`amphp/parallel` provides *true parallel processing* for PHP using multiple processes or native threads, *without blocking and no extensions required*.
To be as flexible as possible, this library comes with a collection of non-blocking concurrency tools that can be used independently as needed, as well as an "opinionated" worker API that allows you to assign units of work to a pool of worker threads or processes.
## Installation
This package can be installed as a [Composer](https://getcomposer.org/) dependency.
```bash
composer require amphp/parallel
```
## Usage
The basic usage of this library is to submit blocking tasks to be executed by a worker pool in order to avoid blocking the main event loop.
```php
$response) {
\printf("Read %d bytes from %s\n", \strlen($response), $url);
}
```
[`file_get_contents`](https://secure.php.net/file_get_contents) is just used as an example for a blocking function here.
If you just want to fetch multiple HTTP resources concurrently, it's better to use [`amphp/http-client`](https://amphp.org/http-client/), our non-blocking HTTP client.
The functions you call must be predefined or autoloadable by Composer so they also exist in the worker processes.
Instead of simple callables, you can also enqueue `Task` instances with `Amp\Parallel\Worker\enqueue()`.
## Documentation
Documentation can be found on [amphp.org/parallel](https://amphp.org/parallel/) as well as in the [`./docs`](./docs) directory.
## Versioning
`amphp/parallel` follows the [semver](http://semver.org/) semantic versioning specification like all other `amphp` packages.
## Security
If you discover any security related issues, please email [`me@kelunik.com`](mailto:me@kelunik.com) instead of using the issue tracker.
## License
The MIT License (MIT). Please see [`LICENSE`](./LICENSE) for more information.
## Development and Contributing
Want to hack on the source? A [Vagrant](http://vagrantup.com) box is provided with the repository to give a common development environment for running concurrent threads and processes, and comes with a bunch of handy tools and scripts for testing and experimentation.
Starting up and logging into the virtual machine is as simple as
```bash
vagrant up && vagrant ssh
```
Once inside the VM, you can install PHP extensions with [Pickle](https://github.com/FriendsOfPHP/pickle), switch versions with `newphp VERSION`, and test for memory leaks with [Valgrind](http://valgrind.org).