The Node.js runtime

Your Cloud Run function runs in an environment consisting of an operating system version with add-on packages, language support, and the Node.js Functions Framework library that supports and invokes your function. This environment is identified by the language version, and is known as the runtime ID.

Function preparation

You can prepare a function directly from the Google Cloud console or write it on your local machine and upload it. To prepare your local machine for Node.js development, see Set up a Node.js development environment.

Supported Node.js runtimes and base images

Runtime	Runtime ID	Stacks	Runtime base image
Node.js 22	nodejs22	google-22 (default) google-22-full	google-22/nodejs22 google-22-full/nodejs22
Node.js 20	nodejs20	google-22 (default) google-22-full	google-22/nodejs20 google-22-full/nodejs20
Node.js 18	nodejs18	google-22 (default) google-22-full	google-22/nodejs18 google-22-full/nodejs18
Node.js 16	nodejs16	google-18-full	google-18-full/nodejs16
Node.js 14	nodejs14	google-18-full	google-18-full/nodejs14
Node.js 12	nodejs12	google-18-full	google-18-full/nodejs12
Node.js 10	nodejs10	google-18-full	google-18-full/nodejs10
Node.js 8	nodejs8	Decommissioned	Decommissioned
Node.js 6	nodejs6	Decommissioned	Decommissioned

Select your runtime

You can select one of the supported Node.js runtimes for your function during deployment.

You can select a runtime version using the Google Cloud console, or the gcloud CLI. Click the tab for instructions on using the tool of your choice:

gcloud

Specify the Node.js base image for your function using the --base-image flag, while deploying your function. For example:

gcloud run deploy FUNCTION \
    --source . \
    --function FUNCTION_ENTRYPOINT \
    --base-image nodejs22

Replace:

• FUNCTION with the name of the function you are deploying. You can omit this parameter entirely, but you will be prompted for the name if you omit it.

• FUNCTION_ENTRYPOINT with the entry point to your function in your source code. This is the code Cloud Run executes when your function runs. The value of this flag must be a function name or fully-qualified class name that exists in your source code.

For detailed instructions on deploying a function using the gcloud CLI, see Deploy functions in Cloud Run.

Console

You can select a runtime version when you create or update a Cloud Run function in the Google Cloud console. For detailed instructions on deploying a function, see Deploy functions in Cloud Run.

To select a runtime in the Google Cloud console when you create a function, follow these steps:

1. In the Google Cloud console, go to the Cloud Run page:

   Go to Cloud Run

2. Click Write a function.

3. In the Runtime list, select a Node.js runtime version.

4. Click Create, and wait for Cloud Run to create the service using a placeholder revision.

5. The console will redirect you to the Source tab where you can see the source code of your function. Click Save and redeploy.

For detailed instructions on updating the runtime version after your function is deployed, see Re-deploy new source code.

Source code structure

For Cloud Run functions to find your function's definition, your source code must follow a specific structure. See Write Cloud Run functions for more information.

Specify dependencies

You can specify dependencies for your functions by listing them in a package.json file. For more information, see Specify dependencies in Node.js.

NPM build script

By default, the Node.js runtime executes npm run build if a build script is detected in package.json. If you require additional control over your build steps before starting your application, you can provide a custom build step by adding a gcp-build script to your package.json file.

You can prevent your build from running the npm run build script by either:

• Adding a gcp-build script with an empty value in your package.json file: "gcp-build":"".

• Setting the build environment variable GOOGLE_NODE_RUN_SCRIPTS to the empty string to prevent all scripts from running.

Asynchronous function completion

When working with asynchronous tasks that involve callbacks or Promise objects, you must explicitly inform the runtime that your function has finished executing these tasks. You can do this in several different ways, as shown in the following samples. The key is that your code must wait for the asynchronous task or Promise to complete before returning; otherwise the asynchronous component of your function may be terminated before it completes.

Event-driven functions

Implicit return

  exports.implicitlyReturning = async (event, context) => {
    return await asyncFunctionThatReturnsAPromise();
  };

Explicit return

  exports.explicitlyReturning = function (event, context) {
    return asyncFunctionThatReturnsAPromise();
  };

HTTP functions

// OK: await-ing a Promise before sending an HTTP response
await Promise.resolve();

// WRONG: HTTP functions should send an
// HTTP response instead of returning.
return Promise.resolve();

// HTTP functions should signal termination by returning an HTTP response.
// This should not be done until all background tasks are complete.
res.send(200);
res.end();

// WRONG: this may not execute since an
// HTTP response has already been sent.
return Promise.resolve();

Warning: failure to properly signal your function's termination may cause your function to either terminate early, or keep running until its timeout is reached.

Use middleware to handle HTTP requests

Node.js HTTP functions provide request and response objects that are compatible with ExpressJS to make consuming HTTP requests simpler. Cloud Run functions automatically reads the request body, so you will always receive the body of a request independent of the media type. This means that HTTP requests should be considered to have been fully read by the time your code is executed. The nesting of ExpressJS apps should be used with this caveat—specifically, middleware that expects the body of a request to be unread might not behave as expected.

Use ES Modules

ECMAScript modules (ES modules or ESM) are a TC39 standard, unflagged feature in Node version 14+ for loading JavaScript modules. Unlike CommonJS, ESM provides an asynchronous API for loading modules. It also provides a popular syntax improvement with import and export statements that can be used within a Cloud Run function (instead of require statements).

To use ESM within a Cloud Run function, you must declare "type": "module" within your package.json.

{
  ...
  "type": "module",
  ...
}

Then you can use import and export statements.

Learn more about using ES modules.