Eldritch

The dark arts of concurrent programming.

A DSL that adds parallel programming constructs to make your life a little easier.

Code quality

Features

async methods

Async methods run concurrently when called. The caller is returned controlled right away and the method runs in the background.

require 'eldritch'

# define an async method
async def send_email(email)
  # ...
end

# ...
send_email(some_email) # runs in the background
# ...

async blocks

Async blocks are run concurrently.

require 'eldritch'

# do some work
async do
  # some long running task ...
end
# continue working

tasks

Async blocks and async methods both return tasks. These can be used to interact with the async block/method. As of now, you can wait for the task to finish or you can get its return value.

require 'eldritch'

task = async do
  # calculate something that will take a long time
end

# ...

# now we need to result of the task
res = 2 + task.value # waits for the task to finish

together blocks

Together blocks are used to control all async blocks and methods within them as a group. Before exiting, together blocks wait for all their async calls to be done before returning.

require 'eldritch'

together do
  1000.times do
    async do
      # do some work
    end
  end
end
# all 1000 tasks are done

These blocks can also take an argument. This argument is a group that can be used to control the async calls in the block. See the documentation for Eldritch::Group for more information.

require 'eldritch'

together do |group|
  5.times do
    async do
      # do something
      group.interrupt if some_condition  # stops all other tasks
    end
  end
end

Installation

Add this line to your application's Gemfile:

gem 'eldritch'

And then execute:

$ bundle

Or install it yourself as:

$ gem install eldritch