contrib/sirupsen/logrus: Add context logging hook (#1240)

contrib/sirupsen/logrus/example_test.go

@@ -0,0 +1,34 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2022 Datadog, Inc.
+
+package logrus
+
+import (
+	"context"
+	"os"
+	"time"
+
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+
+	"github.com/sirupsen/logrus"
+)
+
+func ExampleHook() {
+	// Ensure your tracer is started and stopped
+	// Setup logrus, do this once at the beginning of your program
+	logrus.SetFormatter(&logrus.JSONFormatter{})
+	logrus.AddHook(&DDContextLogHook{})
+	logrus.SetOutput(os.Stdout)
+
+	span, sctx := tracer.StartSpanFromContext(context.Background(), "mySpan")
+	defer span.Finish()
+
+	// Pass the current span context to the logger (Time is set for consistency in output here)
+	cLog := logrus.WithContext(sctx).WithTime(time.Date(2000, 1, 1, 1, 1, 1, 0, time.UTC))
+	// Log as desired using the context-aware logger
+	cLog.Info("Completed some work!")
+	// Output:
+	// {"dd.span_id":0,"dd.trace_id":0,"level":"info","msg":"Completed some work!","time":"2000-01-01T01:01:01Z"}
+}

contrib/sirupsen/logrus/logrus.go

@@ -0,0 +1,32 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2022 Datadog, Inc.
+
+// Package logrus provides a log/span correlation hook for the sirupsen/logrus package (https://github.com/sirupsen/logrus).
+package logrus
+
+import (
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+
+	"github.com/sirupsen/logrus"
+)
+
+// DDContextLogHook ensures that any span in the log context is correlated to log output.
+type DDContextLogHook struct{}
+
+// Levels implements logrus.Hook interface, this hook applies to all defined levels
+func (d *DDContextLogHook) Levels() []logrus.Level {
+	return []logrus.Level{logrus.PanicLevel, logrus.FatalLevel, logrus.ErrorLevel, logrus.WarnLevel, logrus.InfoLevel, logrus.DebugLevel, logrus.TraceLevel}
+}
+
+// Fire implements logrus.Hook interface, attaches trace and span details found in entry context
+func (d *DDContextLogHook) Fire(e *logrus.Entry) error {
+	span, found := tracer.SpanFromContext(e.Context)
+	if !found {
+		return nil
+	}
+	e.Data["dd.trace_id"] = span.Context().TraceID()
+	e.Data["dd.span_id"] = span.Context().SpanID()
+	return nil
+}

contrib/sirupsen/logrus/logrus_test.go

@@ -0,0 +1,31 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2022 Datadog, Inc.
+
+package logrus
+
+import (
+	"context"
+	"testing"
+
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFire(t *testing.T) {
+	tracer.Start()
+	defer tracer.Stop()
+	_, sctx := tracer.StartSpanFromContext(context.Background(), "testSpan", tracer.WithSpanID(1234))
+
+	hook := &DDContextLogHook{}
+	e := logrus.NewEntry(logrus.New())
+	e.Context = sctx
+	err := hook.Fire(e)
+
+	assert.NoError(t, err)
+	assert.Equal(t, uint64(1234), e.Data["dd.trace_id"])
+	assert.Equal(t, uint64(1234), e.Data["dd.span_id"])
+}

go.mod

@@ -74,7 +74,7 @@ require (
 	github.com/philhofer/fwd v1.1.1 // indirect
 	github.com/pierrec/lz4 v2.5.2+incompatible // indirect
 	github.com/segmentio/kafka-go v0.4.29
-	github.com/stretchr/objx v0.2.0 // indirect
+	github.com/sirupsen/logrus v1.7.0
 	github.com/stretchr/testify v1.7.0
 	github.com/syndtr/goleveldb v1.0.0
 	github.com/tidwall/btree v1.1.0 // indirect