implement stats script

client/src/components/landing_page.tsx

@@ -130,7 +130,7 @@ function LandingPage() {
       const lines = data.split('\n');
       const [header, line2] = lines;
       if (!(header.replace(' ', '').startsWith("CPU,MEM"))) {
-        console.warn("unexpected CSV `stats.csv`, expected 'CPU,MEM\\n0.2,0.2\\n', got", header)
+        console.info("Not displaying server stats: received unexpected: ", header)
       }
       if (line2) {
         let values = line2.split(',')
@@ -138,10 +138,9 @@ function LandingPage() {
         setUsageMem(100 * Number(values[1]));
       }
     }).catch(err => {
-      console.info('stats.csv does not exist.')
+      console.info('server stats unavailable')
+      console.debug(err)
     })
-
-
   }, [])
 
   return <div className="landing-page">

relay/index.mjs

@@ -9,6 +9,8 @@ import os from 'os';
 import fs from 'fs';
 import anonymize from 'ip-anonymize';
 import { importTrigger, importStatus } from './import.mjs'
+import process from'process';
+import { spawn } from 'child_process'
 // import fs from 'fs'
 
 /**
@@ -53,8 +55,31 @@ const server = app
     express.static(path.join(getGameDir(owner,repo),".lake","gamedata"))(req, res, next);
   })
   .use('/data/stats', (req, res, next) => {
-    // stats file for server usage
-    express.static(path.join(__dirname, '..', 'games', 'stats.csv'))(req, res, next);
+    // Returns a CSV of the form
+    //
+    // CPU,Mem
+    // 0.21,0.65
+    //
+    // which contains the current server usage.
+
+    const statsProcess = spawn('/bin/bash', [path.join(__dirname, "stats.sh"), process.pid])
+
+    let outputData = ''
+    let errorData = ''
+    statsProcess.stdout.on('data', (data) => {
+      outputData += data.toString();
+    })
+    statsProcess.stderr.on('data', (data) => {
+      errorData += data.toString();
+    })
+    statsProcess.on('close', (code) => {
+      if (code === 0) {
+        res.send(outputData);
+      } else {
+        res.status(500).send(`Error executing script: ${errorData}`)
+        console.error(`stats.sh exited with code ${code}. Error: ${errorData}`)
+      }
+    })
   })
   .use('/', router)
   .listen(PORT, () => console.log(`Listening on ${PORT}`));

relay/stats.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+# first argument is the process ID
+pid="$1"
+
+# number of CPUs available
+nproc=$(nproc --all)
+
+# hacky way to print the content of a CSV file containing CPU/Mem usage of the process
+top -bn2 -p $pid | awk -v nproc=$nproc 'NR > 16 {$12=substr($0,72); printf "CPU, MEM\n%.2f, %.2f\n", $9/nproc, $10}'