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State Machine API documentation

class rackio.RackioStateMachine(name, **kwargs)

Class used to define custom state machines.

This class is used to define custom machines, by defining parameters, states, transitions and by defining methods state behaviour can de defined.

Parameters:

• name (str): state machine name.

Usage:

from rackio import RackioStateMachine, State


class TwoStep(RackioStateMachine):

    # states

    state1  = State('State1', initial=True)
    state2  = State('State2')

    # transitions

    forward = state1.to(state2)
    back = state2.to(state1)

    # parameters

    count = 0

    def on_back(self):

        self.count = 0

    def while_state1(self):

        self.count += 1

        logging.warning("{}: {}".format(self.name, self.count))
        if self.count == 5:
            self.forward()

    def while_state2(self):

        self.count += 1

        logging.warning("{}: {}".format(self.name, self.count))
        if self.count >= 10:
            self.back()

Bindings

class rackio.TagBinding(tag, direction='read')

Class used within Rackio State Machine.

This class is used to bind tag values with an instance of a Rackio State Machine object, in the machine loop, before executing current state, tag bindings of an object are updated with last values from the Tag Engine, after execution, the Tag Engine is updated, the direction of the binding must be provided, otherwise read direction is used.

Usage:

class TwoStep(RackioStateMachine):

    # states

    state1  = State('State1', initial=True)
    state2  = State('State2')

    # transitions

    forward = state1.to(state2)
    back = state2.to(state1)

    # bindings

    t1 = TagBinding("T1")
    t2 = TagBinding("T2", direction="write")

class rackio.GroupBinding(group, direction='read')

Class used within Rackio State Machine.

This class is used to bind a tag group values with an instance of a Rackio State Machine object, in the machine loop, before executing current state, group bindings of an object are updated with last values of all tags in that group from the Tag Engine, after execution, the Tag Engine is updated, the direction of the binding must be provided, otherwise read direction is used.

Usage:

class TwoStep(RackioStateMachine):

    # states

    state1  = State('State1', initial=True)
    state2  = State('State2')

    # transitions

    forward = state1.to(state2)
    back = state2.to(state1)

    # bindings

    g1 = GroupBinding("G1")
    g2 = GroupBinding("G2", direction="write")