fix(opentelemetry-sdk-node): the custom value from env variable for service.instance.id should take priority over random uuid as backup

CHANGELOG.md

@@ -16,6 +16,8 @@ For notes on migrating to 2.x / 0.200.x see [the upgrade guide](doc/upgrade-to-2
 
 ### :bug: Bug Fixes
 
+* fix(opentelemetry-sdk-node): the custom value from env variable for service.instance.id should take priority over random uuid as backup [#6345](https://github.com/open-telemetry/opentelemetry-js/pull/6345) @maryliag
+
 ### :books: Documentation
 
 ### :house: Internal

experimental/packages/opentelemetry-sdk-node/README.md

@@ -149,9 +149,15 @@ If `resourceDetectors` was not set, you can also use the environment variable `O
 For example, to enable only the `env`, `host` detectors:
 
 ```shell
-export OTEL_NODE_RESOURCE_DETECTORS="env,host"
+export OTEL_NODE_RESOURCE_DETECTORS="host,env"
 ```
 
+NOTE: The order set on `OTEL_NODE_RESOURCE_DETECTORS` will be respected and the detectors will be executed in order.
+For example, if you have `OTEL_RESOURCE_ATTRIBUTES="service.instance.id='custom-name'"`, but also `serviceinstance` and `env` on `OTEL_NODE_RESOURCE_DETECTORS`, it can have 2 scenarios:
+
+- `OTEL_NODE_RESOURCE_DETECTORS="serviceinstance,env"` will have the `service.instance.id` as `custom-name`
+- `OTEL_NODE_RESOURCE_DETECTORS="env,serviceinstance"` will have the `service.instance.id` as a random UUID
+
 ### sampler
 
 Configure a custom sampler. By default, all traces will be sampled.

experimental/packages/opentelemetry-sdk-node/src/utils.ts

@@ -76,11 +76,11 @@ const RESOURCE_DETECTOR_SERVICE_INSTANCE_ID = 'serviceinstance';
 export function getResourceDetectorsFromEnv(): Array<ResourceDetector> {
   // When updating this list, make sure to also update the section `resourceDetectors` on README.
   const resourceDetectors = new Map<string, ResourceDetector>([
-    [RESOURCE_DETECTOR_ENVIRONMENT, envDetector],
     [RESOURCE_DETECTOR_HOST, hostDetector],
     [RESOURCE_DETECTOR_OS, osDetector],
     [RESOURCE_DETECTOR_SERVICE_INSTANCE_ID, serviceInstanceIdDetector],
     [RESOURCE_DETECTOR_PROCESS, processDetector],
+    [RESOURCE_DETECTOR_ENVIRONMENT, envDetector],
   ]);
 
   const resourceDetectorsFromEnv = getStringListFromEnv(

experimental/packages/opentelemetry-sdk-node/test/sdk.test.ts

@@ -998,6 +998,60 @@ describe('Node SDK', () => {
       assertServiceInstanceIdIsUUID(resource);
       await sdk.shutdown();
     });
+
+    it('should configure service instance id with service instance id from env variable taking priority over random UUID', async () => {
+      process.env.OTEL_RESOURCE_ATTRIBUTES =
+        'service.instance.id=custom-service,service.name=my-service';
+      process.env.OTEL_NODE_RESOURCE_DETECTORS = 'all';
+      const sdk = new NodeSDK({
+        autoDetectResources: true,
+      });
+
+      sdk.start();
+      const resource = sdk['_resource'];
+      await resource.waitForAsyncAttributes?.();
+
+      assertServiceResource(resource, {
+        name: 'my-service',
+        instanceId: 'custom-service',
+      });
+      await sdk.shutdown();
+    });
+
+    it('should configure service instance id with service instance id from env variable taking priority over random UUID, based on order', async () => {
+      process.env.OTEL_RESOURCE_ATTRIBUTES =
+        'service.instance.id=custom-service,service.name=my-service';
+      process.env.OTEL_NODE_RESOURCE_DETECTORS = 'serviceinstance,env';
+      const sdk = new NodeSDK({
+        autoDetectResources: true,
+      });
+
+      sdk.start();
+      const resource = sdk['_resource'];
+      await resource.waitForAsyncAttributes?.();
+
+      assertServiceResource(resource, {
+        name: 'my-service',
+        instanceId: 'custom-service',
+      });
+      await sdk.shutdown();
+    });
+
+    it('should configure service instance id with service instance id from env variable taking priority over random UUID, based on order', async () => {
+      process.env.OTEL_RESOURCE_ATTRIBUTES =
+        'service.instance.id=custom-service,service.name=my-service';
+      process.env.OTEL_NODE_RESOURCE_DETECTORS = 'env,serviceinstance';
+      const sdk = new NodeSDK({
+        autoDetectResources: true,
+      });
+
+      sdk.start();
+      const resource = sdk['_resource'];
+      await resource.waitForAsyncAttributes?.();
+
+      assertServiceInstanceIdIsUUID(resource);
+      await sdk.shutdown();
+    });
   });
 
   describe('A disabled SDK should be no-op', () => {