feat(http-instrumentation): allow filtering of host name on metrics

open-telemetry · Jun 9, 2023 · 7c26be0 · 7c26be0
1 parent 228e67b
commit 7c26be0
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Showing 4 changed files with 41 additions and 9 deletions.
diff --git a/experimental/packages/opentelemetry-instrumentation-http/src/http.ts b/experimental/packages/opentelemetry-instrumentation-http/src/http.ts
@@ -512,8 +512,15 @@ export class HttpInstrumentation extends InstrumentationBase<Http> {
       };
 
       const startTime = hrTime();
-      const metricAttributes =
-        utils.getIncomingRequestMetricAttributes(spanAttributes);
+      const metricAttributes = utils.getIncomingRequestMetricAttributes(
+        spanAttributes,
+        request,
+        {
+          ignoreHostMetricAttribute:
+            instrumentation._getConfig()
+              .ignoreIncomingRequestHostMetricAttribute,
+        }
+      );
 
       const ctx = propagation.extract(ROOT_CONTEXT, headers);
       const span = instrumentation._startHttpSpan(method, spanOptions, ctx);

diff --git a/experimental/packages/opentelemetry-instrumentation-http/src/types.ts b/experimental/packages/opentelemetry-instrumentation-http/src/types.ts
@@ -60,6 +60,10 @@ export interface IgnoreIncomingRequestFunction {
   (request: IncomingMessage): boolean;
 }
 
+export interface IgnoreIncomingRequestHostFunction {
+  (request: IncomingMessage, host: string): boolean;
+}
+
 export interface IgnoreOutgoingRequestFunction {
   (request: RequestOptions): boolean;
 }
@@ -119,6 +123,8 @@ export interface HttpInstrumentationConfig extends InstrumentationConfig {
     client?: { requestHeaders?: string[]; responseHeaders?: string[] };
     server?: { requestHeaders?: string[]; responseHeaders?: string[] };
   };
+  /** Function for adding filtering for incoming requests' host name which may have unbounded cardinality */
+  ignoreIncomingRequestHostMetricAttribute?: IgnoreIncomingRequestHostFunction;
 }
 
 export interface Err extends Error {

diff --git a/experimental/packages/opentelemetry-instrumentation-http/src/utils.ts b/experimental/packages/opentelemetry-instrumentation-http/src/utils.ts
@@ -35,7 +35,12 @@ import {
 import { getRPCMetadata, RPCType } from '@opentelemetry/core';
 import * as url from 'url';
 import { AttributeNames } from './enums/AttributeNames';
-import { Err, IgnoreMatcher, ParsedRequestOptions } from './types';
+import {
+  Err,
+  IgnoreIncomingRequestHostFunction,
+  IgnoreMatcher,
+  ParsedRequestOptions,
+} from './types';
 
 /**
  * Get an absolute url
@@ -499,21 +504,35 @@ export const getIncomingRequestAttributes = (
 /**
  * Returns incoming request Metric attributes scoped to the request data
  * @param {SpanAttributes} spanAttributes the span attributes
- * @param {{ component: string }} options used to pass data needed to create attributes
+ * @param {IncomingMessage} request the request object
+ * @param {{ ignoreHostMetricAttribute?: IgnoreIncomingRequestHostFunction }} options used to pass data needed to create attributes
  */
 export const getIncomingRequestMetricAttributes = (
-  spanAttributes: SpanAttributes
+  spanAttributes: SpanAttributes,
+  request: IncomingMessage,
+  options: { ignoreHostMetricAttribute?: IgnoreIncomingRequestHostFunction }
 ): MetricAttributes => {
   const metricAttributes: MetricAttributes = {};
   metricAttributes[SemanticAttributes.HTTP_SCHEME] =
     spanAttributes[SemanticAttributes.HTTP_SCHEME];
   metricAttributes[SemanticAttributes.HTTP_METHOD] =
     spanAttributes[SemanticAttributes.HTTP_METHOD];
-  metricAttributes[SemanticAttributes.NET_HOST_NAME] =
-    spanAttributes[SemanticAttributes.NET_HOST_NAME];
   metricAttributes[SemanticAttributes.HTTP_FLAVOR] =
     spanAttributes[SemanticAttributes.HTTP_FLAVOR];
-  //TODO: http.target attribute, it should susbtitute any parameters to avoid high cardinality.
+
+  // The span attributes set this from the request URL or the Host header which does not have bounded cardinality
+  const netHostNameAttributeValue =
+    spanAttributes[SemanticAttributes.NET_HOST_NAME];
+  if (
+    typeof options.ignoreHostMetricAttribute !== 'function' ||
+    (typeof netHostNameAttributeValue === 'string' &&
+      !options.ignoreHostMetricAttribute(request, netHostNameAttributeValue))
+  ) {
+    metricAttributes[SemanticAttributes.NET_HOST_NAME] =
+      netHostNameAttributeValue;
+  }
+
+  //TODO: http.target attribute, it should substitute any parameters to avoid high cardinality.
   return metricAttributes;
 };
 

diff --git a/experimental/packages/opentelemetry-instrumentation-http/test/functionals/utils.test.ts b/experimental/packages/opentelemetry-instrumentation-http/test/functionals/utils.test.ts
@@ -311,7 +311,7 @@ describe('Utility', () => {
       );
     });
 
-    it('should succesfully process without middleware stack', () => {
+    it('should successfully process without middleware stack', () => {
       const request = {
         socket: {},
       } as IncomingMessage;