feat: add applyCustomAttributesOnMetric

experimental/packages/opentelemetry-instrumentation-http/README.md

@@ -55,6 +55,7 @@ Http instrumentation has few options available to choose from. You can set the f
 | Options | Type | Description |
 | ------- | ---- | ----------- |
 | [`applyCustomAttributesOnSpan`](https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-http/src/types.ts#L91) | `HttpCustomAttributeFunction` | Function for adding custom attributes |
+| [`applyCustomAttributesOnMetric`](https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-http/src/types.ts#L118) | `HttpCustomMetricAttributeFunction` | Function for adding custom attributes before metric is recorded |
 | [`requestHook`](https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-http/src/types.ts#93) | `HttpRequestCustomAttributeFunction` | Function for adding custom attributes before request is handled |
 | [`responseHook`](https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-http/src/types.ts#L95) | `HttpResponseCustomAttributeFunction` | Function for adding custom attributes before response is handled |
 | [`startIncomingSpanHook`](https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-http/src/types.ts#L97) | `StartIncomingSpanCustomAttributeFunction` | Function for adding custom attributes before a span is started in incomingRequest |

experimental/packages/opentelemetry-instrumentation-http/src/http.ts

@@ -807,6 +807,19 @@ export class HttpInstrumentation extends InstrumentationBase<HttpInstrumentation
 
     // Record metrics
     const duration = hrTimeToMilliseconds(hrTimeDuration(startTime, hrTime()));
+    if (this.getConfig().applyCustomAttributesOnMetric) {
+      safeExecuteInTheMiddle(
+        () =>
+          this.getConfig().applyCustomAttributesOnMetric!(
+            span,
+            spanKind,
+            metricAttributes
+          ),
+        () => {},
+        true
+      );
+    }
+
     if (spanKind === SpanKind.SERVER) {
       this._httpServerDurationHistogram.record(duration, metricAttributes);
     } else if (spanKind === SpanKind.CLIENT) {

experimental/packages/opentelemetry-instrumentation-http/src/types.ts

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { Span, SpanAttributes } from '@opentelemetry/api';
+import { MetricAttributes, Span, SpanAttributes, SpanKind } from '@opentelemetry/api';
 import type * as http from 'http';
 import type * as https from 'https';
 import {
@@ -80,6 +80,10 @@ export interface StartOutgoingSpanCustomAttributeFunction {
   (request: RequestOptions): SpanAttributes;
 }
 
+export interface HttpCustomMetricAttributeFunction {
+  (span: Span, spanKind: SpanKind, metricAttributes: MetricAttributes): void;
+}
+
 /**
  * Options available for the HTTP instrumentation (see [documentation](https://github.com/open-telemetry/opentelemetry-js/tree/main/packages/opentelemetry-instrumentation-http#http-instrumentation-options))
  */
@@ -104,6 +108,8 @@ export interface HttpInstrumentationConfig extends InstrumentationConfig {
   disableOutgoingRequestInstrumentation?: boolean;
   /** Function for adding custom attributes after response is handled */
   applyCustomAttributesOnSpan?: HttpCustomAttributeFunction;
+  /** Function for adding custom attributes before metric is recorded */
+  applyCustomAttributesOnMetric?: HttpCustomMetricAttributeFunction;
   /** Function for adding custom attributes before request is handled */
   requestHook?: HttpRequestCustomAttributeFunction;
   /** Function for adding custom attributes before response is handled */

experimental/packages/opentelemetry-instrumentation-http/test/functionals/http-enable.test.ts

@@ -23,6 +23,7 @@ import {
   trace,
   SpanAttributes,
   DiagConsoleLogger,
+  MetricAttributes,
 } from '@opentelemetry/api';
 import { NodeTracerProvider } from '@opentelemetry/sdk-trace-node';
 import {
@@ -96,6 +97,10 @@ export const customAttributeFunction = (span: ISpan): void => {
   span.setAttribute('span kind', SpanKind.CLIENT);
 };
 
+export const customMetricAttributeFunction = (span: ISpan, spanKind: SpanKind, attr: MetricAttributes): void => {
+  attr['custom metric attribute function'] = 'test';
+};
+
 export const requestHookFunction = (
   span: ISpan,
   request: ClientRequest | IncomingMessage
@@ -177,6 +182,9 @@ describe('HttpInstrumentation', () => {
           applyCustomAttributesOnSpan: () => {
             throw new Error(applyCustomAttributesOnSpanErrorMessage);
           },
+          applyCustomAttributesOnMetric: () => {
+            throw new Error('bad applyCustomAttributesOnMetric function');
+          },
         };
         instrumentation.setConfig(config);
         instrumentation.enable();
@@ -308,6 +316,7 @@ describe('HttpInstrumentation', () => {
             return false;
           },
           applyCustomAttributesOnSpan: customAttributeFunction,
+          applyCustomAttributesOnMetric: customMetricAttributeFunction,
           requestHook: requestHookFunction,
           responseHook: responseHookFunction,
           startIncomingSpanHook: startIncomingSpanHookFunction,

experimental/packages/opentelemetry-instrumentation-http/test/functionals/https-enable.test.ts

@@ -21,6 +21,7 @@ import {
   Span as ISpan,
   SpanKind,
   trace,
+  MetricAttributes,
 } from '@opentelemetry/api';
 import { AsyncHooksContextManager } from '@opentelemetry/context-async-hooks';
 import { ContextManager } from '@opentelemetry/api';
@@ -88,6 +89,10 @@ export const customAttributeFunction = (span: ISpan): void => {
   span.setAttribute('span kind', SpanKind.CLIENT);
 };
 
+export const customMetricAttributeFunction = (span: ISpan, spanKind: SpanKind, attr: MetricAttributes): void => {
+  attr['custom metric attribute function'] = 'test';
+};
+
 describe('HttpsInstrumentation', () => {
   let contextManager: ContextManager;
 
@@ -130,6 +135,9 @@ describe('HttpsInstrumentation', () => {
           applyCustomAttributesOnSpan: () => {
             throw new Error(applyCustomAttributesOnSpanErrorMessage);
           },
+          applyCustomAttributesOnMetric: () => {
+            throw new Error('bad applyCustomAttributesOnMetric function');
+          },
         });
         instrumentation.enable();
         server = https.createServer(
@@ -217,6 +225,7 @@ describe('HttpsInstrumentation', () => {
             return false;
           },
           applyCustomAttributesOnSpan: customAttributeFunction,
+          applyCustomAttributesOnMetric: customMetricAttributeFunction,
           serverName,
         });
         instrumentation.enable();