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https://github.com/linkyndy/pallets

Simple and reliable workflow engine, written in Ruby
https://github.com/linkyndy/pallets

ruby workflow workflow-engine

Last synced: 28 days ago
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Simple and reliable workflow engine, written in Ruby

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# Pallets



[![Build Status](https://travis-ci.com/linkyndy/pallets.svg?branch=master)](https://travis-ci.com/linkyndy/pallets)



Simple and reliable workflow engine, written in Ruby



## It is plain simple!



```ruby

# my_workflow.rb

require 'pallets'



class MyWorkflow < Pallets::Workflow

  task 'Foo'

  task 'Bar' => 'Foo'

  task 'Baz' => 'Foo'

  task 'Qux' => ['Bar', 'Baz']

end



class Foo < Pallets::Task

  def run

    puts 'I love Pallets! <3'

  end

end

# [other task definitions are ommited, for now]



MyWorkflow.new.run

```



That's basically it! Curious for more? Read on or [check the examples](examples/)!



> Don't forget to run pallets, so it can process your tasks: `bundle exec pallets -r ./my_workflow`



## Features



* faaast!

* reliable

* retries failed tasks

* Redis backend out of the box

* JSON and msgpack serializers out of the box

* Rails support

* beautiful DSL

* convention over configuration

* thoroughly tested



## Installation



```

# Gemfile

gem 'pallets'



# or



gem install pallets

```



## Configuration



```ruby

Pallets.configure do |c|

  # How many workers to process incoming jobs?

  c.concurrency = 2



  c.backend = :redis

  c.serializer = :json



  c.backend_args = { db: 1 }



  # What's the maximum allowed time to process a job?

  c.job_timeout = 1800

  # How many times should a job be retried?

  c.max_failures = 3

end

```



For the complete set of options, see [pallets/configuration.rb](lib/pallets/configuration.rb)



## Cookbook



### DSL



Pallets is designed for developers' happiness. Its DSL aims to be as beautiful

and readable as possible, while still enabling complex scenarios to be performed.



```ruby

# All workflows must subclass Pallets::Workflow

class WashClothes < Pallets::Workflow

  # The simplest task

  task BuyDetergent



  # Another task; since it has no dependencies, it will be executed in parallel

  # with BuyDetergent

  # TIP: Use a String argument when task is not _yet_ loaded

  task 'BuySoftener'



  # We're not doing it in real life, but we use it to showcase our first dependency!

  task DilluteDetergent => BuyDetergent



  # We're getting more complex here! This is the alternate way of defining

  # dependencies (which can be several, by the way!). Choose the style that fits

  # you best

  task TurnOnWashingMachine, depends_on: [BuyDetergent, 'BuySoftener']



  # Specify how many times a task is allowed to fail. If max_failures is reached

  # the task is given up

  task SelectProgram => TurnOnWashingMachine, max_failures: 2

end



# Every task must be a subclass of Pallets::Task

class BuyDetergent < Pallets::Task

  # Tasks must implement this method; here you can define whatever rocket science

  # your task needs to perform!

  def run

    # ...do whatever...

  end

end



# We're omitting the other task definitions for now; you shouldn't!

```



## Motivation



The main reason for Pallets' existence was the need of a fast, simple and reliable workflow engine, one that is easily extensible with various backends and serializer, one that does not lose your data and one that is intelligent enough to concurrently schedule a workflow's tasks.



## Status



Pallets is under active development and it is not _yet_ production-ready.



## How to contribute?



Any contribution is **highly** appreciated! See [CONTRIBUTING.md](CONTRIBUTING.md) for more details.



## License



See [LICENSE](LICENSE)