Add architecture for multiple managers

using the chain of responsibility pattern.

internal/api/api.go

@@ -27,7 +27,7 @@ const (
 // always returns a router for the newest version of our API. We
 // use gorilla/mux because it is more convenient than net/http, e.g.
 // when extracting path parameters.
-func NewRouter(runnerManager runner.Manager, environmentManager environment.Manager) *mux.Router {
+func NewRouter(runnerManager runner.Manager, environmentManager environment.ManagerHandler) *mux.Router {
 	router := mux.NewRouter()
 	// this can later be restricted to a specific host with
 	// `router.Host(...)` and to HTTPS with `router.Schemes("https")`
@@ -37,7 +37,8 @@ func NewRouter(runnerManager runner.Manager, environmentManager environment.Mana
 }
 
 // configureV1Router configures a given router with the routes of version 1 of the Poseidon API.
-func configureV1Router(router *mux.Router, runnerManager runner.Manager, environmentManager environment.Manager) {
+func configureV1Router(router *mux.Router,
+	runnerManager runner.Manager, environmentManager environment.ManagerHandler) {
 	router.NotFoundHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		log.WithField("request", r).Debug("Not Found Handler")
 		w.WriteHeader(http.StatusNotFound)

internal/api/environments.go

@@ -24,7 +24,7 @@ const (
 var ErrMissingURLParameter = errors.New("url parameter missing")
 
 type EnvironmentController struct {
-	manager environment.Manager
+	manager environment.ManagerHandler
 }
 
 type ExecutionEnvironmentsResponse struct {

internal/api/environments_test.go

@@ -21,7 +21,7 @@ import (
 
 type EnvironmentControllerTestSuite struct {
 	suite.Suite
-	manager *environment.ManagerMock
+	manager *environment.ManagerHandlerMock
 	router  *mux.Router
 }
 
@@ -30,7 +30,7 @@ func TestEnvironmentControllerTestSuite(t *testing.T) {
 }
 
 func (s *EnvironmentControllerTestSuite) SetupTest() {
-	s.manager = &environment.ManagerMock{}
+	s.manager = &environment.ManagerHandlerMock{}
 	s.router = NewRouter(nil, s.manager)
 }
 

internal/api/runners.go

@@ -24,7 +24,7 @@ const (
 )
 
 type RunnerController struct {
-	manager      runner.Manager
+	manager      runner.Accessor
 	runnerRouter *mux.Router
 }
 
@@ -52,10 +52,10 @@ func (r *RunnerController) provide(writer http.ResponseWriter, request *http.Req
 	environmentID := dto.EnvironmentID(runnerRequest.ExecutionEnvironmentID)
 	nextRunner, err := r.manager.Claim(environmentID, runnerRequest.InactivityTimeout)
 	if err != nil {
-		switch err {
-		case runner.ErrUnknownExecutionEnvironment:
+		switch {
+		case errors.Is(err, runner.ErrUnknownExecutionEnvironment):
 			writeNotFound(writer, err)
-		case runner.ErrNoRunnersAvailable:
+		case errors.Is(err, runner.ErrNoRunnersAvailable):
 			log.WithField("environment", environmentID).Warn("No runners available")
 			writeInternalServerError(writer, err, dto.ErrorNomadOverload)
 		default: