Merge branch 'develop'

* add metric type summary

* add tests for percentile option

* throw errors for unknown metricType

* set histogram as default metrics type

README.md

@@ -9,7 +9,7 @@ Internally it uses **prom-client**. See: https://github.com/siimon/prom-client
 Included metrics:
 
 * `up`: normally is just 1
-* `http_request_duration_seconds`: http latency histogram labeled with `status_code`, `method` and `path`
+* `http_request_duration_seconds`: http latency histogram/summary labeled with `status_code`, `method` and `path`
 
 ## Install
 
@@ -62,9 +62,14 @@ Extra transformation callbacks:
 * **formatStatusCode**: `function(res)` producing final status code from express `res` object, e.g. you can combine `200`, `201` and `204` to just `2xx`.
 * **transformLabels**: `function(labels, req, res)` transforms the **labels** object, e.g. setting dynamic values to **customLabels**
 
+Metric type:
+
+* **metricType**: two metric types are supported for `http_request_duration_seconds` metric: [histogram](https://prometheus.io/docs/concepts/metric_types/#histogram) and [summary](https://prometheus.io/docs/concepts/metric_types/#summary),  default: **histogram**
+
 Other options:
 
 * **buckets**: buckets used for `http_request_duration_seconds` histogram
+* **percentiles**: percentiles used for `http_request_duration_seconds` summary
 * **autoregister**: if `/metrics` endpoint should be registered. (Default: **true**)
 * **promClient**: options for promClient startup, e.g. **collectDefaultMetrics**. This option was added
   to keep `express-prom-bundle` runnable using confit (e.g. with kraken.js) without writing any JS code,

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "express-prom-bundle",
-  "version": "4.1.0",
+  "version": "4.2.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -1910,9 +1910,9 @@
       "dev": true
     },
     "prom-client": {
-      "version": "11.1.1",
-      "resolved": "https://registry.npmjs.org/prom-client/-/prom-client-11.1.1.tgz",
-      "integrity": "sha512-itUicyrq3Rko56v3ovQAMYwxEouK7lIylp26bjnlt1b/3fzn783riZnZn432I4udYmPsRgNx1F/u9RFvLyH7zA==",
+      "version": "11.2.1",
+      "resolved": "https://registry.npmjs.org/prom-client/-/prom-client-11.2.1.tgz",
+      "integrity": "sha512-7VwtjrkQS50NvDoeYNn2z6wzXB5BMGzUlmMOeLPaITtJsTVXnPywRta7QFiV4pKr0fbRx9oDfUcx1xibabjSAg==",
       "requires": {
         "tdigest": "^0.1.1"
       }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "express-prom-bundle",
-  "version": "4.2.1",
+  "version": "4.3.0",
   "description": "express middleware with popular prometheus metrics in one bundle",
   "main": "src/index.js",
   "keywords": [
@@ -18,7 +18,7 @@
   "license": "MIT",
   "dependencies": {
     "on-finished": "^2.3.0",
-    "prom-client": "~11.1.1",
+    "prom-client": "~11.2.1",
     "url-value-parser": "^2.0.0"
   },
   "devDependencies": {

spec/index.spec.js

@@ -186,6 +186,54 @@ describe('index', () => {
       });
   });
 
+  it('metric type summary works', done => {
+    const app = express();
+    const bundled = bundle({
+      metricType: 'summary',
+      percentiles: [0.5, 0.85, 0.99],
+    });
+    app.use(bundled);
+    app.use('/test', (req, res) => res.send('it worked'));
+
+    const agent = supertest(app);
+    agent.get('/test').end(() => {
+      agent
+        .get('/metrics')
+        .end((err, res) => {
+          expect(res.status).toBe(200);
+          expect(res.text).toMatch(/quantile="0.85"/);
+          done();
+        });
+    });
+  });
+
+  it('metric type histogram works', done => {
+    const app = express();
+    const bundled = bundle({
+      metricType: 'histogram',
+      buckets: [10, 100],
+    });
+    app.use(bundled);
+    app.use('/test', (req, res) => res.send('it worked'));
+
+    const agent = supertest(app);
+    agent.get('/test').end(() => {
+      agent
+        .get('/metrics')
+        .end((err, res) => {
+          expect(res.status).toBe(200);
+          expect(res.text).toMatch(/le="100"/);
+          done();
+        });
+    });
+  });
+
+  it('throws on unknown metricType ', () => {
+    expect(() => {
+      bundle({metricType: 'hello'});
+    }).toThrow();
+  });
+
   describe('usage of normalizePath()', () => {
 
     it('normalizePath can be replaced gloablly', done => {

src/index.js

@@ -62,6 +62,7 @@ function main(opts) {
       includeStatusCode: true,
       normalizePath: main.normalizePath,
       formatStatusCode: main.normalizeStatusCode,
+      metricType: 'histogram',
       promClient: {}
     },
     opts
@@ -106,13 +107,24 @@ function main(opts) {
       if (opts.customLabels){
         labels.push.apply(labels, Object.keys(opts.customLabels));
       }
-      const metric = new promClient.Histogram({
-        name: httpMetricName,
-        help: 'duration histogram of http responses labeled with: ' + labels.join(', '),
-        labelNames: labels,
-        buckets: opts.buckets || [0.003, 0.03, 0.1, 0.3, 1.5, 10]
-      });
-      return metric;
+
+      if (opts.metricType === 'summary') {
+        return new promClient.Summary({
+          name: httpMetricName,
+          help: 'duration summary of http responses labeled with: ' + labels.join(', '),
+          labelNames: labels,
+          percentiles: opts.percentiles || [0.5, 0.75, 0.95, 0.98, 0.99, 0.999]
+        });
+       } else if (opts.metricType === 'histogram' || !opts.metricType) {
+        return new promClient.Histogram({
+          name: httpMetricName,
+          help: 'duration histogram of http responses labeled with: ' + labels.join(', '),
+          labelNames: labels,
+          buckets: opts.buckets || [0.003, 0.03, 0.1, 0.3, 1.5, 10]
+        });
+      } else {
+        throw new Error('metricType option must be histogram or summary');
+      }
     }
   };