Yamcs Command Subscription in python

[Sultan Mesmar]

Hello,

Is there a way to create a command subscription on Yamcs, using python without having to resort  to using websockets? And if websockets are the only way, how can I integrate it in python and specify the command to be subscribed to?

Thank you in advance.

SM

[fabia...@spaceapplications.com]

Hi, the Yamcs Python Client has a method which helps to send one or more commands and optionally following up on acknowledgments status:

https://docs.yamcs.org/python-yamcs-client/tmtc/client/#yamcs.tmtc.client.ProcessorClient.create_command_connection

This uses a combination of both REST and WebSocket. In Yamcs all subscriptions use WebSocket as this allows for a long-running communication channel over HTTP.

In this specific case: the sending of a command is a simple REST method, whereas to receive acknowledgment updates uses WebSocket.

Example usage:

https://docs.yamcs.org/python-yamcs-client/examples/commanding/

[Sultan Mesmar]

Hi.

Thank you for your reply.

I was hoping to find a way to just get the command that was sent and be able to check the parameters that were sent instead of sending them myself. This will help in automating the process.

Is there another way?

SM 

[fabia...@spaceapplications.com]

You mean this?

• Listen to realtime command history updates: https://docs.yamcs.org/python-yamcs-client/tmtc/client/#yamcs.tmtc.client.ProcessorClient.create_command_history_subscription
• Retrieve past commands on-demand: https://docs.yamcs.org/python-yamcs-client/archive/client/#yamcs.archive.client.ArchiveClient.list_command_history

For the first one, any filtering will need to be done on the client.