gitea/modules/log/event_writer_base.go
wxiaoguang 0d54395fb5
Improve logger Pause handling (#24946)
The old EventWriter's Run does: 

```go
for {
    handlePause()
    select {
    case event <- Queue:
         write the log event ...
    }
}
```

So, if an event writer is started before the logger is paused, there is
a chance that the logger isn't paused for the first message.

The new logic is:

```go
for {
    select {
    case event <- Queue:
         handlePause()
         write the log event ...
    }
}
```

Then the event writer can be correctly paused
2023-05-27 22:35:44 +02:00

170 lines
4.0 KiB
Go

// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package log
import (
"context"
"fmt"
"io"
"regexp"
"runtime/pprof"
"time"
)
// EventWriterBase is the base interface for most event writers
// It provides default implementations for most methods
type EventWriterBase interface {
Base() *EventWriterBaseImpl
GetWriterType() string
GetWriterName() string
GetLevel() Level
Run(ctx context.Context)
}
type EventWriterBaseImpl struct {
writerType string
Name string
Mode *WriterMode
Queue chan *EventFormatted
FormatMessage EventFormatter // format the Event to a message and write it to output
OutputWriteCloser io.WriteCloser // it will be closed when the event writer is stopped
GetPauseChan func() chan struct{}
shared bool
stopped chan struct{}
}
var _ EventWriterBase = (*EventWriterBaseImpl)(nil)
func (b *EventWriterBaseImpl) Base() *EventWriterBaseImpl {
return b
}
func (b *EventWriterBaseImpl) GetWriterType() string {
return b.writerType
}
func (b *EventWriterBaseImpl) GetWriterName() string {
return b.Name
}
func (b *EventWriterBaseImpl) GetLevel() Level {
return b.Mode.Level
}
// Run is the default implementation for EventWriter.Run
func (b *EventWriterBaseImpl) Run(ctx context.Context) {
defer b.OutputWriteCloser.Close()
var exprRegexp *regexp.Regexp
if b.Mode.Expression != "" {
var err error
if exprRegexp, err = regexp.Compile(b.Mode.Expression); err != nil {
FallbackErrorf("unable to compile expression %q for writer %q: %v", b.Mode.Expression, b.Name, err)
}
}
handlePaused := func() {
if pause := b.GetPauseChan(); pause != nil {
select {
case <-pause:
case <-ctx.Done():
}
}
}
for {
select {
case <-ctx.Done():
return
case event, ok := <-b.Queue:
if !ok {
return
}
handlePaused()
if exprRegexp != nil {
fileLineCaller := fmt.Sprintf("%s:%d:%s", event.Origin.Filename, event.Origin.Line, event.Origin.Caller)
matched := exprRegexp.Match([]byte(fileLineCaller)) || exprRegexp.Match([]byte(event.Origin.MsgSimpleText))
if !matched {
continue
}
}
var err error
switch msg := event.Msg.(type) {
case string:
_, err = b.OutputWriteCloser.Write([]byte(msg))
case []byte:
_, err = b.OutputWriteCloser.Write(msg)
case io.WriterTo:
_, err = msg.WriteTo(b.OutputWriteCloser)
default:
_, err = b.OutputWriteCloser.Write([]byte(fmt.Sprint(msg)))
}
if err != nil {
FallbackErrorf("unable to write log message of %q (%v): %v", b.Name, err, event.Msg)
}
}
}
}
func NewEventWriterBase(name, writerType string, mode WriterMode) *EventWriterBaseImpl {
if mode.BufferLen == 0 {
mode.BufferLen = 1000
}
if mode.Level == UNDEFINED {
mode.Level = INFO
}
if mode.StacktraceLevel == UNDEFINED {
mode.StacktraceLevel = NONE
}
b := &EventWriterBaseImpl{
writerType: writerType,
Name: name,
Mode: &mode,
Queue: make(chan *EventFormatted, mode.BufferLen),
GetPauseChan: GetManager().GetPauseChan, // by default, use the global pause channel
FormatMessage: EventFormatTextMessage,
}
return b
}
// eventWriterStartGo use "go" to start an event worker's Run method
func eventWriterStartGo(ctx context.Context, w EventWriter, shared bool) {
if w.Base().stopped != nil {
return // already started
}
w.Base().shared = shared
w.Base().stopped = make(chan struct{})
ctxDesc := "Logger: EventWriter: " + w.GetWriterName()
if shared {
ctxDesc = "Logger: EventWriter (shared): " + w.GetWriterName()
}
writerCtx, writerCancel := newProcessTypedContext(ctx, ctxDesc)
go func() {
defer writerCancel()
defer close(w.Base().stopped)
pprof.SetGoroutineLabels(writerCtx)
w.Run(writerCtx)
}()
}
// eventWriterStopWait stops an event writer and waits for it to finish flushing (with a timeout)
func eventWriterStopWait(w EventWriter) {
close(w.Base().Queue)
select {
case <-w.Base().stopped:
case <-time.After(2 * time.Second):
FallbackErrorf("unable to stop log writer %q in time, skip", w.GetWriterName())
}
}