CANd

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})

Performance

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.

Redis

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.