From 7e83b40f9c4cd8f2d57274ead0cc044ad660715a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20S=C3=A1?= <jose.sa@foodora.com>
Date: Tue, 17 Apr 2018 12:36:47 +0200
Subject: [PATCH] POST-937 Move version to top level health check (#39)

---
 example.go                  | 22 ++----------------
 ranger_http/health_check.go | 46 +++++++++++++++++++++++++++++++++----
 version.json                |  1 +
 3 files changed, 45 insertions(+), 24 deletions(-)
 create mode 100644 version.json

diff --git a/example.go b/example.go
index 27b38d3..042ab14 100644
--- a/example.go
+++ b/example.go
@@ -67,8 +67,8 @@ func main() {
 		// /health/check/lb and /health/check
 		// any instance of `func() ranger_http.HealthCheckService` sent as parameter of the configuration will be converted to JSON and printed
 		// if necessary, you also can add a prefix to the endpoints with WithPrefix("/prefix")
-		//     ex: WithHealthCheckFor(ranger_http.NewHealthCheckConfiguration(versionHealthCheck()).WithPrefix("/prefix"))
-		WithHealthCheckFor(ranger_http.NewHealthCheckConfiguration(versionHealthCheck(), etcdHealthCheck()))
+		//     ex: WithHealthCheckFor(ranger_http.NewHealthCheckConfiguration(someHealthCheck()).WithPrefix("/prefix"))
+		WithHealthCheckFor(ranger_http.NewHealthCheckConfiguration(etcdHealthCheck()).WithVersion("version.json"))
 
 	// add some endpoints. based on "github.com/julienschmidt/httprouter"
 	s.GET("/hello", helloEndpoint())
@@ -109,24 +109,6 @@ func helloEndpoint() httprouter.Handle {
 	}
 }
 
-func versionHealthCheck() func() ranger_http.HealthCheckService {
-	type versionHealthCheck struct {
-		Tag    string `json:"tag"`
-		Commit string `json:"commit"`
-	}
-
-	return func() ranger_http.HealthCheckService {
-		return ranger_http.HealthCheckService{
-			Name:   "version",
-			Status: true,
-			Info: versionHealthCheck{
-				Tag:    "0.0.0",
-				Commit: "30ac4383d0260f517d7f171de244fa46c1879c67",
-			},
-		}
-	}
-}
-
 func etcdHealthCheck() func() ranger_http.HealthCheckService {
 	type etcdHealthCheck struct {
 		ResponseTime int `json:"response_time"`
diff --git a/ranger_http/health_check.go b/ranger_http/health_check.go
index 2935801..98d41ed 100644
--- a/ranger_http/health_check.go
+++ b/ranger_http/health_check.go
@@ -3,10 +3,12 @@ package ranger_http
 import (
 	"encoding/json"
 	"fmt"
+	"github.com/julienschmidt/httprouter"
+	"io/ioutil"
 	"net/http"
+	"os"
+	"path/filepath"
 	"time"
-
-	"github.com/julienschmidt/httprouter"
 )
 
 //HealthCheckService
@@ -20,12 +22,19 @@ type HealthCheckService struct {
 type healthCheckConfiguration struct {
 	Prefix   string
 	Services []func() HealthCheckService
+	Version  healthCheckVersion
+}
+
+type healthCheckVersion struct {
+	Tag    string `json:"tag"`
+	Commit string `json:"commit"`
 }
 
 //NewHealthCheckConfiguration
 func NewHealthCheckConfiguration(services ...func() HealthCheckService) healthCheckConfiguration {
 	return healthCheckConfiguration{
 		Services: services,
+		Version:  healthCheckVersion{"n/a", "n/a"},
 	}
 }
 
@@ -36,15 +45,39 @@ func (configuration healthCheckConfiguration) WithPrefix(prefix string) healthCh
 	return configuration
 }
 
+// WithVersion expects the path to a json file for healthCheckVersion
+func (configuration healthCheckConfiguration) WithVersion(versionPath string) healthCheckConfiguration {
+
+	version := healthCheckVersion{}
+	configuration.Version = version
+
+	absPath, _ := filepath.Abs(versionPath)
+	fileBytes, err := ioutil.ReadFile(absPath)
+
+	if err != nil {
+		logger.Warning("Unable to load file "+versionPath, nil)
+	}
+	err = json.Unmarshal(fileBytes, &version)
+	if err != nil {
+		logger.Warning("Error parsing version file "+versionPath, nil)
+	}
+
+	configuration.Version = version
+
+	return configuration
+}
+
 type healthCheckResponse struct {
 	HTTPStatus int                    `json:"http-status"`
 	Time       float64                `json:"time"`
 	Services   map[string]interface{} `json:"checks"`
+	Version    healthCheckVersion     `json:"version"`
+	Host       string                 `json:"host"`
 }
 
 //WithHealthCheckFor ...
 func (s Server) WithHealthCheckFor(configuration healthCheckConfiguration) Server {
-	s.GET(fmt.Sprintf("%s/health/check", configuration.Prefix), HealthCheckHandler(configuration.Services))
+	s.GET(fmt.Sprintf("%s/health/check", configuration.Prefix), HealthCheckHandler(configuration))
 	s.GET(fmt.Sprintf("%s/health/check/lb", configuration.Prefix), HealthCheckHandlerLB())
 	return s
 }
@@ -64,11 +97,14 @@ type healthCheckServiceResponse struct {
 }
 
 // HealthCheckHandler to check the service and external dependencies
-func HealthCheckHandler(services []func() HealthCheckService) httprouter.Handle {
+func HealthCheckHandler(configuration healthCheckConfiguration) httprouter.Handle {
 	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
 		w.Header().Set("Content-Type", "application/json; charset=UTF-8")
 		w.Header().Set("Cache-Control", "no-cache, private, max-age=0")
 
+		services := configuration.Services
+		hostname, _ := os.Hostname()
+
 		mapServices := make(map[string]interface{})
 
 		statusCode := http.StatusOK
@@ -96,6 +132,8 @@ func HealthCheckHandler(services []func() HealthCheckService) httprouter.Handle
 				HTTPStatus: statusCode,
 				Time:       ElapsedTimeSince(sAll),
 				Services:   mapServices,
+				Version:    configuration.Version,
+				Host:       hostname,
 			})
 	}
 }
diff --git a/version.json b/version.json
new file mode 100644
index 0000000..b4943c9
--- /dev/null
+++ b/version.json
@@ -0,0 +1 @@
+{"tag": "this-is-tag", "commit": "this-is-commit"}