Movses AslanyanandClaude Opus 5.5
455b0970b1
A processor in the shared chain reads the active span context and adds its IDs as lowercase hex, so both structlog and stdlib records carry them. The lowercase `trace_id` name is what the provisioned Loki derived field's case-sensitive regex matches; outside a span nothing is added. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
83 lines
3.0 KiB
Python
83 lines
3.0 KiB
Python
import logging
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import sys
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import structlog
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from opentelemetry import trace
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# Loggers that install their own handlers (uvicorn's dictConfig runs before the
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# app is imported). Their handlers are stripped so records propagate to the
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# root handler below and come out as JSON like everything else.
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# uvicorn.access is left alone on purpose: --no-access-log works by setting its
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# propagate=False, and re-enabling propagation would turn access logs back on.
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_FOREIGN_LOGGERS = ("uvicorn", "uvicorn.error")
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def _add_service(service_name: str):
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def processor(logger, method_name, event_dict):
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event_dict["service"] = service_name
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return event_dict
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return processor
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def _add_trace_context(logger, method_name, event_dict):
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"""Stamp the active span's IDs on the record, as lowercase hex.
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The name `trace_id` is load-bearing: Grafana's Loki derived field matches
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the case-sensitive regex trace[_-]?id["=: ]+([a-fA-F0-9]+), so OTel's own
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`otelTraceID` would never become a link. Outside a span (startup, the
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consumers' idle loop) the context is invalid and nothing is added, rather
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than an all-zeros ID that points at no trace.
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"""
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ctx = trace.get_current_span().get_span_context()
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if ctx.is_valid:
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event_dict["trace_id"] = trace.format_trace_id(ctx.trace_id)
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event_dict["span_id"] = trace.format_span_id(ctx.span_id)
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return event_dict
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def configure_logging(service_name: str) -> structlog.stdlib.BoundLogger:
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"""One JSON object per line on stdout, for structlog and stdlib loggers alike.
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`shared` runs for every record, whichever API emitted it: structlog calls
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pass through it via structlog.configure(), stdlib records (uvicorn, the
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consumers' logging.getLogger(...)) via the formatter's foreign_pre_chain.
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"""
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shared = [
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structlog.contextvars.merge_contextvars,
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structlog.stdlib.add_log_level,
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structlog.stdlib.add_logger_name,
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structlog.processors.TimeStamper(fmt="iso", utc=True),
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_add_service(service_name),
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_add_trace_context,
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]
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structlog.configure(
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processors=[*shared, structlog.stdlib.ProcessorFormatter.wrap_for_formatter],
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logger_factory=structlog.stdlib.LoggerFactory(),
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wrapper_class=structlog.stdlib.BoundLogger,
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cache_logger_on_first_use=True,
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)
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formatter = structlog.stdlib.ProcessorFormatter(
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foreign_pre_chain=shared,
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processors=[
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structlog.stdlib.ProcessorFormatter.remove_processors_meta,
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structlog.processors.format_exc_info,
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structlog.processors.JSONRenderer(),
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],
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)
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handler = logging.StreamHandler(sys.stdout)
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handler.setFormatter(formatter)
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root = logging.getLogger()
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root.handlers = [handler]
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root.setLevel(logging.INFO)
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for name in _FOREIGN_LOGGERS:
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foreign = logging.getLogger(name)
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foreign.handlers = []
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foreign.propagate = True
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return structlog.get_logger(service_name)
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