Integrate OSProfiler and Nova

* Add osprofiler wsgi middleware. This middleware is used for 2 things:
  1) It checks that person who want to trace is trusted and knows
     secret HMAC key.
  2) It starts tracing in case of proper trace headers
     and adds the first wsgi trace point with info about the HTTP request

* Add initialization of osprofiler on start of a service
  Currently that includes oslo.messaging notifier instance creation
  to send Ceilometer backend notifications.

oslo-spec: https://review.openstack.org/#/c/103825/
python-novaclient change: https://review.openstack.org/#/c/254699/
based on: https://review.openstack.org/#/c/105096/

Co-Authored-By: Boris Pavlovic <boris@pavlovic.me>
Co-Authored-By: Munoz, Obed N <obed.n.munoz@intel.com>
Co-Authored-By: Roman Podoliaka <rpodolyaka@mirantis.com>
Co-Authored-By: Tovin Seven <vinhnt@vn.fujitsu.com>

Implements: blueprint osprofiler-support-in-nova
Change-Id: I82d2badc8c1fcec27c3fce7c3c20e0f3b76414f1

nova/rpc.py

@@ -32,6 +32,7 @@ from oslo_log import log as logging
 import oslo_messaging as messaging
 from oslo_serialization import jsonutils
 from oslo_service import periodic_task
+from oslo_utils import importutils
 from oslo_utils import timeutils
 
 import nova.conf
@@ -40,6 +41,8 @@ import nova.exception
 from nova.i18n import _
 from nova import objects
 
+profiler = importutils.try_import("osprofiler.profiler")
+
 
 CONF = nova.conf.CONF
 
@@ -150,13 +153,45 @@ class RequestContextSerializer(messaging.Serializer):
         return nova.context.RequestContext.from_dict(context)
 
 
+class ProfilerRequestContextSerializer(RequestContextSerializer):
+    def serialize_context(self, context):
+        _context = super(ProfilerRequestContextSerializer,
+                         self).serialize_context(context)
+
+        prof = profiler.get()
+        if prof:
+            # FIXME(DinaBelova): we'll add profiler.get_info() method
+            # to extract this info -> we'll need to update these lines
+            trace_info = {
+                "hmac_key": prof.hmac_key,
+                "base_id": prof.get_base_id(),
+                "parent_id": prof.get_id()
+            }
+            _context.update({"trace_info": trace_info})
+
+        return _context
+
+    def deserialize_context(self, context):
+        trace_info = context.pop("trace_info", None)
+        if trace_info:
+            profiler.init(**trace_info)
+
+        return super(ProfilerRequestContextSerializer,
+                     self).deserialize_context(context)
+
+
 def get_transport_url(url_str=None):
     return messaging.TransportURL.parse(CONF, url_str, TRANSPORT_ALIASES)
 
 
 def get_client(target, version_cap=None, serializer=None):
     assert TRANSPORT is not None
-    serializer = RequestContextSerializer(serializer)
+
+    if profiler:
+        serializer = ProfilerRequestContextSerializer(serializer)
+    else:
+        serializer = RequestContextSerializer(serializer)
+
     return messaging.RPCClient(TRANSPORT,
                                target,
                                version_cap=version_cap,
@@ -165,7 +200,12 @@ def get_client(target, version_cap=None, serializer=None):
 
 def get_server(target, endpoints, serializer=None):
     assert TRANSPORT is not None
-    serializer = RequestContextSerializer(serializer)
+
+    if profiler:
+        serializer = ProfilerRequestContextSerializer(serializer)
+    else:
+        serializer = RequestContextSerializer(serializer)
+
     return messaging.get_rpc_server(TRANSPORT,
                                     target,
                                     endpoints,