feat: add option to disable summary collection in routeMetrics config

README.md

@@ -140,7 +140,8 @@ See for details [docs](docs/api/fastify-metrics.imetricspluginoptions.md)
 
 | Property                                                                                    | Type                                                                                          | Default Value                           |
 | ------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------- | --------------------------------------- |
-| [enabled?](./docs/fastify-metrics.iroutemetricsconfig.enabled.md)                           | boolean                                                                                       | `true`                                  |
+| [enabled?](./docs/fastify-metrics.iroutemetricsconfig.enabled.md)                           | boolean \| { histogram: boolean, summary: boolean }                                           | `true`                                  |
+| [enableSummaries?](./docs/fastify-metrics.iroutemetricsconfig.enablesummaries.md)           | boolean                                                                                       | `true`                                  |
 | [groupStatusCodes?](./docs/fastify-metrics.iroutemetricsconfig.groupstatuscodes.md)         | boolean                                                                                       | `false`                                 |
 | [invalidRouteGroup?](./docs/fastify-metrics.iroutemetricsconfig.invalidroutegroup.md)       | string                                                                                        | `'__unknown__'`                         |
 | [methodBlacklist?](./docs/fastify-metrics.iroutemetricsconfig.methodblacklist.md)           | readonly string\[\]                                                                           | `['HEAD','OPTIONS','TRACE','CONNECT',]` |
@@ -149,6 +150,24 @@ See for details [docs](docs/api/fastify-metrics.imetricspluginoptions.md)
 | [customLabels?](./fastify-metrics.iroutemetricsconfig.customlabels.md)                      | Record<string, string \| ((request: FastifyRequest, reply: FastifyReply) => string)> | `undefined`                             |
 | [routeBlacklist?](./docs/fastify-metrics.iroutemetricsconfig.routeblacklist.md)             | readonly string\[\]                                                                           | `[]`                                    |
 
+#### Route metrics enabled
+
+The `enabled` configuration option can be either a boolean which enables/disables generation of both histograms and summaries, or it can be set to an object that allows you to pick individually whether you want histograms or summaries to be generated, for example:
+
+```
+{
+  ...
+  routeMetrics: {
+    enabled: {
+      histogram: true,
+      summary: false
+    }
+  }
+}
+```
+
+would result in the library only generating histograms.
+
 ##### Route metrics overrides
 
 You may override default metrics settings. You may provide overrides for two metrics tracking http request durations: `histogram` and `summary`.
@@ -205,7 +224,7 @@ await app.register(metricsPlugin, {
 
 ### HTTP routes metrics in Prometheus
 
-The following table shows what metrics will be available in Prometheus. Note suffixes like `_bucket`, `_sum`, `_count` are added automatically.
+The following table shows what metrics will be available in Prometheus (subject to the `enabled` configuration option). Note suffixes like `_bucket`, `_sum`, `_count` are added automatically.
 
 | metric                                 | labels                           | description                   |
 | -------------------------------------- | -------------------------------- | ----------------------------- |

src/__tests__/route-metrics.spec.ts

@@ -626,4 +626,62 @@ describe('route metrics', () => {
       );
     });
   });
+
+  describe(`{ routeMetrics: { enable: { summary: false } } }`, () => {
+    let app = fastify();
+
+    afterEach(async () => {
+      await app.close();
+    });
+
+    beforeEach(async () => {
+      app = fastify();
+
+      await app.register(fastifyPlugin, {
+        endpoint: '/metrics',
+        routeMetrics: {
+          enabled: {
+            summary: false,
+          },
+          customLabels: {
+            url: (request: FastifyRequest) => request.url,
+          },
+        },
+      });
+      app.get('*', async (_request, reply) => {
+        await reply.send('foo');
+      });
+      await app.ready();
+    });
+
+    test('summaries are not collected', async () => {
+      await expect(
+        app.inject({
+          method: 'GET',
+          url: '/test',
+        })
+      ).resolves.toBeDefined();
+
+      const metrics = await app.inject({
+        method: 'GET',
+        url: '/metrics',
+      });
+
+      expect(typeof metrics.payload).toBe('string');
+
+      const lines = metrics.payload.split('\n');
+
+      expect(lines).toEqual(
+        expect.arrayContaining([
+          'http_request_duration_seconds_count{method="GET",route="*",status_code="200",url="/test"} 1',
+        ])
+      );
+
+      expect(lines).toEqual(
+        expect.not.arrayContaining([
+          'http_request_summary_seconds_count{method="GET",route="*",status_code="200",url="/test"} 1',
+        ])
+      );
+    });
+  });
 });

src/fastify-metrics.ts

@@ -352,8 +352,22 @@
           [this.routeMetrics.labelNames.status]: statusCode,
           ...this.collectCustomLabels(request, reply),
         };
-        metrics.sum(labels);
-        metrics.hist(labels);
+
+        if (this.options.routeMetrics.enabled instanceof Object) {
+          if (!(this.options.routeMetrics.enabled.summary === false)) {
+            metrics.sum(labels);
+          }
+          if (!(this.options.routeMetrics.enabled.histogram === false)) {
+            metrics.hist(labels);
+          }
+          done();
+          return;
+        }
+
+        if (!(this.options.routeMetrics.enabled === false)) {
+          metrics.sum(labels);
+          metrics.hist(labels);
+        }
 
         done();
       });

src/types.ts

@@ -155,12 +155,24 @@ export interface IRouteMetricsOverrides {
  * @public
  */
 export interface IRouteMetricsConfig {
-  /**
-   * Enables collection of fastify routes metrics response time.
-   *
-   * @defaultValue `false`
-   */
-  enabled?: boolean;
+  enabled?:
+    | boolean
+    | {
+        /**
+         * Enables collection of fastify routes metrics response time via
+         * histogram.
+         *
+         * @defaultValue `true`
+         */
+        histogram?: boolean;
+        /**
+         * Enables collection of fastify routes metrics response time via
+         * summary.
+         *
+         * @defaultValue `true`
+         */
+        summary?: boolean;
+      };
 
   /**
    * Collect metrics only for registered routes. If `false`, then metrics for