Update guru doc to support file modification events
Now oslo_reports has supported file modification
events instead of signal handler.
(https://review.openstack.org/#/c/260976)
But gmr.rst doesn't be updated for this change in
Cinder devref folder.
So it's better to let user know there is other way
to trigger a generation of report.
Closes-Bug:
@@ -26,13 +26,34 @@ Generating a GMR
A *GMR* can be generated by sending the *USR2* signal to any Cinder process
with support (see below).
-The *GMR* will then be outputted standard error for that particular process.
+The *GMR* will then output to standard error for that particular process.
For example, suppose that ``cinder-api`` has process id ``8675``, and was run
with ``2>/var/log/cinder/cinder-api-err.log``.
Then, ``kill -USR2 8675`` will trigger the Guru Meditation report to be printed
to ``/var/log/cinder/cinder-api-err.log``.
+There is other way to trigger a generation of report, user should add
+a configuration in Cinder's conf file::
+
+ [oslo_reports]
+ file_event_handler=['The path to a file to watch for changes to trigger '
+ 'the reports, instead of signals. Setting this option '
+ 'disables the signal trigger for the reports.']
+ file_event_handler_interval=['How many seconds to wait between polls when '
+ 'file_event_handler is set, default value '
+ 'is 1']
+
+a *GMR* can be generated by "touch"ing the file which was specified in
+file_event_handler. The *GMR* will then output to standard error for
+that particular process.
+
+For example, suppose that ``cinder-api`` was run with
+``2>/var/log/cinder/cinder-api-err.log``, and the file path is
+``/tmp/guru_report``.
+Then, ``touch /tmp/guru_report`` will trigger the Guru Meditation report to be
+printed to ``/var/log/cinder/cinder-api-err.log``.
+
Structure of a GMR
------------------
