feat(instrumentation-pg): add error type to db duration metric (open-telemetry#2476)

Co-authored-by: Marc Pichler <marc.pichler@dynatrace.com>

Author: maryliag

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

@@ -326,6 +326,7 @@ export class PgInstrumentation extends InstrumentationBase<PgInstrumentationConf
               instrumentationConfig,
               span,
               args[args.length - 1] as PostgresCallback, // nb: not type safe.
+              attributes,
               recordDuration
             );
 
@@ -342,6 +343,7 @@ export class PgInstrumentation extends InstrumentationBase<PgInstrumentationConf
               plugin.getConfig(),
               span,
               queryConfig.callback as PostgresCallback, // nb: not type safe.
+              attributes,
               recordDuration
             );
 

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

@@ -23,9 +23,11 @@ import {
   SpanKind,
   diag,
   UpDownCounter,
+  Attributes,
 } from '@opentelemetry/api';
 import { AttributeNames } from './enums/AttributeNames';
 import {
+  ATTR_ERROR_TYPE,
   SEMATTRS_DB_SYSTEM,
   SEMATTRS_DB_NAME,
   SEMATTRS_DB_CONNECTION_STRING,
@@ -244,6 +246,7 @@ export function patchCallback(
   instrumentationConfig: PgInstrumentationConfig,
   span: Span,
   cb: PostgresCallback,
+  attributes: Attributes,
   recordDuration: { (): void }
 ): PostgresCallback {
   return function patchedCallback(
@@ -252,6 +255,10 @@ export function patchCallback(
     res: object
   ) {
     if (err) {
+      if (Object.prototype.hasOwnProperty.call(err, 'code')) {
+        attributes[ATTR_ERROR_TYPE] = (err as any)['code'];
+      }
+
       span.setStatus({
         code: SpanStatusCode.ERROR,
         message: err.message,

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

@@ -1021,5 +1021,52 @@ describe('pg', () => {
         done();
       });
     });
+
+    it('should generate db.client.operation.duration metric with error attribute', done => {
+      client.query('SELECT foo from bar', async (err, ret) => {
+        assert.notEqual(err, null);
+        const { resourceMetrics, errors } = await metricReader.collect();
+        assert.deepEqual(
+          errors,
+          [],
+          'expected no errors from the callback during metric collection'
+        );
+
+        const metrics = resourceMetrics.scopeMetrics[0].metrics;
+        assert.strictEqual(
+          metrics[0].descriptor.name,
+          METRIC_DB_CLIENT_OPERATION_DURATION
+        );
+        assert.strictEqual(
+          metrics[0].descriptor.description,
+          'Duration of database client operations.'
+        );
+        const dataPoint = metrics[0].dataPoints[0];
+        assert.strictEqual(
+          dataPoint.attributes[SEMATTRS_DB_SYSTEM],
+          DBSYSTEMVALUES_POSTGRESQL
+        );
+        assert.strictEqual(
+          dataPoint.attributes[ATTR_DB_OPERATION_NAME],
+          'SELECT'
+        );
+        assert.strictEqual(dataPoint.attributes[ATTR_ERROR_TYPE], '42P01');
+
+        const v = (dataPoint as DataPoint<Histogram>).value;
+        v.min = v.min ? v.min : 0;
+        v.max = v.max ? v.max : 0;
+        assert.equal(
+          v.min > 0,
+          true,
+          'expect min value for Histogram to be greater than 0'
+        );
+        assert.equal(
+          v.max > 0,
+          true,
+          'expect max value for Histogram to be greater than 0'
+        );
+        done();
+      });
+    });
   });
 });