Python: Fix OTLP HTTP base-endpoint losing /v1/{signal} auto-append

[droideronline]

Summary

Fixes #5912

Per the OpenTelemetry specification, OTEL_EXPORTER_OTLP_ENDPOINT is a base URL for HTTP transport — the SDK automatically appends /v1/traces, /v1/metrics, and /v1/logs when it reads the env var directly. Signal-specific env vars (e.g. OTEL_EXPORTER_OTLP_TRACES_ENDPOINT) are full URLs used verbatim.

_get_exporters_from_env in observability.py was reading the base endpoint and passing it directly as the endpoint= constructor argument to the exporters. The OTel SDK always treats a programmatically-provided endpoint= as a full signal URL (no auto-append). This silently dropped the /v1/{signal} path suffix, causing all HTTP telemetry to be sent to the wrong URL (e.g. http://localhost:4318 instead of http://localhost:4318/v1/traces).

Changes

python/packages/core/agent_framework/observability.py

• Read signal-specific endpoint env vars separately from the base endpoint.
• When using HTTP protocol (http/protobuf or http) and falling back to OTEL_EXPORTER_OTLP_ENDPOINT, auto-append /v1/traces, /v1/metrics, /v1/logs to replicate the OTel spec behaviour.
• Signal-specific env vars continue to be forwarded verbatim (no path appended).
• gRPC behaviour is unchanged — the base endpoint is used as-is.

python/packages/core/tests/core/test_observability.py

• Added test cases covering:
  • HTTP protocol with base endpoint → signal paths are auto-appended.
  • HTTP protocol with signal-specific endpoints → used verbatim (no double-append).
  • gRPC protocol with base endpoint → base URL used as-is (no path appended).

Before / After

Scenario	Before	After
OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318, PROTOCOL=http/protobuf	Sends to http://localhost:4318 ❌	Sends to http://localhost:4318/v1/traces ✅
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://localhost:4318/v1/traces, PROTOCOL=http/protobuf	Sends to http://localhost:4318/v1/traces ✅	Sends to http://localhost:4318/v1/traces ✅
OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317, PROTOCOL=grpc	Sends to http://localhost:4317 ✅	Sends to http://localhost:4317 ✅

Testing

Unit tests added in test_observability.py covering all three scenarios above. No integration-level changes required.

[droideronline]

@TaoChenOSU , @moonbox3 , @eavanvalkenburg , @chetantoshniwal - Kindly review when you get a chance.

[Copilot]

Pull request overview

Fixes OTLP/HTTP exporter endpoint handling in Python observability so that OTEL_EXPORTER_OTLP_ENDPOINT (base URL) correctly results in signal-specific URLs (/v1/traces, /v1/metrics, /v1/logs) when configuring exporters programmatically, matching the OpenTelemetry spec and avoiding telemetry being sent to the wrong path.

Changes:

• Compute HTTP signal endpoints by auto-appending /v1/{signal} when falling back to OTEL_EXPORTER_OTLP_ENDPOINT; keep signal-specific endpoint env vars verbatim.
• Preserve existing gRPC behavior (base endpoint used as-is).
• Add unit tests validating HTTP base endpoint appends, trailing-slash handling, verbatim signal-specific endpoints, and unchanged gRPC behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
python/packages/core/agent_framework/observability.py	Implements correct OTLP/HTTP base-endpoint → signal endpoint derivation while leaving gRPC behavior unchanged.
python/packages/core/tests/core/test_observability.py	Adds focused tests to verify endpoint computation logic across HTTP and gRPC scenarios.

[moonbox3]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
packages/core/agent_framework
observability.py	777	60	92%	378, 380–381, 384, 387, 390–391, 396–397, 403–404, 410–411, 418, 420–422, 425–427, 432–433, 439–440, 446–447, 454, 628–629, 757, 761–763, 765, 769–770, 774, 812, 814, 825–827, 829–831, 835, 843, 967–968, 1130, 1372–1373, 1600, 1640–1641, 1784, 1920, 2117, 2335, 2337
TOTAL	34127	3884	88%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
6800	30 💤	0 ❌	0 🔥	1m 48s ⏱️

[moonbox3]

Non-blocking, two gaps I noticed while reading that this PR doesn't introduce:

1. OTEL_EXPORTER_OTLP_PROTOCOL=http/json is a valid spec value but _create_otlp_exporters only matches ("http/protobuf", "http") (observability.py:418), so http/json is silently ignored. The new auto-append check inherits the same set, which is consistent, just worth knowing.

2. Per-signal protocol env vars (OTEL_EXPORTER_OTLP_TRACES_PROTOCOL, etc.) aren't read in _get_exporters_from_env. A user pinning base to grpc and traces to http/protobuf wouldn't get auto-append on traces. Pre-existing.

Happy to leave both for a follow-up if you'd rather keep this PR scoped to the base-endpoint fix. Fine to merge as-is from my side.