Enabling multi-tenancy for fission objects. (#655)

This feature allows creation of fission objects in different namespaces, in addition to retaining the existing behavior of creating fission objects in default namespace if user doesnt provide one. 
It also removes cluster admin roles for fission-fetcher and fission-builder Service Accounts and grants them only those privileges that they need.

controller/api.go

@@ -26,7 +26,9 @@ import (
 	"github.com/gorilla/mux"
 	log "github.com/sirupsen/logrus"
 	kerrors "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes"
+	apiv1 "k8s.io/client-go/pkg/api/v1"
 
 	"github.com/fission/fission"
 	"github.com/fission/fission/crd"
@@ -109,6 +111,31 @@ func (api *API) respondWithError(w http.ResponseWriter, err error) {
 	http.Error(w, msg, code)
 }
 
+func (api *API) extractQueryParamFromRequest(r *http.Request, queryParam string) string {
+	values := r.URL.Query()
+	return values.Get(queryParam)
+}
+
+// check if namespace exists, if not create it.
+func (api *API) createNsIfNotExists(ns string) error {
+	if ns == metav1.NamespaceDefault {
+		// we dont have to create default ns
+		return nil
+	}
+
+	_, err := api.kubernetesClient.CoreV1Client.Namespaces().Get(ns, metav1.GetOptions{})
+	if err != nil && kerrors.IsNotFound(err) {
+		ns := &apiv1.Namespace{
+			ObjectMeta: metav1.ObjectMeta{
+				Name: ns,
+			},
+		}
+		_, err = api.kubernetesClient.CoreV1Client.Namespaces().Create(ns)
+	}
+
+	return err
+}
+
 func (api *API) getLogDBConfig(dbType string) logDBConfig {
 	dbType = strings.ToUpper(dbType)
 	// retrieve db auth config from the env
@@ -191,6 +218,9 @@ func (api *API) Serve(port int) {
 
 	r.HandleFunc("/v2/deleteTpr", api.Tpr2crdApi).Methods("DELETE")
 
+	r.HandleFunc("/v2/secrets/{secret}", api.SecretGet).Methods("GET")
+	r.HandleFunc("/v2/configmaps/{configmap}", api.ConfigMapGet).Methods("GET")
+
 	r.HandleFunc("/proxy/{dbType}", api.FunctionLogsApiPost).Methods("POST")
 	r.HandleFunc("/proxy/storage/v1/archive", api.StorageServiceProxy)
 	r.HandleFunc("/proxy/logs/{function}", api.FunctionPodLogs).Methods("POST")