openfaas

OpenFaaS

OpenFaaS® (Functions as a Service) is a framework for building Serverless functions with Docker and Kubernetes which has first-class support for metrics. Any process can be packaged as a function enabling you to consume a range of web events without repetitive boiler-plate coding.

How it works

With OpenFaaS you can create your own Go-based functions and that means your Flogo apps (built with the Golang API) can be deployed there too! To make it work, OpenFaaS leverages a dockerfile that executes the build of the function and makes the docker image available to wherever you're running OpenFaaS.

Schema

Settings, Outputs:

{
  "settings": [
  ],
  "output": [
    {
      "name": "context",
      "type": "object"
    },
    {
      "name": "evt",
      "type": "object"
    }
  ]
}

Dockerfile

Due to the build process of OpenFaaS and the required metadata for Project Flogo, the dockerfile to build these Go based apps needs to be modified slightly. The dockerfile in the sampleapp folder has been modified to accomodate for those changes. On line 17, a small statement will update the metadata files with the correct ID for OpenFaaS.

Sample app

As with the Lambda trigger, Flogo apps using the OpenFaaS trigger will break down into a few parts as you can see in the handler.go file

Handle

This method takes care of starting and enabling the Flogo app to handle requests from the OpenFaaS environment

init

This method takes care of the initialization of the Flogo app

shimApp

This method takes care of creating the Flogo app and registering the OpenFaaS trigger with the Flogo engine

RunActivities

RunActivities is where the magic happens. This is where you get the input from any event that might trigger your OpenFaaS function in a map called evt