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

.travis.yml

@@ -1,5 +1,4 @@
 language: node_js
 node_js:
     - "6"
-    - "5"
-    - "4"
+    - "7"

README.md

@@ -2,7 +2,7 @@
 
 # express prometheus bundle
 
-Express middleware with popular prometheus metrics in one bundle. It's also compatible with koa v1 (see below).
+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
 
@@ -11,20 +11,18 @@ Included metrics:
 * `up`: normally is just 1
 * `http_request_duration_seconds`: http latency histogram labeled with `status_code`, `method` and `path`
 
-**Please note version 2.x is NOT backwards compatible with 1.x**
-
 ## Install
 
 ```
 npm install express-prom-bundle
 ```
 
-## Usage
+## Sample Usage
 
 ```javascript
 const promBundle = require("express-prom-bundle");
-const metricsMiddleware = promBundle({/* options */ });
 const app = require("express")();
+const metricsMiddleware = promBundle({includeMethod: true});
 
 app.use(metricsMiddleware);
 app.use(/* your middleware */);
@@ -44,17 +42,38 @@ See the example below.
 
 ## Options
 
-* **buckets**: buckets used for `http_request_seconds` histogram
-* **includeMethod**: include HTTP method (GET, PUT, ...) as a label to `http_request_duration_seconds`
-* **includePath**: include URL path as a label (see below)
-* **normalizePath**: boolean or `function(req)` - path normalization for `includePath` option
+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**)
-* **whitelist**, **blacklist**: array of strings or regexp specifying which metrics to include/exclude
-* **excludeRoutes**: (deprecated) 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 normally use express or meddleware features instead of this options.
+* **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
 
-The goal is to have separate latency statistics by URL path, e.g. `/my-app/user/`, `/products/by-category` etc.
+Let's say you want to have  latency statistics by URL path,
+e.g. separate metrics for `/my-app/user/`, `/products/by-category` etc.
 
 Just taking `req.path` as a label value won't work as IDs are often part of the URL,
 like `/user/12352/profile`. So what we actually need is a path template.
@@ -65,16 +84,14 @@ normalized to `/user/#val/profile` and that will become the value for the label.
 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.
-This is handy if the rest of the middleware is done elsewhere
-e.g. via `kraken.js meddleware`.
 
 ```javascript
 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;
@@ -116,15 +133,15 @@ app.listen(3000);
 
 See an [advanced example on github](https://github.com/jochen-schweizer/express-prom-bundle/blob/master/advanced-example.js)
 
-## koa v1 example
+## koa v2 example
 
 ```javascript
 const promBundle = require("express-prom-bundle");
-const koa = require("koa");
+const Koa = require("koa");
 const c2k = require("koa-connect");
 const metricsMiddleware = promBundle({/* options */ });
 
-const app = koa();
+const app = new Koa();
 
 app.use(c2k(metricsMiddleware));
 app.use(/* your middleware */);
@@ -157,8 +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.originalPath** instead of **req.path**
+    * 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

@@ -4,22 +4,24 @@ const express = require('express');
 const app = express();
 const promBundle = require('express-prom-bundle');
 
-// here we want to remove default metrics provided in prom-client
-// this must be done before initializing promBundle
-clearInterval(promBundle.promClient.defaultMetrics());
-promBundle.promClient.register.clear();
-
 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": "2.2.0",
+  "version": "3.3.0",
   "description": "express middleware with popular prometheus metrics in one bundle",
   "main": "src/index.js",
   "keywords": [
@@ -17,22 +17,25 @@
   "license": "MIT",
   "dependencies": {
     "on-finished": "^2.3.0",
-    "prom-client": "^6.3.0",
+    "prom-client": "~10.2.2",
     "url-value-parser": "^1.0.0"
   },
   "devDependencies": {
-    "coveralls": "^2.11.15",
-    "eslint": "^3.11.1",
-    "express": "^4.14.0",
+    "coveralls": "^2.13.1",
+    "eslint": "^3.19.0",
+    "express": "^4.15.3",
     "istanbul": "^0.4.5",
     "jasme": "^5.2.0",
-    "koa": "^1.2.4",
-    "koa-connect": "^1.0.0",
-    "supertest": "^2.0.1",
+    "koa": "^2.2.0",
+    "koa-connect": "^2.0.0",
+    "supertest": "^3.0.0",
     "supertest-koa-agent": "^0.3.0"
   },
   "repository": {
     "type": "git",
     "url": "https://github.com/jochen-schweizer/express-prom-bundle.git"
+  },
+  "engines": {
+    "node": ">=6.0.0"
   }
 }

spec/index.spec.js

@@ -4,7 +4,7 @@
 const express = require('express');
 const supertest = require('supertest');
 const bundle = require('../');
-const koa = require('koa');
+const Koa = require('koa');
 const c2k = require('koa-connect');
 const supertestKoa = require('supertest-koa-agent');
 const promClient = require('prom-client');
@@ -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'));
@@ -169,7 +185,7 @@ describe('index', () => {
       });
   });
 
-  it('normalizePath can be replaced', done => {
+  it('normalizePath can be replaced gloablly', done => {
     const app = express();
     const original = bundle.normalizePath;
     bundle.normalizePath = () => 'dummy';
@@ -193,18 +209,127 @@ describe('index', () => {
       });
   });
 
+  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('formatStatusCode can be overridden', done => {
+    const app = express();
+    const instance = bundle({
+      formatStatusCode: () => 555
+    });
+    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(/555/);
+            done();
+          });
+      });
+  });
+
+  it('includeStatusCode=false removes status_code label from metrics', done => {
+    const app = express();
+    const instance = bundle({
+      includeStatusCode: false
+    });
+    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).not.toMatch(/200/);
+            done();
+          });
+      });
+  });
+
+  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 = koa();
+    const app = new Koa();
     const bundled = bundle({
       whitelist: ['up']
     });
     app.use(c2k(bundled));
 
-    app.use(function*(next) {
-      if (this.path !== 'test') {
-        return yield next;
-      }
-      this.body = 'it worked';
+    app.use(function(ctx, next) {
+      return next().then(() => ctx.body = 'it worked');
     });
 
     const agent = supertestKoa(app);
@@ -218,4 +343,16 @@ describe('index', () => {
         });
     });
   });
+
+  it('calls promClient.collectDefaultMetrics', () => {
+    const spy = spyOn(promClient, 'collectDefaultMetrics');
+    bundle({
+      promClient: {
+        collectDefaultMetrics: {
+          timeout: 3000
+        }
+      }
+    });
+    expect(spy).toHaveBeenCalledWith({timeout: 3000});
+  });
 });

spec/normalizePath.spec.js

@@ -4,25 +4,8 @@
 const normalizePath = require('../src/normalizePath');
 
 describe('normalizePath', () => {
-  it('returns original if disabled in opts', () => {
-    expect(
-     normalizePath({originalUrl: '/a/12345'}, {normalizePath: false})
-    ).toBe('/a/12345');
-  });
-
-  it('returns run callback if configured', () => {
-    expect(
-      normalizePath(
-        {originalUrl: '/a/12345'},
-        {
-          normalizePath: req => req.originalUrl + '-ok'
-        }
-      )
-    ).toBe('/a/12345-ok');
-  });
-
   it('uses UrlValueParser by default', () => {
-    expect(normalizePath({originalUrl: '/a/12345'}))
+    expect(normalizePath({url: '/a/12345'}))
       .toBe('/a/#val');
   });
 });

spec/normalizeStatusCode.spec.js

@@ -4,20 +4,9 @@
 const normalizeStatusCode = require('../src/normalizeStatusCode');
 
 describe('normalizeStatusCode', () => {
-  it('returns original if disabled in opts', () => {
-    expect(
-     normalizeStatusCode({status_code: 404}, {normalizeStatusCode: false})
-   ).toBe(404);
-  });
-
   it('returns run callback if configured', () => {
     expect(
-      normalizeStatusCode(
-        {status_code: 500},
-        {
-          formatStatusCode: res => String(res.status_code).slice(0, -2) + 'xx'
-        }
-      )
-    ).toBe('5xx');
+      normalizeStatusCode({status_code: 500})
+    ).toBe(500);
   });
 });

src/index.js

@@ -39,7 +39,16 @@ function prepareMetricNames(opts, metricTemplates) {
 }
 
 function main(opts) {
-  opts = Object.assign({autoregister: true}, 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'
@@ -58,14 +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');
@@ -73,14 +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;
     }
   };
@@ -102,7 +116,7 @@ function main(opts) {
   };
 
   const middleware = function (req, res, next) {
-    const path = req.originalUrl;
+    const path = req.originalUrl || req.url; // originalUrl gets lost in koa-connect?
     let labels;
 
     if (opts.autoregister && path.match(/^\/metrics\/?$/)) {
@@ -113,21 +127,24 @@ function main(opts) {
       return next();
     }
 
-    if (metrics[httpMtricName]) {
-      labels = {'status_code': 0};
-      let timer = metrics[httpMtricName].startTimer(labels);
+    if (metrics[httpMetricName]) {
+      labels = {};
+      let timer = metrics[httpMetricName].startTimer(labels);
       onFinished(res, () => {
-        if (opts.normalizeStatusCode) {
-          labels.status_code = main.normalizeStatusCode(res, opts);
-        } else {
-          labels.status_code = res.statusCode;
+        if (opts.includeStatusCode) {
+          labels.status_code = opts.formatStatusCode(res, opts);
         }
-
         if (opts.includeMethod) {
           labels.method = req.method;
         }
         if (opts.includePath) {
-          labels.path = main.normalizePath(req, opts);
+          labels.path = opts.normalizePath(req, opts);
+        }
+        if (opts.customLabels) {
+          Object.assign(labels, opts.customLabels);
+        }
+        if (opts.transformLabels) {
+          opts.transformLabels(labels, req, res);
         }
         timer();
       });

src/normalizePath.js

@@ -4,20 +4,11 @@ const UrlValueParser = require('url-value-parser');
 const url = require('url');
 let urlValueParser;
 
-module.exports = function(req, opts) {
-  opts = opts || {};
-
+module.exports = function(req) {
   // 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).pathname;
-
-  if (opts.normalizePath !== undefined && !opts.normalizePath) {
-    return path;
-  }
-  if (typeof opts.normalizePath === 'function') {
-    return opts.normalizePath(req, opts);
-  }
+  const path = url.parse(req.originalUrl || req.url).pathname;
 
   if (!urlValueParser) {
     urlValueParser = new UrlValueParser();

src/normalizeStatusCode.js

@@ -1,11 +1,5 @@
 'use strict';
 
-module.exports = function(res, opts) {
-  opts = opts || {};
-
-  if (typeof opts.formatStatusCode === 'function') {
-    return opts.formatStatusCode(res, opts);
-  }
-
-  return res.status_code;
+module.exports = function(res) {
+  return res.status_code || res.statusCode;
 };