Guru Meditation Reports¶
Magnum contains a mechanism whereby developers and system administrators can generate a report about the state of a running Magnum executable. This report is called a Guru Meditation Report (GMR for short).
Generating a GMR¶
A GMR can be generated by sending the USR2 signal to any Magnum process with support (see below). The GMR will then be outputted as standard error for that particular process.
For example, suppose that
magnum-api has process id
8675, and was run
kill -USR2 8675 will
trigger the Guru Meditation report to be printed to
Structure of a GMR¶
The GMR is designed to be extensible; any particular executable may add its own sections. However, the base GMR consists of several sections:
Shows information about the package to which this process belongs, including version information.
Shows stack traces and thread ids for each of the threads within this process.
- Green Threads
Shows stack traces for each of the green threads within this process (green threads don’t have thread ids).
Lists all the configuration options currently accessible via the CONF object for the current process.
Adding Support for GMRs to New Executables¶
Adding support for a GMR to a given executable is fairly easy.
First import the module:
from oslo_reports import guru_meditation_report as gmr from magnum import version
Then, register any additional sections (optional):
TextGuruMeditation.register_section('Some Special Section', some_section_generator)
Finally (under main), before running the “main loop” of the executable (usually
service.server(server) or something similar), register the GMR hook:
Extending the GMR¶
As mentioned above, additional sections can be added to the GMR for a
particular executable. For more information, see the inline documentation