Code review comment for lp:~thumper/juju-core/use-loggo

*** Submitted:

Integrate loggo as a hierarchical logger.

The existing logging is very flat and has very little control over what
is output.

I wrote loggo as a Go port of a C++ library I wrote for nux/unity (my
third or fourth logging library). Loggers are very lightweight objects
that have a single pointer to the module. A module is defined by a
dotted name, like "juju.uniter" or "juju.provider.ec2". There is no
limit to the depth of nesting. Logging levels are inherited unless
explicitly set. The root logger, identified by the module "" (empty
string), defaults to WARNING.

The existing log package has been updated to use the loggo methods so we
don't have to change all the call sites immediately. However we should
start to move to more detailed modules for logging as we can have better
control over it.

We should, as a soon to be done step, provide a way, probably using
set-env, to configure logging for various machine agents or unit agents.
  This would allow a high level of control over what information gets
logged.

R=mue, jameinel
CC=
https://codereview.appspot.com/9738051

https://codereview.appspot.com/9738051/