Add Macaron plugin

plugins/macaron/config.go

@@ -0,0 +1,48 @@
+// Copyright The OpenTelemetry 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 macaron
+
+import (
+	"go.opentelemetry.io/otel/api/propagation"
+	"go.opentelemetry.io/otel/api/trace"
+)
+
+// Config is a helper struct to configure Macaron options
+type Config struct {
+	Tracer      trace.Tracer
+	Propagators propagation.Propagators
+}
+
+// Option specifies instrumentation configuration options.
+type Option func(*Config)
+
+// WithTracer specifies a tracer to use for creating spans. If none is
+// specified, a tracer named
+// "go.opentelemetry.io/contrib/plugins/macaron" from the global
+// provider is used.
+func WithTracer(tracer trace.Tracer) Option {
+	return func(cfg *Config) {
+		cfg.Tracer = tracer
+	}
+}
+
+// WithPropagators specifies propagators to use for extracting
+// information from the HTTP requests. If none are specified, global
+// ones will be used.
+func WithPropagators(propagators propagation.Propagators) Option {
+	return func(cfg *Config) {
+		cfg.Propagators = propagators
+	}
+}

plugins/macaron/doc.go

@@ -0,0 +1,20 @@
+// Copyright The OpenTelemetry 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 macaron provides functions to trace the macaron.v1 package
+// (https://github.com/go-macaron/macaron).
+//
+// Currently only the routing of a received message can be
+// instrumented. To do it, use the Middleware function.
+package macaron // import "go.opentelemetry.io/contrib/plugins/macaron"

plugins/macaron/example/Dockerfile

@@ -0,0 +1,20 @@
+# Copyright The OpenTelemetry 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.
+FROM golang:alpine AS base
+COPY . /src/
+WORKDIR /src/plugins/macaron
+
+FROM base AS macaron-server
+RUN go install ./example/server.go
+CMD ["/go/bin/server"]

plugins/macaron/example/docker-compose.yml

@@ -0,0 +1,41 @@
+# Copyright The OpenTelemetry 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.
+version: "3.7"
+services:
+  macaron-client:
+    image: golang:alpine
+    networks:
+      - example
+    command:
+      - "/bin/sh"
+      - "-c"
+      - "wget http://macaron-server:8080/users/123 && cat 123"
+    depends_on:
+      - macaron-server
+  macaron-server:
+    build:
+      dockerfile: $PWD/Dockerfile
+      context: ../../..
+    ports:
+      - "8080:80"
+    command:
+      - "/bin/sh"
+      - "-c"
+      - "/go/bin/server"
+    networks:
+      - example
+    environment:
+      - PORT=80
+networks:
+  example:

plugins/macaron/example/server.go

@@ -0,0 +1,70 @@
+// Copyright The OpenTelemetry 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 main
+
+import (
+	"context"
+	"log"
+
+	macarontrace "go.opentelemetry.io/contrib/plugins/macaron"
+	"gopkg.in/macaron.v1"
+
+	otelglobal "go.opentelemetry.io/otel/api/global"
+	otelkey "go.opentelemetry.io/otel/api/key"
+	oteltrace "go.opentelemetry.io/otel/api/trace"
+	oteltracestdout "go.opentelemetry.io/otel/exporters/trace/stdout"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+var tracer = otelglobal.Tracer("macaron-server")
+
+func main() {
+	initTracer()
+	m := macaron.Classic()
+	m.Use(macarontrace.Middleware("my-server"))
+	m.Get("/users/:id", func(ctx *macaron.Context) string {
+		id := ctx.Params("id")
+		name := getUser(ctx.Req.Context(), id)
+		return name
+	})
+	m.Run()
+}
+
+func initTracer() {
+	exporter, err := oteltracestdout.NewExporter(oteltracestdout.Options{PrettyPrint: true})
+	if err != nil {
+		log.Fatal(err)
+	}
+	cfg := sdktrace.Config{
+		DefaultSampler: sdktrace.AlwaysSample(),
+	}
+	tp, err := sdktrace.NewProvider(
+		sdktrace.WithConfig(cfg),
+		sdktrace.WithSyncer(exporter),
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
+	otelglobal.SetTraceProvider(tp)
+}
+
+func getUser(ctx context.Context, id string) string {
+	_, span := tracer.Start(ctx, "getUser", oteltrace.WithAttributes(otelkey.String("id", id)))
+	defer span.End()
+	if id == "123" {
+		return "macarontrace tester"
+	}
+	return "unknown"
+}

plugins/macaron/go.mod

@@ -0,0 +1,12 @@
+module go.opentelemetry.io/contrib/plugins/macaron
+
+go 1.14
+
+require (
+	github.com/stretchr/testify v1.5.1
+	go.opentelemetry.io/contrib v0.0.0
+	go.opentelemetry.io/otel v0.4.2
+	gopkg.in/macaron.v1 v1.3.5
+)
+
+replace go.opentelemetry.io/contrib => ../../

plugins/macaron/go.sum

@@ -0,0 +1,99 @@
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plugins/macaron/macaron.go

@@ -0,0 +1,79 @@
+// Copyright The OpenTelemetry 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 macaron
+
+import (
+	"fmt"
+	"net/http"
+
+	"gopkg.in/macaron.v1"
+
+	"go.opentelemetry.io/contrib/internal/trace"
+	otelglobal "go.opentelemetry.io/otel/api/global"
+	otelpropagation "go.opentelemetry.io/otel/api/propagation"
+	oteltrace "go.opentelemetry.io/otel/api/trace"
+)
+
+const (
+	tracerKey  = "otel-go-contrib-tracer"
+	tracerName = "go.opentelemetry.io/contrib/plugins/macaron"
+)
+
+// Middleware returns stuff
+func Middleware(service string, opts ...Option) macaron.Handler {
+	cfg := Config{}
+	for _, opt := range opts {
+		opt(&cfg)
+	}
+	if cfg.Tracer == nil {
+		cfg.Tracer = otelglobal.Tracer(tracerName)
+	}
+	if cfg.Propagators == nil {
+		cfg.Propagators = otelglobal.Propagators()
+	}
+	return func(res http.ResponseWriter, req *http.Request, c *macaron.Context) {
+		savedCtx := c.Req.Request.Context()
+		defer func() {
+			c.Req.Request = c.Req.Request.WithContext(savedCtx)
+		}()
+
+		ctx := otelpropagation.ExtractHTTP(savedCtx, cfg.Propagators, c.Req.Header)
+		opts := []oteltrace.StartOption{
+			oteltrace.WithAttributes(trace.NetAttributesFromHTTPRequest("tcp", c.Req.Request)...),
+			oteltrace.WithAttributes(trace.EndUserAttributesFromHTTPRequest(c.Req.Request)...),
+			oteltrace.WithAttributes(trace.HTTPServerAttributesFromHTTPRequest(service, "", c.Req.Request)...),
+			oteltrace.WithSpanKind(oteltrace.SpanKindServer),
+		}
+		// TODO: span name should be router template not the actual request path, eg /user/:id vs /user/123
+		spanName := c.Req.RequestURI
+		if spanName == "" {
+			spanName = fmt.Sprintf("HTTP %s route not found", c.Req.Method)
+		}
+		ctx, span := cfg.Tracer.Start(ctx, spanName, opts...)
+		defer span.End()
+
+		// pass the span through the request context
+		c.Req.Request = c.Req.Request.WithContext(ctx)
+
+		// serve the request to the next middleware
+		c.Next()
+
+		status := c.Resp.Status()
+		attrs := trace.HTTPAttributesFromHTTPStatusCode(status)
+		spanStatus, spanMessage := trace.SpanStatusFromHTTPStatusCode(status)
+		span.SetAttributes(attrs...)
+		span.SetStatus(spanStatus, spanMessage)
+	}
+}