Update to function generate data-config files

Author: stocaaro

packages/backend-function/package.json

@@ -10,6 +10,11 @@
       "types": "./lib/index.d.ts",
       "import": "./lib/index.js",
       "require": "./lib/index.js"
+    },
+    "./runtime": {
+      "types": "./lib/runtime/index.d.ts",
+      "import": "./lib/runtime/index.js",
+      "require": "./lib/runtime/index.js"
     }
   },
   "main": "lib/index.js",

packages/backend-function/src/factory.ts

@@ -44,6 +44,7 @@ import { FunctionEnvironmentTranslator } from './function_env_translator.js';
 import { FunctionEnvironmentTypeGenerator } from './function_env_type_generator.js';
 import { FunctionLayerArnParser } from './layer_parser.js';
 import { convertFunctionSchedulesToRuleSchedules } from './schedule_parser.js';
+import { FunctionDataConfigGenerator } from './function_data_config_generator.js';
 
 const functionStackType = 'function-Lambda';
 
@@ -425,6 +426,10 @@ class AmplifyFunction
     // This will be overwritten with the typed file at the end of synthesis
     functionEnvironmentTypeGenerator.generateProcessEnvShim();
 
+    const functionClientConfigGenerator = new FunctionDataConfigGenerator(id);
+
+    functionClientConfigGenerator.generateDataConfigShim();
+
     let functionLambda: NodejsFunction;
     try {
       functionLambda = new NodejsFunction(scope, `${id}-lambda`, {

packages/backend-function/src/function_data_config_generator.test.ts

@@ -0,0 +1,51 @@
+import { describe, it, mock } from 'node:test';
+import fs from 'fs';
+import fsp from 'fs/promises';
+import { FunctionDataConfigGenerator } from './function_data_config_generator.js';
+import assert from 'assert';
+import { pathToFileURL } from 'url';
+
+void describe('FunctionDataConfigGenerator', () => {
+  void it('generates a type definition file', () => {
+    const fsOpenSyncMock = mock.method(fs, 'openSync');
+    const fsWriteFileSyncMock = mock.method(fs, 'writeFileSync', () => null);
+    fsOpenSyncMock.mock.mockImplementation(() => 0);
+    const functionDataConfigGenerator = new FunctionDataConfigGenerator(
+      'testFunction'
+    );
+    const configExport =
+      'export const { libraryOptions, resourceConfig } = await getAmplifyClientsConfiguration(env);';
+
+    functionDataConfigGenerator.generateDataConfigShim();
+
+    // assert type definition file path
+    assert.equal(
+      fsWriteFileSyncMock.mock.calls[0].arguments[0],
+      `${process.cwd()}/.amplify/generated/data-config/testFunction.ts`
+    );
+
+    // assert content
+    assert.ok(
+      fsWriteFileSyncMock.mock.calls[0].arguments[1]
+        ?.toString()
+        .includes(configExport)
+    );
+
+    mock.restoreAll();
+  });
+
+  void it('generated type definition file has valid syntax', async () => {
+    const targetDirectory = await fsp.mkdtemp('func_data_config_gen_test');
+    const functionDataConfigGenerator = new FunctionDataConfigGenerator(
+      'testFunction'
+    );
+    const filePath = `${process.cwd()}/.amplify/generated/data-config/testFunction.ts`;
+
+    functionDataConfigGenerator.generateDataConfigShim();
+
+    // import to validate syntax of type definition file
+    await import(pathToFileURL(filePath).toString());
+
+    await fsp.rm(targetDirectory, { recursive: true, force: true });
+  });
+});

packages/backend-function/src/function_data_config_generator.ts

@@ -0,0 +1,45 @@
+import fs from 'fs';
+import path from 'path';
+
+const lambdaDataConfigTemplate = (
+  functionName: string
+) => `// This file is auto-generated by Amplify. Edits will be overwritten.
+import { getAmplifyClientsConfiguration } from "@aws-amplify/backend-function/runtime";
+import { env } from "../env/${functionName}";
+export const { libraryOptions, resourceConfig } = await getAmplifyClientsConfiguration(env);
+`;
+
+/**
+ * Generates the data configuration imports
+ */
+export class FunctionDataConfigGenerator {
+  private typeDefFilePath: string;
+
+  private indentation: string = '  ';
+
+  /**
+   * Initialize data configuration file name and location
+   */
+  constructor(private readonly functionName: string) {
+    this.typeDefFilePath = `${process.cwd()}/.amplify/generated/data-config/${
+      this.functionName
+    }.ts`;
+  }
+
+  /**
+   * Generate data-config shim
+   */
+  generateDataConfigShim = () => {
+    this.writeShimFile(lambdaDataConfigTemplate(this.functionName));
+  };
+
+  private writeShimFile = (content: string) => {
+    const typeDefFileDirname = path.dirname(this.typeDefFilePath);
+
+    if (!fs.existsSync(typeDefFileDirname)) {
+      fs.mkdirSync(typeDefFileDirname, { recursive: true });
+    }
+
+    fs.writeFileSync(this.typeDefFilePath, content);
+  };
+}