Include datetime in httpok and memmon script logs

[erral]

Useful to know when the httpOk or Memmon scripts did something, because currently they only log what the did, not when they did it.

[erral]

There is a setuptools error on the python 3.2 tests, that seems to be unrelated to superlance...

[erral]

This addresses #71

[hvelarde]

@erral thanks for addressing this! wouldn't be better to test the presence of the time stamp using assertRegexpMatches?

[erral]

Maybe...

anyway the tests are run also for python 2.6 (https://github.com/Supervisor/superlance/blob/master/.travis.yml#L7) and according to the python docs assertRegexpMatches was introduced on python 2.7

[hvelarde]

can someone review this and give some feedback? @mnaberez? @tseaver?

@erral what do you think on using the server locale? for instance, in one server I see this format on nginx log: [06/Jun/2017:06:25:12 -0300].

if I use the code you implemented it gets printed differently: '2017-06-06T12:51:55.352592'.

[tseaver]

Overall, the intent looks good.

• I would be inclined to centralize the repeated "generate a message line with datestamp" bits into methods on the HTTPOk and Memmon classes, so that I could test it explicitly (the updated tests just skip over it).
• Using a standard ISO format seems much more natural to me for logging than a locale-generated one.

[hvelarde]

yes it could be more natural from the programing point of view, but from the user interface perspective is confusing as I will have to do time zone conversions every time I look at the logs; add to that daylight timezones and you are creating two problems instead of solving one.

[mnaberez]

I suggest logging timestamps the exact same way supervisord does, whatever that may be (it would be in supervisor/loggers.py). This would allow timestamps in the different logs to be compared easily.

[hvelarde]

here's a typical log from supervisor and seems to be using local time:

2017-06-06 14:21:11,574 WARN killing 'instance3' (5835) with SIGKILL
2017-06-06 14:21:11,574 INFO waiting for instance3 to stop
2017-06-06 14:21:11,833 INFO stopped: instance3 (terminated by SIGKILL)
2017-06-06 14:21:11,840 INFO spawned: 'instance3' with pid 2768

it would be interesting to add the level also.