Running Ruby Functions in RIFF

An invoker for RIFF to make it run Ruby functions. Play with the samples to get a feel for it.

Write your function

Your function should be in a Ruby source file that ends with an expression returning a Proc or a lambda. For example (from the samples):

require "base64"

Proc.new { |text| Base64.encode64(text) }

Build a container

Create a Dockerfile that puts your function code into the container and uses the function invoker as a base image. From the same sample:

FROM crdant/ruby-function-invoker:0.0.2-snapshot
ENV FUNCTION_URI /functions/function.rb
ADD base64.rb ${FUNCTION_URI}

Build your container image and push to your image repository

docker build <your source dir> -t <your docker id>/<your function name>:<your function version>
docker push <your function name>:<your function version>

Deploy your function

Create a file `<your function>.yaml" that describes your function to Kubernetes so you can deploy it. The deployment will need to specify the input topic, the output topic, and the function specification.

To define the input topic, add

apiVersion: projectriff.io/v1
kind: Topic
metadata:
  name: <input topic name>

then the output topic

apiVersion: projectriff.io/v1
kind: Topic
metadata:
  name: <output topic name>
spec:
  partitions: 3

and lastly the function

apiVersion: projectriff.io/v1
kind: Function
metadata:
  name: <your function name>
spec:
  protocol: http
  input: <input topic name>
  output: <output topic name>
  container:
    image: <your function name>:<your function version>

currently the invoker only supports protocol: http, though there are other options with RIFF.

Deploy with kubectl apply -f <your function>.yaml.

Use RIFF to send and receive messages

The RIFF repo has a couple of convenient scripts for sending messages to your function and reading them back. Use the publish to send messages, and the topics script to read them.