Use logging in the knotty ui, and pass the log record across directly

This kills firing of Msg* events in favor of just passing along LogRecord
objects.  These objects hold more than just level and message, but can also
have exception information, so the UI can decide what to do with that.

As an aside, when using the 'none' server, this results in the log messages in
the server being displayed directly via the logging module and the UI's
handler, rather than going through the server's event queue.  As a result of
doing it this way, we have to override the event handlers of the base logger
when spawning a worker process, to ensure they log via events rather than
directly.

(Bitbake rev: c23c015cf8af1868faf293b19b80a5faf7e736a5)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake/lib/bb/runqueue.py

@@ -24,11 +24,14 @@ Handles preparation and execution of a queue of tasks
 
 import bb, os, sys
 import subprocess
-from bb import msg, data, event
 import signal
 import stat
 import fcntl
 import copy
+import logging
+from bb import msg, data, event
+
+bblogger = logging.getLogger("BitBake")
 
 try:
     import cPickle as pickle
@@ -1127,6 +1130,11 @@ class RunQueueExecute:
             bb.event.worker_pipe = pipeout
             bb.event.useStdout = False
 
+            # Child processes should send their messages to the UI
+            # process via the server process, not print them
+            # themselves
+            bblogger.handlers = [bb.event.LogHandler()]
+
             self.rq.state = runQueueChildProcess
             # Make the child the process group leader
             os.setpgid(0, 0)