Added gtg endpoint (#20)

* Added gtg endpoint

* Added tests for the gtg endpoint

* Updated badges. Removed coveralls badge branch info

README.md

@@ -1,4 +1,4 @@
-[![CircleCI](https://circleci.com/gh/Financial-Times/content-preview.svg?style=svg)](https://circleci.com/gh/Financial-Times/content-preview) [![Coverage Status](https://coveralls.io/repos/github/Financial-Times/content-preview/badge.svg?branch=master)](https://coveralls.io/github/Financial-Times/content-preview?branch=master)
+[![CircleCI](https://circleci.com/gh/Financial-Times/content-preview.svg?style=shield)](https://circleci.com/gh/Financial-Times/content-preview) [![Coverage Status](https://coveralls.io/repos/github/Financial-Times/content-preview/badge.svg)](https://coveralls.io/github/Financial-Times/content-preview)
 
 # Content Preview Service (content-preview)
 

app.go

@@ -1,16 +1,18 @@
 package main
 
 import (
+	"net/http"
+	"os"
+	"time"
+
 	fthealth "github.com/Financial-Times/go-fthealth/v1a"
 	oldhttphandlers "github.com/Financial-Times/http-handlers-go/httphandlers"
+	"github.com/Financial-Times/service-status-go/gtg"
 	"github.com/Financial-Times/service-status-go/httphandlers"
 	"github.com/Sirupsen/logrus"
 	"github.com/gorilla/handlers"
 	"github.com/gorilla/mux"
 	"github.com/jawher/mow.cli"
-	"net/http"
-	"os"
-	"time"
 )
 
 const serviceDescription = "A RESTful API for retrieving and transforming content to preview data"
@@ -154,6 +156,8 @@ func setupServiceHandler(sc ServiceConfig, metricsHandler Metrics, contentHandle
 		oldhttphandlers.TransactionAwareRequestLoggingHandler(logrus.StandardLogger(), contentHandler))})
 	r.Path(httphandlers.BuildInfoPath).HandlerFunc(httphandlers.BuildInfoHandler)
 	r.Path(httphandlers.PingPath).HandlerFunc(httphandlers.PingHandler)
+	gtgHandler := httphandlers.NewGoodToGoHandler(gtg.StatusChecker(sc.gtgCheck))
+	r.Path(httphandlers.GTGPath).HandlerFunc(gtgHandler)
 	r.Path("/__health").Handler(handlers.MethodHandler{"GET": http.HandlerFunc(fthealth.Handler(sc.serviceName, serviceDescription, sc.nativeContentSourceCheck(), sc.transformerServiceCheck()))})
 	r.Path("/__metrics").Handler(handlers.MethodHandler{"GET": http.HandlerFunc(metricsHttpEndpoint)})
 	return r

app_test.go

@@ -3,22 +3,28 @@ package main
 import (
 	"bytes"
 	"encoding/json"
-	fthealth "github.com/Financial-Times/go-fthealth/v1a"
-	tid "github.com/Financial-Times/transactionid-utils-go"
-	"github.com/gorilla/handlers"
-	"github.com/gorilla/mux"
-	"github.com/stretchr/testify/assert"
+	"fmt"
 	"io"
+	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"os"
 	"testing"
+
+	fthealth "github.com/Financial-Times/go-fthealth/v1a"
+	tid "github.com/Financial-Times/transactionid-utils-go"
+	"github.com/gorilla/handlers"
+	"github.com/gorilla/mux"
+	"github.com/stretchr/testify/assert"
 )
 
 var contentPreviewService *httptest.Server
 var methodeApiMock *httptest.Server
 var methodeArticleTransformerMock *httptest.Server
 
+const sourceAppName = "Native Content Service"
+const transformAppName = "Native Content Transformer Service"
+
 func startMethodeApiMock(status string) {
 	r := mux.NewRouter()
 	if status == "happy" {
@@ -143,8 +149,8 @@ func startContentPreviewService() {
 		methodArticleTransformerUrl,
 		nativeContentAppHealthUri,
 		transformAppHealthUrl,
-		"Native Content Service",
-		"Native Content Transformer Service",
+		sourceAppName,
+		transformAppName,
 		"panic guide",
 		"panic guide",
 		"business impact",
@@ -161,7 +167,7 @@ func startContentPreviewService() {
 	contentPreviewService = httptest.NewServer(h)
 }
 
-func TestShouldReturn200AndTrasformerOutput(t *testing.T) {
+func TestShouldReturn200AndTransformerOutput(t *testing.T) {
 	startMethodeApiMock("happy")
 	startMethodeArticleTransformerMock("happy")
 	startContentPreviewService()
@@ -346,3 +352,71 @@ func TestShouldBeUnhealthyWhenTransformerIsNotHappy(t *testing.T) {
 	}
 
 }
+
+func TestGtgShouldReturn503WhenMethodeApiIsNotHappy(t *testing.T) {
+	startMethodeApiMock("unhappy")
+	startMethodeArticleTransformerMock("happy")
+	startContentPreviewService()
+	defer stopServices()
+
+	resp, err := http.Get(contentPreviewService.URL + "/__gtg")
+	if err != nil {
+		panic(err)
+	}
+	defer resp.Body.Close()
+
+	assert.Equal(t, http.StatusServiceUnavailable, resp.StatusCode, "Response status code should be 503")
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		assert.Fail(t, "No error should be returned when reading the response body")
+	}
+	expectedRespBody := fmt.Sprintf("%s service is not responding with OK. status=%d", sourceAppName, http.StatusInternalServerError)
+	actualRespBody := string(body)
+	assert.Equal(t, expectedRespBody, actualRespBody)
+}
+
+func TestGtgShouldReturn503WhenTransformerIsNotHappy(t *testing.T) {
+	startMethodeApiMock("happy")
+	startMethodeArticleTransformerMock("unhappy")
+	startContentPreviewService()
+	defer stopServices()
+
+	resp, err := http.Get(contentPreviewService.URL + "/__gtg")
+	if err != nil {
+		panic(err)
+	}
+	defer resp.Body.Close()
+
+	assert.Equal(t, http.StatusServiceUnavailable, resp.StatusCode, "Response status code should be 503")
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		assert.Fail(t, "No error should be returned when reading the response body")
+	}
+	expectedRespBody := fmt.Sprintf("%s service is not responding with OK. status=%d", transformAppName, http.StatusInternalServerError)
+	actualRespBody := string(body)
+	assert.Equal(t, expectedRespBody, actualRespBody)
+}
+
+func TestGtgShouldReturn200(t *testing.T) {
+	startMethodeApiMock("happy")
+	startMethodeArticleTransformerMock("happy")
+	startContentPreviewService()
+	defer stopServices()
+
+	resp, err := http.Get(contentPreviewService.URL + "/__gtg")
+	if err != nil {
+		panic(err)
+	}
+	defer resp.Body.Close()
+
+	assert.Equal(t, http.StatusOK, resp.StatusCode, "Response status code should be 200")
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		assert.Fail(t, "No error should be returned when reading the response body")
+	}
+	actualRespBody := string(body)
+	assert.Equal(t, "OK", actualRespBody)
+}

healthchecks.go

@@ -3,8 +3,10 @@ package main
 import (
 	"errors"
 	"fmt"
-	fthealth "github.com/Financial-Times/go-fthealth/v1a"
 	"net/http"
+
+	fthealth "github.com/Financial-Times/go-fthealth/v1a"
+	"github.com/Financial-Times/service-status-go/gtg"
 )
 
 func (sc *ServiceConfig) nativeContentSourceCheck() fthealth.Check {
@@ -33,6 +35,20 @@ func (sc *ServiceConfig) transformerServiceCheck() fthealth.Check {
 	}
 }
 
+func (sc *ServiceConfig) gtgCheck() gtg.Status {
+	msg, err := checkServiceAvailability(sc.sourceAppName, sc.sourceAppHealthUri, sc.sourceAppAuth, "")
+	if err != nil {
+		return gtg.Status{GoodToGo: false, Message: msg}
+	}
+
+	msg, err = checkServiceAvailability(sc.transformAppName, sc.transformAppHealthUri, "", sc.transformAppHostHeader)
+	if err != nil {
+		return gtg.Status{GoodToGo: false, Message: msg}
+	}
+
+	return gtg.Status{GoodToGo: true}
+}
+
 func checkServiceAvailability(serviceName string, healthUri string, auth string, hostHeader string) (string, error) {
 	req, err := http.NewRequest("GET", healthUri, nil)
 	if auth != "" {