Merge pull request #6003 from cpuguy83/add_otel_log_hook

Add open telemetry logging hook for logrus

cmd/containerd/command/main.go

@@ -301,6 +301,8 @@ func applyFlags(context *cli.Context, config *srvconfig.Config) error {
 	if err := setLogFormat(config); err != nil {
 		return err
 	}
+	setLogHooks()
+
 	for _, v := range []struct {
 		name string
 		d    *string
@@ -366,6 +368,10 @@ func setLogFormat(config *srvconfig.Config) error {
 	return nil
 }
 
+func setLogHooks() {
+	logrus.StandardLogger().AddHook(tracing.NewLogrusHook())
+}
+
 func dumpStacks(writeToFile bool) {
 	var (
 		buf       []byte

log/context.go

@@ -52,7 +52,8 @@ const (
 // WithLogger returns a new context with the provided logger. Use in
 // combination with logger.WithField(s) for great effect.
 func WithLogger(ctx context.Context, logger *logrus.Entry) context.Context {
-	return context.WithValue(ctx, loggerKey{}, logger)
+	e := logger.WithContext(ctx)
+	return context.WithValue(ctx, loggerKey{}, e)
 }
 
 // GetLogger retrieves the current logger from the context. If no logger is
@@ -61,7 +62,7 @@ func GetLogger(ctx context.Context) *logrus.Entry {
 	logger := ctx.Value(loggerKey{})
 
 	if logger == nil {
-		return L
+		return L.WithContext(ctx)
 	}
 
 	return logger.(*logrus.Entry)

log/context_test.go

@@ -25,8 +25,6 @@ import (
 
 func TestLoggerContext(t *testing.T) {
 	ctx := context.Background()
-	assert.Equal(t, GetLogger(ctx), L)      // should be same as L variable
-	assert.Equal(t, G(ctx), GetLogger(ctx)) // these should be the same.
 
 	ctx = WithLogger(ctx, G(ctx).WithField("test", "one"))
 	assert.Equal(t, GetLogger(ctx).Data["test"], "one")

tracing/log.go

@@ -0,0 +1,66 @@
+/*
+   Copyright The containerd 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 tracing
+
+import (
+	"github.com/sirupsen/logrus"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// NewLogrusHook creates a new logrus hook
+func NewLogrusHook() *LogrusHook {
+	return &LogrusHook{}
+}
+
+// LogrusHook is a logrus hook which adds logrus events to active spans.
+// If the span is not recording or the span context is invalid, the hook is a no-op.
+type LogrusHook struct{}
+
+// Levels returns the logrus levels that this hook is interested in.
+func (h *LogrusHook) Levels() []logrus.Level {
+	return logrus.AllLevels
+}
+
+// Fire is called when a log event occurs.
+func (h *LogrusHook) Fire(entry *logrus.Entry) error {
+	span := trace.SpanFromContext(entry.Context)
+	if span == nil {
+		return nil
+	}
+
+	if !span.SpanContext().IsValid() || !span.IsRecording() {
+		return nil
+	}
+
+	span.AddEvent(
+		entry.Message,
+		trace.WithAttributes(logrusDataToAttrs(entry.Data)...),
+		trace.WithAttributes(attribute.String("level", entry.Level.String())),
+		trace.WithTimestamp(entry.Time),
+	)
+
+	return nil
+}
+
+func logrusDataToAttrs(data logrus.Fields) []attribute.KeyValue {
+	attrs := make([]attribute.KeyValue, 0, len(data))
+	for k, v := range data {
+		attrs = append(attrs, attribute.Any(k, v))
+	}
+	return attrs
+}