/
circular.go
320 lines (250 loc) · 6.78 KB
/
circular.go
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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
package logging
import (
"bufio"
"bytes"
"context"
"errors"
"fmt"
"io"
"log"
"sync"
"time"
"github.com/siderolabs/go-circular"
"github.com/siderolabs/go-debug"
"github.com/siderolabs/go-tail"
"github.com/siderolabs/talos/internal/app/machined/pkg/runtime"
)
// These constants should some day move to config.
const (
// Some logs are tiny, no need to reserve too much memory.
InitialCapacity = 16384
// Cap each log at 1M.
MaxCapacity = 1048576
// Safety gap to avoid buffer overruns.
SafetyGap = 2048
)
// CircularBufferLoggingManager implements logging to circular fixed size buffer.
type CircularBufferLoggingManager struct {
fallbackLogger *log.Logger
buffers sync.Map
sendersRW sync.RWMutex
senders []runtime.LogSender
sendersChanged chan struct{}
}
// NewCircularBufferLoggingManager initializes new CircularBufferLoggingManager.
func NewCircularBufferLoggingManager(fallbackLogger *log.Logger) *CircularBufferLoggingManager {
return &CircularBufferLoggingManager{
fallbackLogger: fallbackLogger,
sendersChanged: make(chan struct{}),
}
}
// ServiceLog implements runtime.LoggingManager interface.
func (manager *CircularBufferLoggingManager) ServiceLog(id string) runtime.LogHandler {
return &circularHandler{
manager: manager,
id: id,
fields: map[string]interface{}{
// use field name that is not used by anything else
"talos-service": id,
},
}
}
// SetSenders implements runtime.LoggingManager interface.
func (manager *CircularBufferLoggingManager) SetSenders(senders []runtime.LogSender) []runtime.LogSender {
manager.sendersRW.Lock()
prevChanged := manager.sendersChanged
manager.sendersChanged = make(chan struct{})
prevSenders := manager.senders
manager.senders = senders
manager.sendersRW.Unlock()
close(prevChanged)
return prevSenders
}
// getSenders waits for senders to be set and returns them.
func (manager *CircularBufferLoggingManager) getSenders() []runtime.LogSender {
for {
manager.sendersRW.RLock()
senders, changed := manager.senders, manager.sendersChanged
manager.sendersRW.RUnlock()
if len(senders) > 0 {
return senders
}
<-changed
}
}
func (manager *CircularBufferLoggingManager) getBuffer(id string, create bool) (*circular.Buffer, error) {
buf, ok := manager.buffers.Load(id)
if !ok {
if !create {
return nil, nil
}
b, err := circular.NewBuffer(
circular.WithInitialCapacity(InitialCapacity),
circular.WithMaxCapacity(MaxCapacity),
circular.WithSafetyGap(SafetyGap))
if err != nil {
return nil, err // only configuration issue might raise error
}
buf, _ = manager.buffers.LoadOrStore(id, b)
}
return buf.(*circular.Buffer), nil
}
// RegisteredLogs implements runtime.LoggingManager interface.
func (manager *CircularBufferLoggingManager) RegisteredLogs() []string {
var result []string
manager.buffers.Range(func(key, val any) bool {
result = append(result, key.(string))
return true
})
return result
}
type circularHandler struct {
manager *CircularBufferLoggingManager
id string
fields map[string]interface{}
buf *circular.Buffer
}
type nopCloser struct {
io.Writer
}
func (nopCloser) Close() error {
return nil
}
// Writer implements runtime.LogHandler interface.
func (handler *circularHandler) Writer() (io.WriteCloser, error) {
if handler.buf == nil {
var err error
handler.buf, err = handler.manager.getBuffer(handler.id, true)
if err != nil {
return nil, err
}
go func() {
if err := handler.runSenders(); err != nil {
handler.manager.fallbackLogger.Printf("log senders stopped: %s", err)
}
}()
}
switch handler.id {
case "machined":
return &timeStampWriter{w: handler.buf}, nil
default:
return nopCloser{handler.buf}, nil
}
}
// Reader implements runtime.LogHandler interface.
func (handler *circularHandler) Reader(opts ...runtime.LogOption) (io.ReadCloser, error) {
if handler.buf == nil {
var err error
handler.buf, err = handler.manager.getBuffer(handler.id, false)
if err != nil {
return nil, err
}
if handler.buf == nil {
// only Writer() operation creates new buffers
return nil, fmt.Errorf("log %q was not registered", handler.id)
}
}
var opt runtime.LogOptions
for _, o := range opts {
if err := o(&opt); err != nil {
return nil, err
}
}
var r interface {
io.ReadCloser
io.Seeker
}
if opt.Follow {
r = handler.buf.GetStreamingReader()
} else {
r = handler.buf.GetReader()
}
if opt.TailLines != nil {
err := tail.SeekLines(r, *opt.TailLines)
if err != nil {
r.Close() //nolint:errcheck
return nil, fmt.Errorf("error tailing log: %w", err)
}
}
return r, nil
}
func (handler *circularHandler) runSenders() error {
r, err := handler.Reader(runtime.WithFollow())
if err != nil {
return err
}
defer r.Close() //nolint:errcheck
scanner := bufio.NewScanner(r)
for scanner.Scan() {
l := bytes.TrimSpace(scanner.Bytes())
if len(l) == 0 {
continue
}
e := parseLogLine(l, time.Now())
if e.Fields == nil {
e.Fields = handler.fields
} else {
for k, v := range handler.fields {
e.Fields[k] = v
}
}
handler.resend(e)
}
return fmt.Errorf("scanner: %w", scanner.Err())
}
// resend sends and resends given event until success or ErrDontRetry error.
func (handler *circularHandler) resend(e *runtime.LogEvent) {
for {
senders := handler.manager.getSenders()
sendCtx, sendCancel := context.WithTimeout(context.TODO(), 5*time.Second)
sendErrors := make(chan error, len(senders))
for _, sender := range senders {
go func() {
sendErrors <- sender.Send(sendCtx, e)
}()
}
var dontRetry bool
for range senders {
err := <-sendErrors
// don't retry if at least one sender succeed to avoid implementing per-sender queue, etc
if err == nil {
dontRetry = true
continue
}
if debug.Enabled {
handler.manager.fallbackLogger.Print(err)
}
if errors.Is(err, runtime.ErrDontRetry) {
dontRetry = true
}
}
sendCancel()
if dontRetry {
return
}
time.Sleep(time.Second)
}
}
// timeStampWriter is a writer that adds a timestamp to each line.
type timeStampWriter struct {
w io.Writer
}
// Write implements the io.Writer interface.
func (t *timeStampWriter) Write(p []byte) (int, error) {
// Current log.Logger implementation always adds a newline to the message, so we don't need to wait for it.
var buf bytes.Buffer
buf.WriteString(time.Now().Format("2006/01/02 15:04:05.000000"))
buf.WriteByte(' ')
buf.Write(p)
return t.w.Write(buf.Bytes())
}
// Close implements the io.Closer interface.
func (t *timeStampWriter) Close() error {
if c, ok := t.w.(io.Closer); ok {
return c.Close()
}
return nil
}