bitbake: add option to write offline event log file

This patch adds a "-w/--write-log" option to bitbake
that writes an event log file for the current build.

The name of the file is passed as a parameter to the "-w"
argument. If the parameter is the empty string '', the file
name is generated in the form bitbake_eventlog_DATE.json,
where DATE is the current date and time, with second precision.

The "-w" option can also be supplied as the BBEVENTLOG
environment variable.

We add a script, toater-eventreplay, that reads an event
log file and loads the data into a Toaster database, creating
a build entry.

We modify the toasterui to fix minor issues with reading
events from an event log file.

Performance impact is undetectable under no-task executed builds.

(Bitbake rev: 1befb4a783bb7b7b387d4b5ee08830d9516f1ac2)

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/bin/bitbake

@@ -196,6 +196,9 @@ class BitBakeConfigParameters(cookerdata.ConfigParameters):
         parser.add_option("", "--status-only", help = "Check the status of the remote bitbake server.",
                    action = "store_true", dest = "status_only", default = False)
 
+        parser.add_option("-w", "--write-log", help = "Writes the event log of the build to a bitbake event json file. Use '' (empty string) to assign the name automatically.",
+                   action = "store", dest = "writeeventlog")
+
         options, targets = parser.parse_args(sys.argv)
 
         # some environmental variables set also configuration options
@@ -206,6 +209,14 @@ class BitBakeConfigParameters(cookerdata.ConfigParameters):
         if "BBTOKEN" in os.environ:
             options.xmlrpctoken = os.environ["BBTOKEN"]
 
+        if "BBEVENTLOG" is os.environ:
+            options.writeeventlog = os.environ["BBEVENTLOG"]
+
+        # fill in proper log name if not supplied
+        if options.writeeventlog is not None and len(options.writeeventlog) == 0:
+            import datetime
+            options.writeeventlog = "bitbake_eventlog_%s.json" % datetime.datetime.now().strftime("%Y%m%d%H%M%S")
+
         # if BBSERVER says to autodetect, let's do that
         if options.remote_server:
             [host, port] = options.remote_server.split(":", 2)
@@ -266,7 +277,6 @@ def start_server(servermodule, configParams, configuration, features):
     return server
 
 
-
 def main():
 
     configParams = BitBakeConfigParameters()