RFD 39 (vminfod): Discussion about rfd HOT 1 CLOSED

comments on vmadm events

Some example output and details for the sake of discussion: https://gist.github.com/trentm/bfc164985c3dabdc3a61aec856ecd1da

• Is there prior art for event stream output formatting that is guiding this?
  FWIW, see some 'docker events' examples at
  https://docs.docker.com/engine/reference/commandline/events/#examples

    2017-01-05T00:35:58.859401177+08:00 container create 0fdb48addc82871eb34eb23a847cfd033dedd1a0a37bef2e6d9eb3870fc7ff37 (image=alpine:latest, name=test)
    2017-01-05T00:36:04.703631903+08:00 network connect e2e1f5ceda09d4300f3a846f0acfaa9a8bb0d89e775eb744c5acecd60e0529e2 (container=0fdb...ff37, name=bridge, type=bridge)
    2017-01-05T00:36:04.795031609+08:00 container start 0fdb...ff37 (image=alpine:latest, name=test)
    2017-01-05T00:36:09.830268747+08:00 container kill 0fdb...ff37 (image=alpine:latest, name=test, signal=15)
    2017-01-05T00:36:09.840186338+08:00 container die 0fdb...ff37 (exitCode=143, image=alpine:latest, name=test)
  

  This includes some smarts for showing some relevant fields depending on what changed.

• What are the events? Would be nice to spec them.

• Examples in the man page would be nice.

• Why --full? Is this common enough for '-f' short opt? Perhaps '-l, --long'
  a la ls and triton ... commands? Or reverse it and make full info
  the default and use -s,--short. I don't care strongly.

• --ready Perhaps useful to example the motivation for ready event? I assume
  it is for callers to know that they can only establish a starting state
  after that ready event?

• perhaps 'time' instead of 'date'?

• why 'path' and 'prettyPath'? What's an example where path has multiple
  elements? Where are those values from?
  Found one: tag change:

    "changes":[{"prettyPath":"tags.foo","path":["tags","foo"],"action":"added","to":"bar"}]}
  

  So it is about JSON lookup path.

• for 'create' event there is no 'changes' field. Will that surprise using code?

• what is the vm.pid field about?
  [2017-12-13T23:50:52.268Z] ddd12fb0-7ce7-668d-ddac-d3e3f656caac trent0 modify: pid changed :: 84625 -> 4294967295

• what are these transition_ events about?

        [23:59:44.700Z] 4492085e trent1 modify: transition_to removed :: "running" -> undefined
        [23:59:44.700Z] 4492085e trent1 modify: transition_expire removed :: 1513209839551 -> undefined
  

• would it be possible to optionally include the req_id if an event originated
  from an explicit vmadm ... command? Perhaps not.

from rfd.