Add additional info like python-systemd does

Upstream python-systemd has a journald logging handler that also adds
some exception information, as well as thread information.

  https://github.com/systemd/python-systemd/blob/master/systemd/journal.py#L581-L589

While OpenStack doesn't use a lot of threads, we might as well support it
since it's no cost. Also, add PROCESS_NAME just to be compatible with
other programs that might use python journald logging. Not entirely sure
if record.processName and the results of our self.binary_name will be
different.

The exception info is the fun stuff though.

Change-Id: Ibf0d7dae7587639737e0327f0338f30cdfc6aba1

doc/source/journal.rst

@@ -58,8 +58,17 @@ known at the time of logging the message.
 CODE_FILE=, CODE_LINE=, CODE_FUNC=
 
    The code location generating this message, if known. Contains the
-   source filename, the line number and the function name. (This is
-   the same as systemd uses)
+   source filename, the line number and the function name. (This is the
+   same as systemd uses)
+
+THREAD_NAME=, PROCESS_NAME=
+
+   Information about the thread and process, if known. (This is the same
+   as systemd uses)
+
+EXCEPTION_TEXT=, EXCEPTION_INFO=
+
+   Information about an exception, if an exception has been logged.
 
 LOGGER_NAME=
 

oslo_log/handlers.py

@@ -123,12 +123,20 @@ def emit(self, record):
             'CODE_FILE': record.pathname,
             'CODE_LINE': record.lineno,
             'CODE_FUNC': record.funcName,
+            'THREAD_NAME': record.threadName,
+            'PROCESS_NAME': record.processName,
             'LOGGER_NAME': record.name,
             'LOGGER_LEVEL': record.levelname,
             'SYSLOG_IDENTIFIER': self.binary_name,
             'PRIORITY': priority
         }
 
+        if record.exc_text:
+            extras['EXCEPTION_TEXT'] = record.exc_text
+
+        if record.exc_info:
+            extras['EXCEPTION_INFO'] = record.exc_info
+
         for field in self.custom_fields:
             value = record.__dict__.get(field)
             if value:

oslo_log/tests/unit/test_log.py

@@ -334,6 +334,30 @@ def test_emit(self):
                       SYSLOG_IDENTIFIER=mock.ANY,
                       REQUEST_ID=mock.ANY,
                       PROJECT_NAME='mytenant',
+                      PROCESS_NAME='MainProcess',
+                      THREAD_NAME='MainThread',
+                      USER_NAME='myuser'))
+
+    def test_emit_exception(self):
+        l = log.getLogger('nova-exception.foo')
+        local_context = _fake_new_context()
+        try:
+            raise Exception("Some exception")
+        except Exception:
+            l.exception("Foo", context=local_context)
+        self.assertEqual(
+            self.journal.send.call_args,
+            mock.call(mock.ANY, CODE_FILE=mock.ANY,
+                      CODE_FUNC='test_emit_exception',
+                      CODE_LINE=mock.ANY, LOGGER_LEVEL='ERROR',
+                      LOGGER_NAME='nova-exception.foo', PRIORITY=3,
+                      SYSLOG_IDENTIFIER=mock.ANY,
+                      REQUEST_ID=mock.ANY,
+                      EXCEPTION_INFO=mock.ANY,
+                      EXCEPTION_TEXT=mock.ANY,
+                      PROJECT_NAME='mytenant',
+                      PROCESS_NAME='MainProcess',
+                      THREAD_NAME='MainThread',
                       USER_NAME='myuser'))