Feature: Add OpenTracing (gomods#112)

* tracing

* oops

.drone.yml

@@ -0,0 +1,18 @@
+workspace:
+  base: /go
+  path: src/github.com/gomods/athens
+
+pipeline:
+  ping:
+    image: mongo:3.0
+    commands:
+      - sleep 15
+  build:
+    image: golang:1.10
+    commands:
+      - go test ./...
+
+services:
+  mongo:
+    image: mongo:3.0
+    command: [ --smallfiles ]

actions/app.go

@@ -61,7 +61,7 @@ func App() *buffalo.App {
 		if ENV == "development" {
 			app.Use(middleware.ParameterLogger)
 		}
-
+		initializeTracing(app)
 		// Protect against CSRF attacks. https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)
 		// Remove to disable this.
 		csrfMiddleware := csrf.New

actions/home.go

@@ -1,6 +1,9 @@
 package actions
 
 import (
+	"time"
+
+	"github.com/bketelsen/buffet"
 	"github.com/gobuffalo/buffalo"
 )
 
@@ -9,5 +12,13 @@ func proxyHomeHandler(c buffalo.Context) error {
 }
 
 func homeHandler(c buffalo.Context) error {
+	slow(c)
 	return c.Render(200, registry.HTML("index.html"))
 }
+
+func slow(c buffalo.Context) {
+	sp := buffet.ChildSpan("slow", c)
+	defer sp.Finish()
+	time.Sleep(1 * time.Millisecond)
+
+}

actions/tracing.go

@@ -0,0 +1,41 @@
+package actions
+
+import (
+	"log"
+	"time"
+
+	"github.com/bketelsen/buffet"
+	"github.com/gobuffalo/buffalo"
+	opentracing "github.com/opentracing/opentracing-go"
+	"github.com/uber/jaeger-client-go/config"
+	"github.com/uber/jaeger-client-go/rpcmetrics"
+	"github.com/uber/jaeger-lib/metrics/prometheus"
+)
+
+func initializeTracing(app *buffalo.App) {
+	cfg := config.Configuration{
+		Sampler: &config.SamplerConfig{
+			Type:  "const",
+			Param: 1,
+		},
+		Reporter: &config.ReporterConfig{
+			LogSpans:            true,
+			BufferFlushInterval: 1 * time.Second,
+			LocalAgentHostPort:  "0.0.0.0:6831", //hostPort,
+		},
+	}
+	// TODO(ys) a quick hack to ensure random generators get different seeds, which are based on current time.
+	time.Sleep(100 * time.Millisecond)
+	metricsFactory := prometheus.New()
+	tracer, _, err := cfg.New(
+		"athens", //serviceName,
+
+		config.Observer(rpcmetrics.NewObserver(metricsFactory, rpcmetrics.DefaultNameNormalizer)),
+	)
+	if err != nil {
+		log.Fatal("cannot initialize Jaeger Tracer", err)
+	}
+	opentracing.SetGlobalTracer(tracer)
+	app.Use(buffet.OpenTracing(tracer))
+
+}

docker-compose.yml

@@ -1,15 +1,27 @@
-version: '3'
-services:
-  mongo:
-    image: mongo:3.0.15-wheezy
-    ports:
-      - 27017:27017
-  mysql:
-    image: bitnami/mysql:5.7.21-r7
-    ports:
-      - "3306:3306"
-    environment:
-      - "ALLOW_EMPTY_PASSWORD=yes"
-      - "MYSQL_USER=vgp"
-      - "MYSQL_PASSWORD=vgp"
-      - "MYSQL_DATABASE=vgoprox"
+version: '3'
+services:
+  mongo:
+    image: mongo:3.0.15-wheezy
+    ports:
+      - 27017:27017
+  mysql:
+    image: bitnami/mysql:5.7.21-r7
+    ports:
+      - "3306:3306"
+    environment:
+      - "ALLOW_EMPTY_PASSWORD=yes"
+      - "MYSQL_USER=vgp"
+      - "MYSQL_PASSWORD=vgp"
+      - "MYSQL_DATABASE=vgoprox"
+  jaeger:
+    environment:
+      - COLLECTOR_ZIPKIN_HTTP_PORT=9441
+    image: jaegertracing/all-in-one:latest
+    ports:
+      - 14268:14268
+      - 9411:9411
+      - 5775:5775/udp
+      - 6831:6831/udp
+      - 6832:6832/udp
+      - 5778:5778
+      - 16686:16686