fix(sdk-logs): ensure default resource attributes are used as fallbacks when a resource is passed to LoggerProvider (#4564)

Before this Resource.default() attributes would only be used if *no*
resource was given to LoggerProvider. That would mean that
'service.name' and others could be missing, e.g. when called from
NodeSDK.

Co-authored-by: Marc Pichler <[email protected]>

Author: trentm

experimental/CHANGELOG.md

@@ -26,6 +26,7 @@ All notable changes to experimental packages in this project will be documented
 
 * fix(exporter-*-otlp-*): use parseHeaders() to ensure header-values are not 'undefined' #4540
   * Fixes a bug where passing `undefined` as a header value would crash the end-user app after the export timeout elapsed.
+* fix(sdk-logs): ensure default resource attributes are used as fallbacks when a resource is passed to LoggerProvider.
 
 ### :books: (Refine Doc)
 

experimental/packages/sdk-logs/README.md

@@ -46,7 +46,7 @@ const logger = logsAPI.logs.getLogger('default');
 
 // emit a log record
 logger.emit({
-  severityNumber: SeverityNumber.INFO,
+  severityNumber: logsAPI.SeverityNumber.INFO,
   severityText: 'INFO',
   body: 'this is a log record body',
   attributes: { 'log.type': 'LogRecord' },

experimental/packages/sdk-logs/src/LoggerProvider.ts

@@ -33,15 +33,14 @@ export class LoggerProvider implements logsAPI.LoggerProvider {
   private readonly _sharedState: LoggerProviderSharedState;
 
   constructor(config: LoggerProviderConfig = {}) {
-    const {
-      resource = Resource.default(),
-      logRecordLimits,
-      forceFlushTimeoutMillis,
-    } = merge({}, loadDefaultConfig(), config);
+    const mergedConfig = merge({}, loadDefaultConfig(), config);
+    const resource = Resource.default().merge(
+      mergedConfig.resource ?? Resource.empty()
+    );
     this._sharedState = new LoggerProviderSharedState(
       resource,
-      forceFlushTimeoutMillis,
-      reconfigureLimits(logRecordLimits)
+      mergedConfig.forceFlushTimeoutMillis,
+      reconfigureLimits(mergedConfig.logRecordLimits)
     );
     this._shutdownOnce = new BindOnceFuture(this._shutdown, this);
   }

experimental/packages/sdk-logs/test/common/LoggerProvider.test.ts

@@ -63,6 +63,16 @@ describe('LoggerProvider', () => {
         assert.deepStrictEqual(resource, Resource.default());
       });
 
+      it('should fallback to default resource attrs', () => {
+        const passedInResource = new Resource({ foo: 'bar' });
+        const provider = new LoggerProvider({ resource: passedInResource });
+        const { resource } = provider['_sharedState'];
+        assert.deepStrictEqual(
+          resource,
+          Resource.default().merge(passedInResource)
+        );
+      });
+
       it('should have default forceFlushTimeoutMillis if not pass', () => {
         const provider = new LoggerProvider();
         const sharedState = provider['_sharedState'];