Adding JSON metrics route option

README.md

@@ -47,7 +47,7 @@ API and process monitoring with [Prometheus](https://prometheus.io) for Node.js
 - Process Metrics as recommended by Prometheus [itself](https://prometheus.io/docs/instrumenting/writing_clientlibs/#standard-and-runtime-collectors)
 - Endpoint to retrieve the metrics - used for Prometheus scraping
    - Prometheus format
-   - JSON format (`${path}.json`)
+   - JSON format (default to `${path}.json`, can be changed in options)
 - Support custom metrics
 - [Http function to collect request.js HTTP request duration](#requestjs-http-request-duration-collector)
 
@@ -61,6 +61,7 @@ app.use(apiMetrics())
 ### Options
 
 - metricsPath - Path to access the metrics. `default: /metrics`
+- metricsJsonPath - Path to access the json formatted metrics. `default: {metricsPath}.json`
 - defaultMetricsInterval - the interval to collect the process metrics in milliseconds. `default: 10000`
 - durationBuckets - Buckets for response time in seconds. `default: [0.001, 0.005, 0.015, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5]`
 - requestSizeBuckets - Buckets for request size in bytes. `default: [5, 10, 25, 50, 100, 250, 500, 1000, 2500, 5000, 10000]`
@@ -88,6 +89,7 @@ curl http[s]://<host>:[port]/metrics.json
 
 2. If you are using express framework and no route was found for the request (e.g: 404 status code), the request will not be collected. that's because we'll risk memory leak since the route is not a pattern but a hardcoded string.
 
+3. You can specify your own metrics path via options. see : `metricsJsonPath`
 
 ## Custom Metrics
 

src/express-middleware.js

@@ -98,8 +98,8 @@ class ExpressMiddleware {
             res.set('Content-Type', Prometheus.register.contentType);
             return res.end(Prometheus.register.metrics());
         }
-        if (routeUrl === `${this.setupOptions.metricsRoute}.json`) {
-            debug('Request to /metrics endpoint');
+        if (routeUrl === this.setupOptions.metricsJsonRoute) {
+            debug('Request to /metrics/json endpoint');
             return res.json(Prometheus.register.getMetricsAsJSON());
         }
 
@@ -121,4 +121,4 @@ class ExpressMiddleware {
     };
 }
 
-module.exports = ExpressMiddleware;
+module.exports = ExpressMiddleware;

src/index.d.ts

@@ -12,6 +12,7 @@ export class HttpMetricsCollector {
 
 export interface ApiMetricsOpts {
   metricsPath?: string;
+  metricsJsonPath?: string,
   defaultMetricsInterval?: number;
   durationBuckets?: number[];
   requestSizeBuckets?: number[];

src/metrics-middleware.js

@@ -10,9 +10,10 @@ const setupOptions = {};
 
 module.exports = (appVersion, projectName, framework = 'express') => {
     return (options = {}) => {
-        const { metricsPath, defaultMetricsInterval = 10000, durationBuckets, requestSizeBuckets, responseSizeBuckets, useUniqueHistogramName, metricsPrefix, excludeRoutes, includeQueryParams } = options;
+        const { metricsPath, metricsJsonPath, defaultMetricsInterval = 10000, durationBuckets, requestSizeBuckets, responseSizeBuckets, useUniqueHistogramName, metricsPrefix, excludeRoutes, includeQueryParams } = options;
         debug(`Init metrics middleware with options: ${JSON.stringify(options)}`);
         setupOptions.metricsRoute = metricsPath || '/metrics';
+        setupOptions.metricsJsonRoute = metricsJsonPath || `${setupOptions.metricsRoute}.json`;
         setupOptions.excludeRoutes = excludeRoutes || [];
         setupOptions.includeQueryParams = includeQueryParams;
         setupOptions.defaultMetricsInterval = defaultMetricsInterval;