Merge pull request #50381 from sczizzo/bugfix-issue-47800

Automatic merge from submit-queue (batch tested with PRs 50381, 51307, 49645, 50995, 51523) Bugfix: Use local JSON log buffer in parseDockerJSONLog. **What this PR does / why we need it**: The issue described in #47800 is due to a race condition in `ReadLogs`: Because the JSON log buffer (`dockerJSONLog`) is package-scoped, any two goroutines modifying the buffer could race and overwrite the other's changes. In particular, one goroutine could unmarshal a JSON log line into the buffer, then another goroutine could `Reset()` the buffer, and the resulting `Stream` would be empty (`""`). This empty `Stream` is caught in a `case` block and raises an `unexpected stream type` error. This PR creates a new buffer for each execution of `parseDockerJSONLog`, so each goroutine is guaranteed to have a local instance of the buffer. **Which issue this PR fixes**: fixes #47800 **Release note**: ```release-note Fixed an issue (#47800) where `kubectl logs -f` failed with `unexpected stream type ""`. ```

Merge pull request #50381 from sczizzo/bugfix-issue-47800
0955f360 · Kubernetes Submit Queue · GitHub · 44c51821 · dab13823 · 0955f360
Commit 0955f360 authored Sep 01, 2017 by Kubernetes Submit Queue Committed by GitHub Sep 01, 2017
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kuberuntime_logs.go pkg/kubelet/kuberuntime/kuberuntime_logs.go +3 -5

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--- a/pkg/kubelet/kuberuntime/kuberuntime_logs.go
+++ b/pkg/kubelet/kuberuntime/kuberuntime_logs.go
@@ -280,16 +280,14 @@ func parseCRILog(log []byte, msg *logMessage) error {
 	return nil
 }

-// dockerJSONLog is the JSON log buffer used in parseDockerJSONLog.
-var dockerJSONLog = &jsonlog.JSONLog{}
-
 // parseDockerJSONLog parses logs in Docker JSON log format. Docker JSON log format
 // example:
 //   {"log":"content 1","stream":"stdout","time":"2016-10-20T18:39:20.57606443Z"}
 //   {"log":"content 2","stream":"stderr","time":"2016-10-20T18:39:20.57606444Z"}
 func parseDockerJSONLog(log []byte, msg *logMessage) error {
-	dockerJSONLog.Reset()
-	l := dockerJSONLog
+	var l = &jsonlog.JSONLog{}
+	l.Reset()
+
 	// TODO: JSON decoding is fairly expensive, we should evaluate this.
 	if err := json.Unmarshal(log, l); err != nil {
 		return fmt.Errorf("failed with %v to unmarshal log %q", err, l)