Merge pull request #7 from meltwater/status_endpoint

Added a /v1/status endpoint for use with load balancer health checks

.gitignore

@@ -4,3 +4,4 @@ coverage.txt
 .vscode
 vendor/
 .aws
+keys/

README.md

@@ -319,6 +319,10 @@ load balancer in front of them to ensure high availability. The daemon defaults
 bind to 5070/tcp. The `secretary daemon` is completely stateless and can be load balanced
 easily.
 
+The daemon has an HTTP health check endpoint at `/v1/status` that will respond with
+`HTTP 200 OK` if all is well. This can be useful to point a load balancers health check
+mechanism at.
+
 ### Systemd and CoreOS/Fleet
 Create a [Systemd unit](http://www.freedesktop.org/software/systemd/man/systemd.unit.html) file
 in **/etc/systemd/system/secretary.service** with contents like below. Using CoreOS and

daemon.go

@@ -9,19 +9,24 @@ import (
 	"strings"
 )
 
-// DaemonRequest TODO
+// DaemonRequest is the request expected by the /v1/decrypt endpoint
 type DaemonRequest struct {
 	AppID, AppVersion, TaskID string
 
 	// Secret encrypted with master key
 	RequestedSecret string
 }
 
-// DaemonResponse TODO
+// DaemonResponse is the response returned by the /v1/decrypt endpoint
 type DaemonResponse struct {
 	PlaintextSecret string
 }
 
+// DaemonStatusResponse is the response returned by the /v1/status endpoint
+type DaemonStatusResponse struct {
+	Status string
+}
+
 func errorResponse(w http.ResponseWriter, r *http.Request, err interface{}, statusCode int) {
 	log.Printf("HTTP %d from %s: %s", statusCode, r.RemoteAddr, err)
 	http.Error(w, fmt.Sprintf("%s", err), statusCode)
@@ -155,8 +160,22 @@ func decryptEndpointHandler(marathonURL string, masterKey *[32]byte, strategy De
 	}
 }
 
+func statusEndpointHandler() func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		message := DaemonStatusResponse{Status: "OK"}
+		encoded, err := json.Marshal(message)
+		if err != nil {
+			errorResponse(w, r, fmt.Errorf("Failed to serialize json response", err), http.StatusInternalServerError)
+			return
+		}
+
+		w.Write(encoded)
+	}
+}
+
 func daemonCommand(listenAddress string, marathonURL string, masterKey *[32]byte, strategy DecryptionStrategy) {
 	http.HandleFunc("/v1/decrypt", decryptEndpointHandler(marathonURL, masterKey, strategy))
+	http.HandleFunc("/v1/status", statusEndpointHandler())
 	log.Printf("Daemon listening on %s", listenAddress)
 	log.Fatal(http.ListenAndServe(listenAddress, nil))
 }

daemon_test.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDaemonStatus(t *testing.T) {
+	// Start secretary daemon
+	handler := statusEndpointHandler()
+
+	daemon := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		switch r.URL.Path {
+		case "/v1/status":
+			handler(w, r)
+		default:
+			http.Error(w, fmt.Sprintf("Bad URL %s", r.URL.Path), http.StatusNotFound)
+		}
+	}))
+
+	defer daemon.Close()
+
+	response, err := httpGet(daemon.URL + "/v1/status")
+	assert.Nil(t, err)
+
+	var parsedResponse DaemonStatusResponse
+	err = json.Unmarshal(response, &parsedResponse)
+	assert.Nil(t, err)
+	assert.Equal(t, "OK", parsedResponse.Status)
+}