1# Copyright 2023 The gRPC authors.
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7# http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15from __future__ import annotations
16
17import abc
18import contextlib
19import logging
20import threading
21from typing import Any, Generator, Generic, List, Optional, TypeVar
22
23from grpc._cython import cygrpc as _cygrpc
24from grpc._typing import ChannelArgumentType
25
26_LOGGER = logging.getLogger(__name__)
27
28_channel = Any # _channel.py imports this module.
29ClientCallTracerCapsule = TypeVar("ClientCallTracerCapsule")
30ServerCallTracerFactoryCapsule = TypeVar("ServerCallTracerFactoryCapsule")
31
32_plugin_lock: threading.RLock = threading.RLock()
33_OBSERVABILITY_PLUGIN: Optional["ObservabilityPlugin"] = None
34_SERVICES_TO_EXCLUDE: List[bytes] = [
35 b"google.monitoring.v3.MetricService",
36 b"google.devtools.cloudtrace.v2.TraceService",
37]
38
39
40class ServerCallTracerFactory:
41 """An encapsulation of a ServerCallTracerFactory.
42
43 Instances of this class can be passed to a Channel as values for the
44 grpc.experimental.server_call_tracer_factory option
45 """
46
47 def __init__(self, address):
48 self._address = address
49
50 def __int__(self):
51 return self._address
52
53
54class ObservabilityPlugin(
55 Generic[ClientCallTracerCapsule, ServerCallTracerFactoryCapsule],
56 metaclass=abc.ABCMeta,
57):
58 """Abstract base class for observability plugin.
59
60 *This is a semi-private class that was intended for the exclusive use of
61 the gRPC team.*
62
63 The ClientCallTracerCapsule and ClientCallTracerCapsule created by this
64 plugin should be injected to gRPC core using observability_init at the
65 start of a program, before any channels/servers are built.
66
67 Any future methods added to this interface cannot have the
68 @abc.abstractmethod annotation.
69
70 Attributes:
71 _stats_enabled: A bool indicates whether tracing is enabled.
72 _tracing_enabled: A bool indicates whether stats(metrics) is enabled.
73 _registered_methods: A set which stores the registered method names in
74 bytes.
75 """
76
77 _tracing_enabled: bool = False
78 _stats_enabled: bool = False
79
80 @abc.abstractmethod
81 def create_client_call_tracer(
82 self, method_name: bytes, target: bytes
83 ) -> ClientCallTracerCapsule:
84 """Creates a ClientCallTracerCapsule.
85
86 After register the plugin, if tracing or stats is enabled, this method
87 will be called after a call was created, the ClientCallTracer created
88 by this method will be saved to call context.
89
90 The ClientCallTracer is an object which implements `grpc_core::ClientCallTracer`
91 interface and wrapped in a PyCapsule using `client_call_tracer` as name.
92
93 Args:
94 method_name: The method name of the call in byte format.
95 target: The channel target of the call in byte format.
96 registered_method: Whether this method is pre-registered.
97
98 Returns:
99 A PyCapsule which stores a ClientCallTracer object.
100 """
101 raise NotImplementedError()
102
103 @abc.abstractmethod
104 def save_trace_context(
105 self, trace_id: str, span_id: str, is_sampled: bool
106 ) -> None:
107 """Saves the trace_id and span_id related to the current span.
108
109 After register the plugin, if tracing is enabled, this method will be
110 called after the server finished sending response.
111
112 This method can be used to propagate census context.
113
114 Args:
115 trace_id: The identifier for the trace associated with the span as a
116 32-character hexadecimal encoded string,
117 e.g. 26ed0036f2eff2b7317bccce3e28d01f
118 span_id: The identifier for the span as a 16-character hexadecimal encoded
119 string. e.g. 113ec879e62583bc
120 is_sampled: A bool indicates whether the span is sampled.
121 """
122 raise NotImplementedError()
123
124 @abc.abstractmethod
125 def create_server_call_tracer_factory(
126 self,
127 *,
128 xds: bool = False,
129 ) -> Optional[ServerCallTracerFactoryCapsule]:
130 """Creates a ServerCallTracerFactoryCapsule.
131
132 This method will be called at server initialization time to create a
133 ServerCallTracerFactory, which will be registered to gRPC core.
134
135 The ServerCallTracerFactory is an object which implements
136 `grpc_core::ServerCallTracerFactory` interface and wrapped in a PyCapsule
137 using `server_call_tracer_factory` as name.
138
139 Args:
140 xds: Whether the server is xds server.
141 Returns:
142 A PyCapsule which stores a ServerCallTracerFactory object. Or None if
143 plugin decides not to create ServerCallTracerFactory.
144 """
145 raise NotImplementedError()
146
147 @abc.abstractmethod
148 def record_rpc_latency(
149 self, method: str, target: str, rpc_latency: float, status_code: Any
150 ) -> None:
151 """Record the latency of the RPC.
152
153 After register the plugin, if stats is enabled, this method will be
154 called at the end of each RPC.
155
156 Args:
157 method: The fully-qualified name of the RPC method being invoked.
158 target: The target name of the RPC method being invoked.
159 rpc_latency: The latency for the RPC in seconds, equals to the time between
160 when the client invokes the RPC and when the client receives the status.
161 status_code: An element of grpc.StatusCode in string format representing the
162 final status for the RPC.
163 """
164 raise NotImplementedError()
165
166 def set_tracing(self, enable: bool) -> None:
167 """Enable or disable tracing.
168
169 Args:
170 enable: A bool indicates whether tracing should be enabled.
171 """
172 self._tracing_enabled = enable
173
174 def set_stats(self, enable: bool) -> None:
175 """Enable or disable stats(metrics).
176
177 Args:
178 enable: A bool indicates whether stats should be enabled.
179 """
180 self._stats_enabled = enable
181
182 def save_registered_method(self, method_name: bytes) -> None:
183 """Saves the method name to registered_method list.
184
185 When exporting metrics, method name for unregistered methods will be replaced
186 with 'other' by default.
187
188 Args:
189 method_name: The method name in bytes.
190 """
191 raise NotImplementedError()
192
193 @property
194 def tracing_enabled(self) -> bool:
195 return self._tracing_enabled
196
197 @property
198 def stats_enabled(self) -> bool:
199 return self._stats_enabled
200
201 @property
202 def observability_enabled(self) -> bool:
203 return self.tracing_enabled or self.stats_enabled
204
205
206@contextlib.contextmanager
207def get_plugin() -> Generator[Optional[ObservabilityPlugin], None, None]:
208 """Get the ObservabilityPlugin in _observability module.
209
210 Returns:
211 The ObservabilityPlugin currently registered with the _observability
212 module. Or None if no plugin exists at the time of calling this method.
213 """
214 with _plugin_lock:
215 yield _OBSERVABILITY_PLUGIN
216
217
218def set_plugin(observability_plugin: Optional[ObservabilityPlugin]) -> None:
219 """Save ObservabilityPlugin to _observability module.
220
221 Args:
222 observability_plugin: The ObservabilityPlugin to save.
223
224 Raises:
225 ValueError: If an ObservabilityPlugin was already registered at the
226 time of calling this method.
227 """
228 global _OBSERVABILITY_PLUGIN # pylint: disable=global-statement
229 with _plugin_lock:
230 if observability_plugin and _OBSERVABILITY_PLUGIN:
231 raise ValueError("observability_plugin was already set!")
232 _OBSERVABILITY_PLUGIN = observability_plugin
233
234
235def observability_init(observability_plugin: ObservabilityPlugin) -> None:
236 """Initialize observability with provided ObservabilityPlugin.
237
238 This method have to be called at the start of a program, before any
239 channels/servers are built.
240
241 Args:
242 observability_plugin: The ObservabilityPlugin to use.
243
244 Raises:
245 ValueError: If an ObservabilityPlugin was already registered at the
246 time of calling this method.
247 """
248 set_plugin(observability_plugin)
249
250
251def observability_deinit() -> None:
252 """Clear the observability context, including ObservabilityPlugin and
253 ServerCallTracerFactory
254
255 This method have to be called after exit observability context so that
256 it's possible to re-initialize again.
257 """
258 set_plugin(None)
259 _cygrpc.clear_server_call_tracer_factory()
260
261
262def maybe_record_rpc_latency(state: "_channel._RPCState") -> None:
263 """Record the latency of the RPC, if the plugin is registered and stats is enabled.
264
265 This method will be called at the end of each RPC.
266
267 Args:
268 state: a grpc._channel._RPCState object which contains the stats related to the
269 RPC.
270 """
271 # TODO(xuanwn): use channel args to exclude those metrics.
272 for exclude_prefix in _SERVICES_TO_EXCLUDE:
273 if exclude_prefix in state.method.encode("utf8"):
274 return
275 with get_plugin() as plugin:
276 if plugin and plugin.stats_enabled:
277 rpc_latency_s = state.rpc_end_time - state.rpc_start_time
278 rpc_latency_ms = rpc_latency_s * 1000
279 plugin.record_rpc_latency(
280 state.method, state.target, rpc_latency_ms, state.code
281 )
282
283
284def create_server_call_tracer_factory_option(xds: bool) -> ChannelArgumentType:
285 with get_plugin() as plugin:
286 if plugin and plugin.stats_enabled:
287 server_call_tracer_factory_address = (
288 _cygrpc.get_server_call_tracer_factory_address(plugin, xds)
289 )
290 if server_call_tracer_factory_address:
291 return (
292 (
293 "grpc.experimental.server_call_tracer_factory",
294 ServerCallTracerFactory(
295 server_call_tracer_factory_address
296 ),
297 ),
298 )
299 return ()