Architecture¶

Stack

Function Watchdog¶

You can make any Docker image into a serverless function by adding the Function Watchdog (a tiny Golang HTTP server)
The Function Watchdog is the entrypoint allowing HTTP requests to be forwarded to the target process via STDIN. The response is sent back to the caller by writing to STDOUT from your application.

API Gateway / UI Portal¶

The API Gateway provides an external route into your functions and collects Cloud Native metrics through Prometheus.
Your API Gateway will scale functions according to demand by altering the service replica count in the Docker Swarm or Kubernetes API.
A UI is baked in allowing you to invoke functions in your browser and create new ones as needed.

Note

The API Gateway is a RESTful micro-service and you can view the Swagger docs here.

Prometheus/Grafana¶

Example of a Grafana dashboard linked to OpenFaaS showing auto-scaling live in action:

Sample dashboard JSON file available here

CLI¶

Any container or process in a Docker container can be a serverless function in FaaS. Using the FaaS CLI you can deploy your functions or quickly create new functions from templates such as Node.js or Python.

Note

The CLI is effectively a RESTful client for the API Gateway.

When you have OpenFaaS configured you can get started with the CLI here

Function examples¶

You can generate new functions using the FaaS-CLI and built-in templates or use any binary for Windows or Linux in a Docker container.

Python¶

handler.py

import requests

def handle(req):
        r =  requests.get(req, timeout = 1)
        print(req +" => " + str(r.status_code))

Node.js¶

handler.js

"use strict"

module.exports = (callback, context) => {
    callback(null, {"message": "You said: " + context})
}

Other languages...¶

Sample functions in a range of other languages are available in the Github repository.

If there is a language then you would like to see added please contact the project team.