From 5ed54c8a0964fd685d722770dcbe7fae61a12937 Mon Sep 17 00:00:00 2001
From: drewcorlin1 <82601620+drewcorlin1@users.noreply.github.com>
Date: Wed, 15 Nov 2023 11:09:15 -0500
Subject: [PATCH] Update fetch instrumentation to be runtime agnostic (#4063)

Co-authored-by: Marc Pichler <marc.pichler@dynatrace.com>
---
 CHANGELOG.md                                             | 1 +
 experimental/CHANGELOG.md                                | 2 ++
 .../opentelemetry-instrumentation-fetch/src/fetch.ts     | 7 ++++++-
 packages/opentelemetry-sdk-trace-web/src/utils.ts        | 9 +++++++--
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb156b4016..336e211d6f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ For experimental package changes, see the [experimental CHANGELOG](experimental/
 
 ### :bug: (Bug Fix)
 
+* fix(sdk-trace-web): only access location if it is defined [#4063](https://github.com/open-telemetry/opentelemetry-js/pull/4063)
 * fix(sdk-trace-base): processor onStart called with a span having empty attributes
 
 ## 1.18.1
diff --git a/experimental/CHANGELOG.md b/experimental/CHANGELOG.md
index bb1fd6aca0..b9935e26c5 100644
--- a/experimental/CHANGELOG.md
+++ b/experimental/CHANGELOG.md
@@ -11,6 +11,8 @@ All notable changes to experimental packages in this project will be documented
 ### :bug: (Bug Fix)
 
 * fix(sdk-logs): avoid map attribute set when count limit exceeded
+* fix(instrumentation-fetch): only access navigator if it is defined [#4063](https://github.com/open-telemetry/opentelemetry-js/pull/4063)
+  * allows for experimental usage of this instrumentation with non-browser runtimes
 
 ### :books: (Refine Doc)
 
diff --git a/experimental/packages/opentelemetry-instrumentation-fetch/src/fetch.ts b/experimental/packages/opentelemetry-instrumentation-fetch/src/fetch.ts
index d02269c440..90213a8c69 100644
--- a/experimental/packages/opentelemetry-instrumentation-fetch/src/fetch.ts
+++ b/experimental/packages/opentelemetry-instrumentation-fetch/src/fetch.ts
@@ -132,7 +132,12 @@ export class FetchInstrumentation extends InstrumentationBase<
       SemanticAttributes.HTTP_SCHEME,
       parsedUrl.protocol.replace(':', '')
     );
-    span.setAttribute(SemanticAttributes.HTTP_USER_AGENT, navigator.userAgent);
+    if (typeof navigator !== 'undefined') {
+      span.setAttribute(
+        SemanticAttributes.HTTP_USER_AGENT,
+        navigator.userAgent
+      );
+    }
   }
 
   /**
diff --git a/packages/opentelemetry-sdk-trace-web/src/utils.ts b/packages/opentelemetry-sdk-trace-web/src/utils.ts
index b3f583676f..beb93572ca 100644
--- a/packages/opentelemetry-sdk-trace-web/src/utils.ts
+++ b/packages/opentelemetry-sdk-trace-web/src/utils.ts
@@ -131,6 +131,11 @@ export function sortResources(
   });
 }
 
+/** Returns the origin if present (if in browser context). */
+function getOrigin(): string | undefined {
+  return typeof location !== 'undefined' ? location.origin : undefined;
+}
+
 /**
  * Get closest performance resource ignoring the resources that have been
  * already used.
@@ -174,7 +179,7 @@ export function getResource(
   }
   const sorted = sortResources(filteredResources);
 
-  if (parsedSpanUrl.origin !== location.origin && sorted.length > 1) {
+  if (parsedSpanUrl.origin !== getOrigin() && sorted.length > 1) {
     let corsPreFlightRequest: PerformanceResourceTiming | undefined = sorted[0];
     let mainRequest: PerformanceResourceTiming = findMainRequest(
       sorted,
@@ -438,7 +443,7 @@ export function shouldPropagateTraceHeaders(
   }
   const parsedSpanUrl = parseUrl(spanUrl);
 
-  if (parsedSpanUrl.origin === location.origin) {
+  if (parsedSpanUrl.origin === getOrigin()) {
     return true;
   } else {
     return propagateTraceHeaderUrls.some(propagateTraceHeaderUrl =>