feat: add api id and amplify environment name to stash (#2273)

Author: Dane Pilcher

.changeset/strong-toes-sniff.md

@@ -0,0 +1,6 @@
+---
+'@aws-amplify/backend-data': minor
+'@aws-amplify/backend': minor
+---
+
+Add GraphQL API ID and Amplify environment name to custom JS resolver stash

.eslint_dictionary.json

@@ -78,6 +78,7 @@
   "hotswappable",
   "hotswapped",
   "hotswapping",
+  "href",
   "iamv2",
   "identitypool",
   "idps",

packages/backend-data/src/assets/js_resolver_handler.ts

@@ -1,7 +1,9 @@
 /**
  * Pipeline resolver request handler
  */
-export const request = () => {
+export const request = (ctx: Record<string, Record<string, string>>) => {
+  ctx.stash.awsAppsyncApiId = '${amplifyApiId}';
+  ctx.stash.amplifyApiEnvironmentName = '${amplifyApiEnvironmentName}';
   return {};
 };
 /**

packages/backend-data/src/convert_js_resolvers.test.ts

@@ -1,15 +1,20 @@
-import { Template } from 'aws-cdk-lib/assertions';
+import { Match, Template } from 'aws-cdk-lib/assertions';
 import assert from 'node:assert';
 import { beforeEach, describe, it } from 'node:test';
 import { App, Duration, Stack } from 'aws-cdk-lib';
 import {
   AmplifyData,
   AmplifyDataDefinition,
 } from '@aws-amplify/data-construct';
-import { resolve } from 'path';
-import { fileURLToPath } from 'url';
-import { convertJsResolverDefinition } from './convert_js_resolvers.js';
+import { join, resolve } from 'path';
+import { tmpdir } from 'os';
+import { fileURLToPath, pathToFileURL } from 'url';
+import {
+  convertJsResolverDefinition,
+  defaultJsResolverCode,
+} from './convert_js_resolvers.js';
 import { a } from '@aws-amplify/data-schema';
+import { writeFileSync } from 'node:fs';
 
 // stub schema for the AmplifyApi construct
 // not relevant to this test suite
@@ -28,6 +33,33 @@ const createStackAndSetContext = (): Stack => {
   return stack;
 };
 
+void describe('defaultJsResolverCode', () => {
+  void it('returns the default JS resolver code with api id and env name in valid JS', async () => {
+    const code = defaultJsResolverCode('testApiId', 'testEnvName');
+    assert(code.includes("ctx.stash.awsAppsyncApiId = 'testApiId';"));
+    assert(
+      code.includes("ctx.stash.amplifyApiEnvironmentName = 'testEnvName';")
+    );
+
+    const tempDir = tmpdir();
+    const filename = join(tempDir, 'js_resolver_handler.js');
+    writeFileSync(filename, code);
+
+    // windows requires dynamic imports to use file urls
+    const fileUrl = pathToFileURL(filename).href;
+    const resolver = await import(fileUrl);
+    const context = { stash: {}, prev: { result: 'result' } };
+    assert.deepEqual(resolver.request(context), {});
+
+    // assert api id and env name are added to the context stash
+    assert.deepEqual(context.stash, {
+      awsAppsyncApiId: 'testApiId',
+      amplifyApiEnvironmentName: 'testEnvName',
+    });
+    assert.equal(resolver.response(context), 'result');
+  });
+});
+
 void describe('convertJsResolverDefinition', () => {
   let stack: Stack;
   let amplifyApi: AmplifyData;
@@ -158,4 +190,52 @@ void describe('convertJsResolverDefinition', () => {
 
     template.resourceCountIs('AWS::AppSync::Resolver', 1);
   });
+
+  void it('adds api id and environment name to stash', () => {
+    const absolutePath = resolve(
+      fileURLToPath(import.meta.url),
+      '../../lib/assets',
+      'js_resolver_handler.js'
+    );
+
+    const schema = a.schema({
+      customQuery: a
+        .query()
+        .authorization((allow) => allow.publicApiKey())
+        .returns(a.string())
+        .handler(
+          a.handler.custom({
+            entry: absolutePath,
+          })
+        ),
+    });
+    const { jsFunctions } = schema.transform();
+    convertJsResolverDefinition(stack, amplifyApi, jsFunctions);
+
+    const template = Template.fromStack(stack);
+    template.hasResourceProperties('AWS::AppSync::Resolver', {
+      Runtime: {
+        Name: 'APPSYNC_JS',
+        RuntimeVersion: '1.0.0',
+      },
+      Kind: 'PIPELINE',
+      TypeName: 'Query',
+      FieldName: 'customQuery',
+      Code: {
+        'Fn::Join': [
+          '',
+          [
+            "/**\n * Pipeline resolver request handler\n */\nexport const request = (ctx) => {\n    ctx.stash.awsAppsyncApiId = '",
+            {
+              'Fn::GetAtt': [
+                Match.stringLikeRegexp('amplifyDataGraphQLAPI.*'),
+                'ApiId',
+              ],
+            },
+            "';\n    ctx.stash.amplifyApiEnvironmentName = 'NONE';\n    return {};\n};\n/**\n * Pipeline resolver response handler\n */\nexport const response = (ctx) => {\n    return ctx.prev.result;\n};\n",
+          ],
+        ],
+      },
+    });
+  });
 });

packages/backend-data/src/convert_js_resolvers.ts

@@ -4,6 +4,7 @@ import { CfnFunctionConfiguration, CfnResolver } from 'aws-cdk-lib/aws-appsync';
 import { JsResolver } from '@aws-amplify/data-schema-types';
 import { resolve } from 'path';
 import { fileURLToPath } from 'node:url';
+import { readFileSync } from 'fs';
 import { Asset } from 'aws-cdk-lib/aws-s3-assets';
 import { resolveEntryPath } from './resolve_entry_path.js';
 
@@ -18,17 +19,25 @@ const JS_PIPELINE_RESOLVER_HANDLER = './assets/js_resolver_handler.js';
  * It's required for defining a pipeline resolver. The only purpose it serves is returning the output of the last function in the pipeline back to the client.
  *
  * Customer-provided handlers are added as a Functions list in `pipelineConfig.functions`
+ *
+ * Add Amplify API ID and environment name to the context stash for use in the customer-provided handlers.
  */
-const defaultJsResolverAsset = (scope: Construct): Asset => {
+export const defaultJsResolverCode = (
+  amplifyApiId: string,
+  amplifyApiEnvironmentName: string
+): string => {
   const resolvedTemplatePath = resolve(
     fileURLToPath(import.meta.url),
     '../../lib',
     JS_PIPELINE_RESOLVER_HANDLER
   );
 
-  return new Asset(scope, 'default_js_resolver_handler_asset', {
-    path: resolveEntryPath(resolvedTemplatePath),
-  });
+  return readFileSync(resolvedTemplatePath, 'utf-8')
+    .replace(new RegExp(/\$\{amplifyApiId\}/, 'g'), amplifyApiId)
+    .replace(
+      new RegExp(/\$\{amplifyApiEnvironmentName\}/, 'g'),
+      amplifyApiEnvironmentName
+    );
 };
 
 /**
@@ -44,8 +53,6 @@ export const convertJsResolverDefinition = (
     return;
   }
 
-  const jsResolverTemplateAsset = defaultJsResolverAsset(scope);
-
   for (const resolver of jsResolvers) {
     const functions: string[] = resolver.handlers.map((handler, idx) => {
       const fnName = `Fn_${resolver.typeName}_${resolver.fieldName}_${idx + 1}`;
@@ -71,12 +78,15 @@ export const convertJsResolverDefinition = (
 
     const resolverName = `Resolver_${resolver.typeName}_${resolver.fieldName}`;
 
+    const amplifyApiEnvironmentName =
+      scope.node.tryGetContext('amplifyEnvironmentName') ?? 'NONE';
     new CfnResolver(scope, resolverName, {
       apiId: amplifyApi.apiId,
       fieldName: resolver.fieldName,
       typeName: resolver.typeName,
       kind: APPSYNC_PIPELINE_RESOLVER,
-      codeS3Location: jsResolverTemplateAsset.s3ObjectUrl,
+      // Uses synth-time inline code to avoid circular dependency when adding the API ID as an environment variable.
+      code: defaultJsResolverCode(amplifyApi.apiId, amplifyApiEnvironmentName),
       runtime: {
         name: APPSYNC_JS_RUNTIME_NAME,
         runtimeVersion: APPSYNC_JS_RUNTIME_VERSION,