KoolKode BPMN 2.0 Process Engine

This project is not ready for production usage yet.

Provides a basic process engine that can load BPMN 2.0 diagrams and execute contained processes. The BPMN engine requires a relational database that is supported by KoolKode Database in order to persist process definitions, instances and other runtime data. Like Activiti it makes good use of the command pattern during execution of a process instance.

I recommend camunda Modeler to create executable process / collaboration diagrams. There is no need for a graphical editor, but it turns creating process definitions into a more pleasant experience. The engine ships with a class called BusinessProcessBuilder that can be used to create a process without loading it from a BPMN 2.0 XML file.

Concurrency and Locking

The engine uses pessimistic locking of process instances within the DB to prevent concurrent access to process instances. This locking strategy may create deadlocks. Try switching to async continuations / service methods when you are in danger of running into a deadlock (keep in mind that async processing requires a job scheduler).

Installation

Add "koolkode/bpmn" to your composer dependencies.
Run composer update to install the BPMN engine and it's dependencies.
Open a command shell in your project directory and execute ./vendor/bin/kkdb migration:up.
Have the tool generate the .kkdb.php config file for you (supported DBs are Sqlite, MySQL / MariaDB and PostgreSQL).
Edit .kkdb.php and add the path to the migration directory of the koolkode/bpmn package.
Run ./vendor/bin/kkdb migration:up again to apply DB migrations.

Sample config file using Sqlite

Copy the code shown into a file called .kkdb.php next to your composer.json. It configures a Sqlite connection that stores a DB file in your project directory.

<?php

return [
    'ConnectionManager' => [
        'adapter' => [
            'default' => [
                'dsn' => sprintf('sqlite:%s/bpmn.db', __DIR__)
            ]
        ],
        'connection' => [
            'default' => [
                'adapter' => 'default'
            ]
        ]
    ],
    'Migration' => [
        'MigrationManager' => [
            'directories' => [
                sprintf('%s/vendor/koolkode/bpmn/migration', __DIR__)
            ]
        ]
    ]
];

Run ./vendor/bin/kkdb migration:up and proceed with creating a process engine instance.

Creating a Process Engine

You can create a process engine as soon as your DB has been setup as described in the installation instructions. Here is some sample code, that shows how to create a process engine:

<?php

use KoolKode\BPMN\Engine\ProcessEngine;
use KoolKode\Database\ConnectionManager;
use KoolKode\Event\EventDispatcher;
use KoolKode\Expression\ExpressionContextFactory;

require_once __DIR__ . '/vendor/autoload.php';

$manager = ConnectionManager::fromConfigFile(__DIR__ . '/.kkdb.php');
$events = new EventDispatcher();
$expressions = new ExpressionContextFactory();

$engine = new ProcessEngine($manager->getConnection('default'), $events, $expressions);

// Use the repository service to deploy and query process definitions.
$repositoryService = $engine->getRepositoryService();

// Use the runtime service to start process instances and signal / message them.
$runtimeService = $engine->getRuntimeService();

// Use the task service to claim and complete user tasks.
$taskService = $engine->getTaskService();

The services that you aquire from the engine object offer all the features that are needed in order to deploy and run business processes defined using BPMN.

Supported BPMN 2.0 Elements

As of now KoolKode BPMN supports only a limited sub-set of BPMN elements.

Gateways

Exclusive
Inclusive
Parallel
Event-based (exclusive)

Activities

Task
Manual Task
Human Task
Service Task
Script Task (PHP only)
Send Task
Receive Task
Subprocess
Call Activity
Event Subprocess

Events

None - Start / Intermediate / End
Link - Intermediate
Terminate - End
Signal - Start / Intermediate / Boundary / End
Messafe - Start / Intermediate / Boundary / End
Timer - Intermediate

yiqing95/bpmn