Add a simple /healthz endpoint

- Also remove the old hello world code

Signed-off-by: Andrew Keesler <akeesler@vmware.com>

cmd/placeholder-name/main.go

@@ -6,11 +6,11 @@ SPDX-License-Identifier: Apache-2.0
 package main
 
 import (
-	"fmt"
-
-	"github.com/suzerain-io/placeholder-name/pkg/hello"
+	"github.com/suzerain-io/placeholder-name/pkg/handlers"
+	"log"
+	"net/http"
 )
 
 func main() {
-	fmt.Println(hello.NewHelloSayer().SayHello())
+	log.Fatal(http.ListenAndServe(":8080", handlers.New()))
 }

go.mod

@@ -1,3 +1,5 @@
 module github.com/suzerain-io/placeholder-name
 
 go 1.14
+
+require github.com/stretchr/testify v1.6.1

go.sum

@@ -0,0 +1,11 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+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/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

pkg/handlers/handlers.go

@@ -0,0 +1,17 @@
+/*
+Copyright 2020 VMware, Inc.
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package handlers
+
+import "net/http"
+
+const JsonMimeType = "application/json; charset=utf-8"
+const HeaderNameContentType = "Content-Type"
+
+func New() http.Handler {
+	mux := http.NewServeMux()
+	mux.Handle("/healthz", newHealthzHandler())
+	return mux
+}

pkg/handlers/healthz_handler.go

@@ -0,0 +1,28 @@
+/*
+Copyright 2020 VMware, Inc.
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+type healthzResponse struct {
+	Status string `json:"status"`
+}
+
+type healthzHandler struct{}
+
+func (h healthzHandler) ServeHTTP(responseWriter http.ResponseWriter, _ *http.Request) {
+	response := healthzResponse{"OK"}
+	js, _ := json.Marshal(response)
+	responseWriter.Header().Set(HeaderNameContentType, JsonMimeType)
+	_, _ = responseWriter.Write(js)
+}
+
+func newHealthzHandler() http.Handler {
+	return healthzHandler{}
+}

pkg/handlers/healthz_handler_test.go

@@ -0,0 +1,31 @@
+/*
+Copyright 2020 VMware, Inc.
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package handlers_test
+
+import (
+	"github.com/stretchr/testify/require"
+	"github.com/suzerain-io/placeholder-name/pkg/handlers"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestHealthzReturnsOkWithJsonBody(t *testing.T) {
+	expect := require.New(t)
+	server := httptest.NewServer(handlers.New())
+	defer server.Close()
+	client := http.Client{}
+
+	response, err := client.Get(server.URL + "/healthz")
+
+	expect.NoError(err)
+	expect.Equal(http.StatusOK, response.StatusCode)
+	expect.Equal("application/json; charset=utf-8", response.Header.Get("content-type"))
+	body, err := ioutil.ReadAll(response.Body)
+	expect.NoError(err)
+	expect.JSONEq(`{"status": "OK"}`, string(body))
+}

pkg/hello/hello.go

@@ -1,18 +0,0 @@
-/*
-Copyright 2020 VMware, Inc.
-SPDX-License-Identifier: Apache-2.0
-*/
-
-package hello
-
-type HelloSayer interface {
-	SayHello() string
-}
-
-type helloSayerImpl struct{}
-
-func (helloSayerImpl) SayHello() string { return "hello" }
-
-func NewHelloSayer() HelloSayer {
-	return helloSayerImpl{}
-}

pkg/hello/hello_test.go

@@ -1,17 +0,0 @@
-/*
-Copyright 2020 VMware, Inc.
-SPDX-License-Identifier: Apache-2.0
-*/
-
-package hello
-
-import (
-	"testing"
-)
-
-func TestHelloSayerImpl_SayHello(t *testing.T) {
-	actualGreeting := NewHelloSayer().SayHello()
-	if actualGreeting != "hello" {
-		t.Errorf("expected to say hello but said %v", actualGreeting)
-	}
-}