tutorial

Signed-off-by: Christian Henkel <[email protected]>

bt_tools_common/testable_tutorials/testable_tutorials.py

@@ -0,0 +1,171 @@
+# Copyright (c) 2024 - for information on the respective copyright owner
+# see the NOTICE file
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+This takes tutorials written in markdown files and extracts the code blocks
+to be tested. The code blocks are then executed and the output is compared
+to the expected output.
+"""
+
+import os
+import re
+import sys
+import logging
+import subprocess
+import argparse
+import select
+from typing import Optional, List, Tuple
+
+BLOCK_DELIM = '```'
+
+class ROSTerminal:
+    """
+    Class for interacting with a ROS terminal
+    """
+    def __init__(self):
+        self.process = subprocess.Popen(
+            ['bash'], 
+            stdin=subprocess.PIPE, 
+            stdout=subprocess.PIPE, 
+            stderr=subprocess.PIPE,
+            text=True,
+            bufsize=1)
+
+    def execute(self, command: str) -> str:
+        """
+        Executes a command in the terminal
+        """
+        if not command.endswith('\n'):
+            command += '\n'
+        self.process.stdin.write(command)
+        self.process.stdin.flush()
+        self.process.stdin.flush()
+
+        output = []
+        # Read the output
+        while True:
+        # Use select to wait for data to be available on stdout
+            rlist, _, _ = select.select([self.process.stdout], [], [], 2.0)
+
+            if self.process.stdout in rlist:
+                line = self.process.stdout.readline().strip()
+                print(line)
+                if line:
+                    output.append(line)
+                else:
+                    break
+            else:
+                break
+        while True:
+        # Use select to wait for data to be available on stdout
+            rlist, _, _ = select.select([self.process.stdout], [], [], 2.0)
+
+            if self.process.stdout in rlist:
+                line = self.process.stdout.readline().strip()
+                print(line)
+                if line:
+                    output.append(line)
+                else:
+                    break
+            else:
+                break
+
+        error = []
+        # Read the error
+        while True:
+        # Use select to wait for data to be available on stderr
+            rlist, _, _ = select.select([self.process.stderr], [], [], 2.0)
+
+            if self.process.stderr in rlist:
+                line = self.process.stderr.readline().strip()
+                print(line)
+                if line:
+                    error.append(line)
+                else:
+                    break
+            else:
+                break
+
+        if error:
+            logging.error(f'Error: {error}')
+        return output
+
+    def close(self):
+        """
+        Closes the terminal
+        """
+        self.process.stdin.close()
+        self.process.stdout.close()
+        self.process.stderr.close()
+        self.process.kill()
+
+def extract_code_blocks(file_path: str) -> List[Tuple[str, str]]:
+    """
+    Extracts code blocks from a markdown file
+    """
+    code_blocks: List[Tuple[str, str]] = []  # (language, code)
+    with open(file_path, 'r') as file:
+        code: Optional[str] = None
+        language: Optional[str] = None
+        in_code_block: bool = False
+        for line in file:
+            if line.startswith(BLOCK_DELIM):
+                new_language = line.strip(BLOCK_DELIM).strip()
+                if len(new_language) == 0:  # end of code block
+                    code_blocks.append((language, code))
+                    code = None
+                    language = None
+                    in_code_block = False
+                else:
+                    language = new_language
+                    code = ''
+                    in_code_block = True
+            elif in_code_block:
+                if code is not None:
+                    code += line
+    return code_blocks
+
+def run_code_blocks(code_blocks: List[Tuple[str, str]]):
+    """
+    Runs the code blocks
+    """
+    terminal = ROSTerminal()
+    terminal.execute('source /opt/ros/humble/setup.bash')
+    for language, code in code_blocks:
+        if language == 'bash':
+            for line in code.split('\n'):
+                if len(line.strip()) == 0:
+                    continue
+                logging.info(f'cmd: {line}')
+                output = terminal.execute(line)
+                logging.info(f'out: {output}')
+        else:
+            logging.warning(f'Unsupported language: {language}')
+    terminal.close()
+
+def main():
+    """
+    Main function
+    """
+    logging.basicConfig(level=logging.INFO)
+    ap = argparse.ArgumentParser()
+    ap.add_argument('file', help='Markdown file to extract code blocks from')
+    args = ap.parse_args()
+    code_blocks = extract_code_blocks(args.file)
+    print(code_blocks)
+    run_code_blocks(code_blocks)
+
+if __name__ == '__main__':
+    main()

bt_view/tutorial.md

@@ -0,0 +1,17 @@
+# How to visualize a FBL file
+
+## Verify installation
+
+To verify that the installation was successful, run the following command:
+
+```bash
+ls
+```
+
+```bash
+echo $ROS_DISTRO
+```
+
+```bash
+ros2 topic list
+```

btlib/scripts/bt_to_fsm

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+
+import argparse
+from btlib.bt_to_fsm import bt_to_fsm
+from btlib.bts import xml_to_networkx
+
+def main():
+    parser = argparse.ArgumentParser(description='Converts a BT to an FSM')
+    parser.add_argument('bt', type=str, help='The BT to convert')
+    args = parser.parse_args()
+
+    bt, _ = xml_to_networkx(args.bt)
+    btf = bt_to_fsm.Bt2FSM(bt)
+    fsm = btf.convert()
+    btf.plot_fsm(fsm)
+
+if __name__ == '__main__':
+    main()

btlib/setup.py

@@ -33,5 +33,8 @@
     license='Apache-2.0',
     tests_require=[
         'pytest',
-    ]
+    ],
+    scripts=[
+        'scripts/bt_to_fsm',
+    ],
 )

btlib/src/btlib/bt_to_fsm/bt_to_fsm.py

@@ -218,7 +218,7 @@ def _convert_subtree(self, node_id: int) -> nx.DiGraph:
                 f'Category {node["category"]} not implemented.')
         return fsm
 
-    def _plot_fsm(self, fsm: nx.DiGraph):
+    def plot_fsm(self, fsm: nx.DiGraph):
         """Plot the Finite State Machine."""
         import matplotlib.pyplot as plt
         fixed_pos = {

btlib/tutorial.md

@@ -0,0 +1,58 @@
+## Transform a behavior tree into a finite state machine
+
+This tutorial will teach you how to use the algorithm in this package to transform a behavior tree into a functionally equivalent finite state machine.
+
+### Background
+
+This implements the algorithm described in [_Behavior Trees in Robotics and AI: An Introduction_ by Michele Colledanchise, Petter Ögren](https://arxiv.org/pdf/1709.00084).
+Of particular interest is the section __2.2.2 Creating a FSM that works like a BTs__ (page 29).
+
+For our implementation, please refer to [the Bt2FSM class](https://bt-tools.readthedocs.io/en/latest/apidocs/btlib/btlib.bt_to_fsm.bt_to_fsm.html#btlib.bt_to_fsm.bt_to_fsm.Bt2FSM).
+
+### Prerequisites
+
+You need to have this package installed in your workspace.
+If you don't have it, build it:
+
+```bash
+mkdir -p ~/catkin_ws/src
+cd ~/catkin_ws/src
+git clone https://github.com/boschresearch/bt_tools.git
+cd ~/catkin_ws
+catkin build --symlink-install --packages-select btlib
+source ~/catkin_ws/devel/setup.bash
+```
+
+### Input file
+
+You can pass any behavior tree in the [behaviortree.cpp](https://behaviortree.dev) format to the algorithm.
+For example [simple_bt.xml](https://github.com/boschresearch/bt_tools/blob/main/btlib/test/_test_data/bt2fsm/simple_bt.xml):
+
+```xml
+<root BTCPP_format="4">
+    <BehaviorTree>
+        <Sequence>
+            <ServiceBtCondition name="TEST_CONDITION" />
+            <Fallback>
+                <ActionBtAction name="TEST_ACTION_A" />
+                <ActionBtAction name="TEST_ACTION_B" />
+            </Fallback>
+        </Sequence>
+    </BehaviorTree>
+</root>
+```
+
+### Call the algorithm
+
+Then pass it to the script:
+
+```bash
+bt_to_fsm.py ~/catkin_ws/src/bt_tools/btlib/test/_test_data/bt2fsm/simple_bt.xml
+```
+
+### Output
+
+This will generate a file called `fsm.png` in your current directory.
+It will look something like this:
+
+![FSM](imgs/fsm.png)

docs/source/tutorials.rst

@@ -1,15 +1,4 @@
 Tutorials
 =========
 
-How to model check your robot
------------------------------
-
-1. Install the necessary packages:
-```
-sudo apt install THAT
-```
-
-2. Run the model checker:
-```
-convince_toolchain -i model.scxml -o results.json
-```
+.. mdinclude:: ../../btlib/tutorial.md