From 9479cbee81d219afc5520c0fe38f00a162af9f95 Mon Sep 17 00:00:00 2001
From: Jeremy Loy <jeremy.b.loy@icloud.com>
Date: Sun, 2 Sep 2018 20:15:23 -0400
Subject: [PATCH] Add NewRelic middleware example.

---
 examples/new_relic/README.md | 30 +++++++++++++++++++++++++
 examples/new_relic/main.go   | 43 ++++++++++++++++++++++++++++++++++++
 go.mod                       |  1 +
 go.sum                       |  2 ++
 4 files changed, 76 insertions(+)
 create mode 100644 examples/new_relic/README.md
 create mode 100644 examples/new_relic/main.go

diff --git a/examples/new_relic/README.md b/examples/new_relic/README.md
new file mode 100644
index 00000000..70f14942
--- /dev/null
+++ b/examples/new_relic/README.md
@@ -0,0 +1,30 @@
+The [New Relic Go Agent](https://github.com/newrelic/go-agent) provides a nice middleware for the stdlib handler signature. 
+The following is an adaptation of that middleware for Gin.
+
+```golang
+const (
+	// NewRelicTxnKey is the key used to retrieve the NewRelic Transaction from the context
+	NewRelicTxnKey = "NewRelicTxnKey"
+)
+
+// NewRelicMonitoring is a middleware that starts a newrelic transaction, stores it in the context, then calls the next handler
+func NewRelicMonitoring(app newrelic.Application) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		txn := app.StartTransaction(ctx.Request.URL.Path, ctx.Writer, ctx.Request)
+		defer txn.End()
+		ctx.Set(NewRelicTxnKey, txn)
+		ctx.Next()
+	}
+}
+```
+and in `main.go` or equivalent...
+```golang
+router := gin.Default()
+cfg := newrelic.NewConfig(os.Getenv("APP_NAME"), os.Getenv("NEW_RELIC_API_KEY"))
+app, err := newrelic.NewApplication(cfg)
+if err != nil {
+		log.Printf("failed to make new_relic app: %v", err)
+} else {
+		router.Use(adapters.NewRelicMonitoring(app))
+}
+ ```
diff --git a/examples/new_relic/main.go b/examples/new_relic/main.go
new file mode 100644
index 00000000..157aaa8b
--- /dev/null
+++ b/examples/new_relic/main.go
@@ -0,0 +1,43 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+
+	"github.com/gin-gonic/gin"
+	"github.com/newrelic/go-agent"
+)
+
+const (
+	// NewRelicTxnKey is the key used to retrieve the NewRelic Transaction from the context
+	NewRelicTxnKey = "NewRelicTxnKey"
+)
+
+// NewRelicMonitoring is a middleware that starts a newrelic transaction, stores it in the context, then calls the next handler
+func NewRelicMonitoring(app newrelic.Application) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		txn := app.StartTransaction(ctx.Request.URL.Path, ctx.Writer, ctx.Request)
+		defer txn.End()
+		ctx.Set(NewRelicTxnKey, txn)
+		ctx.Next()
+	}
+}
+
+func main() {
+	router := gin.Default()
+
+	cfg := newrelic.NewConfig(os.Getenv("APP_NAME"), os.Getenv("NEW_RELIC_API_KEY"))
+	app, err := newrelic.NewApplication(cfg)
+	if err != nil {
+		log.Printf("failed to make new_relic app: %v", err)
+	} else {
+		router.Use(NewRelicMonitoring(app))
+	}
+
+	router.GET("/", func(c *gin.Context) {
+		c.String(http.StatusOK, "Hello World!\n")
+	})
+	router.Run()
+}
+
diff --git a/go.mod b/go.mod
index bd4ad975..4fab4c5c 100644
--- a/go.mod
+++ b/go.mod
@@ -12,6 +12,7 @@ require (
 	github.com/mattn/go-isatty v0.0.3
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.1 // indirect
+	github.com/newrelic/go-agent v2.1.0+incompatible
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/stretchr/testify v1.2.2
 	github.com/thinkerou/favicon v0.0.0-20170710140520-94a442a49da6
diff --git a/go.sum b/go.sum
index 3382beed..700893b9 100644
--- a/go.sum
+++ b/go.sum
@@ -27,6 +27,8 @@ github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/reflect2 v1.0.1 h1:9f412s+6RmYXLWZSEzVVgPGK7C2PphHj5RJrvfx9AWI=
 github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
+github.com/newrelic/go-agent v2.1.0+incompatible h1:fCuxXeM4eeIKPbzffOWW6y2Dj+eYfc3yylgNZACZqkM=
+github.com/newrelic/go-agent v2.1.0+incompatible/go.mod h1:a8Fv1b/fYhFSReoTU6HDkTYIMZeSVNffmoS726Y0LzQ=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=