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Diffstat (limited to 'dependencies/pkg/mod/go.uber.org/zap@v1.23.0/zapcore/buffered_write_syncer.go')
| -rw-r--r-- | dependencies/pkg/mod/go.uber.org/zap@v1.23.0/zapcore/buffered_write_syncer.go | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/dependencies/pkg/mod/go.uber.org/zap@v1.23.0/zapcore/buffered_write_syncer.go b/dependencies/pkg/mod/go.uber.org/zap@v1.23.0/zapcore/buffered_write_syncer.go new file mode 100644 index 0000000..a40e93b --- /dev/null +++ b/dependencies/pkg/mod/go.uber.org/zap@v1.23.0/zapcore/buffered_write_syncer.go @@ -0,0 +1,219 @@ +// Copyright (c) 2021 Uber Technologies, Inc. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +package zapcore + +import ( + "bufio" + "sync" + "time" + + "go.uber.org/multierr" +) + +const ( + // _defaultBufferSize specifies the default size used by Buffer. + _defaultBufferSize = 256 * 1024 // 256 kB + + // _defaultFlushInterval specifies the default flush interval for + // Buffer. + _defaultFlushInterval = 30 * time.Second +) + +// A BufferedWriteSyncer is a WriteSyncer that buffers writes in-memory before +// flushing them to a wrapped WriteSyncer after reaching some limit, or at some +// fixed interval--whichever comes first. +// +// BufferedWriteSyncer is safe for concurrent use. You don't need to use +// zapcore.Lock for WriteSyncers with BufferedWriteSyncer. +// +// To set up a BufferedWriteSyncer, construct a WriteSyncer for your log +// destination (*os.File is a valid WriteSyncer), wrap it with +// BufferedWriteSyncer, and defer a Stop() call for when you no longer need the +// object. +// +// func main() { +// ws := ... // your log destination +// bws := &zapcore.BufferedWriteSyncer{WS: ws} +// defer bws.Stop() +// +// // ... +// core := zapcore.NewCore(enc, bws, lvl) +// logger := zap.New(core) +// +// // ... +// } +// +// By default, a BufferedWriteSyncer will buffer up to 256 kilobytes of logs, +// waiting at most 30 seconds between flushes. +// You can customize these parameters by setting the Size or FlushInterval +// fields. +// For example, the following buffers up to 512 kB of logs before flushing them +// to Stderr, with a maximum of one minute between each flush. +// +// ws := &BufferedWriteSyncer{ +// WS: os.Stderr, +// Size: 512 * 1024, // 512 kB +// FlushInterval: time.Minute, +// } +// defer ws.Stop() +type BufferedWriteSyncer struct { + // WS is the WriteSyncer around which BufferedWriteSyncer will buffer + // writes. + // + // This field is required. + WS WriteSyncer + + // Size specifies the maximum amount of data the writer will buffered + // before flushing. + // + // Defaults to 256 kB if unspecified. + Size int + + // FlushInterval specifies how often the writer should flush data if + // there have been no writes. + // + // Defaults to 30 seconds if unspecified. + FlushInterval time.Duration + + // Clock, if specified, provides control of the source of time for the + // writer. + // + // Defaults to the system clock. + Clock Clock + + // unexported fields for state + mu sync.Mutex + initialized bool // whether initialize() has run + stopped bool // whether Stop() has run + writer *bufio.Writer + ticker *time.Ticker + stop chan struct{} // closed when flushLoop should stop + done chan struct{} // closed when flushLoop has stopped +} + +func (s *BufferedWriteSyncer) initialize() { + size := s.Size + if size == 0 { + size = _defaultBufferSize + } + + flushInterval := s.FlushInterval + if flushInterval == 0 { + flushInterval = _defaultFlushInterval + } + + if s.Clock == nil { + s.Clock = DefaultClock + } + + s.ticker = s.Clock.NewTicker(flushInterval) + s.writer = bufio.NewWriterSize(s.WS, size) + s.stop = make(chan struct{}) + s.done = make(chan struct{}) + s.initialized = true + go s.flushLoop() +} + +// Write writes log data into buffer syncer directly, multiple Write calls will be batched, +// and log data will be flushed to disk when the buffer is full or periodically. +func (s *BufferedWriteSyncer) Write(bs []byte) (int, error) { + s.mu.Lock() + defer s.mu.Unlock() + + if !s.initialized { + s.initialize() + } + + // To avoid partial writes from being flushed, we manually flush the existing buffer if: + // * The current write doesn't fit into the buffer fully, and + // * The buffer is not empty (since bufio will not split large writes when the buffer is empty) + if len(bs) > s.writer.Available() && s.writer.Buffered() > 0 { + if err := s.writer.Flush(); err != nil { + return 0, err + } + } + + return s.writer.Write(bs) +} + +// Sync flushes buffered log data into disk directly. +func (s *BufferedWriteSyncer) Sync() error { + s.mu.Lock() + defer s.mu.Unlock() + + var err error + if s.initialized { + err = s.writer.Flush() + } + + return multierr.Append(err, s.WS.Sync()) +} + +// flushLoop flushes the buffer at the configured interval until Stop is +// called. +func (s *BufferedWriteSyncer) flushLoop() { + defer close(s.done) + + for { + select { + case <-s.ticker.C: + // we just simply ignore error here + // because the underlying bufio writer stores any errors + // and we return any error from Sync() as part of the close + _ = s.Sync() + case <-s.stop: + return + } + } +} + +// Stop closes the buffer, cleans up background goroutines, and flushes +// remaining unwritten data. +func (s *BufferedWriteSyncer) Stop() (err error) { + var stopped bool + + // Critical section. + func() { + s.mu.Lock() + defer s.mu.Unlock() + + if !s.initialized { + return + } + + stopped = s.stopped + if stopped { + return + } + s.stopped = true + + s.ticker.Stop() + close(s.stop) // tell flushLoop to stop + <-s.done // and wait until it has + }() + + // Don't call Sync on consecutive Stops. + if !stopped { + err = s.Sync() + } + + return err +} |