ironic.common.fsm.
FSM
[source]¶Bases: automaton.machines.FiniteMachine
An ironic state-machine class with some ironic specific additions.
add_state
(state, on_enter=None, on_exit=None, target=None, terminal=None, stable=False)[source]¶Adds a given state to the state machine.
stable – Use this to specify that this state is a stable/passive state. A state must have been previously defined as ‘stable’ before it can be used as a ‘target’
target – The target state for ‘state’ to go to. Before a state can be used as a target it must have been previously added and specified as ‘stable’
Further arguments are interpreted as for parent method add_state
.
add_transition
(start, end, event, replace=False)¶Adds an allowed transition from start -> end for the given event.
start – starting state
end – ending state
event – event that causes start state to transition to end state
replace – replace existing event instead of raising a
Duplicate
exception
when the transition already exists.
initialize
(start_state=None, target_state=None)[source]¶Initialize the FSM.
start_state – the FSM is initialized to start from this state
target_state – if specified, the FSM is initialized to this target state. Otherwise use the default target state
is_stable
(state)[source]¶Is the state stable?
state – the state of interest
InvalidState if the state is invalid
True if it is a stable state; False otherwise
process_event
(event, target_state=None)[source]¶process the event.
event – the event to be processed
target_state – if specified, the ‘final’ target state for the event. Otherwise, use the default target state
target_state
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