Unify service versioning

Services are versioned through top-level package. The package itself
contains an HTTP header that will be bound to the '/version' endpoint of
each of the available services.

Signed-off-by: Dejan Mijic <dejan@mainflux.com>

http/api/transport.go

@@ -10,6 +10,7 @@ import (
 	"github.com/cisco/senml"
 	kithttp "github.com/go-kit/kit/transport/http"
 	"github.com/go-zoo/bone"
+	"github.com/mainflux/mainflux"
 	adapter "github.com/mainflux/mainflux/http"
 	"github.com/mainflux/mainflux/writer"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -41,6 +42,7 @@ func MakeHandler(svc adapter.Service) http.Handler {
 		opts...,
 	))
 
+	r.GetFunc("/version", mainflux.Version())
 	r.Handle("/metrics", promhttp.Handler())
 
 	return r

manager/api/endpoint.go

@@ -7,17 +7,6 @@ import (
 	"github.com/mainflux/mainflux/manager"
 )
 
-func infoEndpoint(svc manager.Service) endpoint.Endpoint {
-	return func(_ context.Context, request interface{}) (interface{}, error) {
-		info, err := svc.Info()
-		if err != nil {
-			return nil, err
-		}
-
-		return infoRes{Version: info.Version}, nil
-	}
-}
-
 func registrationEndpoint(svc manager.Service) endpoint.Endpoint {
 	return func(_ context.Context, request interface{}) (interface{}, error) {
 		user := request.(manager.User)

manager/api/resources.go

@@ -15,25 +15,6 @@ type apiResponse interface {
 	empty() bool
 }
 
-// Info
-type infoReq struct{}
-
-type infoRes struct {
-	Version string `json:"version"`
-}
-
-func (res infoRes) headers() map[string]string {
-	return map[string]string{}
-}
-
-func (res infoRes) code() int {
-	return http.StatusOK
-}
-
-func (res infoRes) empty() bool {
-	return false
-}
-
 type clientReq struct {
 	key    string
 	id     string

manager/api/transport.go

@@ -7,6 +7,7 @@ import (
 
 	kithttp "github.com/go-kit/kit/transport/http"
 	"github.com/go-zoo/bone"
+	"github.com/mainflux/mainflux"
 	"github.com/mainflux/mainflux/manager"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
@@ -19,13 +20,6 @@ func MakeHandler(svc manager.Service) http.Handler {
 
 	r := bone.New()
 
-	r.Get("/info", kithttp.NewServer(
-		infoEndpoint(svc),
-		decodeInfo,
-		encodeResponse,
-		opts...,
-	))
-
 	r.Post("/users", kithttp.NewServer(
 		registrationEndpoint(svc),
 		decodeCredentials,
@@ -124,16 +118,12 @@ func MakeHandler(svc manager.Service) http.Handler {
 		opts...,
 	))
 
+	r.GetFunc("/version", mainflux.Version())
 	r.Handle("/metrics", promhttp.Handler())
 
 	return r
 }
 
-func decodeInfo(_ context.Context, r *http.Request) (interface{}, error) {
-	req := infoReq{}
-	return req, nil
-}
-
 func decodeCredentials(_ context.Context, r *http.Request) (interface{}, error) {
 	var user manager.User
 	if err := json.NewDecoder(r.Body).Decode(&user); err != nil {

manager/info.go

@@ -1,13 +0,0 @@
-package manager
-
-const Version = "1.0.0"
-
-type Info struct {
-	Version string
-}
-
-func getInfo() (Info, error) {
-	info := Info{Version: Version}
-
-	return info, nil
-}

manager/manager.go

@@ -22,14 +22,6 @@ func NewService(users UserRepository, clients ClientRepository, channels Channel
 	}
 }
 
-func (ms *managerService) Info() (Info, error) {
-	info, err := getInfo()
-	if err != nil {
-		return Info{}, err
-	}
-	return info, nil
-}
-
 func (ms *managerService) Register(user User) error {
 	if err := user.validate(); err != nil {
 		return err

manager/service.go

@@ -24,9 +24,6 @@ var (
 // Service specifies an API that must be fullfiled by the domain service
 // implementation, and all of its decorators (e.g. logging & metrics).
 type Service interface {
-	// Version
-	Info() (Info, error)
-
 	// Register creates new user account. In case of the failed registration, a
 	// non-nil error value is returned.
 	Register(User) error

version.go

@@ -0,0 +1,25 @@
+// Package mainflux acts as an umbrella package containing multiple different
+// microservices / deliverables. It provides the top-level platform versioning.
+package mainflux
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+const version string = "1.0.0"
+
+type response struct {
+	Version string
+}
+
+// Version exposes an HTTP handler for retrieving service version.
+func Version() http.HandlerFunc {
+	return http.HandlerFunc(func(rw http.ResponseWriter, _ *http.Request) {
+		res := response{Version: version}
+
+		data, _ := json.Marshal(res)
+
+		rw.Write(data)
+	})
+}