173 lines
2.7 KiB
Go
173 lines
2.7 KiB
Go
package log
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import (
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"bufio"
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"encoding/json"
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"io"
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"os"
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"strings"
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"sync"
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"time"
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"github.com/google/uuid"
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)
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// Should stream from OS
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type osLog struct {
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sync.RWMutex
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subs map[string]*osStream
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}
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type osStream struct {
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stream chan Record
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stop chan bool
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}
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// watch io stream
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func (o *osLog) run() {
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// save outputs
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stdout := *os.Stdout
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stderr := *os.Stderr
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// new os pipe
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r, w := io.Pipe()
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// create new iopipes
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r1, w1, _ := os.Pipe()
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r2, w2, _ := os.Pipe()
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// create tea readers
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tee1 := io.TeeReader(r1, &stdout)
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tee2 := io.TeeReader(r2, &stderr)
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// start copying
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go io.Copy(w, tee1)
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go io.Copy(w, tee2)
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// set default go log output
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//log.SetOutput(w2)
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// replace os stdout and os stderr
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*os.Stdout = *w1
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*os.Stderr = *w2
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// this should short circuit everything
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defer func() {
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// reset stdout and stderr
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*os.Stdout = stdout
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*os.Stderr = stderr
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//log.SetOutput(stderr)
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// close all the outputs
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r.Close()
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r1.Close()
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r2.Close()
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w.Close()
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w1.Close()
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w2.Close()
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}()
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// read from standard error
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scanner := bufio.NewReader(r)
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for {
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// read the line
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line, err := scanner.ReadString('\n')
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if err != nil {
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return
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}
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// check if the line exists
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if len(line) == 0 {
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continue
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}
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// parse the record
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var r Record
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if line[0] == '{' {
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json.Unmarshal([]byte(line), &r)
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} else {
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r = Record{
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Timestamp: time.Now(),
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Value: strings.TrimSuffix(line, "\n"),
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Metadata: make(map[string]string),
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}
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}
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o.Lock()
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// bail if there's no subscribers
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if len(o.subs) == 0 {
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o.Unlock()
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return
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}
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// check subs and send to stream
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for id, sub := range o.subs {
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// send to stream
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select {
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case <-sub.stop:
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delete(o.subs, id)
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case sub.stream <- r:
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// send to stream
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default:
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// do not block
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}
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}
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o.Unlock()
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}
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}
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// Read reads log entries from the logger
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func (o *osLog) Read(...ReadOption) ([]Record, error) {
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return []Record{}, nil
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}
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// Write writes records to log
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func (o *osLog) Write(r Record) error {
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b, _ := json.Marshal(r)
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_, err := os.Stderr.Write(b)
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return err
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}
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// Stream log records
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func (o *osLog) Stream() (Stream, error) {
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o.Lock()
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defer o.Unlock()
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// start stream watcher
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if len(o.subs) == 0 {
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go o.run()
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}
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// create stream
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st := &osStream{
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stream: make(chan Record, 128),
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stop: make(chan bool),
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}
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// save stream
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o.subs[uuid.New().String()] = st
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return st, nil
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}
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func (o *osStream) Chan() <-chan Record {
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return o.stream
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}
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func (o *osStream) Stop() error {
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select {
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case <-o.stop:
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return nil
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default:
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close(o.stop)
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}
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return nil
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}
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func NewLog(opts ...Option) Log {
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return &osLog{
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subs: make(map[string]*osStream),
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}
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}
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