Add basic nomad integration and runner provider

api/api.go

@@ -3,12 +3,19 @@ package api
 import (
 	"encoding/json"
 	"github.com/gorilla/mux"
+	"gitlab.hpi.de/codeocean/codemoon/poseidon/api/dto"
 	"gitlab.hpi.de/codeocean/codemoon/poseidon/logging"
 	"net/http"
 )
 
 var log = logging.GetLogger("api")
 
+const (
+	RouteBase    = "/api/v1"
+	RouteHealth  = "/health"
+	RouteRunners = "/runners"
+)
+
 // NewRouter returns an HTTP handler (http.Handler) which can be
 // used by the net/http package to serve the routes of our API. It
 // always returns a router for the newest version of our API. We
@@ -23,20 +30,34 @@ func NewRouter() http.Handler {
 	return router
 }
 
-// newRouterV1 returns a subrouter containing the routes of version
+// newRouterV1 returns a sub-router containing the routes of version
 // 1 of our API.
 func newRouterV1(router *mux.Router) *mux.Router {
-	v1 := router.PathPrefix("/api/v1").Subrouter()
-	v1.HandleFunc("/health", Health).Methods(http.MethodGet)
+	v1 := router.PathPrefix(RouteBase).Subrouter()
+	v1.HandleFunc(RouteHealth, Health).Methods(http.MethodGet)
+	registerRunnerRoutes(v1.PathPrefix(RouteRunners).Subrouter())
 	return v1
 }
 
-func writeJson(writer http.ResponseWriter, content interface{}) {
+func writeInternalServerError(writer http.ResponseWriter, err error, errorCode dto.ErrorCode) {
+	sendJson(writer, &dto.InternalServerError{Message: err.Error(), ErrorCode: errorCode}, http.StatusInternalServerError)
+}
+
+func writeBadRequest(writer http.ResponseWriter, err error) {
+	sendJson(writer, &dto.ClientError{Message: err.Error()}, http.StatusBadRequest)
+}
+
+func writeNotFound(writer http.ResponseWriter, err error) {
+	sendJson(writer, &dto.ClientError{Message: err.Error()}, http.StatusNotFound)
+}
+
+func sendJson(writer http.ResponseWriter, content interface{}, httpStatusCode int) {
 	writer.Header().Set("Content-Type", "application/json")
+	writer.WriteHeader(httpStatusCode)
 	response, err := json.Marshal(content)
 	if err != nil {
-		log.WithError(err).Warn("JSON marshal error")
-		http.Error(writer, err.Error(), http.StatusInternalServerError)
+		// cannot produce infinite recursive loop, since json.Marshal of dto.InternalServerError won't return an error
+		writeInternalServerError(writer, err, dto.ErrorUnknown)
 		return
 	}
 	if _, err := writer.Write(response); err != nil {