refactor: extract BackendIdentifierResolver (#270)

* refactor: extract BackendIdentifierResolver

.changeset/calm-fans-tie.md

@@ -0,0 +1,5 @@
+---
+'@aws-amplify/backend-cli': patch
+---
+
+Extract BackendIdentifierResolver into its own class

packages/cli/src/backend-identifier/backend_identifier_resolver.test.ts

@@ -0,0 +1,35 @@
+import assert from 'node:assert';
+import { describe, it } from 'node:test';
+import { BackendIdentifierResolver } from './backend_identifier_resolver.js';
+
+describe('BackendIdentifierResolver', () => {
+  it('returns an App Name and Branch identifier', async () => {
+    const backendIdResolver = new BackendIdentifierResolver({
+      resolve: () => Promise.resolve('testAppName'),
+    });
+    assert.deepEqual(await backendIdResolver.resolve({ branch: 'test' }), {
+      appName: 'testAppName',
+      branchName: 'test',
+    });
+  });
+  it('returns a App Id identifier', async () => {
+    const backendIdResolver = new BackendIdentifierResolver({
+      resolve: () => Promise.resolve('testAppName'),
+    });
+    assert.deepEqual(
+      await backendIdResolver.resolve({ appId: 'my-id', branch: 'my-branch' }),
+      {
+        backendId: 'my-id',
+        branchName: 'my-branch',
+      }
+    );
+  });
+  it('returns a Stack name identifier', async () => {
+    const backendIdResolver = new BackendIdentifierResolver({
+      resolve: () => Promise.resolve('testAppName'),
+    });
+    assert.deepEqual(await backendIdResolver.resolve({ stack: 'my-stack' }), {
+      stackName: 'my-stack',
+    });
+  });
+});

packages/cli/src/backend-identifier/backend_identifier_resolver.ts

@@ -0,0 +1,35 @@
+import { BackendIdentifier } from '@aws-amplify/deployed-backend-client';
+import { AppNameResolver } from './local_app_name_resolver.js';
+
+type BackendIdentifierParameters = {
+  stack?: string;
+  appId?: string;
+  branch?: string;
+};
+/**
+ * Translates args to BackendIdentifier.
+ * Throws if translation can't be made (this should never happen if command validation works correctly).
+ */
+export class BackendIdentifierResolver {
+  /**
+   * Instantiates BackendIdentifierResolver
+   */
+  constructor(private appNameResolver: AppNameResolver) {}
+  resolve = async (
+    args: BackendIdentifierParameters
+  ): Promise<BackendIdentifier> => {
+    if (args.stack) {
+      return { stackName: args.stack };
+    } else if (args.appId && args.branch) {
+      return { backendId: args.appId, branchName: args.branch };
+    } else if (args.branch) {
+      return {
+        appName: await this.appNameResolver.resolve(),
+        branchName: args.branch,
+      };
+    }
+    throw new Error(
+      'Unable to resolve BackendIdentifier with provided parameters'
+    );
+  };
+}

packages/cli/src/local_app_name_resolver.ts → packages/cli/src/backend-identifier/local_app_name_resolver.ts

@@ -1,4 +1,4 @@
-import { CwdPackageJsonLoader } from './cwd_package_json_loader.js';
+import { CwdPackageJsonLoader } from '../cwd_package_json_loader.js';
 
 export type AppNameResolver = {
   resolve: () => Promise<string>;

packages/cli/src/commands/generate/config/generate_config_command.test.ts

@@ -9,6 +9,7 @@ import {
 } from '../../../test-utils/command_runner.js';
 import assert from 'node:assert';
 import { ClientConfigGeneratorAdapter } from './client_config_generator_adapter.js';
+import { BackendIdentifierResolver } from '../../../backend-identifier/backend_identifier_resolver.js';
 
 describe('generate config command', () => {
   const clientConfigGeneratorAdapter = new ClientConfigGeneratorAdapter(
@@ -21,9 +22,12 @@ describe('generate config command', () => {
     () => Promise.resolve()
   );
 
+  const backendIdResolver = new BackendIdentifierResolver({
+    resolve: () => Promise.resolve('testAppName'),
+  });
   const generateConfigCommand = new GenerateConfigCommand(
     clientConfigGeneratorAdapter,
-    { resolve: () => Promise.resolve('testAppName') }
+    backendIdResolver
   );
   const parser = yargs().command(
     generateConfigCommand as unknown as CommandModule

packages/cli/src/commands/generate/config/generate_config_command.ts

@@ -1,8 +1,7 @@
 import { ArgumentsCamelCase, Argv, CommandModule } from 'yargs';
 import { ClientConfigFormat } from '@aws-amplify/client-config';
-import { AppNameResolver } from '../../../local_app_name_resolver.js';
 import { ClientConfigGeneratorAdapter } from './client_config_generator_adapter.js';
-import { BackendIdentifier } from '@aws-amplify/deployed-backend-client';
+import { BackendIdentifierResolver } from '../../../backend-identifier/backend_identifier_resolver.js';
 
 export type GenerateConfigCommandOptions = {
   stack: string | undefined;
@@ -37,7 +36,7 @@ export class GenerateConfigCommand
    */
   constructor(
     private readonly clientConfigGenerator: ClientConfigGeneratorAdapter,
-    private readonly appNameResolver: AppNameResolver
+    private readonly backendIdentifierResolver: BackendIdentifierResolver
   ) {
     this.command = 'config';
     this.describe = 'Generates client config';
@@ -49,7 +48,9 @@ export class GenerateConfigCommand
   handler = async (
     args: ArgumentsCamelCase<GenerateConfigCommandOptions>
   ): Promise<void> => {
-    const backendIdentifier = await this.getBackendIdentifier(args);
+    const backendIdentifier = await this.backendIdentifierResolver.resolve(
+      args
+    );
 
     await this.clientConfigGenerator.generateClientConfigToFile(
       backendIdentifier,
@@ -58,26 +59,6 @@ export class GenerateConfigCommand
     );
   };
 
-  /**
-   * Translates args to BackendIdentifier.
-   * Throws if translation can't be made (this should never happen if command validation works correctly).
-   */
-  private getBackendIdentifier = async (
-    args: ArgumentsCamelCase<GenerateConfigCommandOptions>
-  ): Promise<BackendIdentifier> => {
-    if (args.stack) {
-      return { stackName: args.stack };
-    } else if (args.appId && args.branch) {
-      return { backendId: args.appId, branchName: args.branch };
-    } else if (args.branch) {
-      return {
-        appName: await this.appNameResolver.resolve(),
-        branchName: args.branch,
-      };
-    }
-    throw this.missingArgsError;
-  };
-
   /**
    * @inheritDoc
    */

packages/cli/src/commands/generate/generate_command_factory.ts

@@ -3,8 +3,9 @@ import { GenerateCommand } from './generate_command.js';
 import { GenerateConfigCommand } from './config/generate_config_command.js';
 import { fromNodeProviderChain } from '@aws-sdk/credential-providers';
 import { ClientConfigGeneratorAdapter } from './config/client_config_generator_adapter.js';
-import { LocalAppNameResolver } from '../../local_app_name_resolver.js';
 import { CwdPackageJsonLoader } from '../../cwd_package_json_loader.js';
+import { LocalAppNameResolver } from '../../backend-identifier/local_app_name_resolver.js';
+import { BackendIdentifierResolver } from '../../backend-identifier/backend_identifier_resolver.js';
 
 /**
  * Creates wired generate command.
@@ -18,9 +19,13 @@ export const createGenerateCommand = (): CommandModule => {
     new CwdPackageJsonLoader()
   );
 
+  const backendIdentifierResolver = new BackendIdentifierResolver(
+    localAppNameResolver
+  );
+
   const generateConfigCommand = new GenerateConfigCommand(
     clientConfigGenerator,
-    localAppNameResolver
+    backendIdentifierResolver
   );
 
   return new GenerateCommand(generateConfigCommand);

packages/cli/src/commands/sandbox/sandbox_command_factory.ts

@@ -2,10 +2,10 @@ import { CommandModule } from 'yargs';
 
 import { SandboxCommand, SandboxCommandOptions } from './sandbox_command.js';
 import { SandboxSingletonFactory } from '@aws-amplify/sandbox';
-import { LocalAppNameResolver } from '../../local_app_name_resolver.js';
 import { SandboxDeleteCommand } from './sandbox-delete/sandbox_delete_command.js';
 import { SandboxIdResolver } from './sandbox_id_resolver.js';
 import { CwdPackageJsonLoader } from '../../cwd_package_json_loader.js';
+import { LocalAppNameResolver } from '../../backend-identifier/local_app_name_resolver.js';
 
 /**
  * Creates wired sandbox command.

packages/cli/src/commands/sandbox/sandbox_id_resolver.ts

@@ -1,5 +1,5 @@
-import { AppNameResolver } from '../../local_app_name_resolver.js';
 import { userInfo as _userInfo } from 'os';
+import { AppNameResolver } from '../../backend-identifier/local_app_name_resolver.js';
 
 /**
  * Resolves an ID that can be used to uniquely identify sandbox environments