[Playground] [Backend] added validation for snippet endpoints to avoi…

…d error panic (#22686)

* [Playground] [Backend] added validation for snippet endpoints to avoid panic error

* [Playground] [Backend] edited error type

* [Playground] [Backend] updated error message

playground/backend/cmd/server/controller.go

@@ -15,6 +15,10 @@
 package main
 
 import (
+	"context"
+
+	"github.com/google/uuid"
+
 	pb "beam.apache.org/playground/backend/internal/api/v1"
 	"beam.apache.org/playground/backend/internal/cache"
 	"beam.apache.org/playground/backend/internal/cloud_bucket"
@@ -26,8 +30,6 @@ import (
 	"beam.apache.org/playground/backend/internal/logger"
 	"beam.apache.org/playground/backend/internal/setup_tools/life_cycle"
 	"beam.apache.org/playground/backend/internal/utils"
-	"context"
-	"github.com/google/uuid"
 )
 
 const (
@@ -363,6 +365,10 @@ func (controller *playgroundController) SaveSnippet(ctx context.Context, info *p
 		logger.Errorf("SaveSnippet(): unimplemented sdk: %s\n", info.Sdk)
 		return nil, errors.InvalidArgumentError(errorTitleSaveSnippet, "Sdk is not implemented yet: %s", info.Sdk.String())
 	}
+	if controller.db == nil {
+		logger.Error("SaveSnippet(): the runner is trying to save the snippet")
+		return nil, errors.InvalidArgumentError(errorTitleSaveSnippet, "The runner doesn't support snippets")
+	}
 	if info.Files == nil || len(info.Files) == 0 {
 		logger.Error("SaveSnippet(): files are empty")
 		return nil, errors.InvalidArgumentError(errorTitleSaveSnippet, "Snippet must have files")
@@ -399,6 +405,10 @@ func (controller *playgroundController) SaveSnippet(ctx context.Context, info *p
 
 // GetSnippet returns the snippet entity
 func (controller *playgroundController) GetSnippet(ctx context.Context, info *pb.GetSnippetRequest) (*pb.GetSnippetResponse, error) {
+	if controller.db == nil {
+		logger.Error("GetSnippet(): the runner is trying to read the snippet")
+		return nil, errors.InvalidArgumentError(errorTitleGetSnippet, "The runner doesn't support snippets")
+	}
 	snippet, err := controller.db.GetSnippet(ctx, info.GetId())
 	if err != nil {
 		logger.Errorf("GetSnippet(): error during getting the snippet: %s", err.Error())