Functions Framework for Node.js
An open source FaaS (Function as a Service) framework based on Express for writing portable Node.js functions -- brought to you by the Google Cloud Functions team.
The Functions Framework lets you write lightweight functions that run in many different environments, including:
- Google Cloud Functions
- Your local development machine
- Cloud Run and Cloud Run for Anthos
- Knative-based environments
The framework allows you to go from:
/**
* Send "Hello, World!"
* @param req https://expressjs.com/en/api.html#req
* @param res https://expressjs.com/en/api.html#res
*/
exports.helloWorld = (req, res) => {
res.send('Hello, World!');
};
To:
curl http://my-url
# Output: Hello, World!
All without needing to worry about writing an HTTP server or complicated request handling logic.
Watch this video to learn more about the Node Functions Framework.
Features
- Spin up a local development server for quick testing
- Invoke a function in response to a request
- Automatically unmarshal events conforming to the CloudEvents spec
- Portable between serverless platforms
Installation
Add the Functions Framework to your package.json
file using npm
.
npm install @google-cloud/functions-framework
Quickstarts
Quickstart: Hello, World on your local machine
-
Create an
index.js
file with the following contents:exports.helloWorld = (req, res) => { res.send('Hello, World'); };
-
Run the following command:
npx @google-cloud/functions-framework --target=helloWorld
-
Open http://localhost:8080/ in your browser and see Hello, World.
Quickstart: Set up a new project
-
Create a
package.json
file usingnpm init
:npm init
-
Create an
index.js
file with the following contents:const functions = require('@google-cloud/functions-framework'); functions.http('helloWorld', (req, res) => { res.send('Hello, World'); });
-
Now install the Functions Framework:
npm install @google-cloud/functions-framework
-
Add a
start
script topackage.json
, with configuration passed via command-line arguments:"scripts": { "start": "functions-framework --target=helloWorld" }
-
Use
npm start
to start the built-in local development server:npm start ... Serving function... Function: helloWorld URL: http://localhost:8080/
-
Send requests to this function using
curl
from another terminal window:curl localhost:8080 # Output: Hello, World
Quickstart: Build a Deployable Container
-
Build a container from your function using the Functions buildpacks:
pack build \ --builder gcr.io/buildpacks/builder:v1 \ --env GOOGLE_FUNCTION_SIGNATURE_TYPE=http \ --env GOOGLE_FUNCTION_TARGET=helloWorld \ my-first-function
-
Start the built container:
docker run --rm -p 8080:8080 my-first-function # Output: Serving function...
-
Send requests to this function using
curl
from another terminal window:curl localhost:8080 # Output: Hello, World!
Run your function on serverless platforms
Google Cloud Functions
The
Node.js 10 runtime on Google Cloud Functions
is based on the Functions Framework. On Cloud Functions, the Functions Framework
is completely optional: if you don't add it to your package.json
, it will be
installed automatically.
After you've written your function, you can simply deploy it from your local
machine using the gcloud
command-line tool.
Check out the Cloud Functions quickstart.
Cloud Run / Cloud Run for Anthos
After you've written your function, added the Functions Framework and updated your start
script in package.json
, deploy it to Cloud Run with gcloud run deploy
. Check out the Cloud Run quickstart for Node.js.
If you want even more control over the environment, you can deploy to Cloud Run for Anthos. With Cloud Run for Anthos, you can run your function on a GKE cluster, which gives you additional control over the environment (including use of GPU-based instances, longer timeouts and more).
Container environments based on Knative
Cloud Run and Cloud Run for Anthos both implement the Knative Serving API. The Functions Framework is designed to be compatible with Knative environments. Just build and deploy your container to a Knative environment.
Configure the Functions Framework
You can configure the Functions Framework using command-line flags or environment variables. If you specify both, the environment variable will be ignored.
Command-line flag | Environment variable | Description |
---|---|---|
--port |
PORT |
The port on which the Functions Framework listens for requests. Default: 8080 |
--target |
FUNCTION_TARGET |
The name of the exported function to be invoked in response to requests. Default: function |
--signature-type |
FUNCTION_SIGNATURE_TYPE |
The signature used when writing your function. Controls unmarshalling rules and determines which arguments are used to invoke your function. Default: http ; accepted values: http or event or cloudevent |
--source |
FUNCTION_SOURCE |
The path to the directory of your function. Default: cwd (the current working directory) |
You can set command-line flags in your package.json
via the start
script.
For example:
"scripts": {
"start": "functions-framework --target=helloWorld"
}
Enable Google Cloud Functions Events
The Functions Framework can unmarshall incoming
Google Cloud Functions event payloads to data
and context
objects.
These will be passed as arguments to your function when it receives a request.
Note that your function must use the event
-style function signature:
exports.helloEvents = (data, context) => {
console.log(data);
console.log(context);
};
To enable automatic unmarshalling, set the function signature type to event
using a command-line flag or an environment variable. By default, the HTTP
signature will be used and automatic event unmarshalling will be disabled.
For more details on this signature type, check out the Google Cloud Functions documentation on background functions.
Enable CloudEvents
The Functions Framework can unmarshall incoming
CloudEvents payloads to a cloudevent
object.
It will be passed as an argument to your function when it receives a request.
Note that your function must use the cloudevent
-style function signature:
const functions = require('@google-cloud/functions-framework');
functions.cloudEvent('helloCloudEvents', (cloudevent) => {
console.log(cloudevent.specversion);
console.log(cloudevent.type);
console.log(cloudevent.source);
console.log(cloudevent.subject);
console.log(cloudevent.id);
console.log(cloudevent.time);
console.log(cloudevent.datacontenttype);
});
Advanced Docs
More advanced guides and docs can be found in the docs/
folder.
Contributing
Contributions to this library are welcome and encouraged. See CONTRIBUTING for more information on how to get started.