skip built-in exceptions when adding error_summary

We have a lot of cases where we catch a built-in exception then
log. Those exceptions don't add useful information, so do not include
them automatically in the log output.

Change-Id: Ifecb831c0adf4086a9d39feb3eb7e3865db780e6
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

2 files changed, 26 insertions, 0 deletions

diff --git a/oslo_log/formatters.py b/oslo_log/formatters.py
index e6faebc..fc1bc51 100644
--- a/oslo_log/formatters.py
+++ b/oslo_log/formatters.py
@@ -363,6 +363,17 @@ class ContextFormatter(logging.Formatter):
             # that uses the value simpler.
             if not exc_info[0]:
                 exc_info = None
+            elif exc_info[0] in (TypeError, ValueError,
+                                 KeyError, AttributeError):
+                # NOTE(dhellmann): Do not include information about
+                # common built-in exceptions used to detect cases of
+                # bad or missing data. We don't use isinstance() here
+                # to limit this filter to only the built-in
+                # classes. This check is only performed for cases
+                # where the exception info is being detected
+                # automatically so if a caller gives us an exception
+                # we will definitely log it.
+                exc_info = None
 
         # If we have an exception, format it to be included in the
         # output.
diff --git a/oslo_log/tests/unit/test_log.py b/oslo_log/tests/unit/test_log.py
index a4405de..acf6f95 100644
--- a/oslo_log/tests/unit/test_log.py
+++ b/oslo_log/tests/unit/test_log.py
@@ -657,6 +657,21 @@ class ContextFormatterTestCase(LogTestBase):
         expected = 'RuntimeError: test_exception_logging\n'
         self.assertTrue(self.stream.getvalue().endswith(expected))
 
+    def test_skip_logging_builtin_exceptions(self):
+        # NOTE(dhellmann): If there is an exception and %(error_summary)s
+        # does not appear in the format string, ensure that it is
+        # appended to the end of the log lines.
+        ctxt = _fake_context()
+        ctxt.request_id = six.text_type('99')
+        message = self.trans_fixture.lazy('test ' + six.unichr(128))
+        for ignore in [ValueError, TypeError, KeyError, AttributeError]:
+            try:
+                raise ignore('test_exception_logging')
+            except ignore as e:
+                self.log.info(message, context=ctxt)
+                expected = '{}: {}'.format(e.__class__.__name__, e)
+            self.assertNotIn(expected, self.stream.getvalue())
+
     def test_exception_logging_format_string(self):
         # NOTE(dhellmann): If the format string includes
         # %(error_summary)s then ensure the exception message ends up in