func (f *fileListener) Close() error {
f.Lock()
select {
case <-f.stop:
f.Unlock()
return nil // Already stopped
default:
close(f.stop)
}
var firstErr error
if firstErr = f.netListener.Close(); firstErr != nil {
slog.Trace("Error closing file listener: %v", firstErr)
}
for conn := range f.connections {
if err := conn.Close(); err != nil {
if firstErr == nil {
firstErr = err
}
slog.Trace("Error closing connection: %v", err)
}
}
f.Unlock()
f.wg.Wait()
close(f.changes)
return firstErr
}
// Collect file changes that happen FileChangeWindow ms from each
// other, and restart all nodes in the process tree that match
// features of the changed files.
func start(tree *processtree.ProcessTree, filesChanged chan string, done, quit chan bool) {
for {
select {
case <-quit:
done <- true
return
case file := <-filesChanged:
changed := make(map[string]bool)
changed[file] = true
slog.Trace("Restarter got the first file of potentially many")
deadline := time.After(FileChangeWindow)
deadline_expired := false
for !deadline_expired {
select {
case <-quit:
done <- true
return
case file := <-filesChanged:
changed[file] = true
case <-deadline:
deadline_expired = true
}
}
slog.Trace("Restarter has gathered %d changed files", len(changed))
go tree.RestartNodesWithFeatures(changed)
}
}
}
func (f *fileListener) handleConnection(conn net.Conn, ch chan string) {
// Handle writes
stop := make(chan struct{})
go func() {
for {
select {
case s := <-ch:
conn.SetWriteDeadline(time.Now().Add(1 * time.Second))
if _, err := conn.Write([]byte(s + "\n")); err == io.EOF {
return
} else if err != nil {
slog.Trace("Error writing to connection: %v", err)
}
case <-stop:
return
}
}
}()
// Handle reads
scanner := bufio.NewScanner(conn)
for {
if scanner.Scan() {
f.changes <- scanner.Text()
} else {
if err := scanner.Err(); err != nil {
select {
case <-f.stop:
break
default:
slog.Trace("Error reading from connection: %v", err)
}
}
break
}
}
f.Lock()
defer f.Unlock()
close(stop)
delete(f.connections, conn)
f.wg.Done()
}
// Collect file changes that happen FileChangeWindow ms from each
// other, and restart all nodes in the process tree that match
// features of the changed files.
func (r *restarter) start() {
for {
select {
case <-r.quit:
r.done <- true
return
case file := <-r.filesChanged:
changed := make(map[string]bool)
changed[file] = true
slog.Trace("Restarter got the first file of potentially many")
if r.gatherFiles(changed, time.After(FileChangeWindow)) {
return
}
slog.Trace("Restarter has gathered %d changed files", len(changed))
go r.tree.RestartNodesWithFeatures(changed)
}
}
}
func (s *SlaveNode) trace(format string, args ...interface{}) {
if !slog.TraceEnabled() {
return
}
_, file, line, _ := runtime.Caller(1)
var prefix string
if s.Pid != 0 {
prefix = fmt.Sprintf("[%s:%d] %s/(%d)", file, line, s.Name, s.Pid)
} else {
prefix = fmt.Sprintf("[%s:%d] %s/(no PID)", file, line, s.Name)
}
new_args := make([]interface{}, len(args)+1)
new_args[0] = prefix
for i, v := range args {
new_args[i+1] = v
}
slog.Trace("%s "+format, new_args...)
}
func (f *fileListener) serve() {
var tempDelay time.Duration // how long to sleep on accept failure
for {
conn, err := f.netListener.Accept()
if err != nil {
if ne, ok := err.(net.Error); ok && ne.Temporary() {
if tempDelay == 0 {
tempDelay = 5 * time.Millisecond
} else {
tempDelay *= 2
}
if max := 1 * time.Second; tempDelay > max {
tempDelay = max
}
slog.Trace("filelistener: Accept error: %v; retrying in %v", err, tempDelay)
time.Sleep(tempDelay)
continue
}
select {
case <-f.stop:
return
default:
panic(err)
}
}
ch := make(chan string)
f.Lock()
f.connections[conn] = ch
f.wg.Add(1)
f.Unlock()
go f.handleConnection(conn, ch)
}
}