vendor/go.opencensus.io/go.mod

-module go.opencensus.io
-
-require (
-	github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6
-	github.com/golang/protobuf v1.3.1
-	github.com/google/go-cmp v0.3.0
-	github.com/stretchr/testify v1.4.0
-	golang.org/x/net v0.0.0-20190620200207-3b0461eec859
-	golang.org/x/sys v0.0.0-20190502145724-3ef323f4f1fd // indirect
-	golang.org/x/text v0.3.3 // indirect
-	google.golang.org/genproto v0.0.0-20190425155659-357c62f0e4bb // indirect
-	google.golang.org/grpc v1.20.1
-)
-
-go 1.13

vendor/go.opencensus.io/go.sum

-cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
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-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
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-github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
-golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
-golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
-golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3 h1:XQyxROzUlZH+WIQwySDgnISgOivlhjIEwaQaJEJrrN0=
-golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
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-golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/net v0.0.0-20190311183353-d8887717615a h1:oWX7TPOiFAMXLq8o0ikBYfCJVlRHBcsciT5bXOrH628=
-golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859 h1:R/3boaszxrf1GEUWTVDzSKVwLmSJpwZ1yqXm8j0v2QI=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
-golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f h1:wMNYb4v58l5UBM7MYRLPG6ZhfOqbKu7X5eyFl8ZhKvA=
-golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20181108010431-42b317875d0f h1:Bl/8QSvNqXvPGPGXa2z5xUTmV7VDcZyvRZ+QQXkXTZQ=
-golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6 h1:bjcUS9ztw9kFmmIxJInhon/0Is3p+EHBKNgquIzo1OI=
-golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a h1:1BGLXjeY4akVXGgbC9HugT3Jv3hCI0z56oJR5vAMgBU=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190502145724-3ef323f4f1fd h1:r7DufRZuZbWB7j439YfAzP8RPDa9unLkpwQKUYbIMPI=
-golang.org/x/sys v0.0.0-20190502145724-3ef323f4f1fd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
-golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
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-golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
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-google.golang.org/genproto v0.0.0-20190425155659-357c62f0e4bb h1:i1Ppqkc3WQXikh8bXiwHqAN5Rv3/qDCcRk0/Otx73BY=
-google.golang.org/genproto v0.0.0-20190425155659-357c62f0e4bb/go.mod h1:VzzqZJRnGkLBvHegQrXjBqPurQTc5/KpmUdxsrq26oE=
-google.golang.org/grpc v1.19.0 h1:cfg4PD8YEdSFnm7qLV4++93WcmhH2nIUhMjhdCvl3j8=
-google.golang.org/grpc v1.19.0 h1:cfg4PD8YEdSFnm7qLV4++93WcmhH2nIUhMjhdCvl3j8=
-google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
-google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
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-google.golang.org/grpc v1.20.1/go.mod h1:10oTOabMzJvdu6/UiuZezV6QK5dSlG84ov/aaiqXj38=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
-gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

vendor/go.opencensus.io/internal/tagencoding/tagencoding.go

-// Copyright 2017, OpenCensus 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 tagencoding contains the tag encoding
-// used interally by the stats collector.
-package tagencoding // import "go.opencensus.io/internal/tagencoding"
-
-// Values represent the encoded buffer for the values.
-type Values struct {
-	Buffer     []byte
-	WriteIndex int
-	ReadIndex  int
-}
-
-func (vb *Values) growIfRequired(expected int) {
-	if len(vb.Buffer)-vb.WriteIndex < expected {
-		tmp := make([]byte, 2*(len(vb.Buffer)+1)+expected)
-		copy(tmp, vb.Buffer)
-		vb.Buffer = tmp
-	}
-}
-
-// WriteValue is the helper method to encode Values from map[Key][]byte.
-func (vb *Values) WriteValue(v []byte) {
-	length := len(v) & 0xff
-	vb.growIfRequired(1 + length)
-
-	// writing length of v
-	vb.Buffer[vb.WriteIndex] = byte(length)
-	vb.WriteIndex++
-
-	if length == 0 {
-		// No value was encoded for this key
-		return
-	}
-
-	// writing v
-	copy(vb.Buffer[vb.WriteIndex:], v[:length])
-	vb.WriteIndex += length
-}
-
-// ReadValue is the helper method to decode Values to a map[Key][]byte.
-func (vb *Values) ReadValue() []byte {
-	// read length of v
-	length := int(vb.Buffer[vb.ReadIndex])
-	vb.ReadIndex++
-	if length == 0 {
-		// No value was encoded for this key
-		return nil
-	}
-
-	// read value of v
-	v := make([]byte, length)
-	endIdx := vb.ReadIndex + length
-	copy(v, vb.Buffer[vb.ReadIndex:endIdx])
-	vb.ReadIndex = endIdx
-	return v
-}
-
-// Bytes returns a reference to already written bytes in the Buffer.
-func (vb *Values) Bytes() []byte {
-	return vb.Buffer[:vb.WriteIndex]
-}

vendor/go.opencensus.io/metric/metricdata/label.go

-// Copyright 2018, OpenCensus 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 metricdata
-
-// LabelKey represents key of a label. It has optional
-// description attribute.
-type LabelKey struct {
-	Key         string
-	Description string
-}
-
-// LabelValue represents the value of a label.
-// The zero value represents a missing label value, which may be treated
-// differently to an empty string value by some back ends.
-type LabelValue struct {
-	Value   string // string value of the label
-	Present bool   // flag that indicated whether a value is present or not
-}
-
-// NewLabelValue creates a new non-nil LabelValue that represents the given string.
-func NewLabelValue(val string) LabelValue {
-	return LabelValue{Value: val, Present: true}
-}

vendor/go.opencensus.io/metric/metricdata/metric.go

-// Copyright 2018, OpenCensus 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 metricdata
-
-import (
-	"time"
-
-	"go.opencensus.io/resource"
-)
-
-// Descriptor holds metadata about a metric.
-type Descriptor struct {
-	Name        string     // full name of the metric
-	Description string     // human-readable description
-	Unit        Unit       // units for the measure
-	Type        Type       // type of measure
-	LabelKeys   []LabelKey // label keys
-}
-
-// Metric represents a quantity measured against a resource with different
-// label value combinations.
-type Metric struct {
-	Descriptor Descriptor         // metric descriptor
-	Resource   *resource.Resource // resource against which this was measured
-	TimeSeries []*TimeSeries      // one time series for each combination of label values
-}
-
-// TimeSeries is a sequence of points associated with a combination of label
-// values.
-type TimeSeries struct {
-	LabelValues []LabelValue // label values, same order as keys in the metric descriptor
-	Points      []Point      // points sequence
-	StartTime   time.Time    // time we started recording this time series
-}

vendor/go.opencensus.io/metric/metricdata/point.go

-// Copyright 2018, OpenCensus 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 metricdata
-
-import (
-	"time"
-)
-
-// Point is a single data point of a time series.
-type Point struct {
-	// Time is the point in time that this point represents in a time series.
-	Time time.Time
-	// Value is the value of this point. Prefer using ReadValue to switching on
-	// the value type, since new value types might be added.
-	Value interface{}
-}
-
-//go:generate stringer -type ValueType
-
-// NewFloat64Point creates a new Point holding a float64 value.
-func NewFloat64Point(t time.Time, val float64) Point {
-	return Point{
-		Value: val,
-		Time:  t,
-	}
-}
-
-// NewInt64Point creates a new Point holding an int64 value.
-func NewInt64Point(t time.Time, val int64) Point {
-	return Point{
-		Value: val,
-		Time:  t,
-	}
-}
-
-// NewDistributionPoint creates a new Point holding a Distribution value.
-func NewDistributionPoint(t time.Time, val *Distribution) Point {
-	return Point{
-		Value: val,
-		Time:  t,
-	}
-}
-
-// NewSummaryPoint creates a new Point holding a Summary value.
-func NewSummaryPoint(t time.Time, val *Summary) Point {
-	return Point{
-		Value: val,
-		Time:  t,
-	}
-}
-
-// ValueVisitor allows reading the value of a point.
-type ValueVisitor interface {
-	VisitFloat64Value(float64)
-	VisitInt64Value(int64)
-	VisitDistributionValue(*Distribution)
-	VisitSummaryValue(*Summary)
-}
-
-// ReadValue accepts a ValueVisitor and calls the appropriate method with the
-// value of this point.
-// Consumers of Point should use this in preference to switching on the type
-// of the value directly, since new value types may be added.
-func (p Point) ReadValue(vv ValueVisitor) {
-	switch v := p.Value.(type) {
-	case int64:
-		vv.VisitInt64Value(v)
-	case float64:
-		vv.VisitFloat64Value(v)
-	case *Distribution:
-		vv.VisitDistributionValue(v)
-	case *Summary:
-		vv.VisitSummaryValue(v)
-	default:
-		panic("unexpected value type")
-	}
-}
-
-// Distribution contains summary statistics for a population of values. It
-// optionally contains a histogram representing the distribution of those
-// values across a set of buckets.
-type Distribution struct {
-	// Count is the number of values in the population. Must be non-negative. This value
-	// must equal the sum of the values in bucket_counts if a histogram is
-	// provided.
-	Count int64
-	// Sum is the sum of the values in the population. If count is zero then this field
-	// must be zero.
-	Sum float64
-	// SumOfSquaredDeviation is the sum of squared deviations from the mean of the values in the
-	// population. For values x_i this is:
-	//
-	//     Sum[i=1..n]((x_i - mean)^2)
-	//
-	// Knuth, "The Art of Computer Programming", Vol. 2, page 323, 3rd edition
-	// describes Welford's method for accumulating this sum in one pass.
-	//
-	// If count is zero then this field must be zero.
-	SumOfSquaredDeviation float64
-	// BucketOptions describes the bounds of the histogram buckets in this
-	// distribution.
-	//
-	// A Distribution may optionally contain a histogram of the values in the
-	// population.
-	//
-	// If nil, there is no associated histogram.
-	BucketOptions *BucketOptions
-	// Bucket If the distribution does not have a histogram, then omit this field.
-	// If there is a histogram, then the sum of the values in the Bucket counts
-	// must equal the value in the count field of the distribution.
-	Buckets []Bucket
-}
-
-// BucketOptions describes the bounds of the histogram buckets in this
-// distribution.
-type BucketOptions struct {
-	// Bounds specifies a set of bucket upper bounds.
-	// This defines len(bounds) + 1 (= N) buckets. The boundaries for bucket
-	// index i are:
-	//
-	// [0, Bounds[i]) for i == 0
-	// [Bounds[i-1], Bounds[i]) for 0 < i < N-1
-	// [Bounds[i-1], +infinity) for i == N-1
-	Bounds []float64
-}
-
-// Bucket represents a single bucket (value range) in a distribution.
-type Bucket struct {
-	// Count is the number of values in each bucket of the histogram, as described in
-	// bucket_bounds.
-	Count int64
-	// Exemplar associated with this bucket (if any).
-	Exemplar *Exemplar
-}
-
-// Summary is a representation of percentiles.
-type Summary struct {
-	// Count is the cumulative count (if available).
-	Count int64
-	// Sum is the cumulative sum of values  (if available).
-	Sum float64
-	// HasCountAndSum is true if Count and Sum are available.
-	HasCountAndSum bool
-	// Snapshot represents percentiles calculated over an arbitrary time window.
-	// The values in this struct can be reset at arbitrary unknown times, with
-	// the requirement that all of them are reset at the same time.
-	Snapshot Snapshot
-}
-
-// Snapshot represents percentiles over an arbitrary time.
-// The values in this struct can be reset at arbitrary unknown times, with
-// the requirement that all of them are reset at the same time.
-type Snapshot struct {
-	// Count is the number of values in the snapshot. Optional since some systems don't
-	// expose this. Set to 0 if not available.
-	Count int64
-	// Sum is the sum of values in the snapshot. Optional since some systems don't
-	// expose this. If count is 0 then this field must be zero.
-	Sum float64
-	// Percentiles is a map from percentile (range (0-100.0]) to the value of
-	// the percentile.
-	Percentiles map[float64]float64
-}
-
-//go:generate stringer -type Type
-
-// Type is the overall type of metric, including its value type and whether it
-// represents a cumulative total (since the start time) or if it represents a
-// gauge value.
-type Type int
-
-// Metric types.
-const (
-	TypeGaugeInt64 Type = iota
-	TypeGaugeFloat64
-	TypeGaugeDistribution
-	TypeCumulativeInt64
-	TypeCumulativeFloat64
-	TypeCumulativeDistribution
-	TypeSummary
-)

vendor/go.opencensus.io/metric/metricdata/type_string.go

-// Code generated by "stringer -type Type"; DO NOT EDIT.
-
-package metricdata
-
-import "strconv"
-
-const _Type_name = "TypeGaugeInt64TypeGaugeFloat64TypeGaugeDistributionTypeCumulativeInt64TypeCumulativeFloat64TypeCumulativeDistributionTypeSummary"
-
-var _Type_index = [...]uint8{0, 14, 30, 51, 70, 91, 117, 128}
-
-func (i Type) String() string {
-	if i < 0 || i >= Type(len(_Type_index)-1) {
-		return "Type(" + strconv.FormatInt(int64(i), 10) + ")"
-	}
-	return _Type_name[_Type_index[i]:_Type_index[i+1]]
-}

vendor/go.opencensus.io/metric/metricproducer/manager.go

-// Copyright 2019, OpenCensus 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 metricproducer
-
-import (
-	"sync"
-)
-
-// Manager maintains a list of active producers. Producers can register
-// with the manager to allow readers to read all metrics provided by them.
-// Readers can retrieve all producers registered with the manager,
-// read metrics from the producers and export them.
-type Manager struct {
-	mu        sync.RWMutex
-	producers map[Producer]struct{}
-}
-
-var prodMgr *Manager
-var once sync.Once
-
-// GlobalManager is a single instance of producer manager
-// that is used by all producers and all readers.
-func GlobalManager() *Manager {
-	once.Do(func() {
-		prodMgr = &Manager{}
-		prodMgr.producers = make(map[Producer]struct{})
-	})
-	return prodMgr
-}
-
-// AddProducer adds the producer to the Manager if it is not already present.
-func (pm *Manager) AddProducer(producer Producer) {
-	if producer == nil {
-		return
-	}
-	pm.mu.Lock()
-	defer pm.mu.Unlock()
-	pm.producers[producer] = struct{}{}
-}
-
-// DeleteProducer deletes the producer from the Manager if it is present.
-func (pm *Manager) DeleteProducer(producer Producer) {
-	if producer == nil {
-		return
-	}
-	pm.mu.Lock()
-	defer pm.mu.Unlock()
-	delete(pm.producers, producer)
-}
-
-// GetAll returns a slice of all producer currently registered with
-// the Manager. For each call it generates a new slice. The slice
-// should not be cached as registration may change at any time. It is
-// typically called periodically by exporter to read metrics from
-// the producers.
-func (pm *Manager) GetAll() []Producer {
-	pm.mu.Lock()
-	defer pm.mu.Unlock()
-	producers := make([]Producer, len(pm.producers))
-	i := 0
-	for producer := range pm.producers {
-		producers[i] = producer
-		i++
-	}
-	return producers
-}

vendor/go.opencensus.io/plugin/ochttp/client.go

-// Copyright 2018, OpenCensus 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 ochttp
-
-import (
-	"net/http"
-	"net/http/httptrace"
-
-	"go.opencensus.io/trace"
-	"go.opencensus.io/trace/propagation"
-)
-
-// Transport is an http.RoundTripper that instruments all outgoing requests with
-// OpenCensus stats and tracing.
-//
-// The zero value is intended to be a useful default, but for
-// now it's recommended that you explicitly set Propagation, since the default
-// for this may change.
-type Transport struct {
-	// Base may be set to wrap another http.RoundTripper that does the actual
-	// requests. By default http.DefaultTransport is used.
-	//
-	// If base HTTP roundtripper implements CancelRequest,
-	// the returned round tripper will be cancelable.
-	Base http.RoundTripper
-
-	// Propagation defines how traces are propagated. If unspecified, a default
-	// (currently B3 format) will be used.
-	Propagation propagation.HTTPFormat
-
-	// StartOptions are applied to the span started by this Transport around each
-	// request.
-	//
-	// StartOptions.SpanKind will always be set to trace.SpanKindClient
-	// for spans started by this transport.
-	StartOptions trace.StartOptions
-
-	// GetStartOptions allows to set start options per request. If set,
-	// StartOptions is going to be ignored.
-	GetStartOptions func(*http.Request) trace.StartOptions
-
-	// NameFromRequest holds the function to use for generating the span name
-	// from the information found in the outgoing HTTP Request. By default the
-	// name equals the URL Path.
-	FormatSpanName func(*http.Request) string
-
-	// NewClientTrace may be set to a function allowing the current *trace.Span
-	// to be annotated with HTTP request event information emitted by the
-	// httptrace package.
-	NewClientTrace func(*http.Request, *trace.Span) *httptrace.ClientTrace
-
-	// TODO: Implement tag propagation for HTTP.
-}
-
-// RoundTrip implements http.RoundTripper, delegating to Base and recording stats and traces for the request.
-func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
-	rt := t.base()
-	if isHealthEndpoint(req.URL.Path) {
-		return rt.RoundTrip(req)
-	}
-	// TODO: remove excessive nesting of http.RoundTrippers here.
-	format := t.Propagation
-	if format == nil {
-		format = defaultFormat
-	}
-	spanNameFormatter := t.FormatSpanName
-	if spanNameFormatter == nil {
-		spanNameFormatter = spanNameFromURL
-	}
-
-	startOpts := t.StartOptions
-	if t.GetStartOptions != nil {
-		startOpts = t.GetStartOptions(req)
-	}
-
-	rt = &traceTransport{
-		base:   rt,
-		format: format,
-		startOptions: trace.StartOptions{
-			Sampler:  startOpts.Sampler,
-			SpanKind: trace.SpanKindClient,
-		},
-		formatSpanName: spanNameFormatter,
-		newClientTrace: t.NewClientTrace,
-	}
-	rt = statsTransport{base: rt}
-	return rt.RoundTrip(req)
-}
-
-func (t *Transport) base() http.RoundTripper {
-	if t.Base != nil {
-		return t.Base
-	}
-	return http.DefaultTransport
-}
-
-// CancelRequest cancels an in-flight request by closing its connection.
-func (t *Transport) CancelRequest(req *http.Request) {
-	type canceler interface {
-		CancelRequest(*http.Request)
-	}
-	if cr, ok := t.base().(canceler); ok {
-		cr.CancelRequest(req)
-	}
-}

vendor/go.opencensus.io/plugin/ochttp/client_stats.go

-// Copyright 2018, OpenCensus 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 ochttp
-
-import (
-	"context"
-	"io"
-	"net/http"
-	"strconv"
-	"sync"
-	"time"
-
-	"go.opencensus.io/stats"
-	"go.opencensus.io/tag"
-)
-
-// statsTransport is an http.RoundTripper that collects stats for the outgoing requests.
-type statsTransport struct {
-	base http.RoundTripper
-}
-
-// RoundTrip implements http.RoundTripper, delegating to Base and recording stats for the request.
-func (t statsTransport) RoundTrip(req *http.Request) (*http.Response, error) {
-	ctx, _ := tag.New(req.Context(),
-		tag.Upsert(KeyClientHost, req.Host),
-		tag.Upsert(Host, req.Host),
-		tag.Upsert(KeyClientPath, req.URL.Path),
-		tag.Upsert(Path, req.URL.Path),
-		tag.Upsert(KeyClientMethod, req.Method),
-		tag.Upsert(Method, req.Method))
-	req = req.WithContext(ctx)
-	track := &tracker{
-		start: time.Now(),
-		ctx:   ctx,
-	}
-	if req.Body == nil {
-		// TODO: Handle cases where ContentLength is not set.
-		track.reqSize = -1
-	} else if req.ContentLength > 0 {
-		track.reqSize = req.ContentLength
-	}
-	stats.Record(ctx, ClientRequestCount.M(1))
-
-	// Perform request.
-	resp, err := t.base.RoundTrip(req)
-
-	if err != nil {
-		track.statusCode = http.StatusInternalServerError
-		track.end()
-	} else {
-		track.statusCode = resp.StatusCode
-		if req.Method != "HEAD" {
-			track.respContentLength = resp.ContentLength
-		}
-		if resp.Body == nil {
-			track.end()
-		} else {
-			track.body = resp.Body
-			resp.Body = wrappedBody(track, resp.Body)
-		}
-	}
-	return resp, err
-}
-
-// CancelRequest cancels an in-flight request by closing its connection.
-func (t statsTransport) CancelRequest(req *http.Request) {
-	type canceler interface {
-		CancelRequest(*http.Request)
-	}
-	if cr, ok := t.base.(canceler); ok {
-		cr.CancelRequest(req)
-	}
-}
-
-type tracker struct {
-	ctx               context.Context
-	respSize          int64
-	respContentLength int64
-	reqSize           int64
-	start             time.Time
-	body              io.ReadCloser
-	statusCode        int
-	endOnce           sync.Once
-}
-
-var _ io.ReadCloser = (*tracker)(nil)
-
-func (t *tracker) end() {
-	t.endOnce.Do(func() {
-		latencyMs := float64(time.Since(t.start)) / float64(time.Millisecond)
-		respSize := t.respSize
-		if t.respSize == 0 && t.respContentLength > 0 {
-			respSize = t.respContentLength
-		}
-		m := []stats.Measurement{
-			ClientSentBytes.M(t.reqSize),
-			ClientReceivedBytes.M(respSize),
-			ClientRoundtripLatency.M(latencyMs),
-			ClientLatency.M(latencyMs),
-			ClientResponseBytes.M(t.respSize),
-		}
-		if t.reqSize >= 0 {
-			m = append(m, ClientRequestBytes.M(t.reqSize))
-		}
-
-		stats.RecordWithTags(t.ctx, []tag.Mutator{
-			tag.Upsert(StatusCode, strconv.Itoa(t.statusCode)),
-			tag.Upsert(KeyClientStatus, strconv.Itoa(t.statusCode)),
-		}, m...)
-	})
-}
-
-func (t *tracker) Read(b []byte) (int, error) {
-	n, err := t.body.Read(b)
-	t.respSize += int64(n)
-	switch err {
-	case nil:
-		return n, nil
-	case io.EOF:
-		t.end()
-	}
-	return n, err
-}
-
-func (t *tracker) Close() error {
-	// Invoking endSpan on Close will help catch the cases
-	// in which a read returned a non-nil error, we set the
-	// span status but didn't end the span.
-	t.end()
-	return t.body.Close()
-}

vendor/go.opencensus.io/plugin/ochttp/propagation/b3/b3.go

-// Copyright 2018, OpenCensus 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 b3 contains a propagation.HTTPFormat implementation
-// for B3 propagation. See https://github.com/openzipkin/b3-propagation
-// for more details.
-package b3 // import "go.opencensus.io/plugin/ochttp/propagation/b3"
-
-import (
-	"encoding/hex"
-	"net/http"
-
-	"go.opencensus.io/trace"
-	"go.opencensus.io/trace/propagation"
-)
-
-// B3 headers that OpenCensus understands.
-const (
-	TraceIDHeader = "X-B3-TraceId"
-	SpanIDHeader  = "X-B3-SpanId"
-	SampledHeader = "X-B3-Sampled"
-)
-
-// HTTPFormat implements propagation.HTTPFormat to propagate
-// traces in HTTP headers in B3 propagation format.
-// HTTPFormat skips the X-B3-ParentId and X-B3-Flags headers
-// because there are additional fields not represented in the
-// OpenCensus span context. Spans created from the incoming
-// header will be the direct children of the client-side span.
-// Similarly, receiver of the outgoing spans should use client-side
-// span created by OpenCensus as the parent.
-type HTTPFormat struct{}
-
-var _ propagation.HTTPFormat = (*HTTPFormat)(nil)
-
-// SpanContextFromRequest extracts a B3 span context from incoming requests.
-func (f *HTTPFormat) SpanContextFromRequest(req *http.Request) (sc trace.SpanContext, ok bool) {
-	tid, ok := ParseTraceID(req.Header.Get(TraceIDHeader))
-	if !ok {
-		return trace.SpanContext{}, false
-	}
-	sid, ok := ParseSpanID(req.Header.Get(SpanIDHeader))
-	if !ok {
-		return trace.SpanContext{}, false
-	}
-	sampled, _ := ParseSampled(req.Header.Get(SampledHeader))
-	return trace.SpanContext{
-		TraceID:      tid,
-		SpanID:       sid,
-		TraceOptions: sampled,
-	}, true
-}
-
-// ParseTraceID parses the value of the X-B3-TraceId header.
-func ParseTraceID(tid string) (trace.TraceID, bool) {
-	if tid == "" {
-		return trace.TraceID{}, false
-	}
-	b, err := hex.DecodeString(tid)
-	if err != nil || len(b) > 16 {
-		return trace.TraceID{}, false
-	}
-	var traceID trace.TraceID
-	if len(b) <= 8 {
-		// The lower 64-bits.
-		start := 8 + (8 - len(b))
-		copy(traceID[start:], b)
-	} else {
-		start := 16 - len(b)
-		copy(traceID[start:], b)
-	}
-
-	return traceID, true
-}
-
-// ParseSpanID parses the value of the X-B3-SpanId or X-B3-ParentSpanId headers.
-func ParseSpanID(sid string) (spanID trace.SpanID, ok bool) {
-	if sid == "" {
-		return trace.SpanID{}, false
-	}
-	b, err := hex.DecodeString(sid)
-	if err != nil || len(b) > 8 {
-		return trace.SpanID{}, false
-	}
-	start := 8 - len(b)
-	copy(spanID[start:], b)
-	return spanID, true
-}
-
-// ParseSampled parses the value of the X-B3-Sampled header.
-func ParseSampled(sampled string) (trace.TraceOptions, bool) {
-	switch sampled {
-	case "true", "1":
-		return trace.TraceOptions(1), true
-	default:
-		return trace.TraceOptions(0), false
-	}
-}
-
-// SpanContextToRequest modifies the given request to include B3 headers.
-func (f *HTTPFormat) SpanContextToRequest(sc trace.SpanContext, req *http.Request) {
-	req.Header.Set(TraceIDHeader, hex.EncodeToString(sc.TraceID[:]))
-	req.Header.Set(SpanIDHeader, hex.EncodeToString(sc.SpanID[:]))
-
-	var sampled string
-	if sc.IsSampled() {
-		sampled = "1"
-	} else {
-		sampled = "0"
-	}
-	req.Header.Set(SampledHeader, sampled)
-}

vendor/go.opencensus.io/plugin/ochttp/route.go

-// Copyright 2018, OpenCensus 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 ochttp
-
-import (
-	"context"
-	"net/http"
-
-	"go.opencensus.io/tag"
-)
-
-// SetRoute sets the http_server_route tag to the given value.
-// It's useful when an HTTP framework does not support the http.Handler interface
-// and using WithRouteTag is not an option, but provides a way to hook into the request flow.
-func SetRoute(ctx context.Context, route string) {
-	if a, ok := ctx.Value(addedTagsKey{}).(*addedTags); ok {
-		a.t = append(a.t, tag.Upsert(KeyServerRoute, route))
-	}
-}
-
-// WithRouteTag returns an http.Handler that records stats with the
-// http_server_route tag set to the given value.
-func WithRouteTag(handler http.Handler, route string) http.Handler {
-	return taggedHandlerFunc(func(w http.ResponseWriter, r *http.Request) []tag.Mutator {
-		addRoute := []tag.Mutator{tag.Upsert(KeyServerRoute, route)}
-		ctx, _ := tag.New(r.Context(), addRoute...)
-		r = r.WithContext(ctx)
-		handler.ServeHTTP(w, r)
-		return addRoute
-	})
-}
-
-// taggedHandlerFunc is a http.Handler that returns tags describing the
-// processing of the request. These tags will be recorded along with the
-// measures in this package at the end of the request.
-type taggedHandlerFunc func(w http.ResponseWriter, r *http.Request) []tag.Mutator
-
-func (h taggedHandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	tags := h(w, r)
-	if a, ok := r.Context().Value(addedTagsKey{}).(*addedTags); ok {
-		a.t = append(a.t, tags...)
-	}
-}
-
-type addedTagsKey struct{}
-
-type addedTags struct {
-	t []tag.Mutator
-}

vendor/go.opencensus.io/plugin/ochttp/server.go

-// Copyright 2018, OpenCensus 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 ochttp
-
-import (
-	"context"
-	"io"
-	"net/http"
-	"strconv"
-	"sync"
-	"time"
-
-	"go.opencensus.io/stats"
-	"go.opencensus.io/tag"
-	"go.opencensus.io/trace"
-	"go.opencensus.io/trace/propagation"
-)
-
-// Handler is an http.Handler wrapper to instrument your HTTP server with
-// OpenCensus. It supports both stats and tracing.
-//
-// Tracing
-//
-// This handler is aware of the incoming request's span, reading it from request
-// headers as configured using the Propagation field.
-// The extracted span can be accessed from the incoming request's
-// context.
-//
-//    span := trace.FromContext(r.Context())
-//
-// The server span will be automatically ended at the end of ServeHTTP.
-type Handler struct {
-	// Propagation defines how traces are propagated. If unspecified,
-	// B3 propagation will be used.
-	Propagation propagation.HTTPFormat
-
-	// Handler is the handler used to handle the incoming request.
-	Handler http.Handler
-
-	// StartOptions are applied to the span started by this Handler around each
-	// request.
-	//
-	// StartOptions.SpanKind will always be set to trace.SpanKindServer
-	// for spans started by this transport.
-	StartOptions trace.StartOptions
-
-	// GetStartOptions allows to set start options per request. If set,
-	// StartOptions is going to be ignored.
-	GetStartOptions func(*http.Request) trace.StartOptions
-
-	// IsPublicEndpoint should be set to true for publicly accessible HTTP(S)
-	// servers. If true, any trace metadata set on the incoming request will
-	// be added as a linked trace instead of being added as a parent of the
-	// current trace.
-	IsPublicEndpoint bool
-
-	// FormatSpanName holds the function to use for generating the span name
-	// from the information found in the incoming HTTP Request. By default the
-	// name equals the URL Path.
-	FormatSpanName func(*http.Request) string
-
-	// IsHealthEndpoint holds the function to use for determining if the
-	// incoming HTTP request should be considered a health check. This is in
-	// addition to the private isHealthEndpoint func which may also indicate
-	// tracing should be skipped.
-	IsHealthEndpoint func(*http.Request) bool
-}
-
-func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	var tags addedTags
-	r, traceEnd := h.startTrace(w, r)
-	defer traceEnd()
-	w, statsEnd := h.startStats(w, r)
-	defer statsEnd(&tags)
-	handler := h.Handler
-	if handler == nil {
-		handler = http.DefaultServeMux
-	}
-	r = r.WithContext(context.WithValue(r.Context(), addedTagsKey{}, &tags))
-	handler.ServeHTTP(w, r)
-}
-
-func (h *Handler) startTrace(w http.ResponseWriter, r *http.Request) (*http.Request, func()) {
-	if h.IsHealthEndpoint != nil && h.IsHealthEndpoint(r) || isHealthEndpoint(r.URL.Path) {
-		return r, func() {}
-	}
-	var name string
-	if h.FormatSpanName == nil {
-		name = spanNameFromURL(r)
-	} else {
-		name = h.FormatSpanName(r)
-	}
-	ctx := r.Context()
-
-	startOpts := h.StartOptions
-	if h.GetStartOptions != nil {
-		startOpts = h.GetStartOptions(r)
-	}
-
-	var span *trace.Span
-	sc, ok := h.extractSpanContext(r)
-	if ok && !h.IsPublicEndpoint {
-		ctx, span = trace.StartSpanWithRemoteParent(ctx, name, sc,
-			trace.WithSampler(startOpts.Sampler),
-			trace.WithSpanKind(trace.SpanKindServer))
-	} else {
-		ctx, span = trace.StartSpan(ctx, name,
-			trace.WithSampler(startOpts.Sampler),
-			trace.WithSpanKind(trace.SpanKindServer),
-		)
-		if ok {
-			span.AddLink(trace.Link{
-				TraceID:    sc.TraceID,
-				SpanID:     sc.SpanID,
-				Type:       trace.LinkTypeParent,
-				Attributes: nil,
-			})
-		}
-	}
-	span.AddAttributes(requestAttrs(r)...)
-	if r.Body == nil {
-		// TODO: Handle cases where ContentLength is not set.
-	} else if r.ContentLength > 0 {
-		span.AddMessageReceiveEvent(0, /* TODO: messageID */
-			r.ContentLength, -1)
-	}
-	return r.WithContext(ctx), span.End
-}
-
-func (h *Handler) extractSpanContext(r *http.Request) (trace.SpanContext, bool) {
-	if h.Propagation == nil {
-		return defaultFormat.SpanContextFromRequest(r)
-	}
-	return h.Propagation.SpanContextFromRequest(r)
-}
-
-func (h *Handler) startStats(w http.ResponseWriter, r *http.Request) (http.ResponseWriter, func(tags *addedTags)) {
-	ctx, _ := tag.New(r.Context(),
-		tag.Upsert(Host, r.Host),
-		tag.Upsert(Path, r.URL.Path),
-		tag.Upsert(Method, r.Method))
-	track := &trackingResponseWriter{
-		start:  time.Now(),
-		ctx:    ctx,
-		writer: w,
-	}
-	if r.Body == nil {
-		// TODO: Handle cases where ContentLength is not set.
-		track.reqSize = -1
-	} else if r.ContentLength > 0 {
-		track.reqSize = r.ContentLength
-	}
-	stats.Record(ctx, ServerRequestCount.M(1))
-	return track.wrappedResponseWriter(), track.end
-}
-
-type trackingResponseWriter struct {
-	ctx        context.Context
-	reqSize    int64
-	respSize   int64
-	start      time.Time
-	statusCode int
-	statusLine string
-	endOnce    sync.Once
-	writer     http.ResponseWriter
-}
-
-// Compile time assertion for ResponseWriter interface
-var _ http.ResponseWriter = (*trackingResponseWriter)(nil)
-
-func (t *trackingResponseWriter) end(tags *addedTags) {
-	t.endOnce.Do(func() {
-		if t.statusCode == 0 {
-			t.statusCode = 200
-		}
-
-		span := trace.FromContext(t.ctx)
-		span.SetStatus(TraceStatus(t.statusCode, t.statusLine))
-		span.AddAttributes(trace.Int64Attribute(StatusCodeAttribute, int64(t.statusCode)))
-
-		m := []stats.Measurement{
-			ServerLatency.M(float64(time.Since(t.start)) / float64(time.Millisecond)),
-			ServerResponseBytes.M(t.respSize),
-		}
-		if t.reqSize >= 0 {
-			m = append(m, ServerRequestBytes.M(t.reqSize))
-		}
-		allTags := make([]tag.Mutator, len(tags.t)+1)
-		allTags[0] = tag.Upsert(StatusCode, strconv.Itoa(t.statusCode))
-		copy(allTags[1:], tags.t)
-		stats.RecordWithTags(t.ctx, allTags, m...)
-	})
-}
-
-func (t *trackingResponseWriter) Header() http.Header {
-	return t.writer.Header()
-}
-
-func (t *trackingResponseWriter) Write(data []byte) (int, error) {
-	n, err := t.writer.Write(data)
-	t.respSize += int64(n)
-	// Add message event for request bytes sent.
-	span := trace.FromContext(t.ctx)
-	span.AddMessageSendEvent(0 /* TODO: messageID */, int64(n), -1)
-	return n, err
-}
-
-func (t *trackingResponseWriter) WriteHeader(statusCode int) {
-	t.writer.WriteHeader(statusCode)
-	t.statusCode = statusCode
-	t.statusLine = http.StatusText(t.statusCode)
-}
-
-// wrappedResponseWriter returns a wrapped version of the original
-//  ResponseWriter and only implements the same combination of additional
-// interfaces as the original.
-// This implementation is based on https://github.com/felixge/httpsnoop.
-func (t *trackingResponseWriter) wrappedResponseWriter() http.ResponseWriter {
-	var (
-		hj, i0 = t.writer.(http.Hijacker)
-		cn, i1 = t.writer.(http.CloseNotifier)
-		pu, i2 = t.writer.(http.Pusher)
-		fl, i3 = t.writer.(http.Flusher)
-		rf, i4 = t.writer.(io.ReaderFrom)
-	)
-
-	switch {
-	case !i0 && !i1 && !i2 && !i3 && !i4:
-		return struct {
-			http.ResponseWriter
-		}{t}
-	case !i0 && !i1 && !i2 && !i3 && i4:
-		return struct {
-			http.ResponseWriter
-			io.ReaderFrom
-		}{t, rf}
-	case !i0 && !i1 && !i2 && i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Flusher
-		}{t, fl}
-	case !i0 && !i1 && !i2 && i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Flusher
-			io.ReaderFrom
-		}{t, fl, rf}
-	case !i0 && !i1 && i2 && !i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Pusher
-		}{t, pu}
-	case !i0 && !i1 && i2 && !i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Pusher
-			io.ReaderFrom
-		}{t, pu, rf}
-	case !i0 && !i1 && i2 && i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Pusher
-			http.Flusher
-		}{t, pu, fl}
-	case !i0 && !i1 && i2 && i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Pusher
-			http.Flusher
-			io.ReaderFrom
-		}{t, pu, fl, rf}
-	case !i0 && i1 && !i2 && !i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.CloseNotifier
-		}{t, cn}
-	case !i0 && i1 && !i2 && !i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.CloseNotifier
-			io.ReaderFrom
-		}{t, cn, rf}
-	case !i0 && i1 && !i2 && i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.CloseNotifier
-			http.Flusher
-		}{t, cn, fl}
-	case !i0 && i1 && !i2 && i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.CloseNotifier
-			http.Flusher
-			io.ReaderFrom
-		}{t, cn, fl, rf}
-	case !i0 && i1 && i2 && !i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.CloseNotifier
-			http.Pusher
-		}{t, cn, pu}
-	case !i0 && i1 && i2 && !i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.CloseNotifier
-			http.Pusher
-			io.ReaderFrom
-		}{t, cn, pu, rf}
-	case !i0 && i1 && i2 && i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.CloseNotifier
-			http.Pusher
-			http.Flusher
-		}{t, cn, pu, fl}
-	case !i0 && i1 && i2 && i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.CloseNotifier
-			http.Pusher
-			http.Flusher
-			io.ReaderFrom
-		}{t, cn, pu, fl, rf}
-	case i0 && !i1 && !i2 && !i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-		}{t, hj}
-	case i0 && !i1 && !i2 && !i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			io.ReaderFrom
-		}{t, hj, rf}
-	case i0 && !i1 && !i2 && i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Flusher
-		}{t, hj, fl}
-	case i0 && !i1 && !i2 && i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Flusher
-			io.ReaderFrom
-		}{t, hj, fl, rf}
-	case i0 && !i1 && i2 && !i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Pusher
-		}{t, hj, pu}
-	case i0 && !i1 && i2 && !i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Pusher
-			io.ReaderFrom
-		}{t, hj, pu, rf}
-	case i0 && !i1 && i2 && i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Pusher
-			http.Flusher
-		}{t, hj, pu, fl}
-	case i0 && !i1 && i2 && i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Pusher
-			http.Flusher
-			io.ReaderFrom
-		}{t, hj, pu, fl, rf}
-	case i0 && i1 && !i2 && !i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.CloseNotifier
-		}{t, hj, cn}
-	case i0 && i1 && !i2 && !i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.CloseNotifier
-			io.ReaderFrom
-		}{t, hj, cn, rf}
-	case i0 && i1 && !i2 && i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.CloseNotifier
-			http.Flusher
-		}{t, hj, cn, fl}
-	case i0 && i1 && !i2 && i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.CloseNotifier
-			http.Flusher
-			io.ReaderFrom
-		}{t, hj, cn, fl, rf}
-	case i0 && i1 && i2 && !i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.CloseNotifier
-			http.Pusher
-		}{t, hj, cn, pu}
-	case i0 && i1 && i2 && !i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.CloseNotifier
-			http.Pusher
-			io.ReaderFrom
-		}{t, hj, cn, pu, rf}
-	case i0 && i1 && i2 && i3 && !i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.CloseNotifier
-			http.Pusher
-			http.Flusher
-		}{t, hj, cn, pu, fl}
-	case i0 && i1 && i2 && i3 && i4:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.CloseNotifier
-			http.Pusher
-			http.Flusher
-			io.ReaderFrom
-		}{t, hj, cn, pu, fl, rf}
-	default:
-		return struct {
-			http.ResponseWriter
-		}{t}
-	}
-}

vendor/go.opencensus.io/plugin/ochttp/span_annotating_client_trace.go

-// Copyright 2018, OpenCensus 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 ochttp
-
-import (
-	"crypto/tls"
-	"net/http"
-	"net/http/httptrace"
-	"strings"
-
-	"go.opencensus.io/trace"
-)
-
-type spanAnnotator struct {
-	sp *trace.Span
-}
-
-// TODO: Remove NewSpanAnnotator at the next release.
-
-// NewSpanAnnotator returns a httptrace.ClientTrace which annotates
-// all emitted httptrace events on the provided Span.
-// Deprecated: Use NewSpanAnnotatingClientTrace instead
-func NewSpanAnnotator(r *http.Request, s *trace.Span) *httptrace.ClientTrace {
-	return NewSpanAnnotatingClientTrace(r, s)
-}
-
-// NewSpanAnnotatingClientTrace returns a httptrace.ClientTrace which annotates
-// all emitted httptrace events on the provided Span.
-func NewSpanAnnotatingClientTrace(_ *http.Request, s *trace.Span) *httptrace.ClientTrace {
-	sa := spanAnnotator{sp: s}
-
-	return &httptrace.ClientTrace{
-		GetConn:              sa.getConn,
-		GotConn:              sa.gotConn,
-		PutIdleConn:          sa.putIdleConn,
-		GotFirstResponseByte: sa.gotFirstResponseByte,
-		Got100Continue:       sa.got100Continue,
-		DNSStart:             sa.dnsStart,
-		DNSDone:              sa.dnsDone,
-		ConnectStart:         sa.connectStart,
-		ConnectDone:          sa.connectDone,
-		TLSHandshakeStart:    sa.tlsHandshakeStart,
-		TLSHandshakeDone:     sa.tlsHandshakeDone,
-		WroteHeaders:         sa.wroteHeaders,
-		Wait100Continue:      sa.wait100Continue,
-		WroteRequest:         sa.wroteRequest,
-	}
-}
-
-func (s spanAnnotator) getConn(hostPort string) {
-	attrs := []trace.Attribute{
-		trace.StringAttribute("httptrace.get_connection.host_port", hostPort),
-	}
-	s.sp.Annotate(attrs, "GetConn")
-}
-
-func (s spanAnnotator) gotConn(info httptrace.GotConnInfo) {
-	attrs := []trace.Attribute{
-		trace.BoolAttribute("httptrace.got_connection.reused", info.Reused),
-		trace.BoolAttribute("httptrace.got_connection.was_idle", info.WasIdle),
-	}
-	if info.WasIdle {
-		attrs = append(attrs,
-			trace.StringAttribute("httptrace.got_connection.idle_time", info.IdleTime.String()))
-	}
-	s.sp.Annotate(attrs, "GotConn")
-}
-
-// PutIdleConn implements a httptrace.ClientTrace hook
-func (s spanAnnotator) putIdleConn(err error) {
-	var attrs []trace.Attribute
-	if err != nil {
-		attrs = append(attrs,
-			trace.StringAttribute("httptrace.put_idle_connection.error", err.Error()))
-	}
-	s.sp.Annotate(attrs, "PutIdleConn")
-}
-
-func (s spanAnnotator) gotFirstResponseByte() {
-	s.sp.Annotate(nil, "GotFirstResponseByte")
-}
-
-func (s spanAnnotator) got100Continue() {
-	s.sp.Annotate(nil, "Got100Continue")
-}
-
-func (s spanAnnotator) dnsStart(info httptrace.DNSStartInfo) {
-	attrs := []trace.Attribute{
-		trace.StringAttribute("httptrace.dns_start.host", info.Host),
-	}
-	s.sp.Annotate(attrs, "DNSStart")
-}
-
-func (s spanAnnotator) dnsDone(info httptrace.DNSDoneInfo) {
-	var addrs []string
-	for _, addr := range info.Addrs {
-		addrs = append(addrs, addr.String())
-	}
-	attrs := []trace.Attribute{
-		trace.StringAttribute("httptrace.dns_done.addrs", strings.Join(addrs, " , ")),
-	}
-	if info.Err != nil {
-		attrs = append(attrs,
-			trace.StringAttribute("httptrace.dns_done.error", info.Err.Error()))
-	}
-	s.sp.Annotate(attrs, "DNSDone")
-}
-
-func (s spanAnnotator) connectStart(network, addr string) {
-	attrs := []trace.Attribute{
-		trace.StringAttribute("httptrace.connect_start.network", network),
-		trace.StringAttribute("httptrace.connect_start.addr", addr),
-	}
-	s.sp.Annotate(attrs, "ConnectStart")
-}
-
-func (s spanAnnotator) connectDone(network, addr string, err error) {
-	attrs := []trace.Attribute{
-		trace.StringAttribute("httptrace.connect_done.network", network),
-		trace.StringAttribute("httptrace.connect_done.addr", addr),
-	}
-	if err != nil {
-		attrs = append(attrs,
-			trace.StringAttribute("httptrace.connect_done.error", err.Error()))
-	}
-	s.sp.Annotate(attrs, "ConnectDone")
-}
-
-func (s spanAnnotator) tlsHandshakeStart() {
-	s.sp.Annotate(nil, "TLSHandshakeStart")
-}
-
-func (s spanAnnotator) tlsHandshakeDone(_ tls.ConnectionState, err error) {
-	var attrs []trace.Attribute
-	if err != nil {
-		attrs = append(attrs,
-			trace.StringAttribute("httptrace.tls_handshake_done.error", err.Error()))
-	}
-	s.sp.Annotate(attrs, "TLSHandshakeDone")
-}
-
-func (s spanAnnotator) wroteHeaders() {
-	s.sp.Annotate(nil, "WroteHeaders")
-}
-
-func (s spanAnnotator) wait100Continue() {
-	s.sp.Annotate(nil, "Wait100Continue")
-}
-
-func (s spanAnnotator) wroteRequest(info httptrace.WroteRequestInfo) {
-	var attrs []trace.Attribute
-	if info.Err != nil {
-		attrs = append(attrs,
-			trace.StringAttribute("httptrace.wrote_request.error", info.Err.Error()))
-	}
-	s.sp.Annotate(attrs, "WroteRequest")
-}

vendor/go.opencensus.io/plugin/ochttp/stats.go

-// Copyright 2018, OpenCensus 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 ochttp
-
-import (
-	"go.opencensus.io/stats"
-	"go.opencensus.io/stats/view"
-	"go.opencensus.io/tag"
-)
-
-// Deprecated: client HTTP measures.
-var (
-	// Deprecated: Use a Count aggregation over one of the other client measures to achieve the same effect.
-	ClientRequestCount = stats.Int64(
-		"opencensus.io/http/client/request_count",
-		"Number of HTTP requests started",
-		stats.UnitDimensionless)
-	// Deprecated: Use ClientSentBytes.
-	ClientRequestBytes = stats.Int64(
-		"opencensus.io/http/client/request_bytes",
-		"HTTP request body size if set as ContentLength (uncompressed)",
-		stats.UnitBytes)
-	// Deprecated: Use ClientReceivedBytes.
-	ClientResponseBytes = stats.Int64(
-		"opencensus.io/http/client/response_bytes",
-		"HTTP response body size (uncompressed)",
-		stats.UnitBytes)
-	// Deprecated: Use ClientRoundtripLatency.
-	ClientLatency = stats.Float64(
-		"opencensus.io/http/client/latency",
-		"End-to-end latency",
-		stats.UnitMilliseconds)
-)
-
-// The following client HTTP measures are supported for use in custom views.
-var (
-	ClientSentBytes = stats.Int64(
-		"opencensus.io/http/client/sent_bytes",
-		"Total bytes sent in request body (not including headers)",
-		stats.UnitBytes,
-	)
-	ClientReceivedBytes = stats.Int64(
-		"opencensus.io/http/client/received_bytes",
-		"Total bytes received in response bodies (not including headers but including error responses with bodies)",
-		stats.UnitBytes,
-	)
-	ClientRoundtripLatency = stats.Float64(
-		"opencensus.io/http/client/roundtrip_latency",
-		"Time between first byte of request headers sent to last byte of response received, or terminal error",
-		stats.UnitMilliseconds,
-	)
-)
-
-// The following server HTTP measures are supported for use in custom views:
-var (
-	ServerRequestCount = stats.Int64(
-		"opencensus.io/http/server/request_count",
-		"Number of HTTP requests started",
-		stats.UnitDimensionless)
-	ServerRequestBytes = stats.Int64(
-		"opencensus.io/http/server/request_bytes",
-		"HTTP request body size if set as ContentLength (uncompressed)",
-		stats.UnitBytes)
-	ServerResponseBytes = stats.Int64(
-		"opencensus.io/http/server/response_bytes",
-		"HTTP response body size (uncompressed)",
-		stats.UnitBytes)
-	ServerLatency = stats.Float64(
-		"opencensus.io/http/server/latency",
-		"End-to-end latency",
-		stats.UnitMilliseconds)
-)
-
-// The following tags are applied to stats recorded by this package. Host, Path
-// and Method are applied to all measures. StatusCode is not applied to
-// ClientRequestCount or ServerRequestCount, since it is recorded before the status is known.
-var (
-	// Host is the value of the HTTP Host header.
-	//
-	// The value of this tag can be controlled by the HTTP client, so you need
-	// to watch out for potentially generating high-cardinality labels in your
-	// metrics backend if you use this tag in views.
-	Host = tag.MustNewKey("http.host")
-
-	// StatusCode is the numeric HTTP response status code,
-	// or "error" if a transport error occurred and no status code was read.
-	StatusCode = tag.MustNewKey("http.status")
-
-	// Path is the URL path (not including query string) in the request.
-	//
-	// The value of this tag can be controlled by the HTTP client, so you need
-	// to watch out for potentially generating high-cardinality labels in your
-	// metrics backend if you use this tag in views.
-	Path = tag.MustNewKey("http.path")
-
-	// Method is the HTTP method of the request, capitalized (GET, POST, etc.).
-	Method = tag.MustNewKey("http.method")
-
-	// KeyServerRoute is a low cardinality string representing the logical
-	// handler of the request. This is usually the pattern registered on the a
-	// ServeMux (or similar string).
-	KeyServerRoute = tag.MustNewKey("http_server_route")
-)
-
-// Client tag keys.
-var (
-	// KeyClientMethod is the HTTP method, capitalized (i.e. GET, POST, PUT, DELETE, etc.).
-	KeyClientMethod = tag.MustNewKey("http_client_method")
-	// KeyClientPath is the URL path (not including query string).
-	KeyClientPath = tag.MustNewKey("http_client_path")
-	// KeyClientStatus is the HTTP status code as an integer (e.g. 200, 404, 500.), or "error" if no response status line was received.
-	KeyClientStatus = tag.MustNewKey("http_client_status")
-	// KeyClientHost is the value of the request Host header.
-	KeyClientHost = tag.MustNewKey("http_client_host")
-)
-
-// Default distributions used by views in this package.
-var (
-	DefaultSizeDistribution    = view.Distribution(1024, 2048, 4096, 16384, 65536, 262144, 1048576, 4194304, 16777216, 67108864, 268435456, 1073741824, 4294967296)
-	DefaultLatencyDistribution = view.Distribution(1, 2, 3, 4, 5, 6, 8, 10, 13, 16, 20, 25, 30, 40, 50, 65, 80, 100, 130, 160, 200, 250, 300, 400, 500, 650, 800, 1000, 2000, 5000, 10000, 20000, 50000, 100000)
-)
-
-// Package ochttp provides some convenience views for client measures.
-// You still need to register these views for data to actually be collected.
-var (
-	ClientSentBytesDistribution = &view.View{
-		Name:        "opencensus.io/http/client/sent_bytes",
-		Measure:     ClientSentBytes,
-		Aggregation: DefaultSizeDistribution,
-		Description: "Total bytes sent in request body (not including headers), by HTTP method and response status",
-		TagKeys:     []tag.Key{KeyClientMethod, KeyClientStatus},
-	}
-
-	ClientReceivedBytesDistribution = &view.View{
-		Name:        "opencensus.io/http/client/received_bytes",
-		Measure:     ClientReceivedBytes,
-		Aggregation: DefaultSizeDistribution,
-		Description: "Total bytes received in response bodies (not including headers but including error responses with bodies), by HTTP method and response status",
-		TagKeys:     []tag.Key{KeyClientMethod, KeyClientStatus},
-	}
-
-	ClientRoundtripLatencyDistribution = &view.View{
-		Name:        "opencensus.io/http/client/roundtrip_latency",
-		Measure:     ClientRoundtripLatency,
-		Aggregation: DefaultLatencyDistribution,
-		Description: "End-to-end latency, by HTTP method and response status",
-		TagKeys:     []tag.Key{KeyClientMethod, KeyClientStatus},
-	}
-
-	ClientCompletedCount = &view.View{
-		Name:        "opencensus.io/http/client/completed_count",
-		Measure:     ClientRoundtripLatency,
-		Aggregation: view.Count(),
-		Description: "Count of completed requests, by HTTP method and response status",
-		TagKeys:     []tag.Key{KeyClientMethod, KeyClientStatus},
-	}
-)
-
-// Deprecated: Old client Views.
-var (
-	// Deprecated: No direct replacement, but see ClientCompletedCount.
-	ClientRequestCountView = &view.View{
-		Name:        "opencensus.io/http/client/request_count",
-		Description: "Count of HTTP requests started",
-		Measure:     ClientRequestCount,
-		Aggregation: view.Count(),
-	}
-
-	// Deprecated: Use ClientSentBytesDistribution.
-	ClientRequestBytesView = &view.View{
-		Name:        "opencensus.io/http/client/request_bytes",
-		Description: "Size distribution of HTTP request body",
-		Measure:     ClientSentBytes,
-		Aggregation: DefaultSizeDistribution,
-	}
-
-	// Deprecated: Use ClientReceivedBytesDistribution instead.
-	ClientResponseBytesView = &view.View{
-		Name:        "opencensus.io/http/client/response_bytes",
-		Description: "Size distribution of HTTP response body",
-		Measure:     ClientReceivedBytes,
-		Aggregation: DefaultSizeDistribution,
-	}
-
-	// Deprecated: Use ClientRoundtripLatencyDistribution instead.
-	ClientLatencyView = &view.View{
-		Name:        "opencensus.io/http/client/latency",
-		Description: "Latency distribution of HTTP requests",
-		Measure:     ClientRoundtripLatency,
-		Aggregation: DefaultLatencyDistribution,
-	}
-
-	// Deprecated: Use ClientCompletedCount instead.
-	ClientRequestCountByMethod = &view.View{
-		Name:        "opencensus.io/http/client/request_count_by_method",
-		Description: "Client request count by HTTP method",
-		TagKeys:     []tag.Key{Method},
-		Measure:     ClientSentBytes,
-		Aggregation: view.Count(),
-	}
-
-	// Deprecated: Use ClientCompletedCount instead.
-	ClientResponseCountByStatusCode = &view.View{
-		Name:        "opencensus.io/http/client/response_count_by_status_code",
-		Description: "Client response count by status code",
-		TagKeys:     []tag.Key{StatusCode},
-		Measure:     ClientRoundtripLatency,
-		Aggregation: view.Count(),
-	}
-)
-
-// Package ochttp provides some convenience views for server measures.
-// You still need to register these views for data to actually be collected.
-var (
-	ServerRequestCountView = &view.View{
-		Name:        "opencensus.io/http/server/request_count",
-		Description: "Count of HTTP requests started",
-		Measure:     ServerRequestCount,
-		Aggregation: view.Count(),
-	}
-
-	ServerRequestBytesView = &view.View{
-		Name:        "opencensus.io/http/server/request_bytes",
-		Description: "Size distribution of HTTP request body",
-		Measure:     ServerRequestBytes,
-		Aggregation: DefaultSizeDistribution,
-	}
-
-	ServerResponseBytesView = &view.View{
-		Name:        "opencensus.io/http/server/response_bytes",
-		Description: "Size distribution of HTTP response body",
-		Measure:     ServerResponseBytes,
-		Aggregation: DefaultSizeDistribution,
-	}
-
-	ServerLatencyView = &view.View{
-		Name:        "opencensus.io/http/server/latency",
-		Description: "Latency distribution of HTTP requests",
-		Measure:     ServerLatency,
-		Aggregation: DefaultLatencyDistribution,
-	}
-
-	ServerRequestCountByMethod = &view.View{
-		Name:        "opencensus.io/http/server/request_count_by_method",
-		Description: "Server request count by HTTP method",
-		TagKeys:     []tag.Key{Method},
-		Measure:     ServerRequestCount,
-		Aggregation: view.Count(),
-	}
-
-	ServerResponseCountByStatusCode = &view.View{
-		Name:        "opencensus.io/http/server/response_count_by_status_code",
-		Description: "Server response count by status code",
-		TagKeys:     []tag.Key{StatusCode},
-		Measure:     ServerLatency,
-		Aggregation: view.Count(),
-	}
-)
-
-// DefaultClientViews are the default client views provided by this package.
-// Deprecated: No replacement. Register the views you would like individually.
-var DefaultClientViews = []*view.View{
-	ClientRequestCountView,
-	ClientRequestBytesView,
-	ClientResponseBytesView,
-	ClientLatencyView,
-	ClientRequestCountByMethod,
-	ClientResponseCountByStatusCode,
-}
-
-// DefaultServerViews are the default server views provided by this package.
-// Deprecated: No replacement. Register the views you would like individually.
-var DefaultServerViews = []*view.View{
-	ServerRequestCountView,
-	ServerRequestBytesView,
-	ServerResponseBytesView,
-	ServerLatencyView,
-	ServerRequestCountByMethod,
-	ServerResponseCountByStatusCode,
-}

vendor/go.opencensus.io/plugin/ochttp/trace.go

-// Copyright 2018, OpenCensus 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 ochttp
-
-import (
-	"io"
-	"net/http"
-	"net/http/httptrace"
-
-	"go.opencensus.io/plugin/ochttp/propagation/b3"
-	"go.opencensus.io/trace"
-	"go.opencensus.io/trace/propagation"
-)
-
-// TODO(jbd): Add godoc examples.
-
-var defaultFormat propagation.HTTPFormat = &b3.HTTPFormat{}
-
-// Attributes recorded on the span for the requests.
-// Only trace exporters will need them.
-const (
-	HostAttribute       = "http.host"
-	MethodAttribute     = "http.method"
-	PathAttribute       = "http.path"
-	URLAttribute        = "http.url"
-	UserAgentAttribute  = "http.user_agent"
-	StatusCodeAttribute = "http.status_code"
-)
-
-type traceTransport struct {
-	base           http.RoundTripper
-	startOptions   trace.StartOptions
-	format         propagation.HTTPFormat
-	formatSpanName func(*http.Request) string
-	newClientTrace func(*http.Request, *trace.Span) *httptrace.ClientTrace
-}
-
-// TODO(jbd): Add message events for request and response size.
-
-// RoundTrip creates a trace.Span and inserts it into the outgoing request's headers.
-// The created span can follow a parent span, if a parent is presented in
-// the request's context.
-func (t *traceTransport) RoundTrip(req *http.Request) (*http.Response, error) {
-	name := t.formatSpanName(req)
-	// TODO(jbd): Discuss whether we want to prefix
-	// outgoing requests with Sent.
-	ctx, span := trace.StartSpan(req.Context(), name,
-		trace.WithSampler(t.startOptions.Sampler),
-		trace.WithSpanKind(trace.SpanKindClient))
-
-	if t.newClientTrace != nil {
-		req = req.WithContext(httptrace.WithClientTrace(ctx, t.newClientTrace(req, span)))
-	} else {
-		req = req.WithContext(ctx)
-	}
-
-	if t.format != nil {
-		// SpanContextToRequest will modify its Request argument, which is
-		// contrary to the contract for http.RoundTripper, so we need to
-		// pass it a copy of the Request.
-		// However, the Request struct itself was already copied by
-		// the WithContext calls above and so we just need to copy the header.
-		header := make(http.Header)
-		for k, v := range req.Header {
-			header[k] = v
-		}
-		req.Header = header
-		t.format.SpanContextToRequest(span.SpanContext(), req)
-	}
-
-	span.AddAttributes(requestAttrs(req)...)
-	resp, err := t.base.RoundTrip(req)
-	if err != nil {
-		span.SetStatus(trace.Status{Code: trace.StatusCodeUnknown, Message: err.Error()})
-		span.End()
-		return resp, err
-	}
-
-	span.AddAttributes(responseAttrs(resp)...)
-	span.SetStatus(TraceStatus(resp.StatusCode, resp.Status))
-
-	// span.End() will be invoked after
-	// a read from resp.Body returns io.EOF or when
-	// resp.Body.Close() is invoked.
-	bt := &bodyTracker{rc: resp.Body, span: span}
-	resp.Body = wrappedBody(bt, resp.Body)
-	return resp, err
-}
-
-// bodyTracker wraps a response.Body and invokes
-// trace.EndSpan on encountering io.EOF on reading
-// the body of the original response.
-type bodyTracker struct {
-	rc   io.ReadCloser
-	span *trace.Span
-}
-
-var _ io.ReadCloser = (*bodyTracker)(nil)
-
-func (bt *bodyTracker) Read(b []byte) (int, error) {
-	n, err := bt.rc.Read(b)
-
-	switch err {
-	case nil:
-		return n, nil
-	case io.EOF:
-		bt.span.End()
-	default:
-		// For all other errors, set the span status
-		bt.span.SetStatus(trace.Status{
-			// Code 2 is the error code for Internal server error.
-			Code:    2,
-			Message: err.Error(),
-		})
-	}
-	return n, err
-}
-
-func (bt *bodyTracker) Close() error {
-	// Invoking endSpan on Close will help catch the cases
-	// in which a read returned a non-nil error, we set the
-	// span status but didn't end the span.
-	bt.span.End()
-	return bt.rc.Close()
-}
-
-// CancelRequest cancels an in-flight request by closing its connection.
-func (t *traceTransport) CancelRequest(req *http.Request) {
-	type canceler interface {
-		CancelRequest(*http.Request)
-	}
-	if cr, ok := t.base.(canceler); ok {
-		cr.CancelRequest(req)
-	}
-}
-
-func spanNameFromURL(req *http.Request) string {
-	return req.URL.Path
-}
-
-func requestAttrs(r *http.Request) []trace.Attribute {
-	userAgent := r.UserAgent()
-
-	attrs := make([]trace.Attribute, 0, 5)
-	attrs = append(attrs,
-		trace.StringAttribute(PathAttribute, r.URL.Path),
-		trace.StringAttribute(URLAttribute, r.URL.String()),
-		trace.StringAttribute(HostAttribute, r.Host),
-		trace.StringAttribute(MethodAttribute, r.Method),
-	)
-
-	if userAgent != "" {
-		attrs = append(attrs, trace.StringAttribute(UserAgentAttribute, userAgent))
-	}
-
-	return attrs
-}
-
-func responseAttrs(resp *http.Response) []trace.Attribute {
-	return []trace.Attribute{
-		trace.Int64Attribute(StatusCodeAttribute, int64(resp.StatusCode)),
-	}
-}
-
-// TraceStatus is a utility to convert the HTTP status code to a trace.Status that
-// represents the outcome as closely as possible.
-func TraceStatus(httpStatusCode int, statusLine string) trace.Status {
-	var code int32
-	if httpStatusCode < 200 || httpStatusCode >= 400 {
-		code = trace.StatusCodeUnknown
-	}
-	switch httpStatusCode {
-	case 499:
-		code = trace.StatusCodeCancelled
-	case http.StatusBadRequest:
-		code = trace.StatusCodeInvalidArgument
-	case http.StatusUnprocessableEntity:
-		code = trace.StatusCodeInvalidArgument
-	case http.StatusGatewayTimeout:
-		code = trace.StatusCodeDeadlineExceeded
-	case http.StatusNotFound:
-		code = trace.StatusCodeNotFound
-	case http.StatusForbidden:
-		code = trace.StatusCodePermissionDenied
-	case http.StatusUnauthorized: // 401 is actually unauthenticated.
-		code = trace.StatusCodeUnauthenticated
-	case http.StatusTooManyRequests:
-		code = trace.StatusCodeResourceExhausted
-	case http.StatusNotImplemented:
-		code = trace.StatusCodeUnimplemented
-	case http.StatusServiceUnavailable:
-		code = trace.StatusCodeUnavailable
-	case http.StatusOK:
-		code = trace.StatusCodeOK
-	case http.StatusConflict:
-		code = trace.StatusCodeAlreadyExists
-	}
-
-	return trace.Status{Code: code, Message: codeToStr[code]}
-}
-
-var codeToStr = map[int32]string{
-	trace.StatusCodeOK:                 `OK`,
-	trace.StatusCodeCancelled:          `CANCELLED`,
-	trace.StatusCodeUnknown:            `UNKNOWN`,
-	trace.StatusCodeInvalidArgument:    `INVALID_ARGUMENT`,
-	trace.StatusCodeDeadlineExceeded:   `DEADLINE_EXCEEDED`,
-	trace.StatusCodeNotFound:           `NOT_FOUND`,
-	trace.StatusCodeAlreadyExists:      `ALREADY_EXISTS`,
-	trace.StatusCodePermissionDenied:   `PERMISSION_DENIED`,
-	trace.StatusCodeResourceExhausted:  `RESOURCE_EXHAUSTED`,
-	trace.StatusCodeFailedPrecondition: `FAILED_PRECONDITION`,
-	trace.StatusCodeAborted:            `ABORTED`,
-	trace.StatusCodeOutOfRange:         `OUT_OF_RANGE`,
-	trace.StatusCodeUnimplemented:      `UNIMPLEMENTED`,
-	trace.StatusCodeInternal:           `INTERNAL`,
-	trace.StatusCodeUnavailable:        `UNAVAILABLE`,
-	trace.StatusCodeDataLoss:           `DATA_LOSS`,
-	trace.StatusCodeUnauthenticated:    `UNAUTHENTICATED`,
-}
-
-func isHealthEndpoint(path string) bool {
-	// Health checking is pretty frequent and
-	// traces collected for health endpoints
-	// can be extremely noisy and expensive.
-	// Disable canonical health checking endpoints
-	// like /healthz and /_ah/health for now.
-	if path == "/healthz" || path == "/_ah/health" {
-		return true
-	}
-	return false
-}

vendor/go.opencensus.io/resource/resource.go

-// Copyright 2018, OpenCensus 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 resource provides functionality for resource, which capture
-// identifying information about the entities for which signals are exported.
-package resource
-
-import (
-	"context"
-	"fmt"
-	"os"
-	"regexp"
-	"sort"
-	"strconv"
-	"strings"
-)
-
-// Environment variables used by FromEnv to decode a resource.
-const (
-	EnvVarType   = "OC_RESOURCE_TYPE"
-	EnvVarLabels = "OC_RESOURCE_LABELS"
-)
-
-// Resource describes an entity about which identifying information and metadata is exposed.
-// For example, a type "k8s.io/container" may hold labels describing the pod name and namespace.
-type Resource struct {
-	Type   string
-	Labels map[string]string
-}
-
-// EncodeLabels encodes a labels map to a string as provided via the OC_RESOURCE_LABELS environment variable.
-func EncodeLabels(labels map[string]string) string {
-	sortedKeys := make([]string, 0, len(labels))
-	for k := range labels {
-		sortedKeys = append(sortedKeys, k)
-	}
-	sort.Strings(sortedKeys)
-
-	s := ""
-	for i, k := range sortedKeys {
-		if i > 0 {
-			s += ","
-		}
-		s += k + "=" + strconv.Quote(labels[k])
-	}
-	return s
-}
-
-var labelRegex = regexp.MustCompile(`^\s*([[:ascii:]]{1,256}?)=("[[:ascii:]]{0,256}?")\s*,`)
-
-// DecodeLabels decodes a serialized label map as used in the OC_RESOURCE_LABELS variable.
-// A list of labels of the form `<key1>="<value1>",<key2>="<value2>",...` is accepted.
-// Domain names and paths are accepted as label keys.
-// Most users will want to use FromEnv instead.
-func DecodeLabels(s string) (map[string]string, error) {
-	m := map[string]string{}
-	// Ensure a trailing comma, which allows us to keep the regex simpler
-	s = strings.TrimRight(strings.TrimSpace(s), ",") + ","
-
-	for len(s) > 0 {
-		match := labelRegex.FindStringSubmatch(s)
-		if len(match) == 0 {
-			return nil, fmt.Errorf("invalid label formatting, remainder: %s", s)
-		}
-		v := match[2]
-		if v == "" {
-			v = match[3]
-		} else {
-			var err error
-			if v, err = strconv.Unquote(v); err != nil {
-				return nil, fmt.Errorf("invalid label formatting, remainder: %s, err: %s", s, err)
-			}
-		}
-		m[match[1]] = v
-
-		s = s[len(match[0]):]
-	}
-	return m, nil
-}
-
-// FromEnv is a detector that loads resource information from the OC_RESOURCE_TYPE
-// and OC_RESOURCE_labelS environment variables.
-func FromEnv(context.Context) (*Resource, error) {
-	res := &Resource{
-		Type: strings.TrimSpace(os.Getenv(EnvVarType)),
-	}
-	labels := strings.TrimSpace(os.Getenv(EnvVarLabels))
-	if labels == "" {
-		return res, nil
-	}
-	var err error
-	if res.Labels, err = DecodeLabels(labels); err != nil {
-		return nil, err
-	}
-	return res, nil
-}
-
-var _ Detector = FromEnv
-
-// merge resource information from b into a. In case of a collision, a takes precedence.
-func merge(a, b *Resource) *Resource {
-	if a == nil {
-		return b
-	}
-	if b == nil {
-		return a
-	}
-	res := &Resource{
-		Type:   a.Type,
-		Labels: map[string]string{},
-	}
-	if res.Type == "" {
-		res.Type = b.Type
-	}
-	for k, v := range b.Labels {
-		res.Labels[k] = v
-	}
-	// Labels from resource a overwrite labels from resource b.
-	for k, v := range a.Labels {
-		res.Labels[k] = v
-	}
-	return res
-}
-
-// Detector attempts to detect resource information.
-// If the detector cannot find resource information, the returned resource is nil but no
-// error is returned.
-// An error is only returned on unexpected failures.
-type Detector func(context.Context) (*Resource, error)
-
-// MultiDetector returns a Detector that calls all input detectors in order and
-// merges each result with the previous one. In case a type of label key is already set,
-// the first set value is takes precedence.
-// It returns on the first error that a sub-detector encounters.
-func MultiDetector(detectors ...Detector) Detector {
-	return func(ctx context.Context) (*Resource, error) {
-		return detectAll(ctx, detectors...)
-	}
-}
-
-// detectall calls all input detectors sequentially an merges each result with the previous one.
-// It returns on the first error that a sub-detector encounters.
-func detectAll(ctx context.Context, detectors ...Detector) (*Resource, error) {
-	var res *Resource
-	for _, d := range detectors {
-		r, err := d(ctx)
-		if err != nil {
-			return nil, err
-		}
-		res = merge(res, r)
-	}
-	return res, nil
-}

vendor/go.opencensus.io/stats/doc.go

-// Copyright 2017, OpenCensus 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 stats contains support for OpenCensus stats recording.
-
-OpenCensus allows users to create typed measures, record measurements,
-aggregate the collected data, and export the aggregated data.
-
-Measures
-
-A measure represents a type of data point to be tracked and recorded.
-For example, latency, request Mb/s, and response Mb/s are measures
-to collect from a server.
-
-Measure constructors such as Int64 and Float64 automatically
-register the measure by the given name. Each registered measure needs
-to be unique by name. Measures also have a description and a unit.
-
-Libraries can define and export measures. Application authors can then
-create views and collect and break down measures by the tags they are
-interested in.
-
-Recording measurements
-
-Measurement is a data point to be collected for a measure. For example,
-for a latency (ms) measure, 100 is a measurement that represents a 100ms
-latency event. Measurements are created from measures with
-the current context. Tags from the current context are recorded with the
-measurements if they are any.
-
-Recorded measurements are dropped immediately if no views are registered for them.
-There is usually no need to conditionally enable and disable
-recording to reduce cost. Recording of measurements is cheap.
-
-Libraries can always record measurements, and applications can later decide
-on which measurements they want to collect by registering views. This allows
-libraries to turn on the instrumentation by default.
-
-Exemplars
-
-For a given recorded measurement, the associated exemplar is a diagnostic map
-that gives more information about the measurement.
-
-When aggregated using a Distribution aggregation, an exemplar is kept for each
-bucket in the Distribution. This allows you to easily find an example of a
-measurement that fell into each bucket.
-
-For example, if you also use the OpenCensus trace package and you
-record a measurement with a context that contains a sampled trace span,
-then the trace span will be added to the exemplar associated with the measurement.
-
-When exported to a supporting back end, you should be able to easily navigate
-to example traces that fell into each bucket in the Distribution.
-
-*/
-package stats // import "go.opencensus.io/stats"

vendor/go.opencensus.io/stats/measure.go

-// Copyright 2017, OpenCensus 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 stats
-
-import (
-	"sync"
-	"sync/atomic"
-)
-
-// Measure represents a single numeric value to be tracked and recorded.
-// For example, latency, request bytes, and response bytes could be measures
-// to collect from a server.
-//
-// Measures by themselves have no outside effects. In order to be exported,
-// the measure needs to be used in a View. If no Views are defined over a
-// measure, there is very little cost in recording it.
-type Measure interface {
-	// Name returns the name of this measure.
-	//
-	// Measure names are globally unique (among all libraries linked into your program).
-	// We recommend prefixing the measure name with a domain name relevant to your
-	// project or application.
-	//
-	// Measure names are never sent over the wire or exported to backends.
-	// They are only used to create Views.
-	Name() string
-
-	// Description returns the human-readable description of this measure.
-	Description() string
-
-	// Unit returns the units for the values this measure takes on.
-	//
-	// Units are encoded according to the case-sensitive abbreviations from the
-	// Unified Code for Units of Measure: http://unitsofmeasure.org/ucum.html
-	Unit() string
-}
-
-// measureDescriptor is the untyped descriptor associated with each measure.
-// Int64Measure and Float64Measure wrap measureDescriptor to provide typed
-// recording APIs.
-// Two Measures with the same name will have the same measureDescriptor.
-type measureDescriptor struct {
-	subs int32 // access atomically
-
-	name        string
-	description string
-	unit        string
-}
-
-func (m *measureDescriptor) subscribe() {
-	atomic.StoreInt32(&m.subs, 1)
-}
-
-func (m *measureDescriptor) subscribed() bool {
-	return atomic.LoadInt32(&m.subs) == 1
-}
-
-var (
-	mu       sync.RWMutex
-	measures = make(map[string]*measureDescriptor)
-)
-
-func registerMeasureHandle(name, desc, unit string) *measureDescriptor {
-	mu.Lock()
-	defer mu.Unlock()
-
-	if stored, ok := measures[name]; ok {
-		return stored
-	}
-	m := &measureDescriptor{
-		name:        name,
-		description: desc,
-		unit:        unit,
-	}
-	measures[name] = m
-	return m
-}
-
-// Measurement is the numeric value measured when recording stats. Each measure
-// provides methods to create measurements of their kind. For example, Int64Measure
-// provides M to convert an int64 into a measurement.
-type Measurement struct {
-	v    float64
-	m    Measure
-	desc *measureDescriptor
-}
-
-// Value returns the value of the Measurement as a float64.
-func (m Measurement) Value() float64 {
-	return m.v
-}
-
-// Measure returns the Measure from which this Measurement was created.
-func (m Measurement) Measure() Measure {
-	return m.m
-}

vendor/go.opencensus.io/stats/measure_float64.go

-// Copyright 2017, OpenCensus 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 stats
-
-// Float64Measure is a measure for float64 values.
-type Float64Measure struct {
-	desc *measureDescriptor
-}
-
-// M creates a new float64 measurement.
-// Use Record to record measurements.
-func (m *Float64Measure) M(v float64) Measurement {
-	return Measurement{
-		m:    m,
-		desc: m.desc,
-		v:    v,
-	}
-}
-
-// Float64 creates a new measure for float64 values.
-//
-// See the documentation for interface Measure for more guidance on the
-// parameters of this function.
-func Float64(name, description, unit string) *Float64Measure {
-	mi := registerMeasureHandle(name, description, unit)
-	return &Float64Measure{mi}
-}
-
-// Name returns the name of the measure.
-func (m *Float64Measure) Name() string {
-	return m.desc.name
-}
-
-// Description returns the description of the measure.
-func (m *Float64Measure) Description() string {
-	return m.desc.description
-}
-
-// Unit returns the unit of the measure.
-func (m *Float64Measure) Unit() string {
-	return m.desc.unit
-}