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Diffstat (limited to '')
| -rw-r--r-- | synapse/logging/opentracing.py | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py new file mode 100644 index 0000000000..f0ceea2a64 --- /dev/null +++ b/synapse/logging/opentracing.py @@ -0,0 +1,362 @@ +# -*- coding: utf-8 -*- +# Copyright 2019 The Matrix.org Foundation C.I.C.d +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License.import opentracing + + +# NOTE +# This is a small wrapper around opentracing because opentracing is not currently +# packaged downstream (specifically debian). Since opentracing instrumentation is +# fairly invasive it was awkward to make it optional. As a result we opted to encapsulate +# all opentracing state in these methods which effectively noop if opentracing is +# not present. We should strongly consider encouraging the downstream distributers +# to package opentracing and making opentracing a full dependency. In order to facilitate +# this move the methods have work very similarly to opentracing's and it should only +# be a matter of few regexes to move over to opentracing's access patterns proper. + +try: + import opentracing +except ImportError: + opentracing = None +try: + from jaeger_client import Config as JaegerConfig + from synapse.logging.scopecontextmanager import LogContextScopeManager +except ImportError: + JaegerConfig = None + LogContextScopeManager = None + +import contextlib +import logging +import re +from functools import wraps + +from twisted.internet import defer + +logger = logging.getLogger(__name__) + + +class _DumTagNames(object): + """wrapper of opentracings tags. We need to have them if we + want to reference them without opentracing around. Clearly they + should never actually show up in a trace. `set_tags` overwrites + these with the correct ones.""" + + INVALID_TAG = "invalid-tag" + COMPONENT = INVALID_TAG + DATABASE_INSTANCE = INVALID_TAG + DATABASE_STATEMENT = INVALID_TAG + DATABASE_TYPE = INVALID_TAG + DATABASE_USER = INVALID_TAG + ERROR = INVALID_TAG + HTTP_METHOD = INVALID_TAG + HTTP_STATUS_CODE = INVALID_TAG + HTTP_URL = INVALID_TAG + MESSAGE_BUS_DESTINATION = INVALID_TAG + PEER_ADDRESS = INVALID_TAG + PEER_HOSTNAME = INVALID_TAG + PEER_HOST_IPV4 = INVALID_TAG + PEER_HOST_IPV6 = INVALID_TAG + PEER_PORT = INVALID_TAG + PEER_SERVICE = INVALID_TAG + SAMPLING_PRIORITY = INVALID_TAG + SERVICE = INVALID_TAG + SPAN_KIND = INVALID_TAG + SPAN_KIND_CONSUMER = INVALID_TAG + SPAN_KIND_PRODUCER = INVALID_TAG + SPAN_KIND_RPC_CLIENT = INVALID_TAG + SPAN_KIND_RPC_SERVER = INVALID_TAG + + +def only_if_tracing(func): + """Executes the function only if we're tracing. Otherwise return. + Assumes the function wrapped may return None""" + + @wraps(func) + def _only_if_tracing_inner(*args, **kwargs): + if opentracing: + return func(*args, **kwargs) + else: + return + + return _only_if_tracing_inner + + +# Block everything by default +_homeserver_whitelist = None + +tags = _DumTagNames + + +def init_tracer(config): + """Set the whitelists and initialise the JaegerClient tracer + + Args: + config (Config) + The config used by the homeserver. Here it's used to set the service + name to the homeserver's. + """ + global opentracing + if not config.tracer_config.get("tracer_enabled", False): + # We don't have a tracer + opentracing = None + return + + if not opentracing: + logger.error( + "The server has been configure to use opentracing but opentracing is not installed." + ) + raise ModuleNotFoundError("opentracing") + + if not JaegerConfig: + logger.error( + "The server has been configure to use opentracing but opentracing is not installed." + ) + + # Include the worker name + name = config.worker_name if config.worker_name else "master" + + set_homeserver_whitelist(config.tracer_config["homeserver_whitelist"]) + jaeger_config = JaegerConfig( + config={"sampler": {"type": "const", "param": 1}, "logging": True}, + service_name="{} {}".format(config.server_name, name), + scope_manager=LogContextScopeManager(config), + ) + jaeger_config.initialize_tracer() + + # Set up tags to be opentracing's tags + global tags + tags = opentracing.tags + + +@contextlib.contextmanager +def _noop_context_manager(*args, **kwargs): + """Does absolutely nothing really well. Can be entered and exited arbitrarily. + Good substitute for an opentracing scope.""" + yield + + +# Could use kwargs but I want these to be explicit +def start_active_span( + operation_name, + child_of=None, + references=None, + tags=None, + start_time=None, + ignore_active_span=False, + finish_on_close=True, +): + """Starts an active opentracing span. Note, the scope doesn't become active + until it has been entered, however, the span starts from the time this + message is called. + Args: + See opentracing.tracer + Returns: + scope (Scope) or noop_context_manager + """ + if opentracing is None: + return _noop_context_manager() + else: + # We need to enter the scope here for the logcontext to become active + return opentracing.tracer.start_active_span( + operation_name, + child_of=child_of, + references=references, + tags=tags, + start_time=start_time, + ignore_active_span=ignore_active_span, + finish_on_close=finish_on_close, + ) + + +@only_if_tracing +def close_active_span(): + """Closes the active span. This will close it's logcontext if the context + was made for the span""" + opentracing.tracer.scope_manager.active.__exit__(None, None, None) + + +@only_if_tracing +def set_tag(key, value): + """Set's a tag on the active span""" + opentracing.tracer.active_span.set_tag(key, value) + + +@only_if_tracing +def log_kv(key_values, timestamp=None): + """Log to the active span""" + opentracing.tracer.active_span.log_kv(key_values, timestamp) + + +# Note: we don't have a get baggage items because we're trying to hide all +# scope and span state from synapse. I think this method may also be useless +# as a result +@only_if_tracing +def set_baggage_item(key, value): + """Attach baggage to the active span""" + opentracing.tracer.active_span.set_baggage_item(key, value) + + +@only_if_tracing +def set_operation_name(operation_name): + """Sets the operation name of the active span""" + opentracing.tracer.active_span.set_operation_name(operation_name) + + +@only_if_tracing +def set_homeserver_whitelist(homeserver_whitelist): + """Sets the whitelist + + Args: + homeserver_whitelist (iterable of strings): regex of whitelisted homeservers + """ + global _homeserver_whitelist + if homeserver_whitelist: + # Makes a single regex which accepts all passed in regexes in the list + _homeserver_whitelist = re.compile( + "({})".format(")|(".join(homeserver_whitelist)) + ) + + +@only_if_tracing +def whitelisted_homeserver(destination): + """Checks if a destination matches the whitelist + Args: + destination (String)""" + global _homeserver_whitelist + if _homeserver_whitelist: + return _homeserver_whitelist.match(destination) + return False + + +def start_active_span_from_context( + headers, + operation_name, + references=None, + tags=None, + start_time=None, + ignore_active_span=False, + finish_on_close=True, +): + """ + Extracts a span context from Twisted Headers. + args: + headers (twisted.web.http_headers.Headers) + returns: + span_context (opentracing.span.SpanContext) + """ + # Twisted encodes the values as lists whereas opentracing doesn't. + # So, we take the first item in the list. + # Also, twisted uses byte arrays while opentracing expects strings. + if opentracing is None: + return _noop_context_manager() + + header_dict = {k.decode(): v[0].decode() for k, v in headers.getAllRawHeaders()} + context = opentracing.tracer.extract(opentracing.Format.HTTP_HEADERS, header_dict) + + return opentracing.tracer.start_active_span( + operation_name, + child_of=context, + references=references, + tags=tags, + start_time=start_time, + ignore_active_span=ignore_active_span, + finish_on_close=finish_on_close, + ) + + +@only_if_tracing +def inject_active_span_twisted_headers(headers, destination): + """ + Injects a span context into twisted headers inplace + + Args: + headers (twisted.web.http_headers.Headers) + span (opentracing.Span) + + Returns: + Inplace modification of headers + + Note: + The headers set by the tracer are custom to the tracer implementation which + should be unique enough that they don't interfere with any headers set by + synapse or twisted. If we're still using jaeger these headers would be those + here: + https://github.com/jaegertracing/jaeger-client-python/blob/master/jaeger_client/constants.py + """ + + if not whitelisted_homeserver(destination): + return + + span = opentracing.tracer.active_span + carrier = {} + opentracing.tracer.inject(span, opentracing.Format.HTTP_HEADERS, carrier) + + for key, value in carrier.items(): + headers.addRawHeaders(key, value) + + +@only_if_tracing +def inject_active_span_byte_dict(headers, destination): + """ + Injects a span context into a dict where the headers are encoded as byte + strings + + Args: + headers (dict) + span (opentracing.Span) + + Returns: + Inplace modification of headers + + Note: + The headers set by the tracer are custom to the tracer implementation which + should be unique enough that they don't interfere with any headers set by + synapse or twisted. If we're still using jaeger these headers would be those + here: + https://github.com/jaegertracing/jaeger-client-python/blob/master/jaeger_client/constants.py + """ + if not whitelisted_homeserver(destination): + return + + span = opentracing.tracer.active_span + + carrier = {} + opentracing.tracer.inject(span, opentracing.Format.HTTP_HEADERS, carrier) + + for key, value in carrier.items(): + headers[key.encode()] = [value.encode()] + + +def trace_servlet(servlet_name, func): + """Decorator which traces a serlet. It starts a span with some servlet specific + tags such as the servlet_name and request information""" + + @wraps(func) + @defer.inlineCallbacks + def _trace_servlet_inner(request, *args, **kwargs): + with start_active_span_from_context( + request.requestHeaders, + "incoming-client-request", + tags={ + "request_id": request.get_request_id(), + tags.SPAN_KIND: tags.SPAN_KIND_RPC_SERVER, + tags.HTTP_METHOD: request.get_method(), + tags.HTTP_URL: request.get_redacted_uri(), + tags.PEER_HOST_IPV6: request.getClientIP(), + "servlet_name": servlet_name, + }, + ): + result = yield defer.maybeDeferred(func, request, *args, **kwargs) + defer.returnValue(result) + + return _trace_servlet_inner |