#!/usr/bin/env python
#
# License: BSD
# https://raw.githubusercontent.com/splintered-reality/py_trees/devel/LICENSE
#
##############################################################################
# Documentation
##############################################################################
"""
.. argparse::
:module: py_trees.demos.blackboard
:func: command_line_argument_parser
:prog: py-trees-demo-blackboard
.. graphviz:: dot/demo-blackboard.dot
:align: center
:caption: Dot Graph
.. figure:: images/blackboard_demo.png
:align: center
Console Screenshot
"""
##############################################################################
# Imports
##############################################################################
import argparse
import operator
import py_trees
import sys
import py_trees.console as console
##############################################################################
# Classes
##############################################################################
def description():
content = "Demonstrates usage of the blackboard and related behaviours.\n"
content += "\n"
content += "A sequence is populated with a few behaviours that exercise\n"
content += "reading and writing on the Blackboard in interesting ways.\n"
if py_trees.console.has_colours:
banner_line = console.green + "*" * 79 + "\n" + console.reset
s = "\n"
s += banner_line
s += console.bold_white + "Blackboard".center(79) + "\n" + console.reset
s += banner_line
s += "\n"
s += content
s += "\n"
s += banner_line
else:
s = content
return s
def epilog():
if py_trees.console.has_colours:
return console.cyan + "And his noodly appendage reached forth to tickle the blessed...\n" + console.reset
else:
return None
def command_line_argument_parser():
parser = argparse.ArgumentParser(description=description(),
epilog=epilog(),
formatter_class=argparse.RawDescriptionHelpFormatter,
)
render_group = parser.add_mutually_exclusive_group()
render_group.add_argument('-r', '--render', action='store_true', help='render dot tree to file')
render_group.add_argument(
'--render-with-blackboard-variables',
action='store_true',
help='render dot tree to file with blackboard variables'
)
return parser
[docs]class Nested(object):
"""
A more complex object to interact with on the blackboard.
"""
[docs] def __init__(self):
self.foo = "bar"
[docs] def __str__(self):
return str({"foo": self.foo})
[docs]class BlackboardWriter(py_trees.behaviour.Behaviour):
"""
Custom writer that submits a more complicated variable to the blackboard.
"""
[docs] def __init__(self, name="Writer"):
super().__init__(name=name)
self.blackboard = self.attach_blackboard_client()
self.blackboard.register_key(key="dude", access=py_trees.common.Access.READ)
self.blackboard.register_key(key="spaghetti", access=py_trees.common.Access.WRITE)
self.logger.debug("%s.__init__()" % (self.__class__.__name__))
[docs] def update(self):
"""
Write a dictionary to the blackboard and return :data:`~py_trees.common.Status.SUCCESS`.
"""
self.logger.debug("%s.update()" % (self.__class__.__name__))
try:
unused = self.blackboard.dude
except KeyError:
pass
try:
unused = self.blackboard.dudette
except AttributeError:
pass
try:
self.blackboard.dudette = "Jane"
except AttributeError:
pass
self.blackboard.spaghetti = {"type": "Carbonara", "quantity": 1}
self.blackboard.spaghetti = {"type": "Gnocchi", "quantity": 2}
try:
self.blackboard.set("spaghetti", {"type": "Bolognese", "quantity": 3}, overwrite=False)
except AttributeError:
pass
return py_trees.common.Status.SUCCESS
[docs]class ParamsAndState(py_trees.behaviour.Behaviour):
"""
A more esotoric use of multiple blackboards in a behaviour to represent
storage of parameters and state.
"""
[docs] def __init__(self, name="ParamsAndState"):
super().__init__(name=name)
# namespaces can include the separator or may leave it out
# they can also be nested, e.g. /agent/state, /agent/parameters
self.parameters = self.attach_blackboard_client("Params", "parameters")
self.state = self.attach_blackboard_client("State", "state")
self.parameters.register_key(
key="default_speed",
access=py_trees.common.Access.READ
)
self.state.register_key(
key="current_speed",
access=py_trees.common.Access.WRITE
)
[docs] def initialise(self):
try:
self.state.current_speed = self.parameters.default_speed
except KeyError as e:
raise RuntimeError("parameter 'default_speed' not found [{}]".format(str(e)))
[docs] def update(self):
if self.state.current_speed > 40.0:
return py_trees.common.Status.SUCCESS
else:
self.state.current_speed += 1.0
return py_trees.common.Status.RUNNING
def create_root():
root = py_trees.composites.Sequence("Blackboard Demo")
set_blackboard_variable = py_trees.behaviours.SetBlackboardVariable(
name="Set Nested", variable_name="nested", variable_value=Nested()
)
write_blackboard_variable = BlackboardWriter(name="Writer")
check_blackboard_variable = py_trees.behaviours.CheckBlackboardVariableValue(
name="Check Nested Foo",
check=py_trees.common.ComparisonExpression(
variable="nested.foo",
value="bar",
operator=operator.eq
)
)
params_and_state = ParamsAndState()
root.add_children([
set_blackboard_variable,
write_blackboard_variable,
check_blackboard_variable,
params_and_state
])
return root
##############################################################################
# Main
##############################################################################
[docs]def main():
"""
Entry point for the demo script.
"""
args = command_line_argument_parser().parse_args()
print(description())
py_trees.logging.level = py_trees.logging.Level.DEBUG
py_trees.blackboard.Blackboard.enable_activity_stream(maximum_size=100)
blackboard = py_trees.blackboard.Client(name="Configuration")
blackboard.register_key(key="dude", access=py_trees.common.Access.WRITE)
blackboard.register_key(key="/parameters/default_speed", access=py_trees.common.Access.WRITE)
blackboard.dude = "Bob"
blackboard.parameters.default_speed = 30.0
root = create_root()
####################
# Rendering
####################
if args.render:
py_trees.display.render_dot_tree(root, with_blackboard_variables=False)
sys.exit()
if args.render_with_blackboard_variables:
py_trees.display.render_dot_tree(root, with_blackboard_variables=True)
sys.exit()
####################
# Execute
####################
root.setup_with_descendants()
unset_blackboard = py_trees.blackboard.Client(name="Unsetter")
unset_blackboard.register_key(key="foo", access=py_trees.common.Access.WRITE)
print("\n--------- Tick 0 ---------\n")
root.tick_once()
print("\n")
print(py_trees.display.unicode_tree(root, show_status=True))
print("--------------------------\n")
print(py_trees.display.unicode_blackboard())
print("--------------------------\n")
print(py_trees.display.unicode_blackboard(display_only_key_metadata=True))
print("--------------------------\n")
unset_blackboard.unset("foo")
print(py_trees.display.unicode_blackboard_activity_stream())