ODIN Sequencer

A python command sequencer to allow easy scripting of ODIN control systems

• Free software: Apache Software License 2.0

Features

• Detect Changes button - When enabled, it will detect any code changes that have been made to the loaded modules.
• Reload - When clicked, it will reload the loaded modules and any changes that have been made to them will be applied.
• Execute buttons - When clicked, it will execute the sequence.

How to set up

Clone the repository and navigate into the cloned directory

$ git clone git@github.com:stfc-aeg/odin-sequencer.git
$ cd odin-sequencer

Create a Python 3 virtual environment and activate it

$ python3 -m venv ./odin-sequencer-3.8
$ source odin-sequencer-3.8/bin/activate

Install the test dependencies (required for development and testing)

$ pip install -e .[test]

How to run

Run the odin server while in the odin-sequencer directory

$ odin_control --config config/odin_sequencer.cfg

Access the UI by navigating to localhost:8888 in your browser

Loading sequences

By default, the modules located inside the sequences directory in ~/odin-sequencer/src/examples are loaded when the server is started. If you want to load modules from a different directory, then you will need to change the sequence_location value inside the odin_sequencer.cfg file located in ~/odin_sequencer/config. Modules get loaded into the manager when the server is started if there are any modules in the directory specified. The sequence_location value does not necessarily have to point to a directory but it can point to a single module file too.

How to add context

Call add_context during the other adapters initialize (see dummy_context.py for an example)

test_device = TestDevice(123)
self.adapters['odin_sequencer'].add_context('test_device', test_device)

The context can now be used in a sequence by calling get_context (see example_sequences.py for an example)

dev = get_context('test_device')

How to abort an executing sequence

Long-running sequences can choose to check the value of the abort_sequence() function, which is exposed to every loaded sequence module. If true the sequence can be cleanly terminated early. (See example_sequences.py for an example of an abortable sequence.)

How to report progress in an executing sequence

Executing sequences can report progress to the user by calling the set_progress function, which is exposed to every loaded sequence module. This takes two arguments reporting the current and total steps in the sequence. This is used by the API and UI to display progress. (See example_sequences.py for an example.)

How to start a local process worker

With the virtual enviroment activated, navigate to the supervisord directory and start the worker

$ cd odin_sequencer/src/odin_sequencer/supervisord
$ supervisord -c supervisord.conf || supervisorctl -c supervisord.conf start celery

How to start a multiple remote process workers

Navigate to the scripts directory, list the remote works in workers.txt, update the config at the start of start_worker.sh, and then run the script

$ cd scripts
$ sh start_worker.sh

How to stop a multiple remote process workers

Navigate to the scripts directory, list the remote works in workers.txt, update the config at the start of stop_worker.sh, and then run the script

$ cd scripts
$ sh stop_worker.sh

How to run a process during a sequence

Ensure the process queue adapter is loaded in odin_sequencer.cfg

[adapter.process_queue_context]
module = odin_sequencer.process_queue_context.ProcessQueueContextAdapter

Add processing tasks to tasks.py

def add(x, y):
    return x + y

The process_writer context can then be loaded during a sequence to add tasks to queue using run or group

queue = get_context('process_writer')
queue.run('add', True, 4, 3)
queue.group('add', True, range(10), 3)
output = queue.run('add', False, 4, 3)
result = output.get()

run allows for a single task to be run

Parameters:

• String task function name
• Boolean True if the result from the function doesn't need to be returned
• arguments for the task function

group allows for a group of task to be run

Parameters:

• String task function name
• Boolean True if the result from the function doesn't need to be returned
• List list of values of the argument that is to be iterated over
• other arguments for the task function

Credits

This package was created with Cookiecutter and the audreyr/cookiecutter-pypackage project template.