Payload Signaling API
The Signaling API defines the interface that payloads must expose for the satellite bus to inform the payloads of upcoming events.
The API consists of:
- a payload executable on the customer payload used to respond to satellite bus events. This executable will be called by the bus using SSH - referred to as the payload_exec.
- conventions of where window configuration files are placed on the payload file system by the satellite bus.
- schema of window configuration files provided by the satellite bus for payload executables use. These window configuration files contain bus information about the signal as well as relevant data passed through at scheduling time from the Tasking API.
- conventions for arguments that payload executables must accept to handle satellite bus signals
Transmission of data from ground to the payload and from the payload to the ground is handled via the Spire Linux Agent (previously OORT Agent) process on the payload.
It is the responsibility of the payload to implement an executable that can be called with certain parameters after the window configuration file is placed on the payload file system. This executable will interpret the window configuration file and perform the necessary payload actions.
New in version 2
- For Signaling API version 2, file uploads to payloads must be handled by payload executables through the Spire Linux Agent. The documentation for that can be found here
- The bus will no longer automatically place payload uploads in
/signaling/inbox. See here - The configure signal call to the payload_exec will now contain the optional
-t <step_end_time_epoch_s>parameter similar to the execution signal call, which indicates the time the bus expects the configure signal call to return by. See here