20181114 Dev Meeting

Agenda

General:

• Update from previous calls
  • MAVLink microservices versioning as means to better control change.
  • AI @ALL - review RFC in #861 "Local and body frames" for next meeting.
• Tagged: issues, PR
• Pymavlink#237: message CRC checksum is wrong when a mavlink_message_t is converted to a sending buffer

HamishW:

• Test suite - what are constraints (e.g. language)? "Shape" of proposed design - unit tests, clients vs server, what user stories test will meet, how individual libraries should validate.
• What needs to happen for PX4 and ArduPilot to adopt common parameter and mission protocol specs?
• WIP support: https://github.com/ArduPilot/pymavlink/pull/234
• How do we test? https://github.com/ArduPilot/pymavlink/pull/240

@JulianO Maybe discuss

• Command acknowledgement
  • request id for absolute acknowledgement?
  • reliable transport/retransmission

Notes

Call 1

• WIP messages discussion

  • WIP PRto allow messages to warn in production environments
    • Not entirely satisfying, but does mean that people can choose to enable warnings in production environments for WIP message use.
  • Rules for promoting WIP messages to "release" messages should be full PR/review process again. Reason is that WIPs are accepted without full implications of messages being known.

• UTM_GLOBAL_POSITION message - Was discussed in dev call and agreed to merge when minor changes in enum names complete.

• Testing discussion:

  • HamishW wants some advice on testing/how the test generator works in mavgen.
  • James pointed out lots of churn at moment. Recommends talking to PeterBarker and StephenDade.
  • Many test by just building library and dumping into their project.
  • Mavgen and Clojure both do round trip tests

message CRC checksum is wrong when a mavlink_message_t is converted to a sending buffer

• Discuss options to progress.
• MichaelDuB suggested there is a finalize method to generate CRC for buffer.
• JulianO to review and respond.

MAVLink microservices versioning

• Brief discussion
• JamesP stated that it makes sense as a stand alone idea, but very concerned that it is likely to increase complexity and could easily become unwieldy.
• MichaelDuB suggested it needs to be able to support case where intermittent versions are supported. Currently no way to specify that an in-between version is not specified.
• HamishW would like tabled until Lorenz can address concerns.
• No one had any better suggestions.

HamishW Complained about difficulty of reaching consensus to standardise existing protocols

• JamesP pointed out that volunteers communities hard to engage if things don't interest them.
• Also that lots of stuff needs to be maintained in order to keep compatibility (hard for ArduPilot to manage because of very diverse user base) but means that they are reticent to support new things unless strictly necessary.

AI:

@JamesP and @MichaelS (or Lorenz/Thomas) to engage with Local and body frames and add comments. Discuss next week.

@WickedShell File format discussion - Attempt to re-engage in next two weeks.

@JulianOes to review and respond to message CRC checksum is wrong when a mavlink_message_t is converted to a sending buffer

Attendees:

MichaelDuBreuil, JulianOes, HamishWillee, James Pattison, MichaelSchaeuble.