Merge "Polish usage.rst"
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@ -45,21 +45,32 @@ When using oslo.service
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Using oslo.service with oslo-config-generator
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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The ``oslo.service`` provides several entry points to generate a configuration
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The ``oslo.service`` provides several entry points to generate configuration
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files.
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* :func:`oslo.service.service <oslo_service.service.list_opts>`
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The options from the service and eventlet_backdoor modules for
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the [DEFAULT] section.
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The options from the :mod:`~oslo_service.service` and
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:mod:`~oslo_service.eventlet_backdoor` modules for the ``[DEFAULT]``
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section.
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* :func:`oslo.service.periodic_task <oslo_service.periodic_task.list_opts>`
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The options from the periodic_task module for the [DEFAULT] section.
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The options from the :mod:`~oslo_service.periodic_task` module for the
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``[DEFAULT]`` section.
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* :func:`oslo.service.sslutils <oslo_service.sslutils.list_opts>`
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The options from the sslutils module for the [ssl] section.
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The options from the :mod:`~oslo_service.sslutils` module for the
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:oslo.config:group:`ssl` section.
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* :func:`oslo.service.wsgi <oslo_service.wsgi.list_opts>`
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The options from the wsgi module for the [DEFAULT] section.
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The options from the :mod:`~oslo_service.wsgi` module for the ``[DEFAULT]``
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section.
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.. todo:: The ref page for oslo_service.wsgi doesn't seem to be rendering, so
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the above doesn't link.
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.. todo:: Attempting to use :oslo.config:group:`DEFAULT` above only links to
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the first DEFAULT section in the configuration/index doc because the
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#DEFAULT anchor is duplicated for each of the show-options sections.
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**ATTENTION:** The library doesn't provide an oslo.service entry point.
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@ -72,7 +83,7 @@ files.
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Launching and controlling services
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==================================
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oslo_service.service module provides tools for launching OpenStack
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The :mod:`oslo_service.service` module provides tools for launching OpenStack
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services and controlling their lifecycles.
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A service is an instance of any class that
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@ -85,7 +96,8 @@ serve as a base for constructing new services.
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Launchers
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~~~~~~~~~
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oslo_service.service module provides two launchers for running services:
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The :mod:`oslo_service.service` module provides two launchers for running
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services:
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* :py:class:`oslo_service.service.ServiceLauncher` - used for
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running one or more service in a parent process.
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@ -111,8 +123,9 @@ launch a service using it.
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Or one can simply call :func:`oslo_service.service.launch` which will
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automatically pick an appropriate launcher based on a number of workers that
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are passed to it (ServiceLauncher in case workers=1 or None and
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ProcessLauncher in other case).
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are passed to it (:py:class:`~oslo_service.service.ServiceLauncher` if
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``workers=1`` or ``None`` and :py:class:`~oslo_service.service.ProcessLauncher`
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in other case).
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.. code-block:: python
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@ -123,41 +136,43 @@ ProcessLauncher in other case).
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launcher = service.launch(CONF, service.Service(), workers=3)
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*NOTE:* Please be informed that it is highly recommended to use no
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more than one instance of ServiceLauncher and ProcessLauncher classes
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per process.
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.. note:: It is highly recommended to use no more than one instance of the
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:py:class:`~oslo_service.service.ServiceLauncher` or
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:py:class:`~oslo_service.service.ProcessLauncher` class per process.
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Signal handling
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~~~~~~~~~~~~~~~
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oslo_service.service provides handlers for such signals as SIGTERM, SIGINT
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and SIGHUP.
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:mod:`oslo_service.service` provides handlers for such signals as ``SIGTERM``,
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``SIGINT``, and ``SIGHUP``.
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SIGTERM is used for graceful termination of services. This can allow a
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``SIGTERM`` is used for graceful termination of services. This can allow a
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server to wait for all clients to close connections while rejecting new
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incoming requests. Config option graceful_shutdown_timeout specifies how
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many seconds after receiving a SIGTERM signal, a server should continue
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to run, handling the existing connections. Setting graceful_shutdown_timeout
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to zero means that the server will wait indefinitely until all remaining
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requests have been fully served.
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incoming requests. Config option
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:oslo.config:option:`graceful_shutdown_timeout` specifies how many seconds
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after receiving a ``SIGTERM`` signal a server should continue to run, handling
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the existing connections. Setting
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:oslo.config:option:`graceful_shutdown_timeout` to zero means that the server
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will wait indefinitely until all remaining requests have been fully served.
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To force instantaneous termination SIGINT signal must be sent.
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To force instantaneous termination the ``SIGINT`` signal must be sent.
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The behavior on receiving SIGHUP varies based on how the service is configured.
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If the launcher uses the ``reload`` restart_method (the default), then the
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service will reload its configuration and any threads will be completely
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restarted. If the ``mutate`` restart_method is used, then only the
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The behavior on receiving ``SIGHUP`` varies based on how the service is
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configured. If the launcher uses ``restart_method='reload'`` (the default),
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then the service will reload its configuration and any threads will be
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completely restarted. If ``restart_method='mutate'`` is used, then only the
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configuration options marked as mutable will be reloaded and the service
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threads will not be restarted.
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See :py:class:`oslo_service.service.Launcher` for more details on the
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``restart_method`` parameter.
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*NOTE:* SIGHUP is not supported on Windows.
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*NOTE:* Config option graceful_shutdown_timeout is not supported on Windows.
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.. note:: ``SIGHUP`` is not supported on Windows.
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.. note:: Config option :oslo.config:option:`graceful_shutdown_timeout` is not
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supported on Windows.
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Below is the example of a service with a reset method that allows reloading
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logging options by sending a SIGHUP.
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Below is an example of a service with a reset method that allows reloading
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logging options by sending a ``SIGHUP``.
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.. code-block:: python
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@ -187,22 +202,23 @@ logging options by sending a SIGHUP.
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Profiling
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~~~~~~~~~
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Processes spawned through oslo_service.service can be profiled (function
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calltrace) through eventlet_backdoor module. Service has to configure
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backdoor_port option to enable it's workers to listen on TCP ports.
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Then user can send "prof()" command to capture worker processes function
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calltrace.
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Processes spawned through :mod:`oslo_service.service` can be profiled (function
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calltrace) through the :mod:`~oslo_service.eventlet_backdoor` module. The
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service must be configured with the :oslo.config:option:`backdoor_port` option
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to enable its workers to listen on TCP ports. The user can then send the
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``prof()`` command to capture the worker process's function calltrace.
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1) To start profiling send "prof()" command on processes listening port
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1) To start profiling send the ``prof()`` command on the process's listening
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port
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2) To stop profiling and capture "pstat" calltrace to a file, send prof
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command with filename as argument i.e "prof(filename)"
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on worker processes listening port. Stats file (in pstat format) with
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user provided filename by adding .prof as suffix will be generated
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in temp directory.
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2) To stop profiling and capture pstat calltrace to a file, send the
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``prof()`` command with a file basename as an argument (``prof(basename)``)
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to the worker process's listening port. A stats file (in pstat format) will
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be generated in the temp directory with the user-provided basename with a
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``.prof`` suffix .
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For example, to profile neutron server process (which is listening on
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port 8002 configured through backdoor_port option),
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For example, to profile a neutron server process (which is listening on
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port 8002 configured through the :oslo.config:option:`backdoor_port` option):
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.. code-block:: bash
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@ -211,9 +227,8 @@ port 8002 configured through backdoor_port option),
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$ neutron port-delete p1; neutron port-delete p1
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$ echo "prof('neutron')" | nc localhost 8002
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This will generate "/tmp/neutron.prof" as stats file. Later user can print
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the stats from the trace file like below
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This will generate a stats file in ``/tmp/neutron.prof``. Stats can be printed
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from the trace file as follows:
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.. code-block:: python
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