fix(jaeger-remote-sampler): Catch errors retrieving remote config (#4976)

Author: Just-Sieb

experimental/CHANGELOG.md

@@ -11,6 +11,8 @@ All notable changes to experimental packages in this project will be documented
 
 ### :bug: (Bug Fix)
 
+* fix(sampler-jaeger-remote): fixes an issue where package could emit unhandled promise rejections @Just-Sieb
+
 ### :books: (Refine Doc)
 
 ### :house: (Internal)

experimental/packages/sampler-jaeger-remote/src/JaegerRemoteSampler.ts

@@ -58,6 +58,8 @@ export class JaegerRemoteSampler implements Sampler {
       this._syncingConfig = true;
       try {
         await this.getAndUpdateSampler();
+      } catch (err) {
+        diag.warn('Could not update sampler', err);
       } finally {
         this._syncingConfig = false;
       }

experimental/packages/sampler-jaeger-remote/test/JaegerRemoteSampler.test.ts

@@ -80,13 +80,28 @@ describe('JaegerRemoteSampler', () => {
       );
       new JaegerRemoteSampler({
         endpoint,
-        serviceName,
         poolingInterval,
+        serviceName,
         initialSampler: alwaysOnSampler,
       });
       await clock.tickAsync(poolingInterval * 2);
       sinon.assert.callCount(getAndUpdateSamplerStub, 1);
     });
+
+    it('Doesnt throw unhandled promise rejection when failing to get remote config', async () => {
+      getAndUpdateSamplerStub.rejects();
+      const unhandledRejectionListener = sinon.fake();
+      process.once('unhandledRejection', unhandledRejectionListener);
+      new JaegerRemoteSampler({
+        endpoint,
+        serviceName,
+        poolingInterval,
+        initialSampler: alwaysOnSampler,
+      });
+      await clock.tickAsync(poolingInterval * 2);
+      sinon.assert.callCount(getAndUpdateSamplerStub, 2);
+      sinon.assert.callCount(unhandledRejectionListener, 0);
+    });
   });
 
   describe('shouldSample', () => {