Added more custom metrics

README.md

@@ -9,7 +9,7 @@ A small express middleware to get base metrics for any node.js app.
 
 ## Usage
 
-`import { Metrics } from '@plastdev/metrics'`  
+`import { Metrics, MetricType } from '@plastdev/metrics'`  
 `let metrics = new Metrics(options)`
 
 Note: The options Part may be omitted, as all parts are optional.  
@@ -20,16 +20,93 @@ Before your Routes:
 And to enable the *_metrics*-Endpoint:  
 `router.get('/_metrics', metrics.endpoint)`  
 
+### Custom Metrics
+
 To Add your own custom Metrics:
 `metrics.addCustomMetric({
       name: 'test',
-      help: 'Some Test Metric',
-      labelNames: ['tester']
-    })`
+      help: 'Some Test Metric'
+    }, TYPE)`
+
+where TYPE is one of:
+
+- `MetricType.COUNTER`
+- `MetricType.GAUGE`
+- `MetricType.HISTOGRAM`
+- `MetricType.SUMMARY`
+
+All metrics can take a labelNames property in the configuration object. All labelNames that the metric support needs to be declared here. There are 2 ways to add values to the labels
+
+```js
+metrics.addCustomMetric({
+  name: 'metric_name',
+  help: 'metric_help',
+  labelNames: ['method', 'statusCode'],
+}, MetricType.GAUGE);
+
+metrics.customMetrics["NAME"].set({ method: 'GET', statusCode: '200' }, 100); // 1st version, Set value 100 with method set to GET and statusCode to 200
+metrics.customMetrics["NAME"].labels('GET', '200').set(100); // 2nd version, Same as above
+```
+
+It is also possible to use timers with labels, both before and after the timer is created:
+
+```js
+const end = metrics.customMetrics["NAME"].startTimer({ method: 'GET' }); // Set method to GET, we don't know statusCode yet
+xhrRequest(function (err, res) {
+  if (err) {
+    end({ statusCode: '500' }); // Sets value to xhrRequest duration in seconds with statusCode 500
+  } else {
+    end({ statusCode: '200' }); // Sets value to xhrRequest duration in seconds with statusCode 200
+  }
+});
+```
+
+#### Counter
+
+Counters go up, and reset when the process restarts.
+
+- `metrics.customMetrics["NAME"].inc(); // Inc with 1`
+- `metrics.customMetrics["NAME"].inc(10); // Inc with 10`
+
+#### Gauge
+
+Gauges are similar to Counters but Gauges value can be decreased.
+
+- `metrics.customMetrics["NAME"].set(10); // Set to 10`
+- `metrics.customMetrics["NAME"].inc(); // Inc with 1`
+- `metrics.customMetrics["NAME"].inc(10); // Inc with 10`
+- `metrics.customMetrics["NAME"].dec(); // Dec with 1`
+- `metrics.customMetrics["NAME"].dec(10); // Dec with 10`
+
+#### Histograms
+
+Histograms track sizes and frequency of events.
+
+`metrics.customMetrics["NAME"].observe(10);  // Observe value in histogram`
+
+Utility to observe request durations
+
+```js
+const end = metrics.customMetrics["NAME"].startTimer();
+xhrRequest(function (err, res) {
+  const seconds = end(); // Observes and returns the value to xhrRequests duration in seconds
+});
+```
+
+#### Summary
+
+Summaries calculate percentiles of observed values.
+
+`metrics.customMetrics["NAME"].observe(10);`
+
+Utility to observe request durations
 
-then you may increase or decrease the value at any given point:
-`this.metrics.incCustomMetric('test', 'tester', 'called_bar')`
-`this.metrics.decCustomMetric('test', 'tester', 'called_bar')`
+```js
+const end = metrics.customMetrics["NAME"].startTimer();
+xhrRequest(function (err, res) {
+  end(); // Observes the value to xhrRequests duration in seconds
+});
+```
 
 ### Options
 

examples/src/app.ts

@@ -3,7 +3,7 @@
 import * as http from 'http'
 import * as express from 'express'
 
-import { Metrics } from '../../dist/index'
+import { Metrics, MetricType } from '../../dist/index'
 
 class App {
   public app: express.Application
@@ -27,9 +27,8 @@ class App {
 
     this.metrics.addCustomMetric({
       name: 'test',
-      help: 'Some Test Metric',
-      labelNames: ['tester']
-    })
+      help: 'Some Test Metric'
+    }, MetricType.COUNTER)
 
     this.router.use(this.metrics.collect)
 
@@ -39,7 +38,7 @@ class App {
       res.status(200).send('foo')
     })
     this.router.get('/bar', (req:express.Request, res:express.Response) => {
-      this.metrics.incCustomMetric('test', 'tester', 'called_bar')
+      this.metrics["test"].inc()
       res.status(200).send('bar')
     })
     this.router.get('/404', (req:express.Request, res:express.Response) => {

src/index.ts

@@ -11,7 +11,14 @@ export interface Options {
 export interface CustomMetric {
   name: string
   help: string
-  labelNames: string[]
+  labelNames?: string[]
+}
+
+export enum MetricType {
+  GAUGE,
+  COUNTER,
+  HISTOGRAM,
+  SUMMARY
 }
 
 export class Metrics {
@@ -27,11 +34,11 @@ export class Metrics {
   public readonly _numOfRequests: any
   public readonly _numOfErrors: any
 
-  public readonly _customMetrics: any
+  public readonly customMetrics: any
 
   constructor (options: Partial<Options> = {}) {
     this._client = require('prom-client')
-    this._customMetrics = {}
+    this.customMetrics = {}
 
     if (typeof options.ignore !== 'undefined') {
       this._ignore = options.ignore
@@ -87,24 +94,23 @@ export class Metrics {
     }
   }
 
-  public addCustomMetric = (options: CustomMetric): void => {
-    this._customMetrics[options.name] = new this._client.Gauge({
-      name: options.name,
-      help: options.help,
-      labelNames: options.labelNames
-    })
-  }
-
-  public incCustomMetric = (name: string, label: string, value: string): void => {
-    const inc: any = {}
-    inc[label] = value
-    this._customMetrics[name].inc(inc)
-  }
-
-  public decCustomMetric = (name: string, label: string, value: string): void => {
-    const dec: any = {}
-    dec[label] = value
-    this._customMetrics[name].dec(dec)
+  public addCustomMetric = (options: CustomMetric, type: MetricType): void => {
+    switch (type) {
+      case MetricType.COUNTER:
+        this.customMetrics[options.name] = new this._client.Counter(options)
+        break
+      case MetricType.GAUGE:
+        this.customMetrics[options.name] = new this._client.Gauge(options)
+        break
+      case MetricType.HISTOGRAM:
+        this.customMetrics[options.name] = new this._client.Histogram(options)
+        break
+      case MetricType.SUMMARY:
+        this.customMetrics[options.name] = new this._client.Summary(options)
+        break
+      default:
+        break
+    }
   }
 
   public collect = (req: express.Request, res: express.Response, next: express.NextFunction): void => {