# Copyright The OpenTelemetry Authors
#
# 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 typing
import urllib.parse
from opentelemetry import correlationcontext
from opentelemetry.context import get_current
from opentelemetry.context.context import Context
from opentelemetry.trace.propagation import httptextformat
[docs]class CorrelationContextPropagator(httptextformat.HTTPTextFormat):
MAX_HEADER_LENGTH = 8192
MAX_PAIR_LENGTH = 4096
MAX_PAIRS = 180
_CORRELATION_CONTEXT_HEADER_NAME = "otcorrelationcontext"
[docs] def inject(
self,
set_in_carrier: httptextformat.Setter[httptextformat.HTTPTextFormatT],
carrier: httptextformat.HTTPTextFormatT,
context: typing.Optional[Context] = None,
) -> None:
"""Injects CorrelationContext into the carrier.
See
`opentelemetry.trace.propagation.httptextformat.HTTPTextFormat.inject`
"""
correlations = correlationcontext.get_correlations(context=context)
if not correlations:
return
correlation_context_string = _format_correlations(correlations)
set_in_carrier(
carrier,
self._CORRELATION_CONTEXT_HEADER_NAME,
correlation_context_string,
)
def _format_correlations(correlations: typing.Dict[str, object]) -> str:
return ",".join(
key + "=" + urllib.parse.quote_plus(str(value))
for key, value in correlations.items()
)
def _extract_first_element(
items: typing.Iterable[httptextformat.HTTPTextFormatT],
) -> typing.Optional[httptextformat.HTTPTextFormatT]:
if items is None:
return None
return next(iter(items), None)