Handling dependencies

A function is allowed to use external Node.js modules as well as local data. Dependencies in Node.js are managed with npm and expressed in a metadata file called package.json.

To specify a dependency for your function, add it to your package.json file. If you are deploying through the gcloud command-line tool, you can also pre-install dependencies and deploy them alongside your function. By default, the node_modules folder is added to your .gcloudignore file and is not uploaded as part of your deployment. To deploy pre-installed dependencies, remove node_modules/ from the .gcloudignore file before deploying your function.

After you deploy your function, Cloud Functions installs dependencies declared in the package.json file using the npm install command.

In this example, a dependency is listed in the package.json file:

{
  "dependencies": {
    "uuid": "^3.0.1"
  }
}

The dependency is then imported in the function:

JavaScript

const uuid = require('uuid');

// Return a newly generated UUID in the HTTP response.
exports.getUuid = functions.https.onRequest((req, res) => {
  res.send(uuid.v4());
});

TypeScript

import * as uuid from 'uuid';

// Return a newly generated UUID in the HTTP response.
export let getUuid = functions.https.onRequest((req, res) => {
  res.send(uuid.v4());
}

Using npm to install Node.js modules

The easiest way to install a Node.js module is to use the npm install command in the folder containing your Cloud Function. For instance, the following command adds the uuid module:

npm install uuid

This combines two steps:

  1. It marks the latest version of the module as a dependency in your package.json file. This is very important: Cloud Functions only installs modules that are declared in your package.json file.
  2. It downloads the module into your node_modules directory. This lets you use the module when developing locally.

If you don't have npm installed on your machine, get npm.

Additional steps for TypeScript

TypeScript helps you most when you use libraries that have type information. This lets TypeScript catch syntax errors and lets editors give you better autocomplete suggestions. Some libraries, like firebase-admin and firebase-functions, ship with TypeScript definitions included.

Many libraries do not provide their own TypeScript definition. The DefinitelyTyped project provides community-maintained definitions for the most popular node libraries. DefinitelyTyped publishes these definitions under the same NPM package name, but inside the "@types" organization. For example, you can install the type information for the uuid library with the following:

npm install @types/uuid

As you become more familiar with TypeScript, you might find yourself combining both installs:

npm install uuid @types/uuid

Type dependencies should be the same kind as the library dependency. For example, you should not save uuid as a normal dependency and @types/uuid as a dev dependency or peer dependency.

Loading Node.js modules

Use the Node.js require() function to load any Node.js module you have installed. You can also use the require() function to import local files you deploy alongside your function.

If you are writing functions in TypeScript, use the import statement in the same way to load any Node.js module you have installed.

Using private modules

In order to use a private npm module, you must provide credentials (auth token) for the npm registry in a .npmrc file located in the function's directory. The npm documentation explains how to create custom read-only access tokens. We discourage using the .npmrc file created in the home directory because it contains a read-write token. Write permissions are not required during deployment, and could pose a security risk.

Do not include the .npmrc file if you're not using private repositories, as it can increase the deployment time for your functions.

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