bump 6.3.2

update types to correct transformLabels

.eslintrc

@@ -17,6 +17,7 @@
   "extends": "eslint:recommended",
 
   "rules": {
+    "indent": [1, 2],
     "array-bracket-spacing": [2, "never"],
     "block-scoped-var": 2,
     "brace-style": [2, "1tbs"],

.gitignore

@@ -1,3 +1,5 @@
 .npmrc
 node_modules
 coverage
+/.vscode
+

.npmignore

@@ -1,6 +0,0 @@
-advanced-example.js
-docker-compose.yml
-spec
-.travis.yml
-.eslintrc
-coverage

.travis.yml

@@ -1,4 +1,13 @@
 language: node_js
 node_js:
-    - "6"
-    - "7"
+    - "10"
+    - "12"
+    - "14"
+notifications:
+    email: false
+before_install:
+    - npm install prom-client
+script:
+    - npm run lint
+    - npm test
+    - npm run dtslint-next

Makefile

@@ -4,6 +4,7 @@ test:
 	./node_modules/jasme/run.js
 lint:
 	node_modules/eslint/bin/eslint.js src
+	node_modules/.bin/dtslint types
 coverage:
 	node_modules/istanbul/lib/cli.js cover \
 		-i 'src/*' \

README.md

@@ -4,17 +4,17 @@
 
 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
+Since version 5 it uses **prom-client** as a peer dependency. 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
 
 ```
-npm install express-prom-bundle
+npm install prom-client express-prom-bundle
 ```
 
 ## Sample Usage
@@ -46,29 +46,47 @@ 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**
+* **includePath**: URL path (see important 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.
+* **includeUp**: include an auxiliary "up"-metric which always returns 1, default: **true**
+* **metricsPath**: replace the `/metrics` route with a **regex** or exact **string**. Note: it is highly recommended to just stick to the default
+* **metricType**: histogram/summary selection. See more details below
+* **bypass**: function taking express request as an argument and determines whether the given request should be excluded in the metrics, default: **() => false**
 
-Extra transformation callbacks:
+### metricType option ###
 
-* **normalizePath**: `function(req)` generates path values from express `req` (see details below)
+Two metric types are supported for `http_request_duration_seconds` metric:
+* [histogram](https://prometheus.io/docs/concepts/metric_types/#histogram) (default)
+* [summary](https://prometheus.io/docs/concepts/metric_types/#summary)
+
+Additional options for **histogram**:
+* **buckets**: buckets used for the `http_request_duration_seconds` histogram
+
+Additional options for **summary**:
+* **percentiles**: percentiles used for `http_request_duration_seconds` summary
+* **ageBuckets**: ageBuckets configures how many buckets we have in our sliding window for the summary
+* **maxAgeSeconds**: the maxAgeSeconds will tell how old a bucket can be before it is reset
+
+### Transformation callbacks ###
+
+* **normalizePath**: `function(req)`  or `Array`
+  * if function is provided, then it should generate path value from express `req`
+  * if array is provided, then it should be an array of tuples `[regex, replacement]`. The `regex` can be a string and is automatically converted into JS regex.
+  * ... see more details in the section below
+* **urlValueParser**: options passed when instantiating [url-value-parser](https://github.com/disjunction/url-value-parser).
+  This is the easiest way to customize which parts of the URL should be replaced with "#val".
+  See the [docs](https://github.com/disjunction/url-value-parser) of url-value-parser module for details.
 * **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:
+### 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`)
+* **promRegistry**: Optional `promClient.Registry` instance to attach metrics to. Defaults to global `promClient.register`.
 
 ### More details on includePath option
 
@@ -80,10 +98,33 @@ like `/user/12352/profile`. So what we actually need is a path template.
 The module tries to figure out what parts of the path are values or IDs,
 and what is an actual path. The example mentioned before would be
 normalized to `/user/#val/profile` and that will become the value for the label.
+These conversions are handled by `normalizePath` function.
 
-You can override this magical behavior and define your own function by
-providing an optional callback using **normalizePath** option.
-You can also replace the default **normalizePath** function globally.
+You can extend this magical behavior by providing
+additional RegExp rules to be performed,
+or override `normalizePath` with your own function.
+
+#### Example 1 (add custom RegExp):
+
+```javascript
+app.use(promBundle({
+  normalizePath: [
+    // collect paths like "/customer/johnbobson" as just one "/custom/#name"
+    ['^/customer/.*', '/customer/#name'],
+
+    // collect paths like "/bobjohnson/order-list" as just one "/#name/order-list"
+    ['^.*/order-list', '/#name/order-list']
+  ],
+  urlValueParser: {
+    minHexLength: 5,
+    extraMasks: [
+      'ORD[0-9]{5,}' // replace strings like ORD1243423, ORD673562 as #val
+    ]
+  }
+}));
+```
+
+#### Example 2 (override normalizePath function):
 
 ```javascript
 app.use(promBundle(/* options? */));
@@ -93,8 +134,8 @@ app.use(promBundle(/* options? */));
 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;
+  // count all docs as one path, but /docs/login as a separate one
+  return (path.match(/^\/docs/) && !path.match(/^\/login/)) ? '/docs/*' : path;
 };
 ```
 
@@ -103,7 +144,6 @@ For more details:
  * [normalizePath.js](https://github.com/jochen-schweizer/express-prom-bundle/blob/master/src/normalizePath.js) - source code for path processing
 
 
-
 ## express example
 
 setup std. metrics but exclude `up`-metric:
@@ -148,9 +188,47 @@ app.use(/* your middleware */);
 app.listen(3000);
 ```
 
+## using with cluster
+
+You'll need to use an additional **clusterMetrics()** middleware.
+
+In the example below the master process will expose an API with a single endpoint `/metrics`
+which returns an aggregate of all metrics from all the workers.
+
+``` javascript
+const cluster = require('cluster');
+const promBundle = require('./src/index');
+const numCPUs = Math.max(2, require('os').cpus().length);
+const express = require('express');
+
+if (cluster.isMaster) {
+    for (let i = 1; i < numCPUs; i++) {
+        cluster.fork();
+    }
+
+    const metricsApp = express();
+    metricsApp.use('/metrics', promBundle.clusterMetrics());
+    metricsApp.listen(9999);
+
+    console.log('cluster metrics listening on 9999');
+    console.log('call localhost:9999/metrics for aggregated metrics');
+} else {
+    const app = express();
+    app.use(promBundle({
+        autoregister: false, // disable /metrics for single workers
+        includeMethod: true
+    }));
+    app.use((req, res) => res.send(`hello from pid ${process.pid}\n`));
+    app.listen(3000);
+    console.log(`worker ${process.pid} listening on 3000`);
+}
+```
+
 ## using with kraken.js
 
-Here is meddleware config sample, which can be used in a standard **kraken.js** application:
+Here is meddleware config sample, which can be used in a standard **kraken.js** application.
+In this case the stats for URI paths and HTTP methods are collected separately,
+while replacing all HEX values starting from 5 characters and all IP addresses in the path as #val.
 
 ```json
 {
@@ -163,7 +241,18 @@ Here is meddleware config sample, which can be used in a standard **kraken.js**
         "arguments": [
           {
             "includeMethod": true,
-            "buckets": [0.1, 1, 5]
+            "includePath": true,
+            "buckets": [0.1, 1, 5],
+            "promClient": {
+              "collectDefaultMetrics": {
+              }
+            },
+            "urlValueParser": {
+              "minHexLength": 5,
+              "extraMasks": [
+                "^[0-9]+\\.[0-9]+\\.[0-9]+\\.[0-9]+$"
+              ]
+            }
           }
         ]
       }
@@ -172,50 +261,6 @@ 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/
-      * stopping promotion of an anti-pattern - see https://groups.google.com/d/msg/prometheus-developers/XjlOnDCK9qc/ovKzV3AIBwAJ
-      * dealing with **prom-client** being a singleton with a built-in registry
-    * main histogram metric renamed from `http_request_seconds` to `http_request_duration_seconds`
-    * options removed: **prefix**, **keepDefaultMetrics**
-    * factory removed (as the only reason of it was adding the prefix)
-    * upgrade prom-client to 6.3.0
-    * code style changed to the one closer to express
-
-
- * **1.2.1**
-    * upgrade prom-client to 6.1.2
-    * add options: includeMethod, includePath, keepDefaultMetrics
-
 ## License
 
 MIT

advanced-example.js

@@ -2,26 +2,35 @@
 
 const express = require('express');
 const app = express();
+const promClient = require('prom-client');
 const promBundle = require('express-prom-bundle');
 
 const bundle = promBundle({
-  blacklist: [/up/],
   buckets: [0.1, 0.4, 0.7],
   includeMethod: true,
   includePath: true,
   customLabels: {year: null},
   transformLabels: labels => Object.assign(labels, {year: new Date().getFullYear()}),
+  metricsPath: '/prometheus',
   promClient: {
     collectDefaultMetrics: {
-      timeout: 1000
     }
-  }
+  },
+  urlValueParser: {
+    minHexLength: 5,
+    extraMasks: [
+      "^[0-9]+\\.[0-9]+\\.[0-9]+$" // replace dot-separated dates with #val
+    ]
+  },
+  normalizePath: [
+    ['^/foo', '/example'] // replace /foo with /example
+  ]
 });
 
 app.use(bundle);
 
 // native prom-client metric (no prefix)
-const c1 = new bundle.promClient.Counter({name: 'c1', help: 'c1 help'});
+const c1 = new promClient.Counter({name: 'c1', help: 'c1 help'});
 c1.inc(10);
 
 app.get('/foo/:id', (req, res) => {
@@ -37,10 +46,13 @@ app.delete('/foo/:id', (req, res) => {
 app.get('/bar', (req, res) => res.send('bar response\n'));
 
 app.listen(3000, () => console.info(  // eslint-disable-line
-  'listening on 3000\n'
-  + 'test in shell console\n\n'
-  + 'curl localhost:3000/foo/1234\n'
-  + 'curl -X DELETE localhost:3000/foo/5432\n'
-  + 'curl localhost:3000/bar\n'
-  + 'curl localhost:3000/metrics\n'
+  `listening on 3000
+test in shell console:
+
+curl localhost:3000/foo/1234
+curl localhost:3000/foo/09.08.2018
+curl -X DELETE localhost:3000/foo/5432
+curl localhost:3000/bar
+curl localhost:3000/prometheus
+`
 ));

package.json

@@ -1,6 +1,6 @@
 {
   "name": "express-prom-bundle",
-  "version": "3.3.0",
+  "version": "6.3.2",
   "description": "express middleware with popular prometheus metrics in one bundle",
   "main": "src/index.js",
   "keywords": [
@@ -10,32 +10,47 @@
     "path",
     "method"
   ],
+  "files": [
+    "src",
+    "types/index.d.ts"
+  ],
+  "types": "types",
   "scripts": {
-    "test": "node_modules/jasme/run.js"
+    "test": "node_modules/jasme/run.js",
+    "lint": "eslint src",
+    "coverage": "make coverage",
+    "dtslint": "dtslint types",
+    "dtslint-next": "dtslint --onlyTestTsNext types"
   },
   "author": "Konstantin Pogorelov <or@pluseq.com>",
   "license": "MIT",
   "dependencies": {
     "on-finished": "^2.3.0",
-    "prom-client": "~10.2.2",
-    "url-value-parser": "^1.0.0"
+    "url-value-parser": "^2.0.0"
   },
   "devDependencies": {
-    "coveralls": "^2.13.1",
-    "eslint": "^3.19.0",
-    "express": "^4.15.3",
+    "@types/express": "^4.16.1",
+    "coveralls": "^3.0.2",
+    "dtslint": "^0.7.1",
+    "eslint": "^5.11.0",
+    "express": "^4.16.4",
     "istanbul": "^0.4.5",
-    "jasme": "^5.2.0",
-    "koa": "^2.2.0",
-    "koa-connect": "^2.0.0",
-    "supertest": "^3.0.0",
-    "supertest-koa-agent": "^0.3.0"
+    "jasme": "^6.0.0",
+    "koa": "^2.6.2",
+    "koa-connect": "^2.0.1",
+    "prom-client": "^13.0.0",
+    "supertest": "^3.3.0",
+    "supertest-koa-agent": "^0.3.0",
+    "typescript": "^3.4.5"
+  },
+  "peerDependencies": {
+    "prom-client": ">=12.0.0"
   },
   "repository": {
     "type": "git",
     "url": "https://github.com/jochen-schweizer/express-prom-bundle.git"
   },
   "engines": {
-    "node": ">=6.0.0"
+    "node": ">=10"
   }
 }

spec/index.spec.js

@@ -8,6 +8,7 @@ const Koa = require('koa');
 const c2k = require('koa-connect');
 const supertestKoa = require('supertest-koa-agent');
 const promClient = require('prom-client');
+const cluster = require('cluster');
 
 describe('index', () => {
   beforeEach(() => {
@@ -17,7 +18,7 @@ describe('index', () => {
   it('metrics returns up=1', done => {
     const app = express();
     const bundled = bundle({
-      whitelist: ['up']
+      excludeRoutes: ['/irrelevant', /at.all/]
     });
     app.use(bundled);
     app.use('/test', (req, res) => res.send('it worked'));
@@ -34,6 +35,64 @@ describe('index', () => {
     });
   });
 
+  it('"up"-metric can be excluded', done => {
+    const app = express();
+    const bundled = bundle({
+      includeUp: false
+    });
+    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).not.toMatch(/up\s1/);
+          done();
+        });
+    });
+  });
+
+  it('metrics path can be defined with a regex', done => {
+    const app = express();
+    const bundled = bundle({
+      metricsPath: /^\/prometheus$/
+    });
+    app.use(bundled);
+    app.use('/test', (req, res) => res.send('it worked'));
+
+    const agent = supertest(app);
+    agent.get('/test').end(() => {
+      agent
+        .get('/prometheus')
+        .end((err, res) => {
+          expect(res.status).toBe(200);
+          expect(res.text).toMatch(/up\s1/);
+          done();
+        });
+    });
+  });
+
+  it('metrics path can be defined as regexp', done => {
+    const app = express();
+    const bundled = bundle();
+    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(/up\s1/);
+          done();
+        });
+    });
+  });
+
   it('httpDurationMetricName overrides histogram metric name', done => {
     const app = express();
     const bundled = bundle({
@@ -51,9 +110,7 @@ describe('index', () => {
 
   it('metrics should be attached to /metrics by default', done => {
     const app = express();
-    const bundled = bundle({
-      whitelist: ['up']
-    });
+    const bundled = bundle();
     app.use(bundled);
 
     const agent = supertest(app);
@@ -82,27 +139,6 @@ describe('index', () => {
       });
   });
 
-  it('metrics can be filtered using exect match', () => {
-    const instance = bundle({blacklist: ['up']});
-    expect(instance.metrics.up).not.toBeDefined();
-    expect(instance.metrics.http_request_duration_seconds).toBeDefined();
-  });
-  it('metrics can be filtered using regex', () => {
-    const instance = bundle({blacklist: [/http/]});
-    expect(instance.metrics.up).toBeDefined();
-    expect(instance.metrics.http_request_duration_seconds).not.toBeDefined();
-  });
-  it('metrics can be whitelisted', () => {
-    const instance = bundle({whitelist: [/^up$/]});
-    expect(instance.metrics.up).toBeDefined();
-    expect(instance.metrics.nodejs_memory_heap_total_bytes).not.toBeDefined();
-    expect(instance.metrics.http_request_duration_seconds).not.toBeDefined();
-  });
-  it('throws on both white and blacklist', () => {
-    expect(() => {
-      bundle({whitelist: [/up/], blacklist: [/up/]});
-    }).toThrow();
-  });
   it('returns error 500 on incorrect middleware usage', done => {
     const app = express();
     app.use(bundle);
@@ -139,22 +175,67 @@ describe('index', () => {
   it('filters out the excludeRoutes', done => {
     const app = express();
     const instance = bundle({
-      excludeRoutes: ['/test']
+      excludeRoutes: ['/test', /bad.word/]
     });
     app.use(instance);
     app.use('/test', (req, res) => res.send('it worked'));
+    app.use('/some/bad-word', (req, res) => res.send('it worked too'));
     const agent = supertest(app);
     agent
       .get('/test')
       .end(() => {
-        const metricHashMap = instance.metrics.http_request_duration_seconds.hashMap;
-        expect(metricHashMap['status_code:200']).not.toBeDefined();
-
         agent
-          .get('/metrics')
-          .end((err, res) => {
-            expect(res.status).toBe(200);
-            done();
+          .get('/some/bad-word')
+          .end(() => {
+            const metricHashMap = instance.metrics.http_request_duration_seconds.hashMap;
+            expect(metricHashMap['status_code:200']).not.toBeDefined();
+
+            agent
+              .get('/metrics')
+              .end((err, res) => {
+                expect(res.status).toBe(200);
+                done();
+              });
+          });
+      });
+  });
+
+  it('bypass requests', done => {
+    const app = express();
+    const instance = bundle({
+      bypass: (req)=> {
+        // metrics added here to attempt skipping /metrics
+        // this should fail though, because serving /metrics preceeds bypassing
+        return !!req.url.match(/test|bad.word|metrics/)
+      }
+    });
+    app.use(instance);
+    app.use('/test', (req, res) => res.send('it worked'));
+    app.use('/some/bad-word', (req, res) => res.send('it worked too'));
+    app.use('/good-word', (req, res) => res.send('this will be counted'));
+    const agent = supertest(app);
+    agent
+      .get('/test')
+      .end(() => {
+        agent
+          .get('/some/bad-word')
+          .end(() => {
+            agent
+              .get('/good-word')
+              .end(() => {
+                const metricHashMap = instance.metrics.http_request_duration_seconds.hashMap;
+                expect(metricHashMap['status_code:200']).toBeDefined();
+
+                // only /good-word should be counted
+                expect(metricHashMap['status_code:200'].count).toBe(1);
+
+                agent
+                  .get('/metrics')
+                  .end((err, res) => {
+                    expect(res.status).toBe(200);
+                    done();
+                  });
+              });
           });
       });
   });
@@ -185,50 +266,105 @@ describe('index', () => {
       });
   });
 
-  it('normalizePath can be replaced gloablly', done => {
+  it('metric type histogram works', done => {
     const app = express();
-    const original = bundle.normalizePath;
-    bundle.normalizePath = () => 'dummy';
-    const instance = bundle({
-      includePath: true,
+    const bundled = bundle({
+      metricType: 'histogram',
+      buckets: [10, 100],
     });
-    app.use(instance);
+    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(/"dummy"/m);
-            bundle.normalizePath = original;
-            done();
-          });
-      });
+    agent.get('/test').end(() => {
+      agent
+        .get('/metrics')
+        .end((err, res) => {
+          expect(res.status).toBe(200);
+          expect(res.text).toMatch(/le="100"/);
+          done();
+        });
+    });
   });
 
-  it('normalizePath can be overridden', done => {
-    const app = express();
-    const instance = bundle({
-      includePath: true,
-      normalizePath: req => req.originalUrl + '-suffixed'
-    });
-    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(/"\/test-suffixed"/m);
-            done();
-          });
+  it('throws on unknown metricType ', () => {
+    expect(() => {
+      bundle({metricType: 'hello'});
+    }).toThrow();
+  });
+
+  describe('usage of normalizePath()', () => {
+
+    it('normalizePath can be replaced gloablly', done => {
+      const app = express();
+      const original = bundle.normalizePath;
+      bundle.normalizePath = () => 'dummy';
+      const instance = bundle({
+        includePath: true,
       });
+      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(/"dummy"/m);
+              bundle.normalizePath = original;
+              done();
+            });
+        });
+    });
+
+    it('normalizePath function can be overridden', done => {
+      const app = express();
+      const instance = bundle({
+        includePath: true,
+        normalizePath: req => req.originalUrl + '-suffixed'
+      });
+      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(/"\/test-suffixed"/m);
+              done();
+            });
+        });
+    });
+
+    it('normalizePath can be passed as an array of [regex, replacement]', done => {
+      const app = express();
+      const instance = bundle({
+        includePath: true,
+        normalizePath: [
+          ['^/docs/whatever/.*$', '/docs'],
+          [/^\/docs$/, '/mocks']
+        ]
+      });
+      app.use(instance);
+      app.use('/docs/whatever/:andmore', (req, res) => res.send('it worked'));
+      const agent = supertest(app);
+      agent
+        .get('/docs/whatever/unimportant')
+        .end(() => {
+          agent
+            .get('/metrics')
+            .end((err, res) => {
+              expect(res.status).toBe(200);
+              expect(res.text).toMatch(/"\/mocks"/m);
+              done();
+            });
+        });
+    });
   });
 
   it('formatStatusCode can be overridden', done => {
@@ -267,7 +403,7 @@ describe('index', () => {
           .get('/metrics')
           .end((err, res) => {
             expect(res.status).toBe(200);
-            expect(res.text).not.toMatch(/200/);
+            expect(res.text).not.toMatch(/="200"/);
             done();
           });
       });
@@ -323,9 +459,7 @@ describe('index', () => {
 
   it('Koa: metrics returns up=1', done => {
     const app = new Koa();
-    const bundled = bundle({
-      whitelist: ['up']
-    });
+    const bundled = bundle();
     app.use(c2k(bundled));
 
     app.use(function(ctx, next) {
@@ -349,10 +483,91 @@ describe('index', () => {
     bundle({
       promClient: {
         collectDefaultMetrics: {
-          timeout: 3000
         }
       }
     });
-    expect(spy).toHaveBeenCalledWith({timeout: 3000});
+    expect(spy).toHaveBeenCalledWith({});
+  });
+
+  describe('usage of clusterMetrics()', () => {
+    it('clusterMetrics returns 200 even without a cluster', (done) => {
+        const app = express();
+
+        cluster.workers = [];
+
+        app.use('/cluster_metrics', bundle.clusterMetrics());
+        const agent = supertest(app);
+        agent
+          .get('/cluster_metrics')
+          .end((err, res) => {
+            expect(res.status).toBe(200);
+            done();
+          });
+    });
+
+    it('clusterMetrics returns 500 in case of an error', (done) => {
+      const app = express();
+      app.use('/cluster_metrics', bundle.clusterMetrics());
+      const agent = supertest(app);
+
+      // create a fake worker, which would not respond in time
+      cluster.workers = [{
+        isConnected: () => true,
+        send: () => {}
+      }];
+
+      const errorSpy = spyOn(console, 'error'); // mute console.error
+
+      agent
+        .get('/cluster_metrics')
+        .end((err, res) => {
+          expect(res.status).toBe(500);
+          expect(errorSpy).toHaveBeenCalled();
+          done();
+        });
+    }, 6000);
+  });
+
+  describe('metricType: summary', () => {
+    it('metric type summary works', done => {
+      const app = express();
+      const bundled = bundle({
+        metricType: 'summary'
+      });
+      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="0.98"/);
+            done();
+          });
+      });
+    });
+
+    it('custom pecentiles work', 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();
+          });
+      });
+    });
   });
 });

spec/normalizePath.spec.js

@@ -8,4 +8,24 @@ describe('normalizePath', () => {
     expect(normalizePath({url: '/a/12345'}))
       .toBe('/a/#val');
   });
+
+  it('uses normalizePath option', () => {
+    const url = '/hello/world/i/am/finally/free!!!';
+    const result = normalizePath({url}, {
+      normalizePath: [
+        ['/hello','/goodbye'],
+        ['[^/]+$','happy'],
+      ]
+    });
+    expect(result).toBe('/goodbye/world/i/am/finally/happy');
+  });
+
+  it('throws error is bad tuples provided as normalizePath', () => {
+    const subject = () => normalizePath({url: '/test'}, {
+      normalizePath: [
+        ['/hello','/goodbye', 'test']
+      ]
+    });
+    expect(subject).toThrow();
+  });
 });

src/index.js

@@ -1,11 +1,10 @@
-'use strict';
 const onFinished = require('on-finished');
 const promClient = require('prom-client');
 const normalizePath = require('./normalizePath');
 const normalizeStatusCode = require('./normalizeStatusCode');
 
 function matchVsRegExps(element, regexps) {
-  for (let regexp of regexps) {
+  for (const regexp of regexps) {
     if (regexp instanceof RegExp) {
       if (element.match(regexp)) {
         return true;
@@ -17,38 +16,41 @@ function matchVsRegExps(element, regexps) {
   return false;
 }
 
-function filterArrayByRegExps(array, regexps) {
-  return array.filter(element => {
-    return matchVsRegExps(element, regexps);
-  });
-}
+function clusterMetrics() {
+  const aggregatorRegistry = new promClient.AggregatorRegistry();
 
-function prepareMetricNames(opts, metricTemplates) {
-  const names = Object.keys(metricTemplates);
-  if (opts.whitelist) {
-    if (opts.blacklist) {
-      throw new Error('you cannot have whitelist and blacklist at the same time');
+  const metricsMiddleware = function(req, res) {
+    function sendClusterMetrics(clusterMetrics) {
+      res.set('Content-Type', aggregatorRegistry.contentType);
+      res.send(clusterMetrics);
     }
-    return filterArrayByRegExps(names, opts.whitelist);
-  }
-  if (opts.blacklist) {
-    const blacklisted = filterArrayByRegExps(names, opts.blacklist);
-    return names.filter(name => blacklisted.indexOf(name) === -1);
-  }
-  return names;
+
+    function sendClusterMetricsError(err) {
+      console.error(err);
+      return res.sendStatus(500);
+    }
+
+    // since prom-client@13 clusterMetrics() method doesn't take cb param,
+    // but we provide it anyway, as at this stage it's unknown which version of prom-client is used
+    const response = aggregatorRegistry.clusterMetrics((err, clusterMetrics) => {
+      if (err) {
+        return sendClusterMetricsError(err);
+      }
+      sendClusterMetrics(clusterMetrics);
+    });
+
+    // if we find out that it was a promise and our cb was useless...
+    if (response && response.then) {
+      response
+        .then(result => sendClusterMetrics(result))
+        .catch(err => sendClusterMetricsError(err));
+    }
+  };
+
+  return metricsMiddleware;
 }
 
 function main(opts) {
-  opts = Object.assign(
-    {
-      autoregister: true,
-      includeStatusCode: true,
-      normalizePath: main.normalizePath,
-      formatStatusCode: main.normalizeStatusCode,
-      promClient: {}
-    },
-    opts
-  );
   if (arguments[2] && arguments[1] && arguments[1].send) {
     arguments[1].status(500)
       .send('<h1>500 Error</h1>\n'
@@ -58,12 +60,28 @@ function main(opts) {
     return;
   }
 
-  if (opts.prefix || opts.keepDefaultMetrics !== undefined) {
+  opts = Object.assign(
+    {
+      autoregister: true,
+      includeStatusCode: true,
+      normalizePath: main.normalizePath,
+      formatStatusCode: main.normalizeStatusCode,
+      metricType: 'histogram',
+      promClient: {},
+      promRegistry: promClient.register
+    }, opts
+  );
+
+  if (opts.prefix
+    || opts.keepDefaultMetrics !== undefined
+    || opts.whitelist !== undefined
+    || opts.blacklist !== undefined
+  ) {
     throw new Error(
-      'express-prom-bundle detected obsolete options:'
-      + 'prefix and/or keepDefaultMetrics. '
+      'express-prom-bundle detected one of the obsolete options: '
+      + 'prefix, keepDefaultMetrics, whitelist, blacklist. '
       + 'Please refer to oficial docs. '
-      + 'Most likely you upgraded the module without necessary code changes'
+      + 'Most likely you upgraded the module without the necessary code changes'
     );
   }
 
@@ -73,94 +91,126 @@ function main(opts) {
 
   const httpMetricName = opts.httpDurationMetricName || 'http_request_duration_seconds';
 
-  const metricTemplates = {
-    'up': () => new promClient.Gauge({
-      name: 'up',
-      help: '1 = up, 0 = not up'
-    }),
-    [httpMetricName]: () => {
-      const labels = ['status_code'];
-      if (opts.includeMethod) {
-        labels.push('method');
-      }
-      if (opts.includePath) {
-        labels.push('path');
-      }
-      if (opts.customLabels){
-        labels.push.apply(labels, Object.keys(opts.customLabels));
-      }
-      const metric = new promClient.Histogram({
+  function makeHttpMetric() {
+    const labels = ['status_code'];
+    if (opts.includeMethod) {
+      labels.push('method');
+    }
+    if (opts.includePath) {
+      labels.push('path');
+    }
+    if (opts.customLabels) {
+      labels.push.apply(labels, Object.keys(opts.customLabels));
+    }
+
+    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],
+        maxAgeSeconds:  opts.maxAgeSeconds,
+        ageBuckets: opts.ageBuckets,
+        registers: [opts.promRegistry]
+      });
+    } 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]
+        buckets: opts.buckets || [0.003, 0.03, 0.1, 0.3, 1.5, 10],
+        registers: [opts.promRegistry]
       });
-      return metric;
+    } else {
+      throw new Error('metricType option must be histogram or summary');
     }
-  };
-
-  const metrics = {};
-  const names = prepareMetricNames(opts, metricTemplates);
-
-  for (let name of names) {
-    metrics[name] = metricTemplates[name]();
   }
 
-  if (metrics.up) {
+  const metrics = {
+    [httpMetricName]: makeHttpMetric()
+  };
+
+  if (opts.includeUp !== false) {
+    metrics.up = new promClient.Gauge({
+      name: 'up',
+      help: '1 = up, 0 = not up',
+      registers: [opts.promRegistry]
+    });
     metrics.up.set(1);
   }
 
-  const metricsMiddleware = function(req, res) {
+  const metricsMiddleware = function(req, res, next) {
     res.writeHead(200, {'Content-Type': 'text/plain'});
-    res.end(promClient.register.metrics());
+
+    const metricsResponse = opts.promRegistry.metrics();
+    // starting from prom-client@13 .metrics() returns a Promise
+    if (metricsResponse.then) {
+      metricsResponse
+        .then(output => res.end(output))
+        .catch(err => next(err));
+    } else {
+      // compatibility fallback for previous versions of prom-client@<=12
+      res.end(metricsResponse);
+    }
   };
 
+  const metricsMatch = opts.metricsPath instanceof RegExp ? opts.metricsPath
+    : new RegExp('^' + (opts.metricsPath || '/metrics') + '/?$');
+
   const middleware = function (req, res, next) {
     const path = req.originalUrl || req.url; // originalUrl gets lost in koa-connect?
-    let labels;
 
-    if (opts.autoregister && path.match(/^\/metrics\/?$/)) {
+    if (opts.autoregister && path.match(metricsMatch)) {
       return metricsMiddleware(req, res);
     }
 
+    // bypass() is checked only after /metrics was processed
+    // if you wish to disable /metrics use autoregister:false instead
+    if (opts.bypass && opts.bypass(req)) {
+      return next();
+    }
+
     if (opts.excludeRoutes && matchVsRegExps(path, opts.excludeRoutes)) {
       return next();
     }
 
-    if (metrics[httpMetricName]) {
-      labels = {};
-      let timer = metrics[httpMetricName].startTimer(labels);
-      onFinished(res, () => {
-        if (opts.includeStatusCode) {
-          labels.status_code = opts.formatStatusCode(res, opts);
-        }
-        if (opts.includeMethod) {
-          labels.method = req.method;
-        }
-        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();
-      });
-    }
+    const labels = {};
+    const timer = metrics[httpMetricName].startTimer(labels);
+
+    onFinished(res, () => {
+      if (opts.includeStatusCode) {
+        labels.status_code = opts.formatStatusCode(res, opts);
+      }
+      if (opts.includeMethod) {
+        labels.method = req.method;
+      }
+      if (opts.includePath) {
+        labels.path = opts.normalizePath instanceof Function
+          ? opts.normalizePath(req, opts)
+          : main.normalizePath(req, opts);
+      }
+      if (opts.customLabels) {
+        Object.assign(labels, opts.customLabels);
+      }
+      if (opts.transformLabels) {
+        opts.transformLabels(labels, req, res);
+      }
+      timer();
+    });
 
     next();
   };
 
-  middleware.metricTemplates = metricTemplates;
   middleware.metrics = metrics;
   middleware.promClient = promClient;
   middleware.metricsMiddleware = metricsMiddleware;
   return middleware;
 }
 
+// this is kept only for compatibility with the code relying on older version
 main.promClient = promClient;
+
 main.normalizePath = normalizePath;
 main.normalizeStatusCode = normalizeStatusCode;
+main.clusterMetrics = clusterMetrics;
 module.exports = main;

src/normalizePath.js

@@ -2,16 +2,29 @@
 
 const UrlValueParser = require('url-value-parser');
 const url = require('url');
+
+// ATTENTION! urlValueParser is a singleton!
 let urlValueParser;
 
-module.exports = function(req) {
+module.exports = function(req, opts) {
   // originalUrl is taken, because url and path can be changed
   // by middlewares such as 'router'. Note: this function is called onFinish
   /// i.e. always in the tail of the middleware chain
-  const path = url.parse(req.originalUrl || req.url).pathname;
+  let path = url.parse(req.originalUrl || req.url).pathname;
+
+  const normalizePath = opts && opts.normalizePath;
+  if (Array.isArray(normalizePath)) {
+    for (const tuple of normalizePath) {
+      if (!Array.isArray(tuple) || tuple.length !== 2) {
+        throw new Error('Bad tuple provided in normalizePath option, expected: [regex, replacement]');
+      }
+      const regex = typeof tuple[0] === 'string' ? RegExp(tuple[0]) : tuple[0];
+      path = path.replace(regex, tuple[1]);
+    }
+  }
 
   if (!urlValueParser) {
-    urlValueParser = new UrlValueParser();
+    urlValueParser = new UrlValueParser(opts && opts.urlValueParser);
   }
   return urlValueParser.replacePathValues(path);
 };

types/index.d.ts

@@ -0,0 +1,66 @@
+// TypeScript Version: 2.8
+
+import { Request, RequestHandler, Response } from 'express';
+import { DefaultMetricsCollectorConfiguration, Registry } from 'prom-client';
+
+export {};
+
+export = express_prom_bundle;
+
+declare namespace express_prom_bundle {
+  interface Labels {
+    [key: string]: string | number;
+  }
+
+  type NormalizePathEntry = [string | RegExp, string];
+  type NormalizePathFn = (req: Request, opts: Opts) => string;
+  type NormalizeStatusCodeFn = (res: Response) => number | string;
+  type TransformLabelsFn = (labels: Labels, req: Request, res: Response) => void;
+
+  interface Opts {
+    autoregister?: boolean;
+    buckets?: number[];
+
+    customLabels?: { [key: string]: any };
+
+    includeStatusCode?: boolean;
+    includeMethod?: boolean;
+    includePath?: boolean;
+    includeUp?: boolean;
+
+    bypass?: (req: Request) => boolean;
+
+    metricType?: 'summary' | 'histogram';
+    metricsPath?: string;
+    httpDurationMetricName?: string;
+    promClient?: { collectDefaultMetrics?: DefaultMetricsCollectorConfiguration };
+    promRegistry?: Registry;
+    normalizePath?: NormalizePathEntry[] | NormalizePathFn;
+    formatStatusCode?: NormalizeStatusCodeFn;
+    transformLabels?: TransformLabelsFn;
+
+    // https://github.com/disjunction/url-value-parser#options
+    urlValueParser?: {
+      minHexLength?: number;
+      minBase64Length?: number;
+      replaceMasks?: string[];
+      extraMasks?: string[];
+    };
+  }
+
+  interface Middleware extends RequestHandler {
+    metricsMiddleware: RequestHandler;
+  }
+
+  const normalizePath: NormalizePathFn;
+  const normalizeStatusCode: NormalizeStatusCodeFn;
+
+  function clusterMetrics(): RequestHandler;
+}
+
+interface express_prom_bundle {
+  normalizePath: express_prom_bundle.NormalizePathFn;
+  normalizeStatusCode: express_prom_bundle.NormalizeStatusCodeFn;
+}
+
+declare function express_prom_bundle(opts: express_prom_bundle.Opts): express_prom_bundle.Middleware;

types/test.ts

@@ -0,0 +1,79 @@
+import { Request, RequestHandler, Response } from 'express';
+import * as promClient from 'prom-client';
+
+import * as promBundle from 'express-prom-bundle';
+
+// $ExpectType Middleware
+const middleware: RequestHandler = promBundle({ includeMethod: true });
+
+// $ExpectType: string
+middleware.name;
+
+promClient.register.clear();
+
+// $ExpectType Middleware
+promBundle({
+  normalizePath: [
+    // collect paths like "/customer/johnbobson" as just one "/custom/#name"
+    ['^/customer/.*', '/customer/#name'],
+
+    // collect paths like "/bobjohnson/order-list" as just one "/#name/order-list"
+    ['^.*/order-list', '/#name/order-list']
+  ],
+  urlValueParser: {
+    minHexLength: 5,
+    extraMasks: [
+      'ORD[0-9]{5,}' // replace strings like ORD1243423, ORD673562 as #val
+    ]
+  }
+});
+
+promClient.register.clear();
+
+// $ExpectType Middleware
+promBundle({
+  buckets: [0.1, 0.4, 0.7],
+  includeMethod: true,
+  includePath: true,
+  customLabels: { year: null },
+  transformLabels: (labels: promBundle.Labels) => ({
+    ...labels,
+    year: new Date().getFullYear()
+  }),
+  metricType: 'summary',
+  metricsPath: '/prometheus',
+  promClient: {
+    collectDefaultMetrics: {
+    }
+  },
+  promRegistry: new promClient.Registry(),
+  urlValueParser: {
+    minHexLength: 5,
+    extraMasks: [
+      '^[0-9]+\\.[0-9]+\\.[0-9]+$' // replace dot-separated dates with #val
+    ]
+  },
+  normalizePath: [
+    ['^/foo', '/example'] // replace /foo with /example
+  ],
+  formatStatusCode: (res: Response) => res.statusCode + 100
+});
+
+// TypeScript workaround to write a readonly field
+type Writable<T> = { -readonly [K in keyof T]: T[K] };
+const wPromBundle: Writable<promBundle> = promBundle;
+
+wPromBundle.normalizePath = (req: Request, opts: promBundle.Opts) => {
+  const path = promBundle.normalizePath(req, opts);
+
+  // count all docs as one path, but /docs/login as a separate one
+  return path.match(/^\/docs/) && !path.match(/^\/login/) ? '/docs/*' : path;
+};
+
+wPromBundle.normalizeStatusCode = (res: Response) => res.statusCode.toString();
+
+// $ExpectType RequestHandler
+promBundle.clusterMetrics();
+
+// Missing test
+// const stringReturn: string = promBundle.normalizePath({}, {});

types/tsconfig.json

@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "lib": ["es6"],
+    "noImplicitAny": true,
+    "noImplicitThis": true,
+    "strictNullChecks": true,
+    "strictFunctionTypes": true,
+    "baseUrl": ".",
+    "paths": { "express-prom-bundle": ["."] },
+    "noEmit": true,
+    "forceConsistentCasingInFileNames": true
+  }
+}

types/tslint.json

@@ -0,0 +1,3 @@
+{
+  "extends": "dtslint/dtslint.json"
+}