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// Copyright 2020 Google Inc. All Rights Reserved.
// This file is available under the Apache license.
package logstream
import (
"context"
"fmt"
"net"
"sync"
"github.com/golang/glog"
"github.com/jaqx0r/mtail/internal/logline"
"github.com/jaqx0r/mtail/internal/waker"
)
type socketStream struct {
streamBase
cancel context.CancelFunc
oneShot OneShotMode
scheme string // URL Scheme to listen with, either tcp or unix
address string // Given name for the underlying socket path on the filesystem or host/port.
}
func newSocketStream(ctx context.Context, wg *sync.WaitGroup, waker waker.Waker, scheme, address string, oneShot OneShotMode) (LogStream, error) {
if address == "" {
return nil, ErrEmptySocketAddress
}
ctx, cancel := context.WithCancel(ctx)
ss := &socketStream{
cancel: cancel,
oneShot: oneShot,
scheme: scheme,
address: address,
streamBase: streamBase{
sourcename: fmt.Sprintf("%s://%s", scheme, address),
lines: make(chan *logline.LogLine),
},
}
if err := ss.stream(ctx, wg, waker); err != nil {
return nil, err
}
return ss, nil
}
// stream starts goroutines to read data from the stream socket, until Stop is called or the context is cancelled.
func (ss *socketStream) stream(ctx context.Context, wg *sync.WaitGroup, waker waker.Waker) error {
l, err := net.Listen(ss.scheme, ss.address)
if err != nil {
logErrors.Add(ss.address, 1)
return err
}
glog.V(2).Infof("stream(%s): opened new socket listener %+v", ss.sourcename, l)
// signals when a connection has been opened
started := make(chan struct{})
// tracks connection handling routines
var connWg sync.WaitGroup
// Set up for shutdown
wg.Add(1)
go func() {
defer wg.Done()
// If oneshot, wait only for the one conn handler to start, otherwise
// wait for context Done or stopChan.
<-started
if !ss.oneShot {
<-ctx.Done()
}
glog.V(2).Infof("stream(%s): closing listener", ss.sourcename)
err := l.Close()
if err != nil {
glog.Info(err)
}
connWg.Wait()
close(ss.lines)
}()
var connOnce sync.Once
wg.Add(1)
go func() {
defer wg.Done()
for {
c, err := l.Accept()
if err != nil {
glog.Info(err)
return
}
glog.V(2).Infof("stream(%s): got new conn %v", ss.sourcename, c)
connWg.Add(1)
go ss.handleConn(ctx, &connWg, waker, c)
connOnce.Do(func() { close(started) })
if ss.oneShot {
glog.Infof("stream(%s): oneshot mode, exiting accept loop", ss.sourcename)
return
}
}
}()
return nil
}
func (ss *socketStream) handleConn(ctx context.Context, wg *sync.WaitGroup, waker waker.Waker, c net.Conn) {
defer wg.Done()
lr := NewLineReader(ss.sourcename, ss.lines, c, defaultReadBufferSize, ss.cancel)
var total int
defer func() {
glog.V(2).Infof("stream(%s): read total %d bytes from %s", ss.sourcename, c, total)
glog.V(2).Infof("stream(%s): closing connection, %v", ss.sourcename, c)
err := c.Close()
if err != nil {
logErrors.Add(ss.address, 1)
glog.Info(err)
}
lr.Finish(ctx)
logCloses.Add(ss.address, 1)
}()
ctx, cancel := context.WithCancel(ctx)
defer cancel()
SetReadDeadlineOnDone(ctx, c)
for {
n, err := lr.ReadAndSend(ctx)
glog.V(2).Infof("stream(%s): read %d bytes, err is %v", ss.sourcename, n, err)
if n > 0 {
total += n
// No error implies more to read, so restart the loop.
if err == nil && ctx.Err() == nil {
continue
}
}
if IsExitableError(err) {
glog.V(2).Infof("stream(%s): exiting, conn has error %s", ss.sourcename, err)
return
}
// Yield and wait
glog.V(2).Infof("stream(%s): waiting", ss.sourcename)
select {
case <-ctx.Done():
// Exit after next read attempt.
glog.V(2).Infof("stream(%s:%s): context cancelled, exiting after next read timeout", ss.scheme, ss.address)
case <-waker.Wake():
// sleep until next Wake()
glog.V(2).Infof("stream(%s): Wake received", ss.sourcename)
}
}
}
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