aslakhellesoy/petrinet

Petri Net simulation and diagramming

Petrinet

A command line utility for generating animated gifs of petri nets. This tool is designed to support living documentation and test-driven development of systems that can be modelled with petri nets.

Example

An X-Ray machine in a hospital, taken from Modeling Business Processes - A Petri Net-Oriented Approach.

The input for generating this gif is two files:

• a PNML file, for example created with PIPE or other petri net diagramming tool.
• a marking-transition script

Marking-Transition script

This is a simple text file to specify the initial marking of the net, and transitions to fire. The animation above was generated from the following marking file:

wait:3
free:1
enter
make_photo
leave
enter
make_photo
leave
enter
make_photo
leave

This file can be written by hand, or it can be generated.

Generating a Marking-Transition script

There are two typical ways to generate a marking-transition script - either via controlled automated tests, or from a running production system. Both of them require the system to log internal events and commands.

A specialised (but simple) tool could parse those logs and generate a marking-transition script, which can then be fed to petrinet for validation and generation of living documentation in the form of animated petri nets.

Installation

You need the following tools installed:

• Graphviz - the dot executable must be on your PATH
• ImageMagick - the convert executable must be on your PATH
• Ruby

Then run the following from the command line:

gem install petrinet

Usage

You need a .pnml file that describes your net, and a .txt marking-transition file. Generate an animated gif:

petrinet --script my-marking-transition.txt my-petri-net-pnml.xml

This will generate a file named my-marking-transition.gif (the name is derived from the .txt file)

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/aslakhellesoy/petrinet.

License

The gem is available as open source under the terms of the MIT License.