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 (
22 Any,
23 Generator,
24 Generic,
25 List,
26 Optional,
27 Tuple,
28 TypeVar,
29 Union,
30)
31
32from grpc._cython import cygrpc as _cygrpc
33from grpc._typing import ChannelArgumentType
34
35_LOGGER = logging.getLogger(__name__)
36
37_channel = Any # _channel.py imports this module.
38ClientCallTracerCapsule = TypeVar("ClientCallTracerCapsule")
39ServerCallTracerFactoryCapsule = TypeVar("ServerCallTracerFactoryCapsule")
40
41_plugin_lock: threading.RLock = threading.RLock()
42_OBSERVABILITY_PLUGIN: Optional["ObservabilityPlugin"] = None
43_SERVICES_TO_EXCLUDE: List[bytes] = [
44 b"google.monitoring.v3.MetricService",
45 b"google.devtools.cloudtrace.v2.TraceService",
46]
47
48
49class ServerCallTracerFactory:
50 """An encapsulation of a ServerCallTracerFactory.
51
52 Instances of this class can be passed to a Channel as values for the
53 grpc.experimental.server_call_tracer_factory option
54 """
55
56 def __init__(self, address):
57 self._address = address
58
59 def __int__(self):
60 return self._address
61
62
63class ObservabilityPlugin(
64 Generic[ClientCallTracerCapsule, ServerCallTracerFactoryCapsule],
65 metaclass=abc.ABCMeta,
66):
67 """Abstract base class for observability plugin.
68
69 *This is a semi-private class that was intended for the exclusive use of
70 the gRPC team.*
71
72 The ClientCallTracerCapsule and ClientCallTracerCapsule created by this
73 plugin should be injected to gRPC core using observability_init at the
74 start of a program, before any channels/servers are built.
75
76 Any future methods added to this interface cannot have the
77 @abc.abstractmethod annotation.
78
79 Attributes:
80 _stats_enabled: A bool indicates whether tracing is enabled.
81 _tracing_enabled: A bool indicates whether stats(metrics) is enabled.
82 _registered_methods: A set which stores the registered method names in
83 bytes.
84 """
85
86 _tracing_enabled: bool = False
87 _stats_enabled: bool = False
88
89 @abc.abstractmethod
90 def create_client_call_tracer(
91 self, method_name: bytes, target: bytes
92 ) -> ClientCallTracerCapsule:
93 """Creates a ClientCallTracerCapsule.
94
95 After register the plugin, if tracing or stats is enabled, this method
96 will be called after a call was created, the ClientCallTracer created
97 by this method will be saved to call context.
98
99 The ClientCallTracer is an object which implements `grpc_core::ClientCallTracer`
100 interface and wrapped in a PyCapsule using `client_call_tracer` as name.
101
102 Args:
103 method_name: The method name of the call in byte format.
104 target: The channel target of the call in byte format.
105 registered_method: Whether this method is pre-registered.
106
107 Returns:
108 A PyCapsule which stores a ClientCallTracer object.
109 """
110 raise NotImplementedError()
111
112 @abc.abstractmethod
113 def save_trace_context(
114 self, trace_id: str, span_id: str, is_sampled: bool
115 ) -> None:
116 """Saves the trace_id and span_id related to the current span.
117
118 After register the plugin, if tracing is enabled, this method will be
119 called after the server finished sending response.
120
121 This method can be used to propagate census context.
122
123 Args:
124 trace_id: The identifier for the trace associated with the span as a
125 32-character hexadecimal encoded string,
126 e.g. 26ed0036f2eff2b7317bccce3e28d01f
127 span_id: The identifier for the span as a 16-character hexadecimal encoded
128 string. e.g. 113ec879e62583bc
129 is_sampled: A bool indicates whether the span is sampled.
130 """
131 raise NotImplementedError()
132
133 @abc.abstractmethod
134 def create_server_call_tracer_factory(
135 self,
136 *,
137 xds: bool = False,
138 ) -> Optional[ServerCallTracerFactoryCapsule]:
139 """Creates a ServerCallTracerFactoryCapsule.
140
141 This method will be called at server initialization time to create a
142 ServerCallTracerFactory, which will be registered to gRPC core.
143
144 The ServerCallTracerFactory is an object which implements
145 `grpc_core::ServerCallTracerFactory` interface and wrapped in a PyCapsule
146 using `server_call_tracer_factory` as name.
147
148 Args:
149 xds: Whether the server is xds server.
150 Returns:
151 A PyCapsule which stores a ServerCallTracerFactory object. Or None if
152 plugin decides not to create ServerCallTracerFactory.
153 """
154 raise NotImplementedError()
155
156 @abc.abstractmethod
157 def record_rpc_latency(
158 self, method: str, target: str, rpc_latency: float, status_code: Any
159 ) -> None:
160 """Record the latency of the RPC.
161
162 After register the plugin, if stats is enabled, this method will be
163 called at the end of each RPC.
164
165 Args:
166 method: The fully-qualified name of the RPC method being invoked.
167 target: The target name of the RPC method being invoked.
168 rpc_latency: The latency for the RPC in seconds, equals to the time between
169 when the client invokes the RPC and when the client receives the status.
170 status_code: An element of grpc.StatusCode in string format representing the
171 final status for the RPC.
172 """
173 raise NotImplementedError()
174
175 def set_tracing(self, enable: bool) -> None:
176 """Enable or disable tracing.
177
178 Args:
179 enable: A bool indicates whether tracing should be enabled.
180 """
181 self._tracing_enabled = enable
182
183 def set_stats(self, enable: bool) -> None:
184 """Enable or disable stats(metrics).
185
186 Args:
187 enable: A bool indicates whether stats should be enabled.
188 """
189 self._stats_enabled = enable
190
191 def save_registered_method(self, method_name: bytes) -> None:
192 """Saves the method name to registered_method list.
193
194 When exporting metrics, method name for unregistered methods will be replaced
195 with 'other' by default.
196
197 Args:
198 method_name: The method name in bytes.
199 """
200 raise NotImplementedError()
201
202 @property
203 def tracing_enabled(self) -> bool:
204 return self._tracing_enabled
205
206 @property
207 def stats_enabled(self) -> bool:
208 return self._stats_enabled
209
210 @property
211 def observability_enabled(self) -> bool:
212 return self.tracing_enabled or self.stats_enabled
213
214
215@contextlib.contextmanager
216def get_plugin() -> Generator[Optional[ObservabilityPlugin], None, None]:
217 """Get the ObservabilityPlugin in _observability module.
218
219 Returns:
220 The ObservabilityPlugin currently registered with the _observability
221 module. Or None if no plugin exists at the time of calling this method.
222 """
223 with _plugin_lock:
224 yield _OBSERVABILITY_PLUGIN
225
226
227def set_plugin(observability_plugin: Optional[ObservabilityPlugin]) -> None:
228 """Save ObservabilityPlugin to _observability module.
229
230 Args:
231 observability_plugin: The ObservabilityPlugin to save.
232
233 Raises:
234 ValueError: If an ObservabilityPlugin was already registered at the
235 time of calling this method.
236 """
237 global _OBSERVABILITY_PLUGIN # pylint: disable=global-statement
238 with _plugin_lock:
239 if observability_plugin and _OBSERVABILITY_PLUGIN:
240 raise ValueError("observability_plugin was already set!")
241 _OBSERVABILITY_PLUGIN = observability_plugin
242
243
244def observability_init(observability_plugin: ObservabilityPlugin) -> None:
245 """Initialize observability with provided ObservabilityPlugin.
246
247 This method have to be called at the start of a program, before any
248 channels/servers are built.
249
250 Args:
251 observability_plugin: The ObservabilityPlugin to use.
252
253 Raises:
254 ValueError: If an ObservabilityPlugin was already registered at the
255 time of calling this method.
256 """
257 set_plugin(observability_plugin)
258
259
260def observability_deinit() -> None:
261 """Clear the observability context, including ObservabilityPlugin and
262 ServerCallTracerFactory
263
264 This method have to be called after exit observability context so that
265 it's possible to re-initialize again.
266 """
267 set_plugin(None)
268 _cygrpc.clear_server_call_tracer_factory()
269
270
271def maybe_record_rpc_latency(state: "_channel._RPCState") -> None:
272 """Record the latency of the RPC, if the plugin is registered and stats is enabled.
273
274 This method will be called at the end of each RPC.
275
276 Args:
277 state: a grpc._channel._RPCState object which contains the stats related to the
278 RPC.
279 """
280 # TODO(xuanwn): use channel args to exclude those metrics.
281 for exclude_prefix in _SERVICES_TO_EXCLUDE:
282 if exclude_prefix in state.method.encode("utf8"):
283 return
284 with get_plugin() as plugin:
285 if plugin and plugin.stats_enabled:
286 rpc_latency_s = state.rpc_end_time - state.rpc_start_time
287 rpc_latency_ms = rpc_latency_s * 1000
288 plugin.record_rpc_latency(
289 state.method, state.target, rpc_latency_ms, state.code
290 )
291
292
293def create_server_call_tracer_factory_option(
294 xds: bool,
295) -> Union[Tuple[ChannelArgumentType], Tuple[()]]:
296 with get_plugin() as plugin:
297 if plugin and plugin.stats_enabled:
298 server_call_tracer_factory_address = (
299 _cygrpc.get_server_call_tracer_factory_address(plugin, xds)
300 )
301 if server_call_tracer_factory_address:
302 return (
303 (
304 "grpc.experimental.server_call_tracer_factory",
305 ServerCallTracerFactory(
306 server_call_tracer_factory_address
307 ),
308 ),
309 )
310 return ()