116 lines
4.0 KiB
Python
116 lines
4.0 KiB
Python
# Copyright The OpenTelemetry Authors
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# SPDX-License-Identifier: Apache-2.0
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#
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import logging
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import re
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from opentelemetry import 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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from opentelemetry.trace.span import (
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_TRACECONTEXT_MAXIMUM_TRACESTATE_LENGTH,
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TraceState,
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)
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_logger = logging.getLogger(__name__)
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class TraceContextTextMapPropagator(textmap.TextMapPropagator):
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"""Extracts and injects using w3c TraceContext's headers."""
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_TRACEPARENT_HEADER_NAME = "traceparent"
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_TRACESTATE_HEADER_NAME = "tracestate"
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_TRACEPARENT_HEADER_FORMAT = "^[ \t]*([0-9a-f]{2})-([0-9a-f]{32})-([0-9a-f]{16})-([0-9a-f]{2})" + "(-.*)?[ \t]*$"
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_TRACEPARENT_HEADER_FORMAT_RE = re.compile(_TRACEPARENT_HEADER_FORMAT)
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def extract(
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self,
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carrier: textmap.CarrierT,
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context: Context | None = None,
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getter: textmap.Getter[textmap.CarrierT] = textmap.default_getter,
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) -> Context:
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"""Extracts SpanContext from the carrier.
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See `opentelemetry.propagators.textmap.TextMapPropagator.extract`
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"""
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if context is None:
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context = Context()
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header = getter.get(carrier, self._TRACEPARENT_HEADER_NAME)
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if not header:
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return context
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match = re.search(self._TRACEPARENT_HEADER_FORMAT_RE, header[0])
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if not match:
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return context
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version: str = match.group(1)
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trace_id: str = match.group(2)
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span_id: str = match.group(3)
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trace_flags: str = match.group(4)
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if trace_id == "0" * 32 or span_id == "0" * 16:
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return context
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if version == "00":
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if match.group(5): # type: ignore
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return context
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if version == "ff":
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return context
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tracestate_headers = getter.get(carrier, self._TRACESTATE_HEADER_NAME)
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if tracestate_headers is None:
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tracestate = None
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elif (
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# multiple header fields are combined with "," (RFC 9110, section 5.3)
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sum(len(header) for header in tracestate_headers) + len(tracestate_headers) - 1
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> _TRACECONTEXT_MAXIMUM_TRACESTATE_LENGTH
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):
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_logger.warning(
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"tracestate header exceeded the maximum length of %d characters",
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_TRACECONTEXT_MAXIMUM_TRACESTATE_LENGTH,
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)
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tracestate = None
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else:
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tracestate = TraceState.from_header(tracestate_headers)
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span_context = trace.SpanContext(
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trace_id=int(trace_id, 16),
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span_id=int(span_id, 16),
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is_remote=True,
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trace_flags=trace.TraceFlags(int(trace_flags, 16)),
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trace_state=tracestate,
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)
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return trace.set_span_in_context(trace.NonRecordingSpan(span_context), context)
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def inject(
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self,
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carrier: textmap.CarrierT,
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context: Context | None = None,
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setter: textmap.Setter[textmap.CarrierT] = textmap.default_setter,
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) -> None:
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"""Injects SpanContext into the carrier.
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See `opentelemetry.propagators.textmap.TextMapPropagator.inject`
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"""
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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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traceparent_string = f"00-{format_trace_id(span_context.trace_id)}-{format_span_id(span_context.span_id)}-{span_context.trace_flags:02x}"
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setter.set(carrier, self._TRACEPARENT_HEADER_NAME, traceparent_string)
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if span_context.trace_state:
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tracestate_string = span_context.trace_state.to_header()
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setter.set(carrier, self._TRACESTATE_HEADER_NAME, tracestate_string)
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@property
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def fields(self) -> set[str]:
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"""Returns a set with the fields set in `inject`.
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See
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`opentelemetry.propagators.textmap.TextMapPropagator.fields`
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"""
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return {self._TRACEPARENT_HEADER_NAME, self._TRACESTATE_HEADER_NAME}
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