diff --git a/README.md b/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..3953f95490ae62b32b689ab549e51baeab5fac4e
--- /dev/null
+++ b/README.md
@@ -0,0 +1,179 @@
+# pqlog
+
+*pqlog* is an indexing and retrieval service for structured and
+unstructured logs (e.g. *syslog* and more). Its primary capability is
+its ability to *scale down* for small installations, using very few
+resources while maintaining a certain level of usefulness, offering an
+alternative to heavyweight stacks like ELK in this scenario.
+
+## Overview
+
+The system's functionality is split into two parts:
+
+* *Ingestion* (or *indexing*), processing incoming logs and writing
+ them to log storage;
+* *Query*, the ability to interrogate the log storage analytically.
+
+### Ingestion
+
+Ingestion presents an interface for external clients (syslog daemons,
+fluentd, *etc*) to send logs for indexing, in batches. Incoming log
+entries are converted to a unified "flattened" schema.
+
+The flattened schema maps structured attributes to a flat, one-level
+structure by using their paths (dot-separated) as field names. As an
+example, an input record such as:
+
+```json
+{
+ "a": {
+ "foo": "bar",
+ "baz": "arg"
+ },
+ "b": 42
+}
+```
+
+would get internally converted to a "flat" structure like the following:
+
+```json
+{
+ "a.foo": "bar",
+ "a.baz": "arg",
+ "b": 42
+}
+```
+
+So, when querying the database, one should refer to the *foo* field as
+*a.foo*.
+
+The flattened schema supports lists of scalar values (numbers,
+strings), but it does not support nesting structures within lists, as
+it would not know how to unroll them. For instance, the following
+record has a problem:
+
+```json
+{
+ "a": [
+ {
+ "foo": "bar"
+ },
+ {
+ "baz": "arg"
+ }
+ ]
+}
+```
+
+In this situation the ingestion stage will just ignore the problematic
+field (*a* in the above example).
+
+The flattening is ultimately necessary because of an implementation
+detail: the underlying query engine (DuckDB), although it fully
+supports structured schemas, can have trouble reconciling different
+STRUCTs across different Parquet files. But it's a TODO to get rid of
+this limitation.
+
+The flattened records are then written to [Parquet]() files, which are
+rotated periodically (and when they reach a certain size). These files
+can be stored remotely, although the current implementation only
+supports local filesystem.
+
+The ingestion API endpoint is at */ingest*, and it expects a POST
+request with a ND-JSON request body: newline-delimited JSON-encoded
+records, no additional headers or footers.
+
+### Schema unification
+
+As it ingests records, *pqlog* learns the data types of the incoming
+attributes, determining an aggregate schema for all the records. Since
+in the "flat" schema all nodes are leafs, it knows about the following
+fundamental data types:
+
+* `STRING`
+* `NUMBER`
+* `TIMESTAMP` is a RFC3339-formatted string
+* `LIST` is just a repeated `STRING`
+
+The mere existence of an aggregate schema, necessary in order to query
+the data, imposes some restrictions on the structure of the data. It
+is not after all unreasonable to expect the data to have some level of
+consistency, if you want to be able to query it in aggregate.
+
+When the schema detector finds conflicting data types for a field, it
+will try to promote them to a common type where possible, handling
+common cases such as STRING / NUMBER conflicts by upgrading the values
+to STRING. But where such type promotions aren't possible, the
+problematic field will be dropped from the schema.
+
+### Querying
+
+The query engine is [DuckDB](https://duckdb.org), which can just [read
+the Parquet files, even remotely]() and run fast analytical queries on
+them.
+
+One thing of note is that, in the current implementation, it is only
+possible to query fully written Parquet files. The implication is that
+you won't see logs until the ingestion server decides it's time to
+finalize the current Parquet file. For this reason, it might be
+sensible to set the *--rotation-interval* option to a few minutes.
+
+The query API is at */query* and it takes a full SQL query as the *q*
+parameter. The response will be JSON-encoded. Since the table to query
+is created on-the-fly with every request, its name is not known in
+advance to the caller: the SQL query should contain the placeholder
+`$table`, which will be replaced at execution time with the name of
+the temporary table to use.
+
+## Running
+
+The service ships as a single binary, *pqlogd*.
+
+From an operational perspective, the two components of the service
+(ingestion and query) can be run independently, and are controlled by
+the command-line options *--enable-ingest* and *--enable-query*,
+respectively. In all cases, the server will listen on the HTTP address
+specified by *--addr*.
+
+### Ingestion service
+
+The ingestion service needs to know where to store its output. This is
+controlled by the *--dir* command-line option, which currently only
+accepts a local path (S3 support TODO).
+
+Log files be written in this directory, rotated every
+*--rotation-interval*.
+
+The schema detector works better if it can persist its internal state
+and recover it on startup: to make it do so, specify the
+*--state-file* option.
+
+An example:
+
+```
+$ pqlogd --dir ./data --enable-ingest --addr :3000 &
+$ curl -s -XPOST --data-binary '{"a": "foo", "b": 42}' http://localhost:3000/ingest
+$ kill %1 # Causes the Parquet files to be finalized
+```
+
+### Query service
+
+The query service also needs to know where the Parquet data files are
+located, with the *--dir* option.
+
+Continuing the example above:
+
+```
+$ pqlogd --dir ./data --enable-query --addr :3001 &
+$ curl -s -XPOST -d "q=SELECT COUNT(*) AS c FROM \$table WHERE a='foo'" http://localhost:3001/query
+[{"c": 1}]
+```
+
+### Debugging
+
+The server offers some debugging endpoints which might be useful to
+understand what it is doing:
+
+* */schema* will return the current schema in JSON format
+* */debug/schema* will return a human-readable dump of the internal
+ state of the schema guesser
diff --git a/cmd/pqlogd/main.go b/cmd/pqlogd/main.go
index 98fa7f99d13443c30ce407814e46bd21442710c4..3d0efdefb9d823743cb0539c0931fb4efa7da319 100644
--- a/cmd/pqlogd/main.go
+++ b/cmd/pqlogd/main.go
@@ -49,7 +49,7 @@ func main() {
log.Fatal(err)
}
- w := writer.NewRotating(pathGen, *rotationInterval)
+ w := writer.NewRotating(writer.NewLocalSource(), pathGen, *rotationInterval)
defer w.Close()
isrv := pqhttp.NewIngest(w, *stateFile)
diff --git a/http/ingest.go b/http/ingest.go
index 5e874d86669d3f65294b3511fef94bc613a8aff3..98821661581532d2b194a103b053c2d89d99ea5c 100644
--- a/http/ingest.go
+++ b/http/ingest.go
@@ -6,7 +6,6 @@ import (
"io"
"log"
"net/http"
- "strings"
"sync"
"git.autistici.org/ai3/attic/pqlog/schema"
@@ -105,7 +104,7 @@ func (s *IngestServer) ingestBatch(r io.Reader) (int, error) {
s.numSchemaChanges++
s.schema = s.guesser.NewSchema()
s.pschema = s.schema.ParquetSchemaHandler()
- if err := s.writer.Reopen(s.pschema.SchemaHandler); err != nil {
+ if err := s.writer.Reopen(s.pschema); err != nil {
return 0, err
}
if s.stateFile != "" {
@@ -130,10 +129,6 @@ func (s *IngestServer) IngestHandler(w http.ResponseWriter, req *http.Request) {
http.Error(w, "Bad method", http.StatusMethodNotAllowed)
return
}
- if !strings.HasPrefix(req.Header.Get("Content-Type"), "application/json") {
- http.Error(w, "Bad Content-Type", http.StatusBadRequest)
- return
- }
n, err := s.ingestBatch(req.Body)
if err != nil {
@@ -160,12 +155,9 @@ func (s *IngestServer) DebugHandler(w http.ResponseWriter, req *http.Request) {
func (s *IngestServer) SchemaHandler(w http.ResponseWriter, req *http.Request) {
s.mx.Lock()
- out := struct {
- Version int64 `json:"version"`
- Fields map[string]string `json:"fields"`
- }{
- Version: s.schema.Version,
- Fields: s.schema.Debug(),
+ var out *schema.SchemaDebugInfo
+ if s.schema != nil {
+ out = s.schema.Debug()
}
s.mx.Unlock()
diff --git a/http/query.go b/http/query.go
index b614ed0d2da35dcf4d743e986f8f7def186f8fde..555133615e64ec9ee92abc80ca19ca750766ad79 100644
--- a/http/query.go
+++ b/http/query.go
@@ -1,12 +1,14 @@
package pqhttp
import (
+ "bufio"
"context"
"database/sql"
"encoding/json"
"errors"
"fmt"
"io"
+ "log"
"math/rand"
"net/http"
"path/filepath"
@@ -45,18 +47,18 @@ func (q *QueryServer) Close() {
}
func (q *QueryServer) runQuery(ctx context.Context, w io.Writer, query string) error {
- table := fmt.Sprintf("logs-%08x", rand.Int63())
+ table := fmt.Sprintf("logs%08x", rand.Int63())
query = strings.Replace(query, "$table", table, -1)
tx, err := q.db.BeginTx(ctx, nil)
if err != nil {
- return err
+ return fmt.Errorf("failed to create transaction: %w", err)
}
defer tx.Rollback()
_, err = tx.Exec(fmt.Sprintf("CREATE VIEW %s AS SELECT * FROM read_parquet('%s', union_by_name=true)", table, q.glob))
if err != nil {
- return err
+ return fmt.Errorf("failed to create DuckDB view: %w", err)
}
defer func() {
// Well, ok, we have the Rollback() but.
@@ -67,30 +69,41 @@ func (q *QueryServer) runQuery(ctx context.Context, w io.Writer, query string) e
rows, err := tx.Query(query)
if err != nil {
// Report this as a client-originated error.
- return newQueryError(err)
+ return newQueryError(fmt.Errorf("query execution error: %w", err))
}
defer rows.Close()
- io.WriteString(w, "{\"status\":\"ok\",\"results\":[")
+ bw := bufio.NewWriter(w)
+
+ _, _ = io.WriteString(bw, "{\"status\":\"ok\",\"results\":[")
cols, _ := rows.ColumnTypes()
+ first := true
for rows.Next() {
+ if first {
+ first = false
+ } else {
+ _, _ = io.WriteString(bw, ",")
+ }
+
values := make([]any, len(cols))
for i := 0; i < len(cols); i++ {
- values[i] = reflect.Zero(cols[i].ScanType()).Interface()
+ value := reflect.Zero(cols[i].ScanType()).Interface()
+ values[i] = &value
}
if err := rows.Scan(values...); err != nil {
- return err
+ return fmt.Errorf("Scan error: %w", err)
}
row := make(map[string]any, len(cols))
for i := 0; i < len(cols); i++ {
row[cols[i].Name()] = values[i]
}
- if err := json.NewEncoder(w).Encode(row); err != nil {
- return err
+ if err := json.NewEncoder(bw).Encode(row); err != nil {
+ return fmt.Errorf("JSON encode error: %w", err)
}
- io.WriteString(w, ",\n")
}
- io.WriteString(w, "]}\n")
+ _, _ = io.WriteString(bw, "]}\n")
+
+ bw.Flush()
return rows.Err()
}
@@ -115,6 +128,7 @@ func (q *QueryServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
if errors.Is(err, &queryError{}) {
status = http.StatusBadRequest
}
+ log.Printf("query error: %v", err)
http.Error(w, err.Error(), status)
}
}
diff --git a/schema/parquet.go b/schema/parquet.go
index 4ed5189c526fae66532246afaef8ac94ffdf37d7..cb2149f1555656510eeb8e036818f657300719ec 100644
--- a/schema/parquet.go
+++ b/schema/parquet.go
@@ -92,7 +92,7 @@ func (s *Schema) ParquetSchemaHandler() *ParquetSchemaHandler {
func (s *ParquetSchemaHandler) TuplesToRow(tuples []Tuple) []any {
row := make([]any, s.numFields)
- copy(row, s.zeros)
+ //copy(row, s.zeros)
for _, t := range tuples {
idx := s.fieldIndexMap[t.key]
value := t.value
@@ -103,3 +103,7 @@ func (s *ParquetSchemaHandler) TuplesToRow(tuples []Tuple) []any {
}
return row
}
+
+func (s *ParquetSchemaHandler) Zero(i int) any {
+ return s.zeros[i]
+}
diff --git a/schema/schema.go b/schema/schema.go
index 031f2b56db700cc52cb144e85d213522ecb11068..64d0da042dd2fb16dc92bf7c4b4950485d052587 100644
--- a/schema/schema.go
+++ b/schema/schema.go
@@ -135,26 +135,6 @@ func (g typeGuesser) datatype() (Type, upcastFunc, bool) {
return t, nil, true
}
-func (g typeGuesser) debugState() ColumnDebugState {
- var n int
- var ds ColumnDebugState
- for i := 0; i < maxTypeBits; i++ {
- j := Type(1 << i)
- if g.isSet(j) {
- n++
- ds.Types = append(ds.Types, j.String())
- }
- }
- if n > 1 {
- s := "type conflict"
- if up, _, ok := g.supportedUpcast(); ok {
- s = fmt.Sprintf("upcast to %s", up.String())
- }
- ds.Notes = s
- }
- return ds
-}
-
// The Guesser keeps track of the columns we see (after
// flattening the input) and their associated data types, and infers a
// schema over time, to the extent where it is possible to do so.
@@ -220,32 +200,6 @@ func (g *Guesser) Save(path string) error {
return json.NewEncoder(f).Encode(&sg)
}
-// ColumnDebugState holds information about a specific column.
-type ColumnDebugState struct {
- Types []string `json:"types"`
- Notes string `json:"notes,omitempty"`
-}
-
-// GuesserDebugState represents the state of the Guesser in human-readable form.
-type GuesserDebugState struct {
- Columns map[string]ColumnDebugState `json:"fields"`
- Errors map[string]string `json:"errors,omitempty"`
-}
-
-func (g *Guesser) Debug() *GuesserDebugState {
- state := GuesserDebugState{
- Columns: make(map[string]ColumnDebugState),
- Errors: make(map[string]string),
- }
- for name, col := range g.columns {
- state.Columns[name] = col.debugState()
- }
- for name, err := range g.errors {
- state.Errors[name] = err
- }
- return &state
-}
-
// This structure holds the inferred schema of the datastream at a
// specific point in time.
type Schema struct {
@@ -254,15 +208,6 @@ type Schema struct {
upcast map[string]upcastFunc
}
-// Debug returns a map representation of the schema.
-func (s *Schema) Debug() map[string]string {
- deb := make(map[string]string)
- for name, col := range s.columns {
- deb[name] = col.String()
- }
- return deb
-}
-
// GetSchema returns the best possible version of a schema given our
// current data type guesses.
func (g *Guesser) NewSchema() *Schema {
diff --git a/schema/schema_debug.go b/schema/schema_debug.go
new file mode 100644
index 0000000000000000000000000000000000000000..d12d452f26d5d2537cc1a5fe0f6ebefcb6d22821
--- /dev/null
+++ b/schema/schema_debug.go
@@ -0,0 +1,73 @@
+package schema
+
+import "fmt"
+
+func (g typeGuesser) debugState() ColumnDebugState {
+ var n int
+ var ds ColumnDebugState
+ for i := 0; i < maxTypeBits; i++ {
+ j := Type(1 << i)
+ if g.isSet(j) {
+ n++
+ ds.Types = append(ds.Types, j.String())
+ }
+ }
+ if n > 1 {
+ s := "type conflict"
+ if up, _, ok := g.supportedUpcast(); ok {
+ s = fmt.Sprintf("upcast to %s", up.String())
+ }
+ ds.Notes = s
+ }
+ return ds
+}
+
+// ColumnDebugState holds information about a specific column.
+type ColumnDebugState struct {
+ Types []string `json:"types"`
+ Notes string `json:"notes,omitempty"`
+}
+
+// GuesserDebugState represents the state of the Guesser in human-readable form.
+type GuesserDebugState struct {
+ Columns map[string]ColumnDebugState `json:"fields"`
+ Errors map[string]string `json:"errors,omitempty"`
+}
+
+// Debug returns information on the Guesser internals.
+func (g *Guesser) Debug() *GuesserDebugState {
+ state := GuesserDebugState{
+ Columns: make(map[string]ColumnDebugState),
+ Errors: make(map[string]string),
+ }
+ for name, col := range g.columns {
+ state.Columns[name] = col.debugState()
+ }
+ for name, err := range g.errors {
+ state.Errors[name] = err
+ }
+ return &state
+}
+
+type SchemaFieldDebugInfo struct {
+ Name string `json:"name"`
+ Type string `json:"type"`
+}
+
+type SchemaDebugInfo struct {
+ Version int64 `json:"version"`
+ Fields []SchemaFieldDebugInfo `json:"fields"`
+}
+
+// Debug returns a human-friendly representation of the schema.
+func (s *Schema) Debug() *SchemaDebugInfo {
+ var info SchemaDebugInfo
+ info.Version = s.Version
+ for name, col := range s.columns {
+ info.Fields = append(info.Fields, SchemaFieldDebugInfo{
+ Name: name,
+ Type: col.String(),
+ })
+ }
+ return &info
+}
diff --git a/writer/marshal.go b/writer/marshal.go
index 726b8046c23f63cb4a9cbca1205fd70f867b482d..13b765e541f17c480641a205a94adf6505eadc8a 100644
--- a/writer/marshal.go
+++ b/writer/marshal.go
@@ -1,6 +1,7 @@
package writer
import (
+ "git.autistici.org/ai3/attic/pqlog/schema"
"github.com/xitongsys/parquet-go/common"
"github.com/xitongsys/parquet-go/layout"
"github.com/xitongsys/parquet-go/parquet"
@@ -31,13 +32,13 @@ import (
// reason NewSchemaHandlerFromSchemaHandler (which gets called in that
// case) is not 'transparent' and returns something different than the
// original schema...
-func newTuplesWriter(schemaHandler *pqschema.SchemaHandler, pfile source.ParquetFile, np int64) (*pqwriter.ParquetWriter, error) {
+func newTuplesWriter(schemaHandler *schema.ParquetSchemaHandler, pfile source.ParquetFile, np int64) (*pqwriter.ParquetWriter, error) {
res := new(pqwriter.ParquetWriter)
- res.SchemaHandler = schemaHandler
+ res.SchemaHandler = schemaHandler.SchemaHandler
res.PFile = pfile
- res.PageSize = 8 * 1024 //8K
- res.RowGroupSize = 128 * 1024 * 1024 //128M
- res.CompressionType = parquet.CompressionCodec_SNAPPY
+ res.PageSize = 8 * 1024 //8K
+ res.RowGroupSize = 32 * 1024 * 1024 //32M
+ res.CompressionType = parquet.CompressionCodec_ZSTD
res.PagesMapBuf = make(map[string][]*layout.Page)
res.DictRecs = make(map[string]*layout.DictRecType)
res.NP = np
@@ -46,75 +47,88 @@ func newTuplesWriter(schemaHandler *pqschema.SchemaHandler, pfile source.Parquet
res.Footer.Schema = append(res.Footer.Schema, res.SchemaHandler.SchemaElements...)
res.Offset = 4
_, err := res.PFile.Write([]byte("PAR1"))
- res.MarshalFunc = marshalTuples
+ res.MarshalFunc = genMarshalTuples(schemaHandler)
return res, err
}
// marshalTuples is the Parquet marshaler for the tuplesToRow() format.
-func marshalTuples(records []interface{}, schemaHandler *pqschema.SchemaHandler) (*map[string]*layout.Table, error) {
- res := make(map[string]*layout.Table)
- if ln := len(records); ln <= 0 {
- return &res, nil
- }
+func genMarshalTuples(pschema *schema.ParquetSchemaHandler) func([]interface{}, *pqschema.SchemaHandler) (*map[string]*layout.Table, error) {
+ return func(records []interface{}, schemaHandler *pqschema.SchemaHandler) (*map[string]*layout.Table, error) {
+ res := make(map[string]*layout.Table)
+ if ln := len(records); ln <= 0 {
+ return &res, nil
+ }
- // Iterate over columns.
- for i := 0; i < len(records[0].([]interface{})); i++ {
- pathStr := schemaHandler.GetRootInName() + common.PAR_GO_PATH_DELIMITER + schemaHandler.Infos[i+1].InName
- table := layout.NewEmptyTable()
- res[pathStr] = table
- table.Path = common.StrToPath(pathStr)
+ // Iterate over columns.
+ for i := 0; i < len(records[0].([]interface{})); i++ {
+ pathStr := schemaHandler.GetRootInName() + common.PAR_GO_PATH_DELIMITER + schemaHandler.Infos[i+1].InName
+ table := layout.NewEmptyTable()
+ res[pathStr] = table
+ table.Path = common.StrToPath(pathStr)
- schema := schemaHandler.SchemaElements[schemaHandler.MapIndex[pathStr]]
- isOptional := true
- if *schema.RepetitionType != parquet.FieldRepetitionType_OPTIONAL {
- isOptional = false
- }
+ schema := schemaHandler.SchemaElements[schemaHandler.MapIndex[pathStr]]
- if isOptional {
- table.MaxDefinitionLevel = 1
- } else {
- table.MaxDefinitionLevel = 0
- }
+ table.MaxDefinitionLevel, _ = schemaHandler.MaxDefinitionLevel(table.Path)
+ table.MaxRepetitionLevel, _ = schemaHandler.MaxRepetitionLevel(table.Path)
+ table.RepetitionType = schema.GetRepetitionType()
+ table.Schema = schemaHandler.SchemaElements[schemaHandler.MapIndex[pathStr]]
+ table.Info = schemaHandler.Infos[i+1]
+ // Pre-allocate these arrays for efficiency
+ table.Values = make([]interface{}, 0, len(records))
+ table.RepetitionLevels = make([]int32, 0, len(records))
+ table.DefinitionLevels = make([]int32, 0, len(records))
- table.MaxRepetitionLevel = 0
- table.RepetitionType = parquet.FieldRepetitionType_OPTIONAL
- table.Schema = schemaHandler.SchemaElements[schemaHandler.MapIndex[pathStr]]
- table.Info = schemaHandler.Infos[i+1]
- // Pre-allocate these arrays for efficiency
- table.Values = make([]interface{}, 0, len(records))
- table.RepetitionLevels = make([]int32, 0, len(records))
- table.DefinitionLevels = make([]int32, 0, len(records))
+ //log.Printf("table %s: max_dl=%d, max_rl=%d", pathStr, table.MaxDefinitionLevel, table.MaxRepetitionLevel)
- // Iterate over records.
- for j := 0; j < len(records); j++ {
- var val any
- if rec := records[j].([]interface{})[i]; rec != nil {
- //val = types.InterfaceToParquetType(rec, table.Schema.Type)
- val = rec
- }
- switch tval := val.(type) {
- case []any:
- // "Unroll" lists into repeated string values.
- var rl int32
- if len(tval) < 1 {
- tval = []any{""}
- }
- for _, lval := range tval {
- table.Values = append(table.Values, lval)
- table.DefinitionLevels = append(table.DefinitionLevels, 1)
- table.RepetitionLevels = append(table.RepetitionLevels, rl)
- rl++
- }
- default:
- table.Values = append(table.Values, val)
- table.RepetitionLevels = append(table.RepetitionLevels, 0)
- if val == nil || !isOptional {
- table.DefinitionLevels = append(table.DefinitionLevels, 0)
+ // Iterate over records.
+ var dl int32 = 1
+ var rl int32 = 0
+ for j := 0; j < len(records); j++ {
+ val := records[j].([]interface{})[i]
+
+ if val == nil {
+ encodeNil(table, pschema.Zero(i), dl, rl)
} else {
- table.DefinitionLevels = append(table.DefinitionLevels, 1)
+ encode(table, val, dl, rl)
}
}
}
+ return &res, nil
+ }
+}
+
+func encode(table *layout.Table, value any, dl, rl int32) {
+ switch tvalue := value.(type) {
+ case []any:
+ encodeSlice(table, tvalue, dl, rl)
+ default:
+ encodeValue(table, value, dl, rl)
+ }
+}
+
+func encodeValue(table *layout.Table, value any, dl, rl int32) {
+ //value = types.InterfaceToParquetType(value, table.Schema.Type)
+ table.Values = append(table.Values, value)
+ table.DefinitionLevels = append(table.DefinitionLevels, dl)
+ table.RepetitionLevels = append(table.RepetitionLevels, rl)
+}
+
+func encodeNil(table *layout.Table, value any, dl, rl int32) {
+ table.Values = append(table.Values, value)
+ table.DefinitionLevels = append(table.DefinitionLevels, dl-1)
+ table.RepetitionLevels = append(table.RepetitionLevels, rl)
+}
+
+func encodeSlice(table *layout.Table, l []any, dl, rl int32) {
+ if len(l) == 0 {
+ encode(table, nil, dl, rl)
+ return
+ }
+ for i := 0; i < len(l); i++ {
+ var nodeRL = rl + 1
+ if i == 0 {
+ nodeRL = rl
+ }
+ encodeValue(table, l[i], dl, nodeRL)
}
- return &res, nil
}
diff --git a/writer/source.go b/writer/source.go
new file mode 100644
index 0000000000000000000000000000000000000000..b449dfcfd2d308319d66b889593a3e804d36f826
--- /dev/null
+++ b/writer/source.go
@@ -0,0 +1,27 @@
+package writer
+
+import (
+ "os"
+
+ "github.com/xitongsys/parquet-go-source/local"
+ "github.com/xitongsys/parquet-go/source"
+)
+
+type Source interface {
+ Create(string) (source.ParquetFile, error)
+ Rename(string, string) error
+}
+
+type localSource struct{}
+
+func NewLocalSource() Source {
+ return new(localSource)
+}
+
+func (l *localSource) Create(path string) (source.ParquetFile, error) {
+ return local.NewLocalFileWriter(path)
+}
+
+func (l *localSource) Rename(old, new string) error {
+ return os.Rename(old, new)
+}
diff --git a/writer/writer.go b/writer/writer.go
index 223338a71b1e31355a83dccfd3c88563e4bc89c3..fdc8173efab55bb30863e35350af64792174407a 100644
--- a/writer/writer.go
+++ b/writer/writer.go
@@ -5,16 +5,15 @@ import (
"log"
"time"
+ "git.autistici.org/ai3/attic/pqlog/schema"
"git.autistici.org/ai3/attic/pqlog/writer/pathgen"
- "github.com/xitongsys/parquet-go-source/local"
- pqschema "github.com/xitongsys/parquet-go/schema"
"github.com/xitongsys/parquet-go/source"
pqwriter "github.com/xitongsys/parquet-go/writer"
)
// Writer is the interface for our restartable ParquetWriter.
type Writer interface {
- Reopen(*pqschema.SchemaHandler) error
+ Reopen(*schema.ParquetSchemaHandler) error
Write(any) error
Close()
}
@@ -23,15 +22,18 @@ type Writer interface {
// Parquet files, switching to a new one whenever the schema changes.
// It guarantees the creation of consistent Parquet files.
type ParquetWriter struct {
- pg *pathgen.Generator
+ pg *pathgen.Generator
+ src Source
- lw source.ParquetFile
- pw *pqwriter.ParquetWriter
+ lw source.ParquetFile
+ pw *pqwriter.ParquetWriter
+ renameTo string
}
-func New(pg *pathgen.Generator) *ParquetWriter {
+func New(src Source, pg *pathgen.Generator) *ParquetWriter {
return &ParquetWriter{
- pg: pg,
+ src: src,
+ pg: pg,
}
}
@@ -42,14 +44,22 @@ func (w *ParquetWriter) Write(obj any) error {
func (w *ParquetWriter) Close() {
if w.pw != nil {
w.pw.WriteStop()
+ w.pw = nil
}
if w.lw != nil {
w.lw.Close()
+ w.lw = nil
+ }
+ if w.renameTo != "" {
+ if err := w.src.Rename(w.renameTo+".tmp", w.renameTo); err != nil {
+ log.Printf("warning: could not finalize parquet file %s: %v", w.renameTo, err)
+ }
+ w.renameTo = ""
}
}
// (Re)open the output with a new schema.
-func (w *ParquetWriter) Reopen(schemaHandler *pqschema.SchemaHandler) error {
+func (w *ParquetWriter) Reopen(schemaHandler *schema.ParquetSchemaHandler) error {
w.Close()
path, err := w.pg.Next()
@@ -59,10 +69,11 @@ func (w *ParquetWriter) Reopen(schemaHandler *pqschema.SchemaHandler) error {
log.Printf("creating parquet file %s (%d fields)", path, len(schemaHandler.Infos)-1)
- w.lw, err = local.NewLocalFileWriter(path)
+ w.lw, err = w.src.Create(path + ".tmp")
if err != nil {
return fmt.Errorf("can't create Parquet file: %w", err)
}
+ w.renameTo = path
w.pw, err = newTuplesWriter(schemaHandler, w.lw, 4)
if err != nil {
@@ -71,40 +82,47 @@ func (w *ParquetWriter) Reopen(schemaHandler *pqschema.SchemaHandler) error {
return nil
}
+const maxRecordsPerFile = 1000000
+
// A RotatingParquetWriter will rotate the output file on a specific period.
type RotatingParquetWriter struct {
*ParquetWriter
+
+ counter int64
period time.Duration
deadline time.Time
- schemaHandler *pqschema.SchemaHandler
+ schemaHandler *schema.ParquetSchemaHandler
}
-func NewRotating(pg *pathgen.Generator, period time.Duration) *RotatingParquetWriter {
+func NewRotating(src Source, pg *pathgen.Generator, period time.Duration) *RotatingParquetWriter {
return &RotatingParquetWriter{
- ParquetWriter: New(pg),
+ ParquetWriter: New(src, pg),
period: period,
}
}
func (w *RotatingParquetWriter) Write(obj any) error {
now := time.Now()
+ w.counter++
- if now.After(w.deadline) {
+ if now.After(w.deadline) || w.counter > maxRecordsPerFile {
if err := w.Reopen(w.schemaHandler); err != nil {
return err
}
- // Add one minute to avoid hitting the same value.
- w.deadline = now.Add(1 * time.Minute).Round(w.period)
+ // Round to period for more accurate alignment.
+ w.deadline = now.Add(w.period).Round(w.period)
+ log.Printf("rotating output, new deadline=%v", w.deadline)
}
return w.ParquetWriter.Write(obj)
}
-func (w *RotatingParquetWriter) Reopen(schemaHandler *pqschema.SchemaHandler) error {
+func (w *RotatingParquetWriter) Reopen(schemaHandler *schema.ParquetSchemaHandler) error {
if err := w.ParquetWriter.Reopen(schemaHandler); err != nil {
return err
}
w.schemaHandler = schemaHandler
+ w.counter = 0
return nil
}