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/*
*
* Copyright 2018 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package binarylog
import (
"bufio"
"encoding/binary"
"fmt"
"io"
"io/ioutil"
"sync"
"time"
"github.com/golang/protobuf/proto"
pb "google.golang.org/grpc/binarylog/grpc_binarylog_v1"
"google.golang.org/grpc/grpclog"
)
var (
defaultSink Sink = &noopSink{} // TODO(blog): change this default (file in /tmp).
)
// SetDefaultSink sets the sink where binary logs will be written to.
//
// Not thread safe. Only set during initialization.
func SetDefaultSink(s Sink) {
if defaultSink != nil {
defaultSink.Close()
}
defaultSink = s
}
// Sink writes log entry into the binary log sink.
type Sink interface {
// Write will be called to write the log entry into the sink.
//
// It should be thread-safe so it can be called in parallel.
Write(*pb.GrpcLogEntry) error
// Close will be called when the Sink is replaced by a new Sink.
Close() error
}
type noopSink struct{}
func (ns *noopSink) Write(*pb.GrpcLogEntry) error { return nil }
func (ns *noopSink) Close() error { return nil }
// newWriterSink creates a binary log sink with the given writer.
//
// Write() marshalls the proto message and writes it to the given writer. Each
// message is prefixed with a 4 byte big endian unsigned integer as the length.
//
// No buffer is done, Close() doesn't try to close the writer.
func newWriterSink(w io.Writer) *writerSink {
return &writerSink{out: w}
}
type writerSink struct {
out io.Writer
}
func (ws *writerSink) Write(e *pb.GrpcLogEntry) error {
b, err := proto.Marshal(e)
if err != nil {
grpclog.Infof("binary logging: failed to marshal proto message: %v", err)
}
hdr := make([]byte, 4)
binary.BigEndian.PutUint32(hdr, uint32(len(b)))
if _, err := ws.out.Write(hdr); err != nil {
return err
}
if _, err := ws.out.Write(b); err != nil {
return err
}
return nil
}
func (ws *writerSink) Close() error { return nil }
type bufWriteCloserSink struct {
mu sync.Mutex
closer io.Closer
out *writerSink // out is built on buf.
buf *bufio.Writer // buf is kept for flush.
writeStartOnce sync.Once
writeTicker *time.Ticker
}
func (fs *bufWriteCloserSink) Write(e *pb.GrpcLogEntry) error {
// Start the write loop when Write is called.
fs.writeStartOnce.Do(fs.startFlushGoroutine)
fs.mu.Lock()
if err := fs.out.Write(e); err != nil {
fs.mu.Unlock()
return err
}
fs.mu.Unlock()
return nil
}
const (
bufFlushDuration = 60 * time.Second
)
func (fs *bufWriteCloserSink) startFlushGoroutine() {
fs.writeTicker = time.NewTicker(bufFlushDuration)
go func() {
for range fs.writeTicker.C {
fs.mu.Lock()
fs.buf.Flush()
fs.mu.Unlock()
}
}()
}
func (fs *bufWriteCloserSink) Close() error {
if fs.writeTicker != nil {
fs.writeTicker.Stop()
}
fs.mu.Lock()
fs.buf.Flush()
fs.closer.Close()
fs.out.Close()
fs.mu.Unlock()
return nil
}
func newBufWriteCloserSink(o io.WriteCloser) Sink {
bufW := bufio.NewWriter(o)
return &bufWriteCloserSink{
closer: o,
out: newWriterSink(bufW),
buf: bufW,
}
}
// NewTempFileSink creates a temp file and returns a Sink that writes to this
// file.
func NewTempFileSink() (Sink, error) {
tempFile, err := ioutil.TempFile("/tmp", "grpcgo_binarylog_*.txt")
if err != nil {
return nil, fmt.Errorf("failed to create temp file: %v", err)
}
return newBufWriteCloserSink(tempFile), nil
}
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