Merge pull request #129 from mainflux/feature-manager-client

Authentication client

glide.yaml

@@ -15,6 +15,8 @@ import:
     version: 1.3.0
   - package: github.com/prometheus/client_golang
     version: 0.8.0
+  - package: github.com/sony/gobreaker
+    version: 0.3.0
   - package: go.uber.org/zap
     version: 1.7.0
   - package: golang.org/x/crypto

http/README.md

@@ -9,9 +9,9 @@ The service is configured using the environment variables presented in the
 following table. Note that any unset variables will be replaced with their
 default values.
 
-| Variable         | Description       | Default               |
-|------------------|-------------------|-----------------------|
-| ADAPTER_NATS_URL | NATS instance URL | nats://localhost:4222 |
+| Variable              | Description       | Default               |
+|-----------------------|-------------------|-----------------------|
+| HTTP_ADAPTER_NATS_URL | NATS instance URL | nats://localhost:4222 |
 
 ## Deployment
 
@@ -27,7 +27,7 @@ services:
     ports:
       - [host machine port]:8180
     environment:
-      ADAPTER_NATS_URL: [NATS instance URL]
+      HTTP_ADAPTER_NATS_URL: [NATS instance URL]
 ```
 
 To start the service outside of the container, execute the following shell script:
@@ -42,7 +42,7 @@ cd $GOPATH/src/github.com/mainflux/mainflux/cmd/http
 CGO_ENABLED=0 GOOS=[platform identifier] go build -ldflags "-s" -a -installsuffix cgo -o app
 
 # set the environment variables and run the service
-ADAPTER_NATS_URL=[NATS instance URL] app
+HTTP_ADAPTER_NATS_URL=[NATS instance URL] app
 ```
 
 ## Usage

manager/client/client.go

@@ -0,0 +1,82 @@
+// Package client provides a manager service client intended for internal
+// service communication.
+package client
+
+import (
+	"errors"
+	"net/http"
+	"time"
+
+	"github.com/mainflux/mainflux/manager"
+	"github.com/sony/gobreaker"
+)
+
+const (
+	timeout         = time.Second * 5
+	maxFailedReqs   = 3
+	maxFailureRatio = 0.6
+)
+
+// ErrServiceUnreachable indicates that the service instance is not available.
+var ErrServiceUnreachable = errors.New("manager service unavailable")
+
+type managerClient struct {
+	url string
+	cb  *gobreaker.CircuitBreaker
+}
+
+// NewClient instantiates the manager service client given its base URL.
+func NewClient(url string) managerClient {
+	st := gobreaker.Settings{
+		Name: "Manager",
+		ReadyToTrip: func(counts gobreaker.Counts) bool {
+			fr := float64(counts.TotalFailures) / float64(counts.Requests)
+			return counts.Requests >= maxFailedReqs && fr >= maxFailureRatio
+		},
+	}
+
+	mc := managerClient{
+		url: url,
+		cb:  gobreaker.NewCircuitBreaker(st),
+	}
+
+	return mc
+}
+
+func (mc managerClient) Authenticate(req *http.Request) (string, error) {
+	response, err := mc.cb.Execute(func() (interface{}, error) {
+		hc := &http.Client{
+			Timeout: timeout,
+		}
+
+		mgReq, err := http.NewRequest("POST", mc.url+"/identity", nil)
+		if err != nil {
+			return "", ErrServiceUnreachable
+		}
+
+		mgReq.Header.Set("Authorization", req.Header.Get("Authorization"))
+
+		res, err := hc.Do(mgReq)
+		defer res.Body.Close()
+
+		if err != nil {
+			return "", ErrServiceUnreachable
+		}
+
+		if res.StatusCode != http.StatusOK {
+			return manager.ErrUnauthorizedAccess, nil
+		}
+
+		return res.Header.Get("X-Client-Id"), nil
+	})
+
+	if err != nil {
+		return "", err
+	}
+
+	if key, ok := response.(string); !ok {
+		return "", manager.ErrUnauthorizedAccess
+	} else {
+		return key, nil
+	}
+}