add promClient option for smuggling collectDefaultMetrics, upgrade prom-client to ~10.2.2, version 3.3.0

* Update package.json

* Update call to Histogram

* Update package.json

* Update index.js

* Update index.js

README.md

@@ -4,7 +4,7 @@
 
 Express middleware with popular prometheus metrics in one bundle. It's also compatible with koa v1 and v2 (see below).
 
-Internally it uses **prom-client**. See: https://github.com/siimon/prom-client (^9.0.0)
+Internally it uses **prom-client**. See: https://github.com/siimon/prom-client
 
 Included metrics:
 
@@ -17,7 +17,7 @@ Included metrics:
 npm install express-prom-bundle
 ```
 
-## Sample uUsage
+## Sample Usage
 
 ```javascript
 const promBundle = require("express-prom-bundle");
@@ -47,21 +47,28 @@ Which labels to include in `http_request_duration_seconds` metric:
 * **includeStatusCode**: HTTP status code (200, 400, 404 etc.), default: **true**
 * **includeMethod**: HTTP method (GET, PUT, ...), default: **false**
 * **includePath**: URL path (see importent details below), default: **false**
+* **customLabels**: an object containing extra labels, e.g. ```{project_name: 'hello_world'}```.
+  Most useful together with **transformLabels** callback, otherwise it's better to use native Prometheus relabeling.
 
 Extra transformation callbacks:
 
 * **normalizePath**: `function(req)` generates path values from express `req` (see details below)
 * **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**
 
 Other options:
 
 * **buckets**: buckets used for `http_request_duration_seconds` histogram
 * **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,
+  see [advanced example](https://github.com/jochen-schweizer/express-prom-bundle/blob/master/advanced-example.js)
 
 Deprecated:
 
 * **whitelist**, **blacklist**: array of strings or regexp specifying which metrics to include/exclude (there are only 2 metrics)
 * **excludeRoutes**: array of strings or regexp specifying which routes should be skipped for `http_request_duration_seconds` metric. It uses `req.originalUrl` as subject when checking. You want to use express or meddleware features instead of this option.
+* **httpDurationMetricName**: name of the request duration histogram metric. (Default: `http_request_duration_seconds`)
 
 ### More details on includePath option
 
@@ -83,8 +90,8 @@ app.use(promBundle(/* options? */));
 
 // let's reuse the existing one and just add some
 // functionality on top
-const originalNormalize = promBunle.normalizePath;
-promBunle.normalizePath = (req, opts) => {
+const originalNormalize = promBundle.normalizePath;
+promBundle.normalizePath = (req, opts) => {
   const path = originalNormalize(req, opts);
   // count all docs (no matter which file) as a single path
   return path.match(/^\/docs/) ? '/docs/*' : path;
@@ -167,14 +174,32 @@ Here is meddleware config sample, which can be used in a standard **kraken.js**
 
 ## Changelog
 
+ * **3.3.0**
+    * added option **promClient** to be able to call collectDefaultMetrics
+    * upgrade **prom-client** to ~10.2.2 (switch to semver "approximately")
+
+
+ * **3.2.0**
+    * added options **customLabels**, **transformLabels**
+    * upgrade **prom-client** to 10.1.0
+
+
+ * **3.1.0**
+    * upgrade **prom-client** to 10.0.0
+
+
  * **3.0.0**
     * upgrade dependencies, most notably **prom-client** to 9.0.0
     * switch to koa v2 in koa unittest
     * only node v6 or higher is supported (stop supporting node v4 and v5)
     * switch to npm5 and use package-lock.json
     * options added: includeStatusCode, formatStatusCode
+
+
  * **2.1.0**
     * deprecate **excludeRoutes**, use **req.originalUrl** instead of **req.path**
+
+
  * **2.0.0**
     * the reason for the version lift were:
       * compliance to official naming recommendation: https://prometheus.io/docs/practices/naming/

advanced-example.js

@@ -8,13 +8,20 @@ const bundle = promBundle({
   blacklist: [/up/],
   buckets: [0.1, 0.4, 0.7],
   includeMethod: true,
-  includePath: true
+  includePath: true,
+  customLabels: {year: null},
+  transformLabels: labels => Object.assign(labels, {year: new Date().getFullYear()}),
+  promClient: {
+    collectDefaultMetrics: {
+      timeout: 1000
+    }
+  }
 });
 
 app.use(bundle);
 
 // native prom-client metric (no prefix)
-const c1 = new bundle.promClient.Counter('c1', 'c1 help');
+const c1 = new bundle.promClient.Counter({name: 'c1', help: 'c1 help'});
 c1.inc(10);
 
 app.get('/foo/:id', (req, res) => {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "express-prom-bundle",
-  "version": "3.0.0",
+  "version": "3.3.0",
   "description": "express middleware with popular prometheus metrics in one bundle",
   "main": "src/index.js",
   "keywords": [
@@ -17,7 +17,7 @@
   "license": "MIT",
   "dependencies": {
     "on-finished": "^2.3.0",
-    "prom-client": "^9.0.0",
+    "prom-client": "~10.2.2",
     "url-value-parser": "^1.0.0"
   },
   "devDependencies": {

spec/index.spec.js

@@ -34,6 +34,21 @@ describe('index', () => {
     });
   });
 
+  it('httpDurationMetricName overrides histogram metric name', done => {
+    const app = express();
+    const bundled = bundle({
+      httpDurationMetricName: 'my_http_duration'
+    });
+    app.use(bundled);
+
+    const agent = supertest(app);
+    agent.get('/metrics')
+      .end((err, res) => {
+        expect(res.text).toMatch(/my_http_duration/m);
+        done();
+      });
+  });
+
   it('metrics should be attached to /metrics by default', done => {
     const app = express();
     const bundled = bundle({
@@ -148,11 +163,12 @@ describe('index', () => {
     expect(() => bundle({prefix: 'hello'})).toThrow();
   });
 
-  it('tolerates includePath, includeMethod', done => {
+  it('tolerates includePath, includeMethod, includeCustomLabels', done => {
     const app = express();
     const instance = bundle({
       includePath: true,
-      includeMethod: true
+      includeMethod: true,
+      includeCustomLabels: {foo: 'bar'}
     });
     app.use(instance);
     app.use('/test', (req, res) => res.send('it worked'));
@@ -257,6 +273,54 @@ describe('index', () => {
       });
   });
 
+  it('customLabels={foo: "bar"} adds foo="bar" label to metrics', done => {
+    const app = express();
+    const instance = bundle({
+      customLabels: {foo: 'bar'}
+    });
+    app.use(instance);
+    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(/foo="bar"/);
+            done();
+          });
+      });
+  });
+
+  it('tarnsformLabels can set label values', done => {
+    const app = express();
+    const instance = bundle({
+      includePath: true,
+      customLabels: {foo: 'bar'},
+      transformLabels: labels => {
+        labels.foo = 'baz';
+        labels.path += '/ok';
+      }
+    });
+    app.use(instance);
+    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(/foo="baz"/);
+            expect(res.text).toMatch(/path="\/test\/ok"/);
+            done();
+          });
+      });
+  });
+
   it('Koa: metrics returns up=1', done => {
     const app = new Koa();
     const bundled = bundle({
@@ -279,4 +343,16 @@ describe('index', () => {
         });
     });
   });
+
+  it('calls promClient.collectDefaultMetrics', () => {
+    const spy = spyOn(promClient, 'collectDefaultMetrics');
+    bundle({
+      promClient: {
+        collectDefaultMetrics: {
+          timeout: 3000
+        }
+      }
+    });
+    expect(spy).toHaveBeenCalledWith({timeout: 3000});
+  });
 });

src/index.js

@@ -44,7 +44,8 @@ function main(opts) {
       autoregister: true,
       includeStatusCode: true,
       normalizePath: main.normalizePath,
-      formatStatusCode: main.normalizeStatusCode
+      formatStatusCode: main.normalizeStatusCode,
+      promClient: {}
     },
     opts
   );
@@ -66,14 +67,18 @@ function main(opts) {
     );
   }
 
-  const httpMtricName = opts.httpDurationMetricName || 'http_request_duration_seconds';
+  if (opts.promClient.collectDefaultMetrics) {
+    promClient.collectDefaultMetrics(opts.promClient.collectDefaultMetrics);
+  }
+
+  const httpMetricName = opts.httpDurationMetricName || 'http_request_duration_seconds';
 
   const metricTemplates = {
-    'up': () => new promClient.Gauge(
-      'up',
-      '1 = up, 0 = not up'
-    ),
-    'http_request_duration_seconds': () => {
+    'up': () => new promClient.Gauge({
+      name: 'up',
+      help: '1 = up, 0 = not up'
+    }),
+    [httpMetricName]: () => {
       const labels = ['status_code'];
       if (opts.includeMethod) {
         labels.push('method');
@@ -81,14 +86,15 @@ function main(opts) {
       if (opts.includePath) {
         labels.push('path');
       }
-      const metric = new promClient.Histogram(
-        httpMtricName,
-        'duration histogram of http responses labeled with: ' + labels.join(', '),
-        labels,
-        {
-          buckets: opts.buckets || [0.003, 0.03, 0.1, 0.3, 1.5, 10]
-        }
-      );
+      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;
     }
   };
@@ -121,9 +127,9 @@ function main(opts) {
       return next();
     }
 
-    if (metrics[httpMtricName]) {
+    if (metrics[httpMetricName]) {
       labels = {};
-      let timer = metrics[httpMtricName].startTimer(labels);
+      let timer = metrics[httpMetricName].startTimer(labels);
       onFinished(res, () => {
         if (opts.includeStatusCode) {
           labels.status_code = opts.formatStatusCode(res, opts);
@@ -134,6 +140,12 @@ function main(opts) {
         if (opts.includePath) {
           labels.path = opts.normalizePath(req, opts);
         }
+        if (opts.customLabels) {
+          Object.assign(labels, opts.customLabels);
+        }
+        if (opts.transformLabels) {
+          opts.transformLabels(labels, req, res);
+        }
         timer();
       });
     }