From 7da2aa145347942ffb710b80f83eb2cc42708a2c Mon Sep 17 00:00:00 2001
From: schickling-assistant
 <261620128+schickling-assistant@users.noreply.github.com>
Date: Thu, 11 Jun 2026 09:53:48 +0200
Subject: [PATCH] fix(otelite): honor traces endpoint env semantics

---
 .../utils-dev/src/otelite/test-harness.test.ts      | 13 +++++++++++++
 .../@overeng/utils-dev/src/otelite/test-harness.ts  | 13 +++++++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/packages/@overeng/utils-dev/src/otelite/test-harness.test.ts b/packages/@overeng/utils-dev/src/otelite/test-harness.test.ts
index d2aa3c8b3..d591959b6 100644
--- a/packages/@overeng/utils-dev/src/otelite/test-harness.test.ts
+++ b/packages/@overeng/utils-dev/src/otelite/test-harness.test.ts
@@ -1,6 +1,7 @@
 import { describe, expect, it } from '@effect/vitest'
 import { Effect } from 'effect'
 
+import { otlpTracesUrl } from '../node-vitest/Vitest.ts'
 import { captureInProcessTrace, OteliteTestHarness } from './test-harness.ts'
 
 describe('OteliteTestHarness', () => {
@@ -105,6 +106,18 @@ describe('OteliteTestHarness', () => {
         expect(process.env.OTELITE_TEST_ENDPOINT).toBe(previousCustomEndpoint)
         expect(process.env.OTELITE_TEST_SERVICE).toBe(previousCustomService)
         expect(process.env.OTELITE_TEST_EXTRA).toBe(previousExtra)
+
+        const previousPerSignalEndpoint = process.env.OTEL_EXPORTER_OTLP_TRACES_ENDPOINT
+        yield* otel.withEnv(
+          Effect.sync(() => {
+            expect(process.env.OTEL_EXPORTER_OTLP_TRACES_ENDPOINT).toBe(
+              otlpTracesUrl(otel.capture.endpoints.http),
+            )
+          }),
+          { endpointVar: 'OTEL_EXPORTER_OTLP_TRACES_ENDPOINT' },
+        )
+
+        expect(process.env.OTEL_EXPORTER_OTLP_TRACES_ENDPOINT).toBe(previousPerSignalEndpoint)
       }).pipe(Effect.provide(OteliteTestHarness.Default)),
     30_000,
   )
diff --git a/packages/@overeng/utils-dev/src/otelite/test-harness.ts b/packages/@overeng/utils-dev/src/otelite/test-harness.ts
index 2f13953c6..20e634570 100644
--- a/packages/@overeng/utils-dev/src/otelite/test-harness.ts
+++ b/packages/@overeng/utils-dev/src/otelite/test-harness.ts
@@ -113,6 +113,13 @@ const makeInProcessLayer = (
   )
 }
 
+const endpointEnvValue = (handle: CaptureHandle, endpointVar?: string): string => {
+  if (endpointVar === 'OTEL_EXPORTER_OTLP_TRACES_ENDPOINT') {
+    return otlpTracesUrl(handle.endpoints.http)
+  }
+  return handle.endpoints.http
+}
+
 export class OteliteTestHarness extends Effect.Service<OteliteTestHarness>()(
   '@overeng/utils-dev/otelite/OteliteTestHarness',
   {
@@ -166,8 +173,10 @@ export class OteliteTestHarness extends Effect.Service<OteliteTestHarness>()(
             envSemaphore.withPermits(1)(
               Effect.scoped(
                 scopedEnv({
-                  [envOptions.endpointVar ?? 'OTEL_EXPORTER_OTLP_ENDPOINT']:
-                    captureHandle.endpoints.http,
+                  [envOptions.endpointVar ?? 'OTEL_EXPORTER_OTLP_ENDPOINT']: endpointEnvValue(
+                    captureHandle,
+                    envOptions.endpointVar,
+                  ),
                   [envOptions.serviceNameVar ?? 'OTEL_SERVICE_NAME']: options.serviceName,
                   ...envOptions.extra,
                 }).pipe(Effect.zipRight(effect)),