Use median instead of warmup requests

README.md

@@ -18,13 +18,6 @@ TARGET_URL=https://frumentum.nl
 # The interval in seconds to check the URL, defaults to 60
 # Set to 0 to only check once
 INTERVAL=60
-# The number of times to check the URL before conducting the final measurement, defaults to 5
-# see the section below for further explanation
-WARMUP_COUNT=5
+# responsetimer uses the median response time of X requests
+REQ_COUNT=5
 ```
-
-> [!NOTE]
-> responsetimer sends a few requests to the URL before conducting the final measurement.
-> This is done to ensure actions like DNS lookups do not affect the actual response time.
-> The number of requests is determined by the `WARMUP_COUNT` environment variable, and can be set to `0` to completely
-> disable the warmup feature.

src/index.js

@@ -3,13 +3,15 @@ const PAGE_ID = process.env.PAGE_ID;
 const METRIC_ID = process.env.METRIC_ID;
 const TARGET_URL = process.env.TARGET_URL;
 const INTERVAL = Number(process.env.INTERVAL ?? '60');
-const WARMUP_COUNT = parseInt(process.env.WARMUP_COUNT ?? '5');
+const REQ_COUNT = parseInt(process.env.REQ_COUNT ?? '5');
 
 let msg = [];
 if (!API_KEY) msg.push('- Missing api key. Please set the API_KEY env variable.');
 if (!PAGE_ID) msg.push('- Missing page id. Please set the PAGE_ID env variable.');
 if (!METRIC_ID) msg.push('- Missing metric id. Please set the METRIC_ID env variable.');
 if (!TARGET_URL) msg.push('- Missing target url. Please set the TARGET_URL env variable.');
+if (isNaN(INTERVAL) || INTERVAL < 0) msg.push('- Invalid interval. Please set the INTERVAL env variable to a positive integer.');
+if (isNaN(REQ_COUNT) || REQ_COUNT < 1) msg.push('- Invalid request count. Please set the REQ_COUNT env variable to an integer greater than 0.');
 
 if (msg.length !== 0) {
     console.error('Encountered one or more configuration errors:')
@@ -24,20 +26,18 @@ let request = async () => await fetch(TARGET_URL, {
 });
 
 let run = async () => {
-    if (WARMUP_COUNT > 0) {
-        console.log(`Sending warmup requests to ${TARGET_URL}...`);
-        for (let i = 0; i < WARMUP_COUNT; i++) {
-            await request();
-            performance.now();
-        }
-        console.log('Warmed up!');
+    let times = [];
+    console.log(`Sending requests to ${TARGET_URL}...`);
+    for (let i = 1; i <= REQ_COUNT; i++) {
+        let start = performance.now();
+        await request();
+        let time = performance.now() - start;
+        times.push(time);
+        console.log(`Request ${i}/${REQ_COUNT} took ${time}ms`);
     }
+    let median = times.sort((a, b) => a - b)[Math.floor(times.length / 2)];
 
-    console.log(`Sending requests to ${TARGET_URL}...`);
-    let start = performance.now();
-    await request();
-    let time = performance.now() - start;
-    console.log(`Done! Took ${time}ms`);
+    console.log(`Done! Median is ${median}ms`);
 
     console.log('Posting times to statuspage...');
     let resp = await fetch(`https://api.statuspage.io/v1/pages/${PAGE_ID}/metrics/${METRIC_ID}/data.json`, {
@@ -49,7 +49,7 @@ let run = async () => {
         body: JSON.stringify({
             data: {
                 timestamp: Math.floor(Date.now() / 1000),
-                value: time
+                value: median
             }
         })
     });