130 lines
2.6 KiB
Go
130 lines
2.6 KiB
Go
// Copyright 2019 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package logging
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import (
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"bytes"
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"sync"
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"time"
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"github.com/go-kit/kit/log"
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"github.com/go-logfmt/logfmt"
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)
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const (
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garbageCollectEvery = 10 * time.Second
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expireEntriesAfter = 1 * time.Minute
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maxEntries = 1024
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)
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type logfmtEncoder struct {
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*logfmt.Encoder
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buf bytes.Buffer
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}
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var logfmtEncoderPool = sync.Pool{
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New: func() interface{} {
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var enc logfmtEncoder
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enc.Encoder = logfmt.NewEncoder(&enc.buf)
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return &enc
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},
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}
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// Deduper implement log.Logger, dedupes log lines.
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type Deduper struct {
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next log.Logger
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repeat time.Duration
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quit chan struct{}
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mtx sync.RWMutex
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seen map[string]time.Time
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}
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// Dedupe log lines to next, only repeating every repeat duration.
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func Dedupe(next log.Logger, repeat time.Duration) *Deduper {
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d := &Deduper{
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next: next,
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repeat: repeat,
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quit: make(chan struct{}),
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seen: map[string]time.Time{},
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}
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go d.run()
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return d
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}
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// Stop the Deduper.
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func (d *Deduper) Stop() {
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close(d.quit)
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}
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func (d *Deduper) run() {
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ticker := time.NewTicker(garbageCollectEvery)
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defer ticker.Stop()
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for {
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select {
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case <-ticker.C:
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d.mtx.Lock()
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now := time.Now()
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for line, seen := range d.seen {
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if now.Sub(seen) > expireEntriesAfter {
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delete(d.seen, line)
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}
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}
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d.mtx.Unlock()
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case <-d.quit:
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return
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}
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}
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}
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// Log implements log.Logger.
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func (d *Deduper) Log(keyvals ...interface{}) error {
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line, err := encode(keyvals...)
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if err != nil {
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return err
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}
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d.mtx.RLock()
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last, ok := d.seen[line]
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d.mtx.RUnlock()
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if ok && time.Since(last) < d.repeat {
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return nil
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}
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d.mtx.Lock()
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if len(d.seen) < maxEntries {
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d.seen[line] = time.Now()
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}
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d.mtx.Unlock()
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return d.next.Log(keyvals...)
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}
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func encode(keyvals ...interface{}) (string, error) {
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enc := logfmtEncoderPool.Get().(*logfmtEncoder)
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enc.buf.Reset()
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defer logfmtEncoderPool.Put(enc)
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if err := enc.EncodeKeyvals(keyvals...); err != nil {
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return "", err
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}
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// Add newline to the end of the buffer
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if err := enc.EndRecord(); err != nil {
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return "", err
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}
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return enc.buf.String(), nil
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}
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