Add log context help to build log plugin (#108)

log/context.go

@@ -0,0 +1,48 @@
+//
+// Copyright 2021 SkyAPM org
+//
+// 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 log
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/SkyAPM/go2sky"
+)
+
+type SkyWalkingContext struct {
+	ServiceName         string
+	ServiceInstanceName string
+	TraceID             string
+	TraceSegmentID      string
+	SpanID              int32
+}
+
+// FromContext from context for logging
+func FromContext(ctx context.Context) *SkyWalkingContext {
+	return &SkyWalkingContext{
+		ServiceName:         go2sky.ServiceName(ctx),
+		ServiceInstanceName: go2sky.ServiceInstanceName(ctx),
+		TraceID:             go2sky.TraceID(ctx),
+		TraceSegmentID:      go2sky.TraceSegmentID(ctx),
+		SpanID:              go2sky.SpanID(ctx),
+	}
+}
+
+func (context *SkyWalkingContext) String() string {
+	return fmt.Sprintf("[%s,%s,%s,%s,%d]", context.ServiceName, context.ServiceInstanceName,
+		context.TraceID, context.TraceSegmentID, context.SpanID)
+}

log/context_test.go

@@ -0,0 +1,47 @@
+//
+// Copyright 2021 SkyAPM org
+//
+// 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 log
+
+import (
+	"context"
+	"fmt"
+	"testing"
+)
+
+func TestFromContext(t *testing.T) {
+	ctx := context.Background()
+	skyWalkingContext := FromContext(ctx)
+	verifyContext(t, skyWalkingContext)
+}
+
+func verifyContext(t *testing.T, ctx *SkyWalkingContext) {
+	if ctx == nil {
+		t.Error("nil context")
+		return
+	}
+
+	contextString := ctx.String()
+	if contextString == "" {
+		t.Error("empty context string")
+	}
+
+	exceptString := fmt.Sprintf("[%s,%s,%s,%s,%d]", ctx.ServiceName, ctx.ServiceInstanceName,
+		ctx.TraceID, ctx.TraceSegmentID, ctx.SpanID)
+	if contextString != exceptString {
+		t.Errorf("wrong context string, excepted:%s, actual:%s", exceptString, contextString)
+	}
+}

log/doc.go

@@ -0,0 +1,20 @@
+//
+// Copyright 2021 SkyAPM org
+//
+// 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 log help to build trace context data into log plugins.
+*/
+package log