Functions Framework for R

An open source FaaS (Function as a service) framework for writing portable R functions.

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:

hello <- function(req, res){
  return("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.

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

install.packages("devtools", repos='http://cran.us.r-project.org')
library(devtools)
install_github("averikitsch/functions-framework-r/src/functionsframework")

Quickstart: Hello, World on your local machine

Create a main.R file with the following contents:

hello <- function(req, res){
  return("Hello World!")
}

Create a create-app.R file with the following contents:

library(functionsframework)
createApp()

or add to the end of main.R.

Run the following command:

Rscript create-app.R --target=hello

Open http://localhost:8080/ in your browser and see Hello world!.

Run your function on serverless platforms

Cloud Run

Once you've written your function and added the Functions Framework to your file, all that's left is to create a container image. Check out the Cloud Run quickstart to create a container image and deploy it to Cloud Run. You'll write a Dockerfile when you build your container. This Dockerfile allows you to specify exactly what goes into your container (including custom binaries, a specific operating system, and more).

Container environments based on Knative

Cloud Run implements 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
--source	FUNCTION_SOURCE	The path to the file containing your function. Default: main.R (in the current working directory)

Contributing

Contributions to this library are welcome and encouraged. See CONTRIBUTING for more information on how to get started.