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podWatcher: Refactor
continuous-integration/drone/push Build is passing Details

This commit is contained in:
Rob Watson 2022-06-14 21:11:06 +02:00
parent d8e57c3d0e
commit e33612cced
1 changed files with 49 additions and 45 deletions
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94
logs/pod_watcher.go
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@ -20,36 +20,39 @@ import (
const nl = "\n"
type stream struct {
// logStream represents the logStream from an individual pod.
type logStream struct {
podName string
container string
namespace string
done chan struct{}
}
func newStream(podName, namespace string) stream {
return stream{podName: podName, namespace: namespace, done: make(chan struct{})}
func newStream(podName, container, namespace string) logStream {
return logStream{
podName: podName,
container: container,
namespace: namespace,
done: make(chan struct{}),
}
}
func (s stream) close() {
close(s.done)
}
type streamError struct {
type logError struct {
err error
stream stream
logStream logStream
recoverable bool
}
func (re *streamError) Error() string {
func (re *logError) Error() string {
return re.err.Error()
}
func newStreamError(err error, stream stream) *streamError {
return &streamError{err: err, stream: stream}
func newLogError(err error, stream logStream) *logError {
return &logError{err: err, logStream: stream}
}
func newRecoverableError(err error, stream stream) *streamError {
return &streamError{err: err, stream: stream, recoverable: true}
func newRecoverableLogError(err error, stream logStream) *logError {
return &logError{err: err, logStream: stream, recoverable: true}
}
// PodWatcher consumes and merges the logs for a specified set of pods.
@ -59,7 +62,7 @@ type PodWatcher struct {
container string
labelSelector labels.Selector
spec map[string]*corev1.Pod
status map[string]stream
status map[string]logStream
streamResults chan error
dst io.Writer
closeChan chan struct{}
@ -74,7 +77,7 @@ func NewPodWatcher(client KubernetesClient, namespace string, container string,
container: container,
labelSelector: labelSelector,
spec: make(map[string]*corev1.Pod),
status: make(map[string]stream),
status: make(map[string]logStream),
streamResults: make(chan error),
dst: dst,
closeChan: make(chan struct{}),
@ -115,8 +118,8 @@ func (pw *PodWatcher) watchPods(ctx context.Context, wg *sync.WaitGroup) error {
ticker := time.NewTicker(tickerInterval)
defer ticker.Stop()
logStream := make(chan string)
streamErrors := make(chan error)
logLines := make(chan string)
logErrorChan := make(chan error)
resultChan := watcher.ResultChan()
for {
@ -126,7 +129,7 @@ func (pw *PodWatcher) watchPods(ctx context.Context, wg *sync.WaitGroup) error {
case <-pw.closeChan:
for _, stream := range pw.status {
stream.close()
pw.removePod(stream)
}
return nil
@ -135,14 +138,14 @@ func (pw *PodWatcher) watchPods(ctx context.Context, wg *sync.WaitGroup) error {
// process the logs of any missing pods.
for podName, pod := range pw.spec {
if _, ok := pw.status[podName]; !ok {
pw.logger.Printf("[PodWatcher] adding pod, name = %s", pod.Name)
s := newStream(pod.Name, pod.Namespace)
pw.status[pod.Name] = s
pw.logger.Printf("[PodWatcher] adding pod, name = %s, container = %s, namespace = %s,", pod.Name, pw.container, pod.Namespace)
stream := newStream(pod.Name, pw.container, pod.Namespace)
pw.status[pod.Name] = stream
wg.Add(1)
go func() {
if err := copyPodLogs(ctx, wg, pw.client, s, pw.container, logStream); err != nil {
streamErrors <- err
if err := copyLogStream(ctx, wg, pw.client, stream, logLines); err != nil {
logErrorChan <- err
}
}()
}
@ -154,27 +157,28 @@ func (pw *PodWatcher) watchPods(ctx context.Context, wg *sync.WaitGroup) error {
}
}
// logStream is never closed
case l := <-logStream:
if _, err := pw.dst.Write([]byte(l)); err != nil {
// logLines is never closed
case line := <-logLines:
if _, err := pw.dst.Write([]byte(line)); err != nil {
return fmt.Errorf("error writing logs: %v", err)
}
// streamErrors is never closed
case err := <-streamErrors:
var streamErr *streamError
if errors.As(err, &streamErr) && streamErr.recoverable {
// logErrorChan is never closed
case err := <-logErrorChan:
var logErr *logError
if errors.As(err, &logErr) && logErr.recoverable {
// if the error is recoverable, we just remove the pod from the status
// map. It will be recreated and retried on the next iteration.
pw.removePod(streamErr.stream)
pw.removePod(logErr.logStream)
} else {
return fmt.Errorf("error streaming logs: %w", streamErr)
return fmt.Errorf("error streaming logs: %w", logErr)
}
case evt, ok := <-resultChan:
if !ok {
return nil
}
switch evt.Type {
case watch.Added, watch.Modified:
pod := evt.Object.(*corev1.Pod)
@ -189,40 +193,40 @@ func (pw *PodWatcher) watchPods(ctx context.Context, wg *sync.WaitGroup) error {
}
}
func (pw *PodWatcher) removePod(stream stream) {
func (pw *PodWatcher) removePod(stream logStream) {
pw.logger.Printf("[PodWatcher] removing pod, name = %s", stream.podName)
stream.close()
close(stream.done)
delete(pw.status, stream.podName)
}
func copyPodLogs(ctx context.Context, wg *sync.WaitGroup, client KubernetesClient, stream stream, container string, logStream chan string) error {
func copyLogStream(ctx context.Context, wg *sync.WaitGroup, client KubernetesClient, stream logStream, logsLines chan string) error {
defer wg.Done()
req := client.Typed.CoreV1().Pods(stream.namespace).GetLogs(stream.podName, &corev1.PodLogOptions{Follow: true, Container: container})
logs, err := req.Stream(ctx)
req := client.Typed.CoreV1().Pods(stream.namespace).GetLogs(stream.podName, &corev1.PodLogOptions{Follow: true, Container: stream.container})
logReader, err := req.Stream(ctx)
// If one container is still being created, do not treat this as a fatal error.
var statusErr *apierrors.StatusError
if errors.As(err, &statusErr) && statusErr.Status().Reason == metav1.StatusReasonBadRequest && strings.Contains(statusErr.Error(), "ContainerCreating") {
return newRecoverableError(err, stream)
return newRecoverableLogError(err, stream)
} else if err != nil {
return newStreamError(err, stream)
return newLogError(err, stream)
}
// Closing the reader ensures that the goroutine below is not leaked.
defer func() { _ = logs.Close() }()
defer func() { _ = logReader.Close() }()
done := make(chan error, 1)
go func() {
scanner := bufio.NewScanner(logs)
defer close(done)
scanner := bufio.NewScanner(logReader)
for scanner.Scan() {
logStream <- "[" + stream.podName + "] " + scanner.Text() + nl
logsLines <- "[" + stream.podName + "] " + scanner.Text() + nl
}
if err := scanner.Err(); err != nil {
done <- newStreamError(fmt.Errorf("error scanning logs: %v", err), stream)
done <- newLogError(fmt.Errorf("error scanning logs: %v", err), stream)
return
}
done <- nil
}()
for {