Christoph Hochstrasser

PHP Project Automation with Bob

After not being satisfied with Ant, Phing and Pake — I’ve scratched my own itch and made Bob — a simple project automation tool.

Bob was written as a tool for me to automate those tiny, repetitive tasks that pop up every once in a while — like commands which have to be run on the shell every time with the same arguments, or some maintenance for the database.

These task do almost never need a fancy CLI frontend. They just need a place where they can be put and simple means to link them together.

Here is an uncomplete list of possible use cases right from the top of my head:

  • Generating an archive of all files and upload it somewhere for deployment.
  • Running all tests (maybe with sub-tasks to run only unit or integration tests).
  • Code Generation (often created application artifacts like controllers, domain classes).
  • Launching a development server.
  • Doing Database migrations.
  • Automating certain maintenance stuff.
  • Doing tasks necessary when a new release is due, for example bump the application’s version number, create some tags in the VCS and make a tarball.

I wrote Bob because I had enough of the verboseness of Phing’s and Ant’s XML based DSLs and wasn’t quite satisfied with Pake’s PHP based DSL either.

I had these Design Goals in mind for Bob:

  • The Build configs must be plain PHP files, so existing application code, libraries and functions can be easily used. This should also lower the barrier of contribution for the project’s team members in a PHP project. When the barrier of contribution is too high build files start to rot. I’m seeing this happen with our Ant Build Configs at work.
  • Shell scripts are easy and simple, but not an option because of their portability (mainly Windows).
  • I wanted to make use of Closures for defining task actions, to get defining tasks as concise as possible with PHP. I really disliked the way Pake does not use Closures (since it has to support PHP 5.2.x) and instead forces me to define a separate, named function for the task action which leads — in my opinion — to unnecessary verboseness.
  • I really like Rake, therefore it influenced the design of Bob and its DSL quite a bit.
  • Keep it simple. The tool should not have more than several hundred lines of code.
  • I wanted to experiment with an own coding style, I would like to call it “Lean PHP”. I plan to do an extra article on that.

Install

The recommended way of installing Bob is through Composer.

Create a composer.json in your project’s root and put this into it:

{
    "require": {
        "chh/bob": "master-dev"
    }
}

Then run on the shell:

$ wget http://getcomposer.org/composer.phar
php composer.phar install

Bob is then ready to use in vendor/bin/bob.phar.

Quickstart

To start using Bob, create a bob_config.php in your project’s root directory. This file will contain all tasks.

This is how a simple bob_config.php can look like:

<?php

namespace Bob;

task('hello', function() {
    println('Hello World');
});

task('foo', function() {
    println('Foo');
});

To run this task launch Bob with hello as argument. Bob treats all arguments passed after the flags as task names. These tasks are run in the specified order:

$ php vendor/bin/bob.phar hello
Hello World
$ php vendor/bin/bob.phar hello foo
Hello World
Foo

When no task is given on the command line, then Bob attempts to run the default task.

Tasks can be described by using the desc() function before defining a task. Now let’s add a simple description to our hello task:

desc('Echoes Hello World');
task('hello', function() {
    ...
});

Descriptions are shown alongside their tasks when Bob is run with the --tasks flag:

$ php vendor/bin/bob.phar --tasks
(in yourproject/)
bob hello # Echoes Hello World

To make dependencies between tasks, just pass an array of task names as second argument to the call to task.

Let’s change the definition of our first task to reference the foo task as a dependency:

task('hello', array('foo'), function() {
    println('Hello World')
});

And now run Bob again:

$ php vendor/bin/bob.phar hello
Foo
Hello World

We can use this now to set the hello task as default task, by adding it as dependency:

task('default', array('hello'));

When we run Bob without task names then the hello task is now run:

$ php vendor/bin/bob.phar
Foo
Hello World

This was only a quick overview of what Bob is able to do. To see more examples, read on in the next section.

Practical Recipes

These are some common scenarios for using Bob. More examples can be found in Bob’s own bob_config.php.

Update composer packages when the composer.json has changed

This is good example for a file task. Here we run composer.phar update when the composer.json is newer than the composer.lock created by composer. This keeps our dependencies up to date and could be run before running the unit tests.

fileTask('composer.lock', array('composer.json'), function() {
    sh('composer.phar update');
});

Running unit tests

This runs all tests with PHPUnit and copies the provided phpunit.dist.xml to a phpunit.xml before running the tests.

task('test', array('phpunit.xml'), function() {
    sh('phpunit');
});

# Copies the phpunit.dist.xml to phpunit.xml, when phpunit.xml does
# not exist.
fileTask('phpunit.xml', array('phpunit.dist.xml'), function() {
    copy('phpunit.dist.xml', 'phpunit.xml');
});

Running a local PHP development server

This requires PHP 5.4.0 at least for the builtin CLI Web Server.

task('server', function() {
    # The Symfony Process Component is included with Bob.
    $phpFinder = new \Symfony\Component\Process\PhpExecutableFinder;
    $php = $phpFinder->find();

    $process = new \Symfony\Component\Process\Process(join(' ', array(
        $php, '-S', 'localhost:8080', '-t', 'public/', 'public/index.php'
    )));

    $process->setTimeout(null);

    # Write Error output to STDERR and normal output to
    # STDOUT, so we see the server's logging messages:
    $process->run(function($type, $output) {
        $type == 'err' ? fwrite(STDERR, $output) : echo $output;
    });
});

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