Goalee is a Python 3.5+ library that implements several concepts of GoalDSL and it is used by the code generator to produce the source code from a given Goaldsl model. Goalee can also be used as a standalone Python library for implementing goal-driven targets for applications.
Download this repository and simply install using pip package manager.
git clone https://github.com/robotics-4-all/goalee
cd goalee
pip install .
The source code of a goal validator is shown below. Two Goals are defined,
a TopicMessageParamGoal and a TopicMessageReceivedGoal.
#!/usr/bin/env python3
from goalee import Target, RedisMiddleware
from goalee.topic_goals import TopicMessageReceivedGoal, TopicMessageParamGoal
if __name__ == '__main__':
middleware = RedisMiddleware()
t = Target(middleware)
g1 = TopicMessageReceivedGoal(topic='sensors.sonar.front',
max_duration=10.0)
g2 = TopicMessageParamGoal(topic='sensors.sonar.front',
max_duration=10.0,
condition=lambda msg: True if msg['range'] > 5 \
else False)
t.add_goal(g1)
t.add_goal(g2)
t.run_seq()
The first goal waits for a message to be received at topic
sensors.sonar.front, for a maximum duration of 10 seconds, while the second
goal uses a condition to filter messages arrived at sensors.sonar.front. In
this example g2 completes when a message that satisfies the condition range > 5 arrives.
Conditions are defined using lambda functions in Python.
After creation of goal instances, you have to create a target and add goals to it. Target requires a Middleware to connect to and listen to topics. In the above example a local Redis is used as the communication middleware.
middleware = RedisMiddleware()
t = Target(middleware)
Targets can be executed in Concurrent (t.run_concurrent()) or Sequential (t.run_seq()) mode. In sequential
mode goals are executed in the order they were added using the add_goal
method.
Several examples can be found here.