README.md
# Qyu 九
[](https://rubygems.org/gems/qyu)
[](https://travis-ci.org/QyuTeam/qyu)
[](https://codeclimate.com/github/QyuTeam/qyu/maintainability)
[](https://codecov.io/gh/QyuTeam/qyu)
[](https://rubyweekly.com/link/44495/web)
## Requirements:
* Ruby 2.4.0 or newer
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'qyu'
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install qyu
## Configuration
To start using Qyu; you need a queue configuration and a state store configuration. Here's an example:
```ruby
Qyu.configure(
queue: {
type: :memory
},
store: {
type: :memory,
lease_period: 60
},
# optional Defaults to STDOUT
logger: Logger.new(STDOUT)
)
```
## Usage
[1] Connect all instances to the same state store and message queue
[2] Create a workflow
[3] Initialize a worker as follows
```ruby
w = Qyu::Worker.new do
# callbacks
callback :execute, :before do
Qyu.logger.info 'Waiting for task..'
end
callback :execute, :after do
Qyu.logger.info 'Done'
end
# payload validation
validates :times, presence: true, type: :integer
# failure queue
failure_queue false
# timeout in seconds for each task processed by the worker
timeout 120
end
w.work('queue-name') do |task|
# to get the payload passed to the task
task.payload
# = { 'param_1' => true, 'param_2': [10, 11, 12], 'param_3' => 2 }
# get the job
task.job
# to manually start a task
task.job.create_task(task, 'next-task-name', payload)
rescue StandardError => ex
# If you rescue the error for debugging or reporting purposes, you have to raise it at the end
#
# do something
#
raise ex
end
```
[4] Start worker
[5] Start creating Jobs using the previously created workflow
## Plugins
The memory queue and store is just for testing purposes. For production; use one of the following:
#### Stores
*ActiveRecord:* https://github.com/QyuTeam/qyu-store-activerecord
*Redis:* https://github.com/QyuTeam/qyu-store-redis
#### Queues
*Amazon SQS:* https://github.com/QyuTeam/qyu-queue-sqs
*Redis:* https://github.com/QyuTeam/qyu-queue-redis
## Glossary
#### Workflow
The workflow specifies the entry points (`starts`), the tasks, their order, eventual dependencies between them, and synchronisation conditions.
#### Job
A job is essentially a collection of tasks and an initial JSON payload.
#### Task
A task is one unit of work. It is an instance of an entry from a workflow. You can think of it as the workflow's entries define the classes, while a task is a materialised instance of it, saved in the state store and enqueued on the message queue.
In the state store a task has:
* `id`
* `name` - it appears as the key in the workflow's `tasks`
* `queue_name` - the queue where the task was enqueued on creation
* `payload` - the entry/input parameters for the particular task
* `parent_task_id` - the ID of the task which created/enqueued the current task
When a task is created (saved & enqueued) then its `id` is put in a JSON message `{ task_id: task.id}` and enqueued on the specified task's message queue.
When a worker picks up the message from the queue, decodes the task id, and retrieves it from the state store.
#### Worker
A worker is sitting on a queue, waiting for something.
#### Sync Worker
A worker waiting for other workers to finish
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/QyuTeam/qyu.