Remade in Golang (#1)

* Update to Golang with Prometheus instrumentation

* Add logging

* Use gin instead of net/http

* Remove unnecessary library

* Instrument gin app

* Add CI/CD

* Remove docker

* Add latest master go

* Add build status

* Cleanup

Author: vincetse

.travis.yml

@@ -1,5 +1,7 @@
-language: python
-services:
-  - docker
+language: go
+go:
+- 1.8
+- 1.9
+- master
 script:
-  - docker build -t infrastructureascode/hello-world .
+- make all

Dockerfile

@@ -1,10 +1,14 @@
-FROM alpine
+# Copied from https://github.com/prometheus/client_golang/blob/master/examples/simple/Dockerfile
 
-RUN apk update && \
-    apk upgrade && \
-    apk add nginx && \
-    mkdir -p /run/nginx
+FROM golang:1.9.2 AS builder
+WORKDIR /go/src/github.com/infrastructure-as-code/docker-hello-world
+ENV GIN_MODE debug
+COPY Makefile *.go ./
+RUN make all
 
-COPY default.conf /etc/nginx/conf.d/default.conf
-EXPOSE 80
-CMD nginx -g "daemon off;"
+FROM scratch
+LABEL maintainer "Vince Tse <[email protected]>"
+COPY --from=builder /go/src/github.com/infrastructure-as-code/docker-hello-world/hello_world .
+ENV GIN_MODE release
+EXPOSE 8080
+ENTRYPOINT ["/hello_world"]

Makefile

@@ -0,0 +1,9 @@
+all: deps test
+	CGO_ENABLED=0 go build -a -o hello_world
+
+test:
+	GIN_MODE=debug go test
+
+deps:
+	go get -d
+	go get github.com/stretchr/testify

README.md

@@ -1,16 +1,19 @@
+[![Build Status](https://travis-ci.org/infrastructure-as-code/docker-hello-world.svg?branch=master)](https://travis-ci.org/infrastructure-as-code/docker-hello-world)
+
 # infrastructureascode/hello-world
 
-A Docker "Hello World" web server inspired by the [tutum/hello-world](https://hub.docker.com/r/tutum/hello-world/) image which seems to have become unmaintained, and returns HTTP/400 more often than it should.
+A [Prometheus](https://prometheus.io/)-instrumented Docker "Hello World" web server.
 
 ## Features
 
-1. Always returns a HTTP 200 status code and a "Hello, world!" message.
-1. Has a health check endpoint, `/health`, that returns an empty response.
+1. Always returns a HTTP 200 status code and a "Hello, World!" message at the `/` path.
+1. Has a metrics endpoint at `/metrics` that returns Prometheus metrics.
+1. Has a health check endpoint, `/health`, that returns an empty response and a HTTP 200 response.
 
 ## Building
 
 ```
-docker build --rm infrastructureascode/hello-world .
+docker build --rm -t infrastructureascode/hello-world .
 ```
 
 ## Usage
@@ -20,12 +23,15 @@ docker build --rm infrastructureascode/hello-world .
 docker run \
   --detach \
   --name hello-world \
-  --publish 8000:80 \
+  --publish 8000:8080 \
   infrastructureascode/hello-world
 
 # curl the container
 curl http://0.0.0.0:8000/
 
 # curl the health check endpoint which returns an empty response
 curl http://0.0.0.0:8000/health
+
+# curl Prometheus metrics
+curl http://0.0.0.0:8000/metrics
 ```

default.conf

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"net/http"
+  "os"
+
+  "github.com/gin-gonic/gin"
+  "github.com/zsais/go-gin-prometheus"
+)
+
+var hostname = getHostname()
+
+func getHostname() string {
+  var name, err = os.Hostname()
+  if err != nil {
+    panic(err)
+  }
+  return name
+}
+
+func helloFunc(c *gin.Context) {
+  c.Writer.Header().Set("X-Hostname", hostname)
+  c.String(http.StatusOK, "Hello, World!")
+}
+
+func healthFunc(c *gin.Context) {
+  c.Writer.Header().Set("X-Hostname", hostname)
+  c.String(http.StatusOK, "")
+}
+
+func setupRouter() *gin.Engine {
+  router := gin.Default()
+  ginprom := ginprometheus.NewPrometheus("gin")
+  ginprom.Use(router)
+  router.GET("/", helloFunc)
+  router.GET("/health", healthFunc)
+  return router
+}
+
+func main() {
+  router := setupRouter()
+  router.Run()
+}

hello_world.go

@@ -0,0 +1,42 @@
+
+package main
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDefaultRoute(t *testing.T) {
+  router := setupRouter()
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest("GET", "/", nil)
+	router.ServeHTTP(w, req)
+
+  assert.Equal(t, 200, w.Code)
+	assert.Equal(t, "Hello, World!", w.Body.String())
+}
+
+func TestHealthRoute(t *testing.T) {
+  router := setupRouter()
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest("GET", "/health", nil)
+	router.ServeHTTP(w, req)
+
+  assert.Equal(t, 200, w.Code)
+	assert.Equal(t, "", w.Body.String())
+}
+
+func TestMetricsRoute(t *testing.T) {
+  router := setupRouter()
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest("GET", "/metrics", nil)
+	router.ServeHTTP(w, req)
+
+  assert.Equal(t, 200, w.Code)
+}