gopiper

README

gopiper

Overview

NOTE: THIS APP IS ON A PRE-ALPHA STATE. EVERYTHING IS GOING TO CHANGE

gopiper is a tool written in Go for creating high perfomance message processing pipelines. This approach makes heavy use of Go channels.

The purpose of this tool is provide a minimal framework to create components (elements that process messages in a pipeline) and an abstraction over the orchestration of these components using lua as configuration language.

Creating components

Components are compiled as Go plugins and are loaded at runtime. To create a component you just need to implement the Component interface and a Factory interface.

type Factory interface {
  Create(postponed chan Message) Component
  Destroy()
  SetAttribute(key string, value interface{}) error
  PoolSize() int
  ChannelSize() int
}

type Component interface {
  Handle(Message, HandledCallback)
}

Since the approach of tis app uses a pool of worker, it's recommended to process messages in a synchronous way. The pipeline's internal logic takes care of managing workers so you should not return from the Handle() function until you are completely done with the message.

A component receives a Message interface, gets data from the message and performs some work with it. When the job is done, the component should call the HandledCallback to inform the pipeline that the message has been processed.

type Message interface {
  GetData() interface{}
  SetData(interface{})
  GetAttribute(string) interface{}
  SetAttribute(string, interface{})
  Status() *Report
  Release()
}

Error handling

After processing a message you should use the HandledCallback callback to inform the result of the processing.

type Report struct {
  Status      int
  Description string
}

Status codes are the following:

Status	Action
0	Done, the next component should process the messag
1	Continue, the component expects more messages before send a message to the next worker
2 - 99	Reserved
100 - 199	Retry, the message has been failed to process. Should be retried.
200 - 299	Fail, the message has been failed to process. Should not be retried
300+	Drop, silently drop the message.

You can also include a description for your status for debugging purposes.

Building a pipeline

Using lua

The easiest way of build a pipeline is using the lua API. You can load components and start the pipeline as you can see in the following example:

-- Import the module
local gopiper = require('gopiper')

-- Insert desired components on compontents table
local components = {
  gopiper.loadComponent('stdin_component.so', {}),
  gopiper.loadComponent('stdout_component.so', {}),
}

-- Create the pipeline
gopiper.createPipeline(components)

Using from Go

// TODO

Using from C

// TODO

Instrumentation

// TODO