ex_telem_get_newest.py

"""
Example using get_newest_packet().
"""
import trek
 
# NOTE:  This example requires the TReK Data GUI to be started and the PDSS Payload
# Packet with APID 7 to be activated with a Real-Time data mode.
 
tlm_api = trek.TelemetryApi()
pkt = trek.Packet()
packet_buffer = bytearray(4096)
 
 
def main() -> None:
    """
    Main Routine
    """
 
    try:
        pkt_key_list: list[str]
 
        # Connect to a data store.
        tlm_api.connect("DefaultDataStore")
 
        # Calling this method allows the API to clean up resources that may be
        # left over from a user program that crashed.  Not checking the return
        # value as it is safe to continue if this method fails.
        tlm_api.cleanse()
 
        # Get a list of the packet keys currently being processed.  If you know
        # your packet key already, this isn't needed.
        pkt_key_list = tlm_api.get_source_list()
 
        for idx, key in enumerate(pkt_key_list):
            print(f"Packet key {idx+1}: {key}")
 
        # Get the packet definition so that parameters can be extracted
        # from the packet.
        tlm_api.get_packet_definition("PdssPayload.RT.PL.7", pkt)
 
        # Get the latest packet from the data store.
        tlm_api.get_newest_packet("PdssPayload.RT.PL.7", packet_buffer)
 
        # Use the packet definition to extract the data.
        _ = pkt.extract(packet_buffer, len(packet_buffer))
 
        # The packet has been extracted and can now get the values using the Packet class
        # methods.  Look up a parameter and get its value.
        param = pkt.find_parameter("MSID016")
 
        param_value = param.get_value()
 
        print(f"Value is: {param_value}")
 
        # It is always best to call Disconnect when you are finished with the
        # API.  There are system resources that can be freed when you no
        # longer need the API.
        tlm_api.disconnect()
 
    except trek.TrekError as err:
        # Locate friendly message why it failed.
        print(err.find_error_code())
        print(err)
 
 
if __name__ == "__main__":
    main()