#!/usr/bin/env python
#
# License: BSD
# https://raw.githubusercontent.com/splintered-reality/py_trees/devel/LICENSE
#
##############################################################################
# Documentation
##############################################################################
"""
A py_trees demo.
.. argparse::
:module: py_trees.demos.pick_up_where_you_left_off
:func: command_line_argument_parser
:prog: py-trees-demo-pick-up-where-you-left-off
.. graphviz:: dot/pick_up_where_you_left_off.dot
.. image:: images/pick_up_where_you_left_off.gif
"""
##############################################################################
# Imports
##############################################################################
import argparse
import functools
import sys
import time
import typing
import py_trees
import py_trees.console as console
##############################################################################
# Classes
##############################################################################
[docs]def description(root: py_trees.behaviour.Behaviour) -> str:
"""
Print description and usage information about the program.
Returns:
the program description string
"""
content = "A demonstration of the 'pick up where you left off' idiom.\n\n"
content += "A common behaviour tree pattern that allows you to resume\n"
content += "work after being interrupted by a high priority interrupt.\n"
content += "\n"
content += "EVENTS\n"
content += "\n"
content += " - 2 : task one done, task two running\n"
content += " - 3 : high priority interrupt\n"
content += " - 7 : task two restarts\n"
content += " - 9 : task two done\n"
content += "\n"
if py_trees.console.has_colours:
banner_line = console.green + "*" * 79 + "\n" + console.reset
s = banner_line
s += (
console.bold_white
+ "Pick Up Where you Left Off".center(79)
+ "\n"
+ console.reset
)
s += banner_line
s += "\n"
s += content
s += "\n"
s += py_trees.display.unicode_tree(root)
s += "\n"
s += banner_line
else:
s = content
return s
[docs]def epilog() -> typing.Optional[str]:
"""
Print a noodly epilog for --help.
Returns:
the noodly message
"""
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
[docs]def command_line_argument_parser() -> argparse.ArgumentParser:
"""
Process command line arguments.
Returns:
the argument parser
"""
parser = argparse.ArgumentParser(
description=description(create_root()),
epilog=epilog(),
formatter_class=argparse.RawDescriptionHelpFormatter,
)
group = parser.add_mutually_exclusive_group()
group.add_argument(
"-r", "--render", action="store_true", help="render dot tree to file"
)
group.add_argument(
"-i",
"--interactive",
action="store_true",
help="pause and wait for keypress at each tick",
)
return parser
[docs]def pre_tick_handler(behaviour_tree: py_trees.trees.BehaviourTree) -> None:
"""Print a banner immediately before every tick of the tree.
Args:
behaviour_tree (:class:`~py_trees.trees.BehaviourTree`): the tree custodian
"""
print("\n--------- Run %s ---------\n" % behaviour_tree.count)
[docs]def post_tick_handler(
snapshot_visitor: py_trees.visitors.SnapshotVisitor,
behaviour_tree: py_trees.trees.BehaviourTree,
) -> None:
"""Print an ascii tree with the current snapshot status."""
print(
"\n"
+ py_trees.display.unicode_tree(
root=behaviour_tree.root,
visited=snapshot_visitor.visited,
previously_visited=snapshot_visitor.previously_visited,
)
)
[docs]def create_root() -> py_trees.behaviour.Behaviour:
"""
Create the root behaviour and it's subtree.
Returns:
the root behaviour
"""
task_one = py_trees.behaviours.StatusQueue(
name="Task 1",
queue=[
py_trees.common.Status.RUNNING,
py_trees.common.Status.RUNNING,
],
eventually=py_trees.common.Status.SUCCESS,
)
task_two = py_trees.behaviours.StatusQueue(
name="Task 2",
queue=[
py_trees.common.Status.RUNNING,
py_trees.common.Status.RUNNING,
],
eventually=py_trees.common.Status.SUCCESS,
)
high_priority_interrupt = py_trees.decorators.RunningIsFailure(
name="Running is Failure",
child=py_trees.behaviours.Periodic(name="High Priority", n=3),
)
piwylo = py_trees.idioms.pick_up_where_you_left_off(
name="Pick Up\nWhere You\nLeft Off", tasks=[task_one, task_two]
)
root = py_trees.composites.Selector(name="Root", memory=False)
root.add_children([high_priority_interrupt, piwylo])
return root
##############################################################################
# Main
##############################################################################
[docs]def main() -> None:
"""Entry point for the demo script."""
args = command_line_argument_parser().parse_args()
py_trees.logging.level = py_trees.logging.Level.DEBUG
root = create_root()
print(description(root))
####################
# Rendering
####################
if args.render:
py_trees.display.render_dot_tree(root)
sys.exit()
####################
# Tree Stewardship
####################
behaviour_tree = py_trees.trees.BehaviourTree(root)
behaviour_tree.add_pre_tick_handler(pre_tick_handler)
behaviour_tree.visitors.append(py_trees.visitors.DebugVisitor())
snapshot_visitor = py_trees.visitors.SnapshotVisitor()
behaviour_tree.add_post_tick_handler(
functools.partial(post_tick_handler, snapshot_visitor)
)
behaviour_tree.visitors.append(snapshot_visitor)
behaviour_tree.setup(timeout=15)
####################
# Tick Tock
####################
if args.interactive:
py_trees.console.read_single_keypress()
for _unused_i in range(1, 11):
try:
behaviour_tree.tick()
if args.interactive:
py_trees.console.read_single_keypress()
else:
time.sleep(0.5)
except KeyboardInterrupt:
break
print("\n")