マニフェストにリストされている firestore-send-email 拡張機能インスタンスが使用されます。Local Emulator Suite は、その拡張機能のソースコードを ~/.cache/firebase/extensions にダウンロードします。ソースコードのダウンロードが完了すると Local Emulator Suite が開始されます。これにより、拡張機能のバックグラウンドでトリガーされる任意の関数をトリガーしたり、アプリを Local Emulator Suite に接続して、そのアプリとの統合をテストしたりできるようになります。
Emulator Suite UI を使用して、メール ドキュメント コレクションにデータを追加したり、Trigger Email 拡張機能で必要な他のバックエンド リソースを設定したりできます。
継続的インテグレーションのワークフローなどの非対話型テスト環境では、拡張機能を評価するためのテスト スクリプトを作成し、必要な Cloud Firestore データの設定、関数のトリガーなどの操作を行うこともできます。次のように Local Emulator Suite を呼び出して、テスト スクリプトを実行します。
[null,null,["最終更新日 2025-08-13 UTC。"],[],[],null,["\u003cbr /\u003e\n\n| **Beta.** This emulator is currently in beta. It might be\n| changed in backward-incompatible ways. As always, feedback is greatly\n| appreciated. Let us know what you think!\n\nBefore using the Extensions emulator with your app, make sure that\nyou [understand the overall Firebase Local Emulator Suite workflow](/docs/emulator-suite/connect_and_prototype?database=Firestore),\nand that you [install and configure](/docs/emulator-suite/install_and_configure)\nthe Local Emulator Suite and review its [CLI commands](/docs/emulator-suite/install_and_configure#startup).\n\nThis guide also assumes you are familiar with [Firebase Extensions](/docs/extensions)\nand how to [use them in your Firebase apps](/docs/extensions/overview-use-extensions).\n\nWhat can I do with the Extensions emulator?\n\nWith the Extensions emulator, you can install and manage extensions in a\nsafe local environment and better understand their capabilities while minimizing\nbilling costs. The emulator runs your extension's functions locally, including\nbackground event-triggered functions using the emulators for\nCloud Firestore, Realtime Database, Cloud Storage for Firebase, Authentication and\nPub/Sub, and Eventarc-triggered functions implemented in\nCloud Functions v2.\n| **Note:** Some extensions may call Google Cloud APIs and access services for which emulators do not exists in the Local Emulator Suite. Running the extension will still access those live services and may result in billing costs. Be sure to review extension descriptions carefully before evaluating them, so you understand billing impacts. We recommend you create and use a demo project for running the Extensions emulator, as described next.\n\nChoose a Firebase project\n\nThe Firebase Local Emulator Suite emulates products for a single Firebase project.\n\nTo select the project to use, before you start the emulators, in the CLI run\n`firebase use` in your working directory. Or, you can pass\nthe `--project` flag to each emulator\ncommand.\n| **Note:** It's generally a good practice to use one project ID for all emulator invocations, so the Emulator Suite UI, different product emulators, and all running instances of a particular emulator can communicate correctly in all cases. In fact, by default, the Local Emulator Suite will warn on detecting multiple project IDs in use, though you can override this behavior. For guidance on setting and managing project IDs, see the [Installation and configuration guide](/docs/emulator-suite/install_and_configure#project_id_configuration).\n\nLocal Emulator Suite supports emulation of *real* Firebase projects and\n*demo* projects.\n\n| Project type | Features | Use with emulators |\n|--------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| Real | A real Firebase project is one you created and configured (most likely via the Firebase console). Real projects have live resources, like database instances, storage buckets, functions, or any other resource you set up for that Firebase project. | When working with real Firebase projects, you can run emulators for any or all of the supported products. For any products you are not emulating, your apps and code will interact with the *live* resource (database instance, storage bucket, function, etc.). |\n| Demo | A demo Firebase project has no *real* Firebase configuration and no live resources. These projects are usually accessed via codelabs or other tutorials. Project IDs for demo projects have the `demo-` prefix. | When working with demo Firebase projects, your apps and code interact with emulators *only*. If your app attempts to interact with a resource for which an emulator isn't running, that code will fail. |\n\nWe recommend you use demo projects wherever possible. Benefits include:\n\n- Easier setup, since you can run the emulators without ever creating a Firebase project\n- Stronger safety, since if your code accidentally invokes non-emulated (production) resources, there is no chance of data change, usage and billing\n- Better offline support, since there is no need to access the internet to download your SDK configuration.\n\n| **Note:** If you want to emulate cross-service interactions such as database-triggered Cloud Functions or Rules that rely on Authentication you must make sure that the project ID in your code (in `initializeApp()`, etc.) matches the project ID used by the Firebase CLI.\n\nInstall and evaluate an extension\n\nUsing the Extensions emulator to evaluate whether an extension meets your\nneeds is straightforward.\n\nLet's assume you're interested in the Trigger Email\n(`firestore-send-email`) [extension](/docs/extensions/official/firestore-send-email),\nthough the following workflow covers any extension. When run with local emulators,\nTrigger Email will automatically make use of the Cloud Firestore and\nCloud Functions emulators.\n\nTo evaluate an extension locally:\n\n1. Add the extension to the local extensions manifest. An extensions manifest is\n a list of extension instances and their configurations.\n\n ```\n firebase ext:install --local firebase/firestore-send-email\n ```\n\n Running the above command will prompt you to configure the latest version of\n `firebase/firestore-send-email` extension and save the configuration to\n the manifest, but it won't deploy the configuration to your project. For\n more about this, see [Manage extensions configuration with manifests](/docs/extensions/manifest)\n2. Start the Local Emulator Suite as you would normally.\n\n ```\n firebase emulators:start\n ```\n\nNow, using the `firestore-send-email` extension instance listed in\nyour manifest, the Local Emulator Suite will download the source code of\nthat extension to `~/.cache/firebase/extensions`. Once soures have been\ndownloaded, the Local Emulator Suite will start and you'll be able to\ntrigger any of the extension's background triggered functions and connect your\napp to the Local Emulator Suite to test their integration with your app.\n\nYou can use Emulator Suite UI to add data to the email documents collection\nand set up other backend resources, as required by the Trigger Email extension.\n\nAlternatively, for non-interactive testing environments like continuous\nintegration workflows, you can write a test script for evaluating the extension\nthat, among other steps, populates necessary Cloud Firestore data and\ntriggers functions. You would then invoke the Local Emulator Suite\nto execute your test script: \n\n firebase emulators:exec my-test.sh\n\n| **Note:** You can use the Extensions emulator to evaluate extensions that publish custom events. The Extensions emulator works together with the Cloud Functions emulator to help you test custom event-handling functions you implement with Cloud Functions v2 code. See [Connect your app to the Cloud Functions Emulator](/docs/emulator-suite/connect_functions).\n\nHow testing with the Extensions emulator differs from production\n\nThe Extensions emulator lets you test extensions in a way that closely\nmatches the production experience. However, there are some differences from\nproduction behavior.\n\nCloud IAM\n\nThe Firebase Emulator Suite does not attempt to replicate or respect any\nIAM-related behavior for running. Emulators adhere to the Firebase Security\nRules provided, but in situations where IAM would normally be used, for example\nto set Cloud Functions invoking service account and thus permissions, the\nemulator is not configurable and will use the globally-available account on\nyour developer machine, similar to running a local script directly.\n\nTriggering type limitation\n\nCurrently, the Firebase Local Emulator Suite only supports HTTP request-triggered\nfunctions, Eventarc custom event triggers for extensions, and background\nevent-triggered functions for Cloud Firestore, Realtime Database,\nCloud Storage for Firebase, Authentication and Pub/Sub. To evaluate extensions\nthat use other types of triggered functions, you need to\n[install your extension](/docs/extensions/install-extensions)\nin a test Firebase project.\n\nWhat next?\n\n- For a curated set of videos and detailed how-to examples, follow the [Firebase Emulators Training Playlist](/learn/pathways/firebase-emulators)."]]
