Adeeb Shihadeh 7150c145ae selfdrived: remove redundant sound card check (#33767) | 1 week ago | |
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.. | ||
include | 4 months ago | |
messaging | 3 weeks ago | |
README.md | 4 months ago | |
SConscript | 1 month ago | |
__init__.py | 4 months ago | |
car.capnp | 2 weeks ago | |
custom.capnp | 4 months ago | |
legacy.capnp | 4 months ago | |
log.capnp | 1 week ago | |
maptile.capnp | 4 months ago | |
services.py | 4 weeks ago |
cereal is the messaging system for openpilot. It uses msgq as a pub/sub backend, and Cap'n proto for serialization of the structs.
You'll find the message types in log.capnp. It uses Cap'n proto and defines one struct called Event
.
All Events
have a logMonoTime
and a valid
. Then a big union defines the packet type.
When making changes to the messaging spec you want to maintain backwards-compatibility, such that old logs can be parsed with a new version of cereal. Adding structs and adding members to structs is generally safe, most other things are not. Read more details here.
Forks of openpilot might want to add things to the messaging spec, however this could conflict with future changes made in mainline cereal/openpilot. Rebasing against mainline openpilot then means breaking backwards-compatibility with all old logs of your fork. So we added reserved events in custom.capnp that we will leave empty in mainline cereal/openpilot. If you only modify those, you can ensure your fork will remain backwards-compatible with all versions of mainline openpilot and your fork.
import cereal.messaging as messaging
# in subscriber
sm = messaging.SubMaster(['sensorEvents'])
while 1:
sm.update()
print(sm['sensorEvents'])
# in publisher
pm = messaging.PubMaster(['sensorEvents'])
dat = messaging.new_message('sensorEvents', size=1)
dat.sensorEvents[0] = {"gyro": {"v": [0.1, -0.1, 0.1]}}
pm.send('sensorEvents', dat)