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Add Warning for Endpoint Mismatch in OTLP GRPC Exporter #3619
Description
While trying to initialize a HTTP exporter, I mistakenly passed a GRPC one which led to the silent truncation of the endpoint value. This caused confusion and resulted in hours of debugging. The source of the confusion was this import line:
Instead of
from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporterI copy pasted from the commonly available examples, which use:
from opentelemetry.exporter.otlp.proto.grpc.trace_exporter import OTLPSpanExporterThis issue might be a common occurrence for newcomers, as almost all the examples use the GRPC exporter. To prevent this from happening in the future, I propose adding a warning message in the OTLP GRPC Exporter when there is a mismatch between the configured endpoint and the provided endpoint. This would provide clear, actionable feedback to the user and improve the overall user experience.
Here’s the proposed change:
if parsed_url.netloc:
self._endpoint = parsed_url.netloc
if parsed_url.path:
logger.warning(f"Endpoint set to {self._endpoint}, which differs from the provided endpoint {endpoint}. If you're trying to configure a HTTP endpoint, please ensure you're using the correct exporter.")This change replaces the existing code:
if parsed_url.netloc:
self._endpoint = parsed_url.netloc
Activity
chrikrah commentedon Sep 10, 2026
Reproduces on
main(5aa2f8f).exporter.py:299-300keepsparsed_url.netloc, so the path isdropped with no warning. The port survives, because it is part of
netloc.self._endpointparsed_url.pathhttps://otlp.example.com/v1/tracesotlp.example.com/v1/traceshttps://otlp.example.com:4317/v1/tracesotlp.example.com:4317/v1/traceshttps://otlp.example.com/otlp.example.com/otlp.example.com:4317otlp.example.com:43174317Identical on the
OTEL_EXPORTER_OTLP_ENDPOINTroute, since both converge at:288. A gRPC target hasno path component, so a warning is the only available fix.
Row 4 breaks the guard #3620 proposed. A scheme-less
host:portparses asscheme='otlp.example.com',path='4317', soif parsed_url.pathandparsed_url.path.strip("/")both warn on an endpoint that works. The warning has to sit inside
if parsed_url.netloc.G004nowalso forbids the f-string #3620 used.
One more thing that costs a reviewer time:
loggercarriesDuplicateFilter, which drops a repeat ofthe same format string within a 20 second bucket, so an
assertLogstest passes against a mutatedguard. Patching
logger.warningcatches it.6 production lines and 2 tests.
69 passedinexporter/opentelemetry-exporter-otlp-proto-grpc/tests/,and each test fails against a reverted fix. Open a PR?
Add changelog entry for open-telemetry#3619
Add warning for endpoint path mismatch in OTLP gRPC exporter
Add changelog entry for open-telemetry#3619