A library implementing workflows (or state machines) for Python projects.
XWorkflows is a library to add workflows, or state machines, to Python objects.
It has been fully tested with all versions of Python from 2.6 to 3.3
It allows to easilly define a workflow, attach it to a class, and use its transitions:
import xworkflows class MyWorkflow(xworkflows.Workflow): # A list of state names states = ( ('foo', "Foo"), ('bar', "Bar"), ('baz', "Baz"), ) # A list of transition definitions; items are (name, source states, target). transitions = ( ('foobar', 'foo', 'bar'), ('gobaz', ('foo', 'bar'), 'baz'), ('bazbar', 'baz', 'bar'), ) initial_state = 'foo' class MyObject(xworkflows.WorkflowEnabled): state = MyWorkflow() @xworkflows.transition() def foobar(self): return 42 # It is possible to use another method for a given transition. @xworkflows.transition('gobaz') def blah(self): return 13 >>> o = MyObject() >>> o.state <StateWrapper: <State: 'foo'>> >>> o.state.is_foo True >>> o.state.name 'foo' >>> o.state.title 'Foo' >>> o.foobar() 42 >>> o.state <StateWrapper: <State: 'bar'>> >>> o.state.name 'bar' >>> o.state.title 'Bar' >>> o.blah() 13 >>> o.state <StateWrapper: <State: 'baz'>> >>> o.state.name 'baz' >>> o.state.title 'Baz'
Custom functions can be hooked to transactions, in order to run before/after a transition, when entering a state, when leaving a state, …:
class MyObject(xworkflows.WorkflowEnabled): state = MyWorkflow() @xworkflows.before_transition('foobar') def my_hook(self, *args, **kwargs): # *args and **kwargs are those passed to MyObject.foobar(...) pass @xworkflows.on_enter_state('bar') def my_other_hook(self, result, *args, **kwargs): # Will be called just after any transition entering 'bar' # result is the value returned by that transition # *args, **kwargs are the arguments/keyword arguments passed to the # transition. pass