fix(instrumentation-pg): ensure db.client.operation.duration metric is recorded for Promises API usage of pg

plugins/node/opentelemetry-instrumentation-pg/src/instrumentation.ts

@@ -406,6 +406,7 @@
               // Return a pass-along promise which ends the span and then goes to user's orig resolvers
               return new Promise(resolve => {
                 utils.handleExecutionResult(plugin.getConfig(), span, result);
+                recordDuration();
                 span.end();
                 resolve(result);
               });
@@ -416,6 +417,7 @@
                   code: SpanStatusCode.ERROR,
                   message: error.message,
                 });
+                recordDuration();
                 span.end();
                 reject(error);
               });

plugins/node/opentelemetry-instrumentation-pg/test/pg-pool.test.ts

@@ -277,6 +277,7 @@ describe('pg-pool', () => {
         await client.query('SELECT NOW()');
       } finally {
         client.release();
+        await newPool.end();
       }
       const spans = memoryExporter.getFinishedSpans();
       assert.strictEqual(spans.length, 0);
@@ -519,6 +520,11 @@ describe('pg-pool', () => {
           );
 
           const metrics = resourceMetrics.scopeMetrics[0].metrics;
+          assert.strictEqual(
+            metrics[0].descriptor.name,
+            'db.client.operation.duration'
+          );
+
           assert.strictEqual(
             metrics[1].descriptor.name,
             'db.client.connection.count'
@@ -567,5 +573,39 @@ describe('pg-pool', () => {
         });
       });
     });
+
+    it('should generate `db.client.*` metrics (Promises-style)', async (...args) => {
+      const client = await pool.connect();
+
+      try {
+        const ret = await client.query('SELECT NOW()');
+        assert.ok(ret);
+      } finally {
+        client.release();
+      }
+
+      const { resourceMetrics, errors } = await metricReader.collect();
+      assert.deepEqual(
+        errors,
+        [],
+        'expected no errors from the callback during metric collection'
+      );
+
+      // We just test the expected metric *names* here. The particulars of the
+      // metric values are already tested in other test cases.
+      const metrics = resourceMetrics.scopeMetrics[0].metrics;
+      assert.strictEqual(
+        metrics[0].descriptor.name,
+        'db.client.operation.duration'
+      );
+      assert.strictEqual(
+        metrics[1].descriptor.name,
+        'db.client.connection.count'
+      );
+      assert.strictEqual(
+        metrics[2].descriptor.name,
+        'db.client.connection.pending_requests'
+      );
+    });
   });
 });