields.
+				continue
+			}
+			if !v.Field(i).CanInterface() {
+				// reflect isn't clear exactly what this means, but we can't use it.
+				continue
+			}
+			name := ""
+			omitempty := false
+			if tag, found := fld.Tag.Lookup("json"); found {
+				if tag == "-" {
+					continue
+				}
+				if comma := strings.Index(tag, ","); comma != -1 {
+					if n := tag[:comma]; n != "" {
+						name = n
+					}
+					rest := tag[comma:]
+					if strings.Contains(rest, ",omitempty,") || strings.HasSuffix(rest, ",omitempty") {
+						omitempty = true
+					}
+				} else {
+					name = tag
+				}
+			}
+			if omitempty && isEmpty(v.Field(i)) {
+				continue
+			}
+			if i > 0 {
+				buf.WriteByte(',')
+			}
+			if fld.Anonymous && fld.Type.Kind() == reflect.Struct && name == "" {
+				buf.WriteString(f.prettyWithFlags(v.Field(i).Interface(), flags|flagRawStruct, depth+1))
+				continue
+			}
+			if name == "" {
+				name = fld.Name
+			}
+			// field names can't contain characters which need escaping
+			buf.WriteByte('"')
+			buf.WriteString(name)
+			buf.WriteByte('"')
+			buf.WriteByte(':')
+			buf.WriteString(f.prettyWithFlags(v.Field(i).Interface(), 0, depth+1))
+		}
+		if flags&flagRawStruct == 0 {
+			buf.WriteByte('}')
+		}
+		return buf.String()
+	case reflect.Slice, reflect.Array:
+		buf.WriteByte('[')
+		for i := 0; i < v.Len(); i++ {
+			if i > 0 {
+				buf.WriteByte(',')
+			}
+			e := v.Index(i)
+			buf.WriteString(f.prettyWithFlags(e.Interface(), 0, depth+1))
+		}
+		buf.WriteByte(']')
+		return buf.String()
+	case reflect.Map:
+		buf.WriteByte('{')
+		// This does not sort the map keys, for best perf.
+		it := v.MapRange()
+		i := 0
+		for it.Next() {
+			if i > 0 {
+				buf.WriteByte(',')
+			}
+			// If a map key supports TextMarshaler, use it.
+			keystr := ""
+			if m, ok := it.Key().Interface().(encoding.TextMarshaler); ok {
+				txt, err := m.MarshalText()
+				if err != nil {
+					keystr = fmt.Sprintf("<error-MarshalText: %s>", err.Error())
+				} else {
+					keystr = string(txt)
+				}
+				keystr = prettyString(keystr)
+			} else {
+				// prettyWithFlags will produce already-escaped values
+				keystr = f.prettyWithFlags(it.Key().Interface(), 0, depth+1)
+				if t.Key().Kind() != reflect.String {
+					// JSON only does string keys.  Unlike Go's standard JSON, we'll
+					// convert just about anything to a string.
+					keystr = prettyString(keystr)
+				}
+			}
+			buf.WriteString(keystr)
+			buf.WriteByte(':')
+			buf.WriteString(f.prettyWithFlags(it.Value().Interface(), 0, depth+1))
+			i++
+		}
+		buf.WriteByte('}')
+		return buf.String()
+	case reflect.Ptr, reflect.Interface:
+		if v.IsNil() {
+			return "null"
+		}
+		return f.prettyWithFlags(v.Elem().Interface(), 0, depth)
+	}
+	return fmt.Sprintf(`"<unhandled-%s>"`, t.Kind().String())
+}
+
+func prettyString(s string) string {
+	// Avoid escaping (which does allocations) if we can.
+	if needsEscape(s) {
+		return strconv.Quote(s)
+	}
+	b := bytes.NewBuffer(make([]byte, 0, 1024))
+	b.WriteByte('"')
+	b.WriteString(s)
+	b.WriteByte('"')
+	return b.String()
+}
+
+// needsEscape determines whether the input string needs to be escaped or not,
+// without doing any allocations.
+func needsEscape(s string) bool {
+	for _, r := range s {
+		if !strconv.IsPrint(r) || r == '\\' || r == '"' {
+			return true
+		}
+	}
+	return false
+}
+
+func isEmpty(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		return v.Len() == 0
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Complex64, reflect.Complex128:
+		return v.Complex() == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	}
+	return false
+}
+
+func invokeMarshaler(m logr.Marshaler) (ret interface{}) {
+	defer func() {
+		if r := recover(); r != nil {
+			ret = fmt.Sprintf("<panic: %s>", r)
+		}
+	}()
+	return m.MarshalLog()
+}
+
+func invokeStringer(s fmt.Stringer) (ret string) {
+	defer func() {
+		if r := recover(); r != nil {
+			ret = fmt.Sprintf("<panic: %s>", r)
+		}
+	}()
+	return s.String()
+}
+
+func invokeError(e error) (ret string) {
+	defer func() {
+		if r := recover(); r != nil {
+			ret = fmt.Sprintf("<panic: %s>", r)
+		}
+	}()
+	return e.Error()
+}
+
+// Caller represents the original call site for a log line, after considering
+// logr.Logger.WithCallDepth and logr.Logger.WithCallStackHelper.  The File and
+// Line fields will always be provided, while the Func field is optional.
+// Users can set the render hook fields in Options to examine logged key-value
+// pairs, one of which will be {"caller", Caller} if the Options.LogCaller
+// field is enabled for the given MessageClass.
+type Caller struct {
+	// File is the basename of the file for this call site.
+	File string `json:"file"`
+	// Line is the line number in the file for this call site.
+	Line int `json:"line"`
+	// Func is the function name for this call site, or empty if
+	// Options.LogCallerFunc is not enabled.
+	Func string `json:"function,omitempty"`
+}
+
+func (f Formatter) caller() Caller {
+	// +1 for this frame, +1 for Info/Error.
+	pc, file, line, ok := runtime.Caller(f.depth + 2)
+	if !ok {
+		return Caller{"<unknown>", 0, ""}
+	}
+	fn := ""
+	if f.opts.LogCallerFunc {
+		if fp := runtime.FuncForPC(pc); fp != nil {
+			fn = fp.Name()
+		}
+	}
+
+	return Caller{filepath.Base(file), line, fn}
+}
+
+const noValue = "<no-value>"
+
+func (f Formatter) nonStringKey(v interface{}) string {
+	return fmt.Sprintf("<non-string-key: %s>", f.snippet(v))
+}
+
+// snippet produces a short snippet string of an arbitrary value.
+func (f Formatter) snippet(v interface{}) string {
+	const snipLen = 16
+
+	snip := f.pretty(v)
+	if len(snip) > snipLen {
+		snip = snip[:snipLen]
+	}
+	return snip
+}
+
+// sanitize ensures that a list of key-value pairs has a value for every key
+// (adding a value if needed) and that each key is a string (substituting a key
+// if needed).
+func (f Formatter) sanitize(kvList []interface{}) []interface{} {
+	if len(kvList)%2 != 0 {
+		kvList = append(kvList, noValue)
+	}
+	for i := 0; i < len(kvList); i += 2 {
+		_, ok := kvList[i].(string)
+		if !ok {
+			kvList[i] = f.nonStringKey(kvList[i])
+		}
+	}
+	return kvList
+}
+
+// Init configures this Formatter from runtime info, such as the call depth
+// imposed by logr itself.
+// Note that this receiver is a pointer, so depth can be saved.
+func (f *Formatter) Init(info logr.RuntimeInfo) {
+	f.depth += info.CallDepth
+}
+
+// Enabled checks whether an info message at the given level should be logged.
+func (f Formatter) Enabled(level int) bool {
+	return level <= f.opts.Verbosity
+}
+
+// GetDepth returns the current depth of this Formatter.  This is useful for
+// implementations which do their own caller attribution.
+func (f Formatter) GetDepth() int {
+	return f.depth
+}
+
+// FormatInfo renders an Info log message into strings.  The prefix will be
+// empty when no names were set (via AddNames), or when the output is
+// configured for JSON.
+func (f Formatter) FormatInfo(level int, msg string, kvList []interface{}) (prefix, argsStr string) {
+	args := make([]interface{}, 0, 64) // using a constant here impacts perf
+	prefix = f.prefix
+	if f.outputFormat == outputJSON {
+		args = append(args, "logger", prefix)
+		prefix = ""
+	}
+	if f.opts.LogTimestamp {
+		args = append(args, "ts", time.Now().Format(f.opts.TimestampFormat))
+	}
+	if policy := f.opts.LogCaller; policy == All || policy == Info {
+		args = append(args, "caller", f.caller())
+	}
+	args = append(args, "level", level, "msg", msg)
+	return prefix, f.render(args, kvList)
+}
+
+// FormatError renders an Error log message into strings.  The prefix will be
+// empty when no names were set (via AddNames),  or when the output is
+// configured for JSON.
+func (f Formatter) FormatError(err error, msg string, kvList []interface{}) (prefix, argsStr string) {
+	args := make([]interface{}, 0, 64) // using a constant here impacts perf
+	prefix = f.prefix
+	if f.outputFormat == outputJSON {
+		args = append(args, "logger", prefix)
+		prefix = ""
+	}
+	if f.opts.LogTimestamp {
+		args = append(args, "ts", time.Now().Format(f.opts.TimestampFormat))
+	}
+	if policy := f.opts.LogCaller; policy == All || policy == Error {
+		args = append(args, "caller", f.caller())
+	}
+	args = append(args, "msg", msg)
+	var loggableErr interface{}
+	if err != nil {
+		loggableErr = err.Error()
+	}
+	args = append(args, "error", loggableErr)
+	return f.prefix, f.render(args, kvList)
+}
+
+// AddName appends the specified name.  funcr uses '/' characters to separate
+// name elements.  Callers should not pass '/' in the provided name string, but
+// this library does not actually enforce that.
+func (f *Formatter) AddName(name string) {
+	if len(f.prefix) > 0 {
+		f.prefix += "/"
+	}
+	f.prefix += name
+}
+
+// AddValues adds key-value pairs to the set of saved values to be logged with
+// each log line.
+func (f *Formatter) AddValues(kvList []interface{}) {
+	// Three slice args forces a copy.
+	n := len(f.values)
+	f.values = append(f.values[:n:n], kvList...)
+
+	vals := f.values
+	if hook := f.opts.RenderValuesHook; hook != nil {
+		vals = hook(f.sanitize(vals))
+	}
+
+	// Pre-render values, so we don't have to do it on each Info/Error call.
+	buf := bytes.NewBuffer(make([]byte, 0, 1024))
+	f.flatten(buf, vals, false, true) // escape user-provided keys
+	f.valuesStr = buf.String()
+}
+
+// AddCallDepth increases the number of stack-frames to skip when attributing
+// the log line to a file and line.
+func (f *Formatter) AddCallDepth(depth int) {
+	f.depth += depth
+}

vendor/github.com/go-logr/logr/go.mod

+module github.com/go-logr/logr
+
+go 1.16

vendor/github.com/go-logr/logr/logr.go

+/*
+Copyright 2019 The logr Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// This design derives from Dave Cheney's blog:
+//     http://dave.cheney.net/2015/11/05/lets-talk-about-logging
+
+// Package logr defines a general-purpose logging API and abstract interfaces
+// to back that API.  Packages in the Go ecosystem can depend on this package,
+// while callers can implement logging with whatever backend is appropriate.
+//
+// Usage
+//
+// Logging is done using a Logger instance.  Logger is a concrete type with
+// methods, which defers the actual logging to a LogSink interface.  The main
+// methods of Logger are Info() and Error().  Arguments to Info() and Error()
+// are key/value pairs rather than printf-style formatted strings, emphasizing
+// "structured logging".
+//
+// With Go's standard log package, we might write:
+//   log.Printf("setting target value %s", targetValue)
+//
+// With logr's structured logging, we'd write:
+//   logger.Info("setting target", "value", targetValue)
+//
+// Errors are much the same.  Instead of:
+//   log.Printf("failed to open the pod bay door for user %s: %v", user, err)
+//
+// We'd write:
+//   logger.Error(err, "failed to open the pod bay door", "user", user)
+//
+// Info() and Error() are very similar, but they are separate methods so that
+// LogSink implementations can choose to do things like attach additional
+// information (such as stack traces) on calls to Error(). Error() messages are
+// always logged, regardless of the current verbosity.  If there is no error
+// instance available, passing nil is valid.
+//
+// Verbosity
+//
+// Often we want to log information only when the application in "verbose
+// mode".  To write log lines that are more verbose, Logger has a V() method.
+// The higher the V-level of a log line, the less critical it is considered.
+// Log-lines with V-levels that are not enabled (as per the LogSink) will not
+// be written.  Level V(0) is the default, and logger.V(0).Info() has the same
+// meaning as logger.Info().  Negative V-levels have the same meaning as V(0).
+// Error messages do not have a verbosity level and are always logged.
+//
+// Where we might have written:
+//   if flVerbose >= 2 {
+//       log.Printf("an unusual thing happened")
+//   }
+//
+// We can write:
+//   logger.V(2).Info("an unusual thing happened")
+//
+// Logger Names
+//
+// Logger instances can have name strings so that all messages logged through
+// that instance have additional context.  For example, you might want to add
+// a subsystem name:
+//
+//   logger.WithName("compactor").Info("started", "time", time.Now())
+//
+// The WithName() method returns a new Logger, which can be passed to
+// constructors or other functions for further use.  Repeated use of WithName()
+// will accumulate name "segments".  These name segments will be joined in some
+// way by the LogSink implementation.  It is strongly recommended that name
+// segments contain simple identifiers (letters, digits, and hyphen), and do
+// not contain characters that could muddle the log output or confuse the
+// joining operation (e.g. whitespace, commas, periods, slashes, brackets,
+// quotes, etc).
+//
+// Saved Values
+//
+// Logger instances can store any number of key/value pairs, which will be
+// logged alongside all messages logged through that instance.  For example,
+// you might want to create a Logger instance per managed object:
+//
+// With the standard log package, we might write:
+//   log.Printf("decided to set field foo to value %q for object %s/%s",
+//       targetValue, object.Namespace, object.Name)
+//
+// With logr we'd write:
+//   // Elsewhere: set up the logger to log the object name.
+//   obj.logger = mainLogger.WithValues(
+//       "name", obj.name, "namespace", obj.namespace)
+//
+//   // later on...
+//   obj.logger.Info("setting foo", "value", targetValue)
+//
+// Best Practices
+//
+// Logger has very few hard rules, with the goal that LogSink implementations
+// might have a lot of freedom to differentiate.  There are, however, some
+// things to consider.
+//
+// The log message consists of a constant message attached to the log line.
+// This should generally be a simple description of what's occurring, and should
+// never be a format string.  Variable information can then be attached using
+// named values.
+//
+// Keys are arbitrary strings, but should generally be constant values.  Values
+// may be any Go value, but how the value is formatted is determined by the
+// LogSink implementation.
+//
+// Logger instances are meant to be passed around by value. Code that receives
+// such a value can call its methods without having to check whether the
+// instance is ready for use.
+//
+// Calling methods with the null logger (Logger{}) as instance will crash
+// because it has no LogSink. Therefore this null logger should never be passed
+// around. For cases where passing a logger is optional, a pointer to Logger
+// should be used.
+//
+// Key Naming Conventions
+//
+// Keys are not strictly required to conform to any specification or regex, but
+// it is recommended that they:
+//   * be human-readable and meaningful (not auto-generated or simple ordinals)
+//   * be constant (not dependent on input data)
+//   * contain only printable characters
+//   * not contain whitespace or punctuation
+//   * use lower case for simple keys and lowerCamelCase for more complex ones
+//
+// These guidelines help ensure that log data is processed properly regardless
+// of the log implementation.  For example, log implementations will try to
+// output JSON data or will store data for later database (e.g. SQL) queries.
+//
+// While users are generally free to use key names of their choice, it's
+// generally best to avoid using the following keys, as they're frequently used
+// by implementations:
+//   * "caller": the calling information (file/line) of a particular log line
+//   * "error": the underlying error value in the `Error` method
+//   * "level": the log level
+//   * "logger": the name of the associated logger
+//   * "msg": the log message
+//   * "stacktrace": the stack trace associated with a particular log line or
+//                   error (often from the `Error` message)
+//   * "ts": the timestamp for a log line
+//
+// Implementations are encouraged to make use of these keys to represent the
+// above concepts, when necessary (for example, in a pure-JSON output form, it
+// would be necessary to represent at least message and timestamp as ordinary
+// named values).
+//
+// Break Glass
+//
+// Implementations may choose to give callers access to the underlying
+// logging implementation.  The recommended pattern for this is:
+//   // Underlier exposes access to the underlying logging implementation.
+//   // Since callers only have a logr.Logger, they have to know which
+//   // implementation is in use, so this interface is less of an abstraction
+//   // and more of way to test type conversion.
+//   type Underlier interface {
+//       GetUnderlying() <underlying-type>
+//   }
+//
+// Logger grants access to the sink to enable type assertions like this:
+//   func DoSomethingWithImpl(log logr.Logger) {
+//       if underlier, ok := log.GetSink()(impl.Underlier) {
+//          implLogger := underlier.GetUnderlying()
+//          ...
+//       }
+//   }
+//
+// Custom `With*` functions can be implemented by copying the complete
+// Logger struct and replacing the sink in the copy:
+//   // WithFooBar changes the foobar parameter in the log sink and returns a
+//   // new logger with that modified sink.  It does nothing for loggers where
+//   // the sink doesn't support that parameter.
+//   func WithFoobar(log logr.Logger, foobar int) logr.Logger {
+//      if foobarLogSink, ok := log.GetSink()(FoobarSink); ok {
+//         log = log.WithSink(foobarLogSink.WithFooBar(foobar))
+//      }
+//      return log
+//   }
+//
+// Don't use New to construct a new Logger with a LogSink retrieved from an
+// existing Logger. Source code attribution might not work correctly and
+// unexported fields in Logger get lost.
+//
+// Beware that the same LogSink instance may be shared by different logger
+// instances. Calling functions that modify the LogSink will affect all of
+// those.
+package logr
+
+import (
+	"context"
+)
+
+// New returns a new Logger instance.  This is primarily used by libraries
+// implementing LogSink, rather than end users.
+func New(sink LogSink) Logger {
+	logger := Logger{}
+	logger.setSink(sink)
+	sink.Init(runtimeInfo)
+	return logger
+}
+
+// setSink stores the sink and updates any related fields. It mutates the
+// logger and thus is only safe to use for loggers that are not currently being
+// used concurrently.
+func (l *Logger) setSink(sink LogSink) {
+	l.sink = sink
+}
+
+// GetSink returns the stored sink.
+func (l Logger) GetSink() LogSink {
+	return l.sink
+}
+
+// WithSink returns a copy of the logger with the new sink.
+func (l Logger) WithSink(sink LogSink) Logger {
+	l.setSink(sink)
+	return l
+}
+
+// Logger is an interface to an abstract logging implementation.  This is a
+// concrete type for performance reasons, but all the real work is passed on to
+// a LogSink.  Implementations of LogSink should provide their own constructors
+// that return Logger, not LogSink.
+//
+// The underlying sink can be accessed through GetSink and be modified through
+// WithSink. This enables the implementation of custom extensions (see "Break
+// Glass" in the package documentation). Normally the sink should be used only
+// indirectly.
+type Logger struct {
+	sink  LogSink
+	level int
+}
+
+// Enabled tests whether this Logger is enabled.  For example, commandline
+// flags might be used to set the logging verbosity and disable some info logs.
+func (l Logger) Enabled() bool {
+	return l.sink.Enabled(l.level)
+}
+
+// Info logs a non-error message with the given key/value pairs as context.
+//
+// The msg argument should be used to add some constant description to the log
+// line.  The key/value pairs can then be used to add additional variable
+// information.  The key/value pairs must alternate string keys and arbitrary
+// values.
+func (l Logger) Info(msg string, keysAndValues ...interface{}) {
+	if l.Enabled() {
+		if withHelper, ok := l.sink.(CallStackHelperLogSink); ok {
+			withHelper.GetCallStackHelper()()
+		}
+		l.sink.Info(l.level, msg, keysAndValues...)
+	}
+}
+
+// Error logs an error, with the given message and key/value pairs as context.
+// It functions similarly to Info, but may have unique behavior, and should be
+// preferred for logging errors (see the package documentations for more
+// information). The log message will always be emitted, regardless of
+// verbosity level.
+//
+// The msg argument should be used to add context to any underlying error,
+// while the err argument should be used to attach the actual error that
+// triggered this log line, if present. The err parameter is optional
+// and nil may be passed instead of an error instance.
+func (l Logger) Error(err error, msg string, keysAndValues ...interface{}) {
+	if withHelper, ok := l.sink.(CallStackHelperLogSink); ok {
+		withHelper.GetCallStackHelper()()
+	}
+	l.sink.Error(err, msg, keysAndValues...)
+}
+
+// V returns a new Logger instance for a specific verbosity level, relative to
+// this Logger.  In other words, V-levels are additive.  A higher verbosity
+// level means a log message is less important.  Negative V-levels are treated
+// as 0.
+func (l Logger) V(level int) Logger {
+	if level < 0 {
+		level = 0
+	}
+	l.level += level
+	return l
+}
+
+// WithValues returns a new Logger instance with additional key/value pairs.
+// See Info for documentation on how key/value pairs work.
+func (l Logger) WithValues(keysAndValues ...interface{}) Logger {
+	l.setSink(l.sink.WithValues(keysAndValues...))
+	return l
+}
+
+// WithName returns a new Logger instance with the specified name element added
+// to the Logger's name.  Successive calls with WithName append additional
+// suffixes to the Logger's name.  It's strongly recommended that name segments
+// contain only letters, digits, and hyphens (see the package documentation for
+// more information).
+func (l Logger) WithName(name string) Logger {
+	l.setSink(l.sink.WithName(name))
+	return l
+}
+
+// WithCallDepth returns a Logger instance that offsets the call stack by the
+// specified number of frames when logging call site information, if possible.
+// This is useful for users who have helper functions between the "real" call
+// site and the actual calls to Logger methods.  If depth is 0 the attribution
+// should be to the direct caller of this function.  If depth is 1 the
+// attribution should skip 1 call frame, and so on.  Successive calls to this
+// are additive.
+//
+// If the underlying log implementation supports a WithCallDepth(int) method,
+// it will be called and the result returned.  If the implementation does not
+// support CallDepthLogSink, the original Logger will be returned.
+//
+// To skip one level, WithCallStackHelper() should be used instead of
+// WithCallDepth(1) because it works with implementions that support the
+// CallDepthLogSink and/or CallStackHelperLogSink interfaces.
+func (l Logger) WithCallDepth(depth int) Logger {
+	if withCallDepth, ok := l.sink.(CallDepthLogSink); ok {
+		l.setSink(withCallDepth.WithCallDepth(depth))
+	}
+	return l
+}
+
+// WithCallStackHelper returns a new Logger instance that skips the direct
+// caller when logging call site information, if possible.  This is useful for
+// users who have helper functions between the "real" call site and the actual
+// calls to Logger methods and want to support loggers which depend on marking
+// each individual helper function, like loggers based on testing.T.
+//
+// In addition to using that new logger instance, callers also must call the
+// returned function.
+//
+// If the underlying log implementation supports a WithCallDepth(int) method,
+// WithCallDepth(1) will be called to produce a new logger. If it supports a
+// WithCallStackHelper() method, that will be also called. If the
+// implementation does not support either of these, the original Logger will be
+// returned.
+func (l Logger) WithCallStackHelper() (func(), Logger) {
+	var helper func()
+	if withCallDepth, ok := l.sink.(CallDepthLogSink); ok {
+		l.setSink(withCallDepth.WithCallDepth(1))
+	}
+	if withHelper, ok := l.sink.(CallStackHelperLogSink); ok {
+		helper = withHelper.GetCallStackHelper()
+	} else {
+		helper = func() {}
+	}
+	return helper, l
+}
+
+// contextKey is how we find Loggers in a context.Context.
+type contextKey struct{}
+
+// FromContext returns a Logger from ctx or an error if no Logger is found.
+func FromContext(ctx context.Context) (Logger, error) {
+	if v, ok := ctx.Value(contextKey{}).(Logger); ok {
+		return v, nil
+	}
+
+	return Logger{}, notFoundError{}
+}
+
+// notFoundError exists to carry an IsNotFound method.
+type notFoundError struct{}
+
+func (notFoundError) Error() string {
+	return "no logr.Logger was present"
+}
+
+func (notFoundError) IsNotFound() bool {
+	return true
+}
+
+// FromContextOrDiscard returns a Logger from ctx.  If no Logger is found, this
+// returns a Logger that discards all log messages.
+func FromContextOrDiscard(ctx context.Context) Logger {
+	if v, ok := ctx.Value(contextKey{}).(Logger); ok {
+		return v
+	}
+
+	return Discard()
+}
+
+// NewContext returns a new Context, derived from ctx, which carries the
+// provided Logger.
+func NewContext(ctx context.Context, logger Logger) context.Context {
+	return context.WithValue(ctx, contextKey{}, logger)
+}
+
+// RuntimeInfo holds information that the logr "core" library knows which
+// LogSinks might want to know.
+type RuntimeInfo struct {
+	// CallDepth is the number of call frames the logr library adds between the
+	// end-user and the LogSink.  LogSink implementations which choose to print
+	// the original logging site (e.g. file & line) should climb this many
+	// additional frames to find it.
+	CallDepth int
+}
+
+// runtimeInfo is a static global.  It must not be changed at run time.
+var runtimeInfo = RuntimeInfo{
+	CallDepth: 1,
+}
+
+// LogSink represents a logging implementation.  End-users will generally not
+// interact with this type.
+type LogSink interface {
+	// Init receives optional information about the logr library for LogSink
+	// implementations that need it.
+	Init(info RuntimeInfo)
+
+	// Enabled tests whether this LogSink is enabled at the specified V-level.
+	// For example, commandline flags might be used to set the logging
+	// verbosity and disable some info logs.
+	Enabled(level int) bool
+
+	// Info logs a non-error message with the given key/value pairs as context.
+	// The level argument is provided for optional logging.  This method will
+	// only be called when Enabled(level) is true. See Logger.Info for more
+	// details.
+	Info(level int, msg string, keysAndValues ...interface{})
+
+	// Error logs an error, with the given message and key/value pairs as
+	// context.  See Logger.Error for more details.
+	Error(err error, msg string, keysAndValues ...interface{})
+
+	// WithValues returns a new LogSink with additional key/value pairs.  See
+	// Logger.WithValues for more details.
+	WithValues(keysAndValues ...interface{}) LogSink
+
+	// WithName returns a new LogSink with the specified name appended.  See
+	// Logger.WithName for more details.
+	WithName(name string) LogSink
+}
+
+// CallDepthLogSink represents a Logger that knows how to climb the call stack
+// to identify the original call site and can offset the depth by a specified
+// number of frames.  This is useful for users who have helper functions
+// between the "real" call site and the actual calls to Logger methods.
+// Implementations that log information about the call site (such as file,
+// function, or line) would otherwise log information about the intermediate
+// helper functions.
+//
+// This is an optional interface and implementations are not required to
+// support it.
+type CallDepthLogSink interface {
+	// WithCallDepth returns a LogSink that will offset the call
+	// stack by the specified number of frames when logging call
+	// site information.
+	//
+	// If depth is 0, the LogSink should skip exactly the number
+	// of call frames defined in RuntimeInfo.CallDepth when Info
+	// or Error are called, i.e. the attribution should be to the
+	// direct caller of Logger.Info or Logger.Error.
+	//
+	// If depth is 1 the attribution should skip 1 call frame, and so on.
+	// Successive calls to this are additive.
+	WithCallDepth(depth int) LogSink
+}
+
+// CallStackHelperLogSink represents a Logger that knows how to climb
+// the call stack to identify the original call site and can skip
+// intermediate helper functions if they mark themselves as
+// helper. Go's testing package uses that approach.
+//
+// This is useful for users who have helper functions between the
+// "real" call site and the actual calls to Logger methods.
+// Implementations that log information about the call site (such as
+// file, function, or line) would otherwise log information about the
+// intermediate helper functions.
+//
+// This is an optional interface and implementations are not required
+// to support it. Implementations that choose to support this must not
+// simply implement it as WithCallDepth(1), because
+// Logger.WithCallStackHelper will call both methods if they are
+// present. This should only be implemented for LogSinks that actually
+// need it, as with testing.T.
+type CallStackHelperLogSink interface {
+	// GetCallStackHelper returns a function that must be called
+	// to mark the direct caller as helper function when logging
+	// call site information.
+	GetCallStackHelper() func()
+}
+
+// Marshaler is an optional interface that logged values may choose to
+// implement. Loggers with structured output, such as JSON, should
+// log the object return by the MarshalLog method instead of the
+// original value.
+type Marshaler interface {
+	// MarshalLog can be used to:
+	//   - ensure that structs are not logged as strings when the original
+	//     value has a String method: return a different type without a
+	//     String method
+	//   - select which fields of a complex type should get logged:
+	//     return a simpler struct with fewer fields
+	//   - log unexported fields: return a different struct
+	//     with exported fields
+	//
+	// It may return any value of any type.
+	MarshalLog() interface{}
+}

vendor/github.com/go-logr/stdr/README.md

+# Minimal Go logging using logr and Go's standard library
+
+[![Go Reference](https://pkg.go.dev/badge/github.com/go-logr/stdr.svg)](https://pkg.go.dev/github.com/go-logr/stdr)
+
+This package implements the [logr interface](https://github.com/go-logr/logr)
+in terms of Go's standard log package(https://pkg.go.dev/log).

vendor/github.com/go-logr/stdr/go.mod

+module github.com/go-logr/stdr
+
+go 1.16
+
+require github.com/go-logr/logr v1.2.2

vendor/github.com/go-logr/stdr/go.sum

+github.com/go-logr/logr v1.2.2 h1:ahHml/yUpnlb96Rp8HCvtYVPY8ZYpxq3g7UYchIYwbs=
+github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=

vendor/github.com/go-logr/stdr/stdr.go

+/*
+Copyright 2019 The logr Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package stdr implements github.com/go-logr/logr.Logger in terms of
+// Go's standard log package.
+package stdr
+
+import (
+	"log"
+	"os"
+
+	"github.com/go-logr/logr"
+	"github.com/go-logr/logr/funcr"
+)
+
+// The global verbosity level.  See SetVerbosity().
+var globalVerbosity int
+
+// SetVerbosity sets the global level against which all info logs will be
+// compared.  If this is greater than or equal to the "V" of the logger, the
+// message will be logged.  A higher value here means more logs will be written.
+// The previous verbosity value is returned.  This is not concurrent-safe -
+// callers must be sure to call it from only one goroutine.
+func SetVerbosity(v int) int {
+	old := globalVerbosity
+	globalVerbosity = v
+	return old
+}
+
+// New returns a logr.Logger which is implemented by Go's standard log package,
+// or something like it.  If std is nil, this will use a default logger
+// instead.
+//
+// Example: stdr.New(log.New(os.Stderr, "", log.LstdFlags|log.Lshortfile)))
+func New(std StdLogger) logr.Logger {
+	return NewWithOptions(std, Options{})
+}
+
+// NewWithOptions returns a logr.Logger which is implemented by Go's standard
+// log package, or something like it.  See New for details.
+func NewWithOptions(std StdLogger, opts Options) logr.Logger {
+	if std == nil {
+		// Go's log.Default() is only available in 1.16 and higher.
+		std = log.New(os.Stderr, "", log.LstdFlags)
+	}
+
+	if opts.Depth < 0 {
+		opts.Depth = 0
+	}
+
+	fopts := funcr.Options{
+		LogCaller: funcr.MessageClass(opts.LogCaller),
+	}
+
+	sl := &logger{
+		Formatter: funcr.NewFormatter(fopts),
+		std:       std,
+	}
+
+	// For skipping our own logger.Info/Error.
+	sl.Formatter.AddCallDepth(1 + opts.Depth)
+
+	return logr.New(sl)
+}
+
+// Options carries parameters which influence the way logs are generated.
+type Options struct {
+	// Depth biases the assumed number of call frames to the "true" caller.
+	// This is useful when the calling code calls a function which then calls
+	// stdr (e.g. a logging shim to another API).  Values less than zero will
+	// be treated as zero.
+	Depth int
+
+	// LogCaller tells stdr to add a "caller" key to some or all log lines.
+	// Go's log package has options to log this natively, too.
+	LogCaller MessageClass
+
+	// TODO: add an option to log the date/time
+}
+
+// MessageClass indicates which category or categories of messages to consider.
+type MessageClass int
+
+const (
+	// None ignores all message classes.
+	None MessageClass = iota
+	// All considers all message classes.
+	All
+	// Info only considers info messages.
+	Info
+	// Error only considers error messages.
+	Error
+)
+
+// StdLogger is the subset of the Go stdlib log.Logger API that is needed for
+// this adapter.
+type StdLogger interface {
+	// Output is the same as log.Output and log.Logger.Output.
+	Output(calldepth int, logline string) error
+}
+
+type logger struct {
+	funcr.Formatter
+	std StdLogger
+}
+
+var _ logr.LogSink = &logger{}
+var _ logr.CallDepthLogSink = &logger{}
+
+func (l logger) Enabled(level int) bool {
+	return globalVerbosity >= level
+}
+
+func (l logger) Info(level int, msg string, kvList ...interface{}) {
+	prefix, args := l.FormatInfo(level, msg, kvList)
+	if prefix != "" {
+		args = prefix + ": " + args
+	}
+	_ = l.std.Output(l.Formatter.GetDepth()+1, args)
+}
+
+func (l logger) Error(err error, msg string, kvList ...interface{}) {
+	prefix, args := l.FormatError(err, msg, kvList)
+	if prefix != "" {
+		args = prefix + ": " + args
+	}
+	_ = l.std.Output(l.Formatter.GetDepth()+1, args)
+}
+
+func (l logger) WithName(name string) logr.LogSink {
+	l.Formatter.AddName(name)
+	return &l
+}
+
+func (l logger) WithValues(kvList ...interface{}) logr.LogSink {
+	l.Formatter.AddValues(kvList)
+	return &l
+}
+
+func (l logger) WithCallDepth(depth int) logr.LogSink {
+	l.Formatter.AddCallDepth(depth)
+	return &l
+}
+
+// Underlier exposes access to the underlying logging implementation.  Since
+// callers only have a logr.Logger, they have to know which implementation is
+// in use, so this interface is less of an abstraction and more of way to test
+// type conversion.
+type Underlier interface {
+	GetUnderlying() StdLogger
+}
+
+// GetUnderlying returns the StdLogger underneath this logger.  Since StdLogger
+// is itself an interface, the result may or may not be a Go log.Logger.
+func (l logger) GetUnderlying() StdLogger {
+	return l.std
+}

vendor/github.com/golang/groupcache/LICENSE

-Apache License
-Version 2.0, January 2004
-http://www.apache.org/licenses/
-
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-indirect, to cause the direction or management of such entity, whether by
-contract or otherwise, or (ii) ownership of fifty percent (50%) or more of the
-outstanding shares, or (iii) beneficial ownership of such entity.
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-but not limited to software source code, documentation source, and configuration
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-available under the License, as indicated by a copyright notice that is included
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-"Derivative Works" shall mean any work, whether in Source or Object form, that
-is based on (or derived from) the Work and for which the editorial revisions,
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-
-5. Submission of Contributions.
-
-Unless You explicitly state otherwise, any Contribution intentionally submitted
-for inclusion in the Work by You to the Licensor shall be under the terms and
-conditions of this License, without any additional terms or conditions.
-Notwithstanding the above, nothing herein shall supersede or modify the terms of
-any separate license agreement you may have executed with Licensor regarding
-such Contributions.
-
-6. Trademarks.
-
-This License does not grant permission to use the trade names, trademarks,
-service marks, or product names of the Licensor, except as required for
-reasonable and customary use in describing the origin of the Work and
-reproducing the content of the NOTICE file.
-
-7. Disclaimer of Warranty.
-
-Unless required by applicable law or agreed to in writing, Licensor provides the
-Work (and each Contributor provides its Contributions) on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied,
-including, without limitation, any warranties or conditions of TITLE,
-NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. You are
-solely responsible for determining the appropriateness of using or
-redistributing the Work and assume any risks associated with Your exercise of
-permissions under this License.
-
-8. Limitation of Liability.
-
-In no event and under no legal theory, whether in tort (including negligence),
-contract, or otherwise, unless required by applicable law (such as deliberate
-and grossly negligent acts) or agreed to in writing, shall any Contributor be
-liable to You for damages, including any direct, indirect, special, incidental,
-or consequential damages of any character arising as a result of this License or
-out of the use or inability to use the Work (including but not limited to
-damages for loss of goodwill, work stoppage, computer failure or malfunction, or
-any and all other commercial damages or losses), even if such Contributor has
-been advised of the possibility of such damages.
-
-9. Accepting Warranty or Additional Liability.
-
-While redistributing the Work or Derivative Works thereof, You may choose to
-offer, and charge a fee for, acceptance of support, warranty, indemnity, or
-other liability obligations and/or rights consistent with this License. However,
-in accepting such obligations, You may act only on Your own behalf and on Your
-sole responsibility, not on behalf of any other Contributor, and only if You
-agree to indemnify, defend, and hold each Contributor harmless for any liability
-incurred by, or claims asserted against, such Contributor by reason of your
-accepting any such warranty or additional liability.
-
-END OF TERMS AND CONDITIONS
-
-APPENDIX: How to apply the Apache License to your work
-
-To apply the Apache License to your work, attach the following boilerplate
-notice, with the fields enclosed by brackets "[]" replaced with your own
-identifying information. (Don't include the brackets!) The text should be
-enclosed in the appropriate comment syntax for the file format. We also
-recommend that a file or class name and description of purpose be included on
-the same "printed page" as the copyright notice for easier identification within
-third-party archives.
-
-   Copyright [yyyy] [name of copyright owner]
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-     http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.

vendor/github.com/golang/groupcache/lru/lru.go

-/*
-Copyright 2013 Google Inc.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-     http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-// Package lru implements an LRU cache.
-package lru
-
-import "container/list"
-
-// Cache is an LRU cache. It is not safe for concurrent access.
-type Cache struct {
-	// MaxEntries is the maximum number of cache entries before
-	// an item is evicted. Zero means no limit.
-	MaxEntries int
-
-	// OnEvicted optionally specifies a callback function to be
-	// executed when an entry is purged from the cache.
-	OnEvicted func(key Key, value interface{})
-
-	ll    *list.List
-	cache map[interface{}]*list.Element
-}
-
-// A Key may be any value that is comparable. See http://golang.org/ref/spec#Comparison_operators
-type Key interface{}
-
-type entry struct {
-	key   Key
-	value interface{}
-}
-
-// New creates a new Cache.
-// If maxEntries is zero, the cache has no limit and it's assumed
-// that eviction is done by the caller.
-func New(maxEntries int) *Cache {
-	return &Cache{
-		MaxEntries: maxEntries,
-		ll:         list.New(),
-		cache:      make(map[interface{}]*list.Element),
-	}
-}
-
-// Add adds a value to the cache.
-func (c *Cache) Add(key Key, value interface{}) {
-	if c.cache == nil {
-		c.cache = make(map[interface{}]*list.Element)
-		c.ll = list.New()
-	}
-	if ee, ok := c.cache[key]; ok {
-		c.ll.MoveToFront(ee)
-		ee.Value.(*entry).value = value
-		return
-	}
-	ele := c.ll.PushFront(&entry{key, value})
-	c.cache[key] = ele
-	if c.MaxEntries != 0 && c.ll.Len() > c.MaxEntries {
-		c.RemoveOldest()
-	}
-}
-
-// Get looks up a key's value from the cache.
-func (c *Cache) Get(key Key) (value interface{}, ok bool) {
-	if c.cache == nil {
-		return
-	}
-	if ele, hit := c.cache[key]; hit {
-		c.ll.MoveToFront(ele)
-		return ele.Value.(*entry).value, true
-	}
-	return
-}
-
-// Remove removes the provided key from the cache.
-func (c *Cache) Remove(key Key) {
-	if c.cache == nil {
-		return
-	}
-	if ele, hit := c.cache[key]; hit {
-		c.removeElement(ele)
-	}
-}
-
-// RemoveOldest removes the oldest item from the cache.
-func (c *Cache) RemoveOldest() {
-	if c.cache == nil {
-		return
-	}
-	ele := c.ll.Back()
-	if ele != nil {
-		c.removeElement(ele)
-	}
-}
-
-func (c *Cache) removeElement(e *list.Element) {
-	c.ll.Remove(e)
-	kv := e.Value.(*entry)
-	delete(c.cache, kv.key)
-	if c.OnEvicted != nil {
-		c.OnEvicted(kv.key, kv.value)
-	}
-}
-
-// Len returns the number of items in the cache.
-func (c *Cache) Len() int {
-	if c.cache == nil {
-		return 0
-	}
-	return c.ll.Len()
-}
-
-// Clear purges all stored items from the cache.
-func (c *Cache) Clear() {
-	if c.OnEvicted != nil {
-		for _, e := range c.cache {
-			kv := e.Value.(*entry)
-			c.OnEvicted(kv.key, kv.value)
-		}
-	}
-	c.ll = nil
-	c.cache = nil
-}

vendor/github.com/gorilla/handlers/LICENSE

-Copyright (c) 2013 The Gorilla Handlers Authors. All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are met:
-
-  Redistributions of source code must retain the above copyright notice, this
-  list of conditions and the following disclaimer.
-
-  Redistributions in binary form must reproduce the above copyright notice,
-  this list of conditions and the following disclaimer in the documentation
-  and/or other materials provided with the distribution.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
-ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
-FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/gorilla/handlers/README.md

-gorilla/handlers
-================
-[![GoDoc](https://godoc.org/github.com/gorilla/handlers?status.svg)](https://godoc.org/github.com/gorilla/handlers)
-[![CircleCI](https://circleci.com/gh/gorilla/handlers.svg?style=svg)](https://circleci.com/gh/gorilla/handlers)
-[![Sourcegraph](https://sourcegraph.com/github.com/gorilla/handlers/-/badge.svg)](https://sourcegraph.com/github.com/gorilla/handlers?badge)
-
-
-Package handlers is a collection of handlers (aka "HTTP middleware") for use
-with Go's `net/http` package (or any framework supporting `http.Handler`), including:
-
-* [**LoggingHandler**](https://godoc.org/github.com/gorilla/handlers#LoggingHandler) for logging HTTP requests in the Apache [Common Log
-  Format](http://httpd.apache.org/docs/2.2/logs.html#common).
-* [**CombinedLoggingHandler**](https://godoc.org/github.com/gorilla/handlers#CombinedLoggingHandler) for logging HTTP requests in the Apache [Combined Log
-  Format](http://httpd.apache.org/docs/2.2/logs.html#combined) commonly used by
-  both Apache and nginx.
-* [**CompressHandler**](https://godoc.org/github.com/gorilla/handlers#CompressHandler) for gzipping responses.
-* [**ContentTypeHandler**](https://godoc.org/github.com/gorilla/handlers#ContentTypeHandler) for validating requests against a list of accepted
-  content types.
-* [**MethodHandler**](https://godoc.org/github.com/gorilla/handlers#MethodHandler) for matching HTTP methods against handlers in a
-  `map[string]http.Handler`
-* [**ProxyHeaders**](https://godoc.org/github.com/gorilla/handlers#ProxyHeaders) for populating `r.RemoteAddr` and `r.URL.Scheme` based on the
-  `X-Forwarded-For`, `X-Real-IP`, `X-Forwarded-Proto` and RFC7239 `Forwarded`
-  headers when running a Go server behind a HTTP reverse proxy.
-* [**CanonicalHost**](https://godoc.org/github.com/gorilla/handlers#CanonicalHost) for re-directing to the preferred host when handling multiple 
-  domains (i.e. multiple CNAME aliases).
-* [**RecoveryHandler**](https://godoc.org/github.com/gorilla/handlers#RecoveryHandler) for recovering from unexpected panics.
-
-Other handlers are documented [on the Gorilla
-website](https://www.gorillatoolkit.org/pkg/handlers).
-
-## Example
-
-A simple example using `handlers.LoggingHandler` and `handlers.CompressHandler`:
-
-```go
-import (
-    "net/http"
-    "github.com/gorilla/handlers"
-)
-
-func main() {
-    r := http.NewServeMux()
-
-    // Only log requests to our admin dashboard to stdout
-    r.Handle("/admin", handlers.LoggingHandler(os.Stdout, http.HandlerFunc(ShowAdminDashboard)))
-    r.HandleFunc("/", ShowIndex)
-
-    // Wrap our server with our gzip handler to gzip compress all responses.
-    http.ListenAndServe(":8000", handlers.CompressHandler(r))
-}
-```
-
-## License
-
-BSD licensed. See the included LICENSE file for details.
-

vendor/github.com/gorilla/handlers/canonical.go

-package handlers
-
-import (
-	"net/http"
-	"net/url"
-	"strings"
-)
-
-type canonical struct {
-	h      http.Handler
-	domain string
-	code   int
-}
-
-// CanonicalHost is HTTP middleware that re-directs requests to the canonical
-// domain. It accepts a domain and a status code (e.g. 301 or 302) and
-// re-directs clients to this domain. The existing request path is maintained.
-//
-// Note: If the provided domain is considered invalid by url.Parse or otherwise
-// returns an empty scheme or host, clients are not re-directed.
-//
-// Example:
-//
-//  r := mux.NewRouter()
-//  canonical := handlers.CanonicalHost("http://www.gorillatoolkit.org", 302)
-//  r.HandleFunc("/route", YourHandler)
-//
-//  log.Fatal(http.ListenAndServe(":7000", canonical(r)))
-//
-func CanonicalHost(domain string, code int) func(h http.Handler) http.Handler {
-	fn := func(h http.Handler) http.Handler {
-		return canonical{h, domain, code}
-	}
-
-	return fn
-}
-
-func (c canonical) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	dest, err := url.Parse(c.domain)
-	if err != nil {
-		// Call the next handler if the provided domain fails to parse.
-		c.h.ServeHTTP(w, r)
-		return
-	}
-
-	if dest.Scheme == "" || dest.Host == "" {
-		// Call the next handler if the scheme or host are empty.
-		// Note that url.Parse won't fail on in this case.
-		c.h.ServeHTTP(w, r)
-		return
-	}
-
-	if !strings.EqualFold(cleanHost(r.Host), dest.Host) {
-		// Re-build the destination URL
-		dest := dest.Scheme + "://" + dest.Host + r.URL.Path
-		if r.URL.RawQuery != "" {
-			dest += "?" + r.URL.RawQuery
-		}
-		http.Redirect(w, r, dest, c.code)
-		return
-	}
-
-	c.h.ServeHTTP(w, r)
-}
-
-// cleanHost cleans invalid Host headers by stripping anything after '/' or ' '.
-// This is backported from Go 1.5 (in response to issue #11206) and attempts to
-// mitigate malformed Host headers that do not match the format in RFC7230.
-func cleanHost(in string) string {
-	if i := strings.IndexAny(in, " /"); i != -1 {
-		return in[:i]
-	}
-	return in
-}

vendor/github.com/gorilla/handlers/compress.go

-// Copyright 2013 The Gorilla Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package handlers
-
-import (
-	"compress/flate"
-	"compress/gzip"
-	"io"
-	"net/http"
-	"strings"
-
-	"github.com/felixge/httpsnoop"
-)
-
-const acceptEncoding string = "Accept-Encoding"
-
-type compressResponseWriter struct {
-	compressor io.Writer
-	w          http.ResponseWriter
-}
-
-func (cw *compressResponseWriter) WriteHeader(c int) {
-	cw.w.Header().Del("Content-Length")
-	cw.w.WriteHeader(c)
-}
-
-func (cw *compressResponseWriter) Write(b []byte) (int, error) {
-	h := cw.w.Header()
-	if h.Get("Content-Type") == "" {
-		h.Set("Content-Type", http.DetectContentType(b))
-	}
-	h.Del("Content-Length")
-
-	return cw.compressor.Write(b)
-}
-
-func (cw *compressResponseWriter) ReadFrom(r io.Reader) (int64, error) {
-	return io.Copy(cw.compressor, r)
-}
-
-type flusher interface {
-	Flush() error
-}
-
-func (w *compressResponseWriter) Flush() {
-	// Flush compressed data if compressor supports it.
-	if f, ok := w.compressor.(flusher); ok {
-		f.Flush()
-	}
-	// Flush HTTP response.
-	if f, ok := w.w.(http.Flusher); ok {
-		f.Flush()
-	}
-}
-
-// CompressHandler gzip compresses HTTP responses for clients that support it
-// via the 'Accept-Encoding' header.
-//
-// Compressing TLS traffic may leak the page contents to an attacker if the
-// page contains user input: http://security.stackexchange.com/a/102015/12208
-func CompressHandler(h http.Handler) http.Handler {
-	return CompressHandlerLevel(h, gzip.DefaultCompression)
-}
-
-// CompressHandlerLevel gzip compresses HTTP responses with specified compression level
-// for clients that support it via the 'Accept-Encoding' header.
-//
-// The compression level should be gzip.DefaultCompression, gzip.NoCompression,
-// or any integer value between gzip.BestSpeed and gzip.BestCompression inclusive.
-// gzip.DefaultCompression is used in case of invalid compression level.
-func CompressHandlerLevel(h http.Handler, level int) http.Handler {
-	if level < gzip.DefaultCompression || level > gzip.BestCompression {
-		level = gzip.DefaultCompression
-	}
-
-	const (
-		gzipEncoding  = "gzip"
-		flateEncoding = "deflate"
-	)
-
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		// detect what encoding to use
-		var encoding string
-		for _, curEnc := range strings.Split(r.Header.Get(acceptEncoding), ",") {
-			curEnc = strings.TrimSpace(curEnc)
-			if curEnc == gzipEncoding || curEnc == flateEncoding {
-				encoding = curEnc
-				break
-			}
-		}
-
-		// always add Accept-Encoding to Vary to prevent intermediate caches corruption
-		w.Header().Add("Vary", acceptEncoding)
-
-		// if we weren't able to identify an encoding we're familiar with, pass on the
-		// request to the handler and return
-		if encoding == "" {
-			h.ServeHTTP(w, r)
-			return
-		}
-
-		if r.Header.Get("Upgrade") != "" {
-			h.ServeHTTP(w, r)
-			return
-		}
-
-		// wrap the ResponseWriter with the writer for the chosen encoding
-		var encWriter io.WriteCloser
-		if encoding == gzipEncoding {
-			encWriter, _ = gzip.NewWriterLevel(w, level)
-		} else if encoding == flateEncoding {
-			encWriter, _ = flate.NewWriter(w, level)
-		}
-		defer encWriter.Close()
-
-		w.Header().Set("Content-Encoding", encoding)
-		r.Header.Del(acceptEncoding)
-
-		cw := &compressResponseWriter{
-			w:          w,
-			compressor: encWriter,
-		}
-
-		w = httpsnoop.Wrap(w, httpsnoop.Hooks{
-			Write: func(httpsnoop.WriteFunc) httpsnoop.WriteFunc {
-				return cw.Write
-			},
-			WriteHeader: func(httpsnoop.WriteHeaderFunc) httpsnoop.WriteHeaderFunc {
-				return cw.WriteHeader
-			},
-			Flush: func(httpsnoop.FlushFunc) httpsnoop.FlushFunc {
-				return cw.Flush
-			},
-			ReadFrom: func(rff httpsnoop.ReadFromFunc) httpsnoop.ReadFromFunc {
-				return cw.ReadFrom
-			},
-		})
-
-		h.ServeHTTP(w, r)
-	})
-}

vendor/github.com/gorilla/handlers/cors.go

-package handlers
-
-import (
-	"net/http"
-	"strconv"
-	"strings"
-)
-
-// CORSOption represents a functional option for configuring the CORS middleware.
-type CORSOption func(*cors) error
-
-type cors struct {
-	h                      http.Handler
-	allowedHeaders         []string
-	allowedMethods         []string
-	allowedOrigins         []string
-	allowedOriginValidator OriginValidator
-	exposedHeaders         []string
-	maxAge                 int
-	ignoreOptions          bool
-	allowCredentials       bool
-	optionStatusCode       int
-}
-
-// OriginValidator takes an origin string and returns whether or not that origin is allowed.
-type OriginValidator func(string) bool
-
-var (
-	defaultCorsOptionStatusCode = 200
-	defaultCorsMethods          = []string{"GET", "HEAD", "POST"}
-	defaultCorsHeaders          = []string{"Accept", "Accept-Language", "Content-Language", "Origin"}
-	// (WebKit/Safari v9 sends the Origin header by default in AJAX requests)
-)
-
-const (
-	corsOptionMethod           string = "OPTIONS"
-	corsAllowOriginHeader      string = "Access-Control-Allow-Origin"
-	corsExposeHeadersHeader    string = "Access-Control-Expose-Headers"
-	corsMaxAgeHeader           string = "Access-Control-Max-Age"
-	corsAllowMethodsHeader     string = "Access-Control-Allow-Methods"
-	corsAllowHeadersHeader     string = "Access-Control-Allow-Headers"
-	corsAllowCredentialsHeader string = "Access-Control-Allow-Credentials"
-	corsRequestMethodHeader    string = "Access-Control-Request-Method"
-	corsRequestHeadersHeader   string = "Access-Control-Request-Headers"
-	corsOriginHeader           string = "Origin"
-	corsVaryHeader             string = "Vary"
-	corsOriginMatchAll         string = "*"
-)
-
-func (ch *cors) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	origin := r.Header.Get(corsOriginHeader)
-	if !ch.isOriginAllowed(origin) {
-		if r.Method != corsOptionMethod || ch.ignoreOptions {
-			ch.h.ServeHTTP(w, r)
-		}
-
-		return
-	}
-
-	if r.Method == corsOptionMethod {
-		if ch.ignoreOptions {
-			ch.h.ServeHTTP(w, r)
-			return
-		}
-
-		if _, ok := r.Header[corsRequestMethodHeader]; !ok {
-			w.WriteHeader(http.StatusBadRequest)
-			return
-		}
-
-		method := r.Header.Get(corsRequestMethodHeader)
-		if !ch.isMatch(method, ch.allowedMethods) {
-			w.WriteHeader(http.StatusMethodNotAllowed)
-			return
-		}
-
-		requestHeaders := strings.Split(r.Header.Get(corsRequestHeadersHeader), ",")
-		allowedHeaders := []string{}
-		for _, v := range requestHeaders {
-			canonicalHeader := http.CanonicalHeaderKey(strings.TrimSpace(v))
-			if canonicalHeader == "" || ch.isMatch(canonicalHeader, defaultCorsHeaders) {
-				continue
-			}
-
-			if !ch.isMatch(canonicalHeader, ch.allowedHeaders) {
-				w.WriteHeader(http.StatusForbidden)
-				return
-			}
-
-			allowedHeaders = append(allowedHeaders, canonicalHeader)
-		}
-
-		if len(allowedHeaders) > 0 {
-			w.Header().Set(corsAllowHeadersHeader, strings.Join(allowedHeaders, ","))
-		}
-
-		if ch.maxAge > 0 {
-			w.Header().Set(corsMaxAgeHeader, strconv.Itoa(ch.maxAge))
-		}
-
-		if !ch.isMatch(method, defaultCorsMethods) {
-			w.Header().Set(corsAllowMethodsHeader, method)
-		}
-	} else {
-		if len(ch.exposedHeaders) > 0 {
-			w.Header().Set(corsExposeHeadersHeader, strings.Join(ch.exposedHeaders, ","))
-		}
-	}
-
-	if ch.allowCredentials {
-		w.Header().Set(corsAllowCredentialsHeader, "true")
-	}
-
-	if len(ch.allowedOrigins) > 1 {
-		w.Header().Set(corsVaryHeader, corsOriginHeader)
-	}
-
-	returnOrigin := origin
-	if ch.allowedOriginValidator == nil && len(ch.allowedOrigins) == 0 {
-		returnOrigin = "*"
-	} else {
-		for _, o := range ch.allowedOrigins {
-			// A configuration of * is different than explicitly setting an allowed
-			// origin. Returning arbitrary origin headers in an access control allow
-			// origin header is unsafe and is not required by any use case.
-			if o == corsOriginMatchAll {
-				returnOrigin = "*"
-				break
-			}
-		}
-	}
-	w.Header().Set(corsAllowOriginHeader, returnOrigin)
-
-	if r.Method == corsOptionMethod {
-		w.WriteHeader(ch.optionStatusCode)
-		return
-	}
-	ch.h.ServeHTTP(w, r)
-}
-
-// CORS provides Cross-Origin Resource Sharing middleware.
-// Example:
-//
-//  import (
-//      "net/http"
-//
-//      "github.com/gorilla/handlers"
-//      "github.com/gorilla/mux"
-//  )
-//
-//  func main() {
-//      r := mux.NewRouter()
-//      r.HandleFunc("/users", UserEndpoint)
-//      r.HandleFunc("/projects", ProjectEndpoint)
-//
-//      // Apply the CORS middleware to our top-level router, with the defaults.
-//      http.ListenAndServe(":8000", handlers.CORS()(r))
-//  }
-//
-func CORS(opts ...CORSOption) func(http.Handler) http.Handler {
-	return func(h http.Handler) http.Handler {
-		ch := parseCORSOptions(opts...)
-		ch.h = h
-		return ch
-	}
-}
-
-func parseCORSOptions(opts ...CORSOption) *cors {
-	ch := &cors{
-		allowedMethods:   defaultCorsMethods,
-		allowedHeaders:   defaultCorsHeaders,
-		allowedOrigins:   []string{},
-		optionStatusCode: defaultCorsOptionStatusCode,
-	}
-
-	for _, option := range opts {
-		option(ch)
-	}
-
-	return ch
-}
-
-//
-// Functional options for configuring CORS.
-//
-
-// AllowedHeaders adds the provided headers to the list of allowed headers in a
-// CORS request.
-// This is an append operation so the headers Accept, Accept-Language,
-// and Content-Language are always allowed.
-// Content-Type must be explicitly declared if accepting Content-Types other than
-// application/x-www-form-urlencoded, multipart/form-data, or text/plain.
-func AllowedHeaders(headers []string) CORSOption {
-	return func(ch *cors) error {
-		for _, v := range headers {
-			normalizedHeader := http.CanonicalHeaderKey(strings.TrimSpace(v))
-			if normalizedHeader == "" {
-				continue
-			}
-
-			if !ch.isMatch(normalizedHeader, ch.allowedHeaders) {
-				ch.allowedHeaders = append(ch.allowedHeaders, normalizedHeader)
-			}
-		}
-
-		return nil
-	}
-}
-
-// AllowedMethods can be used to explicitly allow methods in the
-// Access-Control-Allow-Methods header.
-// This is a replacement operation so you must also
-// pass GET, HEAD, and POST if you wish to support those methods.
-func AllowedMethods(methods []string) CORSOption {
-	return func(ch *cors) error {
-		ch.allowedMethods = []string{}
-		for _, v := range methods {
-			normalizedMethod := strings.ToUpper(strings.TrimSpace(v))
-			if normalizedMethod == "" {
-				continue
-			}
-
-			if !ch.isMatch(normalizedMethod, ch.allowedMethods) {
-				ch.allowedMethods = append(ch.allowedMethods, normalizedMethod)
-			}
-		}
-
-		return nil
-	}
-}
-
-// AllowedOrigins sets the allowed origins for CORS requests, as used in the
-// 'Allow-Access-Control-Origin' HTTP header.
-// Note: Passing in a []string{"*"} will allow any domain.
-func AllowedOrigins(origins []string) CORSOption {
-	return func(ch *cors) error {
-		for _, v := range origins {
-			if v == corsOriginMatchAll {
-				ch.allowedOrigins = []string{corsOriginMatchAll}
-				return nil
-			}
-		}
-
-		ch.allowedOrigins = origins
-		return nil
-	}
-}
-
-// AllowedOriginValidator sets a function for evaluating allowed origins in CORS requests, represented by the
-// 'Allow-Access-Control-Origin' HTTP header.
-func AllowedOriginValidator(fn OriginValidator) CORSOption {
-	return func(ch *cors) error {
-		ch.allowedOriginValidator = fn
-		return nil
-	}
-}
-
-// OptionStatusCode sets a custom status code on the OPTIONS requests.
-// Default behaviour sets it to 200 to reflect best practices. This is option is not mandatory
-// and can be used if you need a custom status code (i.e 204).
-//
-// More informations on the spec:
-// https://fetch.spec.whatwg.org/#cors-preflight-fetch
-func OptionStatusCode(code int) CORSOption {
-	return func(ch *cors) error {
-		ch.optionStatusCode = code
-		return nil
-	}
-}
-
-// ExposedHeaders can be used to specify headers that are available
-// and will not be stripped out by the user-agent.
-func ExposedHeaders(headers []string) CORSOption {
-	return func(ch *cors) error {
-		ch.exposedHeaders = []string{}
-		for _, v := range headers {
-			normalizedHeader := http.CanonicalHeaderKey(strings.TrimSpace(v))
-			if normalizedHeader == "" {
-				continue
-			}
-
-			if !ch.isMatch(normalizedHeader, ch.exposedHeaders) {
-				ch.exposedHeaders = append(ch.exposedHeaders, normalizedHeader)
-			}
-		}
-
-		return nil
-	}
-}
-
-// MaxAge determines the maximum age (in seconds) between preflight requests. A
-// maximum of 10 minutes is allowed. An age above this value will default to 10
-// minutes.
-func MaxAge(age int) CORSOption {
-	return func(ch *cors) error {
-		// Maximum of 10 minutes.
-		if age > 600 {
-			age = 600
-		}
-
-		ch.maxAge = age
-		return nil
-	}
-}
-
-// IgnoreOptions causes the CORS middleware to ignore OPTIONS requests, instead
-// passing them through to the next handler. This is useful when your application
-// or framework has a pre-existing mechanism for responding to OPTIONS requests.
-func IgnoreOptions() CORSOption {
-	return func(ch *cors) error {
-		ch.ignoreOptions = true
-		return nil
-	}
-}
-
-// AllowCredentials can be used to specify that the user agent may pass
-// authentication details along with the request.
-func AllowCredentials() CORSOption {
-	return func(ch *cors) error {
-		ch.allowCredentials = true
-		return nil
-	}
-}
-
-func (ch *cors) isOriginAllowed(origin string) bool {
-	if origin == "" {
-		return false
-	}
-
-	if ch.allowedOriginValidator != nil {
-		return ch.allowedOriginValidator(origin)
-	}
-
-	if len(ch.allowedOrigins) == 0 {
-		return true
-	}
-
-	for _, allowedOrigin := range ch.allowedOrigins {
-		if allowedOrigin == origin || allowedOrigin == corsOriginMatchAll {
-			return true
-		}
-	}
-
-	return false
-}
-
-func (ch *cors) isMatch(needle string, haystack []string) bool {
-	for _, v := range haystack {
-		if v == needle {
-			return true
-		}
-	}
-
-	return false
-}