Add metrics support to IPA

This utilizes the new metrics support in ironic-lib to allow the agent to
report timing metrics for agent API methods as configured in ironic-lib.

Additionally, this adds developer docs on how to use metrics in IPA,
including some caveats specific to ironic-lib.metrics use in IPA.

Co-Authored-By: Jay Faulkner <jay@jvf.cc>
Co-Authored-By: Alex Weeks <alex.weeks@gmail.com>
Change-Id: Ic08d4ff78b6fb614b474b956a32eac352a14262a
Partial-bug: #1526219

doc/source/index.rst

@@ -18,6 +18,7 @@ Index
 .. toctree::
 
     troubleshooting
+    metrics
 
 How it works
 ============

doc/source/metrics.rst

@@ -0,0 +1,53 @@
+.. _metrics:
+
+===============================================
+Emitting metrics from Ironic-Python-Agent (IPA)
+===============================================
+
+This document describes how to emit metrics from IPA, including timers and
+counters in code to directly emitting hardware metrics from a custom
+HardwareManager.
+
+Overview
+========
+IPA uses the metrics implementation from ironic-lib, with a few caveats due
+to the dynamic configuration done at lookup time. You cannot cache the metrics
+instance as the MetricsLogger returned will change after lookup if configs
+different than the default setting have been used. This also means that the
+method decorator supported by ironic-lib cannot be used in IPA.
+
+Using a context manager
+=======================
+Using the context manager is the recommended way for sending metrics that time
+or count sections of code. However, given that you cannot cache the
+MetricsLogger, you have to explicitly call get_metrics_logger() from
+ironic-lib every time. For example:
+
+  from ironic_lib import metrics_utils
+
+  def my_method():
+    with metrics_utils.get_metrics_logger(__name__).timer():
+      return _do_work()
+
+As a note, these metric collectors do work for custom HardwareManagers as
+well, however, you may want to metric the portions of a method that determine
+compatability separate from portions of a method that actually do work, in
+order to assure the metrics are relevant and useful on all hardware.
+
+Explicitly sending metrics
+==========================
+A feature that may be particularly helpful for deployers writing custom
+HardwareManagers is the ability to explicitly send metrics. As an example,
+you could add a cleaning step which would retrieve metrics about a device and
+ship them using the provided metrics library. For example:
+
+  from ironic_lib import metrics_utils
+
+  def my_cleaning_step():
+    for name, value in _get_smart_data():
+      metrics_utils.get_metrics_logger(__name__).send_gauge(name, value)
+
+References
+==========
+For more information, please read the source of the metrics module in
+`ironic-lib <http://git.openstack.org/cgit/openstack/ironic-lib/tree/ironic_lib>`_.

ironic_python_agent/agent.py

@@ -20,6 +20,7 @@ import threading
 import time
 
 from oslo_concurrency import processutils
+from oslo_config import cfg
 from oslo_log import log
 import pkg_resources
 from six.moves.urllib import parse as urlparse
@@ -35,7 +36,6 @@ from ironic_python_agent import inspector
 from ironic_python_agent import ironic_api_client
 from ironic_python_agent import utils
 
-
 LOG = log.getLogger(__name__)
 
 # Time(in seconds) to wait for any of the interfaces to be up
@@ -45,6 +45,9 @@ NETWORK_WAIT_TIMEOUT = 60
 # Time(in seconds) to wait before reattempt
 NETWORK_WAIT_RETRY = 5
 
+cfg.CONF.import_group('metrics', 'ironic_lib.metrics_utils')
+cfg.CONF.import_group('metrics_statsd', 'ironic_lib.metrics_statsd')
+
 
 def _time():
     """Wraps time.time() for simpler testing."""
@@ -340,6 +343,15 @@ class IronicPythonAgent(base.ExecuteCommandMixin):
             hardware.cache_node(self.node)
             self.heartbeat_timeout = content['heartbeat_timeout']
 
+            # Update config with values from Ironic
+            config = content.get('config', {})
+            if config.get('metrics'):
+                for opt, val in config.items():
+                    setattr(cfg.CONF.metrics, opt, val)
+            if config.get('metrics_statsd'):
+                for opt, val in config.items():
+                    setattr(cfg.CONF.metrics_statsd, opt, val)
+
         wsgi = simple_server.make_server(
             self.listen_address[0],
             self.listen_address[1],

ironic_python_agent/api/controllers/root.py

@@ -12,9 +12,9 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+from ironic_lib import metrics_utils
 import pecan
 from pecan import rest
-
 from wsme import types as wtypes
 import wsmeext.pecan as wsme_pecan
 
@@ -81,6 +81,7 @@ class RootController(rest.RestController):
         # NOTE: The reason why convert() it's being called for every
         #       request is because we need to get the host url from
         #       the request object to make the links.
+        with metrics_utils.get_metrics_logger(__name__).timer('get'):
             return Root.convert()
 
     @pecan.expose()

ironic_python_agent/api/controllers/v1/command.py

@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from ironic_lib import metrics_utils
 import pecan
 from pecan import rest
 from wsme import types
@@ -78,6 +79,7 @@ class CommandController(rest.RestController):
     @wsme_pecan.wsexpose(CommandResultList)
     def get_all(self):
         """Get all command results."""
+        with metrics_utils.get_metrics_logger(__name__).timer('get_all'):
             agent = pecan.request.agent
             results = agent.list_command_results()
             return CommandResultList.from_results(results)
@@ -91,6 +93,7 @@ class CommandController(rest.RestController):
         :returns: a :class:`ironic_python_agent.api.controller.v1.command.
                   CommandResult` object.
         """
+        with metrics_utils.get_metrics_logger(__name__).timer('get_one'):
             agent = pecan.request.agent
             result = agent.get_command_result(result_id)
 
@@ -109,6 +112,7 @@ class CommandController(rest.RestController):
         :returns: a :class:`ironic_python_agent.api.controller.v1.command.
                   CommandResult` object.
         """
+        with metrics_utils.get_metrics_logger(__name__).timer('post'):
             # the POST body is always the last arg,
             # so command must be a kwarg here
             if command is None:

ironic_python_agent/api/controllers/v1/status.py

@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from ironic_lib import metrics_utils
 import pecan
 from pecan import rest
 from wsme import types
@@ -48,6 +49,7 @@ class StatusController(rest.RestController):
     @wsme_pecan.wsexpose(AgentStatus)
     def get_all(self):
         """Get current status of the running agent."""
+        with metrics_utils.get_metrics_logger(__name__).timer('get_all'):
             agent = pecan.request.agent
             status = agent.get_status()
             return AgentStatus.from_agent_status(status)

ironic_python_agent/extensions/standby.py

@@ -533,7 +533,6 @@ class StandbyExtension(base.BaseAgentExtension):
         stream_raw_images = image_info.get('stream_raw_images', False)
         # don't write image again if already cached
         if self.cached_image_id != image_info['id']:
-
             if self.cached_image_id is not None:
                 LOG.debug('Already had %s cached, overwriting',
                           self.cached_image_id)