add excludeRoutes option

README.md

@@ -45,6 +45,7 @@ See the example below.
  * **prefix**:  prefix added to every metric name
  * **whitelist**, **blacklist**: array of strings or regexp specifying which metrics to include/exclude
  * **buckets**: buckets used for `http_request_seconds` histogram
+ * **excludeRoutes**: array of strings or regexp specifying which routes should be skipped for `http_request_seconds` metric. It uses `req.path` as subject when checking
 
 ## Example
 
@@ -63,9 +64,13 @@ const express = require("express"),
 app.get("/status", (req, res) => res.send("i am healthy"));
 
 app.use(promBundle({
-    prefix: "demo_app:something"
+    prefix: "demo_app:something",
+    excludeRoutes: ["/foo"]
 }));
 
+// this call will NOT appear in metrics, because it matches excludeRoutes
+app.get("/foo", (req, res) => res.send("bar"));
+
 // calls to this route will appear in metrics
 app.get("/hello", (req, res) => res.send("ok"));
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "express-prom-bundle",
-  "version": "1.1.5",
+  "version": "1.1.6",
   "description": "express middleware with popular prometheus metrics in one bundle",
   "main": "src/index.js",
   "keywords": [

spec/indexSpec.js

@@ -70,6 +70,28 @@ describe("index", () => {
                 const labeled = metricHashMap["status_code:200"];
                 expect(labeled.count).toBe(1);
 
+                agent
+                    .get("/metrics")
+                    .end((err, res) => {
+                        expect(res.status).toBe(200);
+                        done();
+                    });
+            });
+    });
+    it("filters out the excludeRoutes", done => {
+       const app = express();
+        const instance = bundle({
+            excludeRoutes: ["/test"]
+        });
+        app.use(instance);
+        app.use("/test", (req, res) => res.send("it worked"));
+        const agent = supertest(app);
+        agent
+            .get("/test")
+            .end(() => {
+                const metricHashMap = instance.metrics.http_request_seconds.hashMap;
+                expect(metricHashMap["status_code:200"]).not.toBeDefined();
+
                 agent
                     .get("/metrics")
                     .end((err, res) => {

src/index.js

@@ -4,18 +4,23 @@ const
     PromFactory = require("./PromFactory"),
     onFinished = require("on-finished");
 
-function filterArrayByRegExps(array, regexps) {
-    return array.filter(element => {
-        for (let regexp of regexps) {
-            if (regexp instanceof RegExp) {
-                if (element.match(regexp)) {
-                    return true;
-                }
-            } else if (element == regexp) {
+function matchVsRegExps(element, regexps) {
+    for (let regexp of regexps) {
+        if (regexp instanceof RegExp) {
+            if (element.match(regexp)) {
                 return true;
             }
+        } else if (element == regexp) {
+            return true;
         }
-        return false;
+    }
+    return false;
+}
+
+
+function filterArrayByRegExps(array, regexps) {
+    return array.filter(element => {
+        return matchVsRegExps(element, regexps);
     });
 }
 
@@ -87,11 +92,6 @@ function main(opts) {
     }
 
     const middleware = function (req, res, next) {
-        let timer, labels;
-        if (metrics["http_request_seconds"]) {
-            labels = {"status_code": 0};
-            timer = metrics["http_request_seconds"].startTimer(labels);
-        }
         if (req.path == "/metrics") {
             let memoryUsage = process.memoryUsage();
             if (metrics["nodejs_memory_heap_total_bytes"]) {
@@ -106,7 +106,14 @@ function main(opts) {
             return;
         }
 
-        if (timer) {
+        if (opts.excludeRoutes && matchVsRegExps(req.path, opts.excludeRoutes)) {
+            return next();
+        }
+
+        let labels;
+        if (metrics["http_request_seconds"]) {
+            labels = {"status_code": 0};
+            let timer = metrics["http_request_seconds"].startTimer(labels);
             onFinished(res, () => {
                 labels["status_code"] = res.statusCode;
                 timer();