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https://github.com/dotboris/eldritch
A ruby DSL that adds concurrent programming constructs to make parallelism easier.
https://github.com/dotboris/eldritch
async-methods dsl ruby
Last synced: about 2 months ago
JSON representation
A ruby DSL that adds concurrent programming constructs to make parallelism easier.
- Host: GitHub
- URL: https://github.com/dotboris/eldritch
- Owner: dotboris
- License: mit
- Created: 2014-03-20T00:52:13.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2019-01-04T23:04:31.000Z (over 5 years ago)
- Last Synced: 2024-07-14T15:46:51.988Z (2 months ago)
- Topics: async-methods, dsl, ruby
- Language: Ruby
- Homepage:
- Size: 90.8 KB
- Stars: 278
- Watchers: 8
- Forks: 7
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
Awesome Lists containing this project
README
Eldritch
========
[](http://travis-ci.org/dotboris/eldritch)
[](http://coveralls.io/r/dotboris/eldritch)
[](http://codeclimate.com/github/dotboris/eldritch)
_The dark arts of concurrent programming._
A DSL that adds parallel programming constructs to make your life a little
easier.
Usage
-----
1. Install it `gem install eldritch`
1. Require it `require 'eldritch'`
1. Use it (see features below)
By default eldritch will inject the DSL into the global scope. If you don't want
this, you can require `eldritch/safe` instead of `eldritch`.
```ruby
require 'eldricth/safe'
class MyClass
include Eldritch::DSL
extend Eldritch::DSL
# The DSL is available in this class
end
```
Development
-----------
### Setup
```sh
bundler install
```
### Running tests
```sh
bundler exec rake
```
### Running examples
```sh
ruby -I lib examples/{your favorite example}.rb
```
### Generate doc
```sh
bundle exec rake doc
```
Features
--------
### async methods
Async methods run concurrently when called. The caller is returned control right
away and the method runs in the background.
```ruby
require 'eldritch'
# define an async method
async def send_email(email)
# ...
end
send_email(some_email) # runs in the background
```
#### ruby 1.9.3 and 2.0.0
For all versions of ruby before 2.1.0, you need to define async methods like so:
```ruby
def foo
# stuff
end
async :foo
```
Since ruby 2.1.0, def returns the name of the method defined as a symbol. This
allows for the cleaner `async def foo` syntax.
### async blocks
Async blocks are run concurrently.
```ruby
require 'eldritch'
async do
# runs in the background
end
```
### tasks
Async blocks and async methods both return tasks. These can be used to interact
with the async block/method.
```ruby
require 'eldritch'
task = async do
# calculate something that will take a long time
end
# 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.
```ruby
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.
```ruby
require 'eldritch'
together do |group|
5.times do
async do
# do something
group.interrupt if some_condition # stops all other tasks
end
end
end
```
A note on GIL
-------------
MRI has this nasty little feature called a _GIL_ or _Global Interpreter Lock_.
This lock makes it so that only one thread can run at a time. Let's say that you
have 4 cores, running threaded code on MRI will only make use of 1 core.
Sometimes, you might not gain a speed boost if you make code parallel. This
could the case even if theory says otherwise.
Not all ruby implementations use a _GIL_. For example, jRuby does not use a
_GIL_.
If your ruby implementation has a _GIL_, you will probably see a speed boost if
your code does a lot of IO or anything that's blocking. In that case running on
a single core is not that much of a hindrance, because most of the threads will
be blocked and your code should run more often.