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Added experimental HTTP backpropagators
The experimental back propagators inject trace response headers into HTTP responses. These are meant to be used by instrumentations and are not considered stable.
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‎CHANGELOG.md‎

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@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
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- Added `SpanKind` to `should_sample` parameters, suggest using parent span context's tracestate
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instead of manually passed in tracestate in `should_sample`
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([#1764](https://github.com/open-telemetry/opentelemetry-python/pull/1764))
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- Added experimental HTTP back propagators.
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([#1762](https://github.com/open-telemetry/opentelemetry-python/pull/1762))
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### Changed
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- Adjust `B3Format` propagator to be spec compliant by not modifying context

‎opentelemetry-instrumentation/setup.py‎

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@@ -24,4 +24,6 @@
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with open(VERSION_FILENAME) as f:
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exec(f.read(), PACKAGE_INFO)
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setuptools.setup(version=PACKAGE_INFO["__version__"],)
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setuptools.setup(
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version=PACKAGE_INFO["__version__"],
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)

‎opentelemetry-instrumentation/src/opentelemetry/instrumentation/propagators.py‎

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@@ -0,0 +1,106 @@
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# Copyright The OpenTelemetry Authors
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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This module implements experimental propagators to inject trace response context
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into HTTP responses. This is useful for server side frameworks that start traces
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when server requests and want to share the trace context with the client so the
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client can add it's spans to the same trace.
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This is part of an upcoming W3C spec and will eventually make it to the Otel spec.
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https://w3c.github.io/trace-context/#trace-context-http-response-headers-format
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"""
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import typing
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from abc import ABC, abstractmethod
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import opentelemetry.trace as trace
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from opentelemetry.context.context import Context
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from opentelemetry.propagators import textmap
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from opentelemetry.trace import format_span_id, format_trace_id
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_HTTP_HEADER_ACCESS_CONTROL_EXPOSE_HEADERS = "Access-Control-Expose-Headers"
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_RESPONSE_PROPAGATOR = None
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def get_global_response_propagator():
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return _RESPONSE_PROPAGATOR
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def set_global_response_propagator(propagator):
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global _RESPONSE_PROPAGATOR # pylint:disable=global-statement
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_RESPONSE_PROPAGATOR = propagator
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class DictHeaderSetter:
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def set(self, carrier, key, value): # pylint: disable=no-self-use
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old_value = carrier.get(key, "")
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if old_value:
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value = "{0}, {1}".format(old_value, value)
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carrier[key] = value
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default_setter = DictHeaderSetter()
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class FuncSetter:
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def __init__(self, func):
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self._func = func
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def set(self, carrier, key, value):
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self._func(carrier, key, value)
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class ResponsePropagator(ABC):
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@abstractmethod
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def inject(
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self,
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carrier: textmap.CarrierT,
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context: typing.Optional[Context] = None,
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setter: textmap.Setter = default_setter,
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) -> None:
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"""Injects SpanContext into the HTTP response carrier."""
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class TraceResponsePropagator(ResponsePropagator):
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"""Experimental propagator that injects tracecontext into HTTP responses."""
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def inject(
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self,
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carrier: textmap.CarrierT,
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context: typing.Optional[Context] = None,
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setter: textmap.Setter = default_setter,
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) -> None:
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"""Injects SpanContext into the HTTP response carrier."""
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span = trace.get_current_span(context)
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span_context = span.get_span_context()
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if span_context == trace.INVALID_SPAN_CONTEXT:
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return
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header_name = "traceresponse"
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setter.set(
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carrier,
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header_name,
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"00-{trace_id}-{span_id}-{:02x}".format(
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span_context.trace_flags,
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trace_id=format_trace_id(span_context.trace_id),
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span_id=format_span_id(span_context.span_id),
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),
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)
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setter.set(
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carrier,
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_HTTP_HEADER_ACCESS_CONTROL_EXPOSE_HEADERS,
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header_name,
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)

‎opentelemetry-instrumentation/tests/test_bootstrap.py‎

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@@ -23,7 +23,10 @@
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def sample_packages(packages, rate):
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sampled = sample(list(packages), int(len(packages) * rate),)
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sampled = sample(
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list(packages),
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int(len(packages) * rate),
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)
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return {k: v for k, v in packages.items() if k in sampled}
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‎opentelemetry-instrumentation/tests/test_propagators.py‎

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# Copyright The OpenTelemetry Authors
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# pylint: disable=protected-access
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from opentelemetry import trace
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from opentelemetry.instrumentation import propagators
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from opentelemetry.instrumentation.propagators import (
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DictHeaderSetter,
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TraceResponsePropagator,
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get_global_response_propagator,
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set_global_response_propagator,
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)
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from opentelemetry.test.test_base import TestBase
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class TestGlobals(TestBase):
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def test_get_set(self):
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original = propagators._RESPONSE_PROPAGATOR
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propagators._RESPONSE_PROPAGATOR = None
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self.assertIsNone(get_global_response_propagator())
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prop = TraceResponsePropagator()
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set_global_response_propagator(prop)
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self.assertIs(prop, get_global_response_propagator())
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propagators._RESPONSE_PROPAGATOR = original
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class TestDictHeaderSetter(TestBase):
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def test_simple(self):
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setter = DictHeaderSetter()
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carrier = {}
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setter.set(carrier, "kk", "vv")
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self.assertIn("kk", carrier)
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self.assertEqual(carrier["kk"], "vv")
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def test_append(self):
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setter = DictHeaderSetter()
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carrier = {"kk": "old"}
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setter.set(carrier, "kk", "vv")
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self.assertIn("kk", carrier)
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self.assertEqual(carrier["kk"], "old, vv")
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class TestTraceResponsePropagator(TestBase):
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def test_inject(self):
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span = trace.NonRecordingSpan(
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trace.SpanContext(
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trace_id=1,
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span_id=2,
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is_remote=False,
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trace_flags=trace.DEFAULT_TRACE_OPTIONS,
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trace_state=trace.DEFAULT_TRACE_STATE,
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),
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)
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ctx = trace.set_span_in_context(span)
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prop = TraceResponsePropagator()
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carrier = {}
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prop.inject(carrier, ctx)
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self.assertEqual(
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carrier["Access-Control-Expose-Headers"], "traceresponse"
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)
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self.assertEqual(
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carrier["traceresponse"],
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"00-00000000000000000000000000000001-0000000000000002-00",
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)

‎opentelemetry-instrumentation/tests/test_utils.py‎

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@@ -31,12 +31,24 @@ def test_http_status_to_status_code(self):
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(HTTPStatus.UNAUTHORIZED, StatusCode.ERROR),
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(HTTPStatus.FORBIDDEN, StatusCode.ERROR),
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(HTTPStatus.NOT_FOUND, StatusCode.ERROR),
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(HTTPStatus.UNPROCESSABLE_ENTITY, StatusCode.ERROR,),
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(HTTPStatus.TOO_MANY_REQUESTS, StatusCode.ERROR,),
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(
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HTTPStatus.UNPROCESSABLE_ENTITY,
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StatusCode.ERROR,
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),
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(
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HTTPStatus.TOO_MANY_REQUESTS,
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StatusCode.ERROR,
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),
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(HTTPStatus.NOT_IMPLEMENTED, StatusCode.ERROR),
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(HTTPStatus.SERVICE_UNAVAILABLE, StatusCode.ERROR),
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(HTTPStatus.GATEWAY_TIMEOUT, StatusCode.ERROR,),
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(HTTPStatus.HTTP_VERSION_NOT_SUPPORTED, StatusCode.ERROR,),
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(
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HTTPStatus.GATEWAY_TIMEOUT,
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StatusCode.ERROR,
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),
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(
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HTTPStatus.HTTP_VERSION_NOT_SUPPORTED,
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StatusCode.ERROR,
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),
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(600, StatusCode.ERROR),
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(99, StatusCode.ERROR),
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):

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