cand (pronounced candy) is the solution to your CAN
send/receieve/decode/encode woes.
cand listens to and decodes CAN messages with a provided DBC file, and also
listens for, encodes, and sends CAN messages you ask it to send.
Run cand as a daemon and use cand.client to interact with it. For example:
from cand.client import Bus
bus = Bus()
bus.send('dbwNode_Status', {'SystemStatus': 'ESTOP', 'Counter': 11})
print(bus.get('dbwNode_Encoder_Data'))
# (1652836556992745935, {'Encoder0': 133, 'Encoder1': 152, 'Time': 10000})cand and the cand.client.Bus interface are very fast. Neither Bus.get()
nor Bus.send() calls block for very long, because they simply query or write
to the Redis backend. cand monitors its outbound CAN send performance and
will leave log messages when the TX buffer starts to grow too large. Messages
will not be lost, however.
Note: cand will work through its backlog of messages to be sent regardless of the size; we should change that behavior eventually.
cand uses Redis as the storage and request backend between itself and
clients. You can specify the Redis host and port for cand as well as the
client.