Description

# Functions Framework for Python [](https://badge.fury.io/py/functions-framework) [![Python unit CI][ff_python_unit_img]][ff_python_unit_link] [![Python lint CI][ff_python_lint_img]][ff_python_lint_link] [![Python conformace CI][ff_python_conformance_img]][ff_python_conformance_link]  An open source FaaS (Function as a service) framework for writing portable Python 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 Run Functions](https://cloud.google.com/functions/) * Your local development machine * [Knative](https://github.com/knative/)-based environments The framework allows you to go from: ```python def hello(request): return "Hello world!" ``` To: ```sh curl http://my-url # Output: Hello world! ``` All without needing to worry about writing an HTTP server or complicated request handling logic. ## 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](https://cloudevents.io/) spec * Portable between serverless platforms ## Installation Install the Functions Framework via `pip`: ```sh pip install functions-framework ``` Or, for deployment, add the Functions Framework to your `requirements.txt` file: ``` functions-framework==3.* ``` ## Quickstarts ### Quickstart: HTTP Function (Hello World) Create an `main.py` file with the following contents: ```python import flask import functions_framework @functions_framework.http def hello(request: flask.Request) -> flask.typing.ResponseReturnValue: return "Hello world!" ``` > Your function is passed a single parameter, `(request)`, which is a Flask [`Request`](https://flask.palletsprojects.com/en/3.0.x/api/#flask.Request) object. Run the following command: ```sh functions-framework --target hello --debug * Serving Flask app "hello" (lazy loading) * Environment: production WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead. * Debug mode: on * Running on http://0.0.0.0:8080/ (Press CTRL+C to quit) ``` (You can also use `functions-framework-python` if you have multiple language frameworks installed). Open http://localhost:8080/ in your browser and see *Hello world!*. Or send requests to this function using `curl` from another terminal window: ```sh curl localhost:8080 # Output: Hello world! ``` ### Quickstart: CloudEvent Function Create an `main.py` file with the following contents: ```python import functions_framework from cloudevents.http.event import CloudEvent @functions_framework.cloud_event def hello_cloud_event(cloud_event: CloudEvent) -> None: print(f"Received event with ID: {cloud_event['id']} and data {cloud_event.data}") ``` > Your function is passed a single [CloudEvent](https://github.com/cloudevents/sdk-python/blob/main/cloudevents/sdk/event/v1.py) parameter. Run the following command to run `hello_cloud_event` target locally: ```sh functions-framework --target=hello_cloud_event ``` In a different terminal, `curl` the Functions Framework server: ```sh curl -X POST localhost:8080 \ -H "Content-Type: application/cloudevents+json" \ -d '{ "specversion" : "1.0", "type" : "example.com.cloud.event", "source" : "https://example.com/cloudevents/pull", "subject" : "123", "id" : "A234-1234-1234", "time" : "2018-04-05T17:31:00Z", "data" : "hello world" }' ``` Output from the terminal running `functions-framework`: ``` Received event with ID: A234-1234-1234 and data hello world ``` More info on sending [CloudEvents](http://cloudevents.io) payloads, see [`examples/cloud_run_cloud_events`](examples/cloud_run_cloud_events/) instruction. ### Quickstart: Error handling The framework includes an error handler that is similar to the [`flask.Flask.errorhandler`](https://flask.palletsprojects.com/en/1.1.x/api/#flask.Flask.errorhandler) function, which allows you to handle specific error types with a decorator: ```python import functions_framework @functions_framework.errorhandler(ZeroDivisionError) def handle_zero_division(e): return "I'm a teapot", 418 def function(request): 1 / 0 return "Success", 200 ``` This function will catch the `ZeroDivisionError` and return a different response instead. ### Quickstart: Pub/Sub emulator 1. Create a `main.py` file with the following contents: ```python def hello(event, context): print("Received", context.event_id) ``` 1. Start the Functions Framework on port 8080: ```sh functions-framework --target=hello --signature-type=event --debug --port=8080 ``` 1. In a second terminal, start the