EvQueue is a free and open source task scheduler and queueing engine.
It handles the planning of simple tasks but also that of workflows, chaining basic pieces of code to more complex endeavours.
The description of how tasks are linked together is based on XML and XPath, making workflow structure rely on standard and well-known technologies.
EvQueue’s queueing engine is written in C++ and is event-driven, making it leightweight and very fast.
The web interface is written in PHP. It allows monitoring of running tasks and workflows, new workflows creation (including a GUI mode), and tasks scheduling.
Alongside the web interface, evQueue exposes a network API allowing remote control (launch workflows, monitor tasks…).
Execution of heavy tasks is indeed a recurring issue in web systems, where clients behave in an asynchronous fashion.
Using evQueue solves this issue by offering a simple follow-up system through AJAX calls on the client side, and an excellent visibility for system administrators backstage.
Documentation on how to install and use evQueue, as well as workflow examples, are available on the evQueue website.
EvQueue is being developped and maintained by the IT department of French consumer-protection NGO UFC-Que Choisir.
It is published under a Free Software license since March 2015.
It has been used in a production environment by the organisation’s IT for almost three years; to date, more than four millions workflows have been executed.
Official website: http://www.evqueue.net