refactor(runtime): move subgraph execution batching out

.changeset/@graphql-mesh_fusion-runtime-605-dependencies.md

@@ -0,0 +1,7 @@
+---
+'@graphql-mesh/fusion-runtime': patch
+---
+
+dependencies updates: 
+
+- Added dependency [`@graphql-tools/batch-execute@workspace:^` ↗︎](https://www.npmjs.com/package/@graphql-tools/batch-execute/v/workspace:^) (to `dependencies`)

.changeset/chatty-humans-collect.md

@@ -0,0 +1,7 @@
+---
+'@graphql-mesh/fusion-runtime': minor
+---
+
+Extract subgraph execution batching logic outside, so batching is handled by the Gateway not Stitching
+
+**BREAKING**; `UnifiedGraphHandlerOpts` no longer takes `batch` option, it is handled by the runtime itself

packages/fusion-runtime/package.json

@@ -48,6 +48,7 @@
     "@graphql-mesh/transport-common": "workspace:^",
     "@graphql-mesh/types": "^0.103.6",
     "@graphql-mesh/utils": "^0.103.6",
+    "@graphql-tools/batch-execute": "workspace:^",
     "@graphql-tools/delegate": "workspace:^",
     "@graphql-tools/executor": "^1.3.10",
     "@graphql-tools/federation": "workspace:^",

packages/fusion-runtime/src/federation/supergraph.ts

@@ -158,7 +158,6 @@ export const handleFederationSupergraph: UnifiedGraphHandler = function ({
   onDelegateHooks,
   additionalTypeDefs: additionalTypeDefsFromConfig = [],
   additionalResolvers: additionalResolversFromConfig = [],
-  batch = true,
   logger,
 }: UnifiedGraphHandlerOpts): UnifiedGraphHandlerResult {
   const additionalTypeDefs = [...asArray(additionalTypeDefsFromConfig)];
@@ -204,7 +203,6 @@ export const handleFederationSupergraph: UnifiedGraphHandler = function ({
         stitchingDirectivesTransformer,
         onSubgraphExecute,
       }),
-    batch,
     onStitchingOptions(opts) {
       subschemas = opts.subschemas;
       opts.typeDefs = handleResolveToDirectives(

packages/fusion-runtime/src/unifiedGraphManager.ts

@@ -64,11 +64,6 @@ export interface UnifiedGraphHandlerOpts {
   onDelegationPlanHooks?: OnDelegationPlanHook<any>[];
   onDelegationStageExecuteHooks?: OnDelegationStageExecuteHook<any>[];
   onDelegateHooks?: OnDelegateHook<unknown>[];
-  /**
-   * Whether to batch the subgraph executions.
-   * @default true
-   */
-  batch?: boolean;
 
   logger?: Logger;
 }
@@ -327,7 +322,6 @@ export class UnifiedGraphManager<TContext> implements AsyncDisposable {
           onDelegationPlanHooks: this.onDelegationPlanHooks,
           onDelegationStageExecuteHooks: this.onDelegationStageExecuteHooks,
           onDelegateHooks: this.opts.onDelegateHooks,
-          batch: this.batch,
           logger: this.opts.transportContext?.logger,
         });
         this.unifiedGraph = newUnifiedGraph;
@@ -340,6 +334,7 @@ export class UnifiedGraphManager<TContext> implements AsyncDisposable {
           getSubgraphSchema,
           transportExecutorStack: this._transportExecutorStack,
           getDisposeReason: () => this.disposeReason,
+          batch: this.batch,
         });
         this.inContextSDK = inContextSDK;
         this.lastLoadTime = Date.now();

packages/fusion-runtime/src/utils.ts

@@ -13,6 +13,7 @@ import {
   loggerForExecutionRequest,
   requestIdByRequest,
 } from '@graphql-mesh/utils';
+import { getBatchingExecutor } from '@graphql-tools/batch-execute';
 import {
   DelegationPlanBuilder,
   MergedTypeResolver,
@@ -168,6 +169,7 @@ export function getOnSubgraphExecute({
   transportExecutorStack,
   transports,
   getDisposeReason,
+  batch = true,
 }: {
   onSubgraphExecuteHooks: OnSubgraphExecuteHook[];
   transports?: Transports;
@@ -176,6 +178,7 @@ export function getOnSubgraphExecute({
   getSubgraphSchema(subgraphName: string): GraphQLSchema;
   transportExecutorStack: AsyncDisposableStack;
   getDisposeReason?: () => GraphQLError | undefined;
+  batch?: boolean;
 }) {
   const subgraphExecutorMap = new Map<string, Executor>();
   return function onSubgraphExecute(
@@ -237,6 +240,12 @@ export function getOnSubgraphExecute({
       // Caches the lazy executor to prevent race conditions
       subgraphExecutorMap.set(subgraphName, executor);
     }
+    if (batch) {
+      executor = getBatchingExecutor(
+        executionRequest.context || subgraphExecutorMap,
+        executor,
+      );
+    }
     return executor(executionRequest);
   };
 }

yarn.lock

@@ -3481,6 +3481,7 @@ __metadata:
     "@graphql-mesh/transport-common": "workspace:^"
     "@graphql-mesh/types": "npm:^0.103.6"
     "@graphql-mesh/utils": "npm:^0.103.6"
+    "@graphql-tools/batch-execute": "workspace:^"
     "@graphql-tools/delegate": "workspace:^"
     "@graphql-tools/executor": "npm:^1.3.10"
     "@graphql-tools/federation": "workspace:^"