SimplePipeline

SimplePipeline is a simple framework for sequentially executing a series of code components. Each code component takes a payload, modifies it, and moves it down the pipe for the next component and so forth. One of the design goals is to make it as flexible as possible, yet keep it simple.

Installation

Install the gem from RubyGems:

gem install simple_pipeline

If you use Bundler, just add it to your Gemfile and run bundle install

gem 'simple_pipeline'

I have only tested this gem on Ruby 2.3.0, but there shouldn't be any reason why it wouldn't work on earlier Ruby versions as well.

Usage

pipeline = SimplePipeline.new

pipeline.add Pipe1.new
pipeline.add Pipe2.new
pipeline.add Pipe3.new

payload = {:some_key => some_value}

pipeline.process payload

SimplePipeline will call the process method on each of the pipes in the order that they were added to the pipeline.

Pipes

A pipe can be any Ruby object that has a process method that accepts a single argument (the payload object). For example:

class Pipe1
    def process (payload)
        # Do something with the payload object
    end
end

Payload

The payload can be an Array, Hash, or any other Ruby object. Individual pipes have the responsibility to know what to do with the payload that is passed into the process method.

Timeout

You can use the SimplePipeline::Timeout mixin to enforce a timeout value (in seconds) for a pipe. If the execution of the process method exceeds the specified timeout value, a Timeout::Error will be thrown.

class TimeoutPipe
    include SimplePipeline::Timeout

    set_timeout 3 # Set the timeout value to be three seconds

    def process (payload)
        # Do something
    end
end

pipeline = SimplePipeline.new
pipeline.add TimeoutPipe.new

payload = {:some_key => some_value}

# Will throw a Timeout::Error if execution of process on the TimeoutPipe instance takes longer than 3 seconds
pipeline.process payload

You can also set the timeout value on a per instance basis.

pipeline = SimplePipeline.new

pipe1 = TimeoutPipe.new
pipe1.set_timeout 10

pipe2 = TimeoutPipe.new
pipe2.set_timeout 60

pipeline.add pipe1
pipeline.add pipe2

This will override the timeout value set by the class definition.

Related Projects

• PiecePipe, an alternative implementation of the pipeline pattern.

License

SimplePipeline is released under the MIT license.