Reading system metrics
This example demonstrates how to use Deno's built-in methods to read system metrics such as memory information, load averages and memory usage.
Get metrics like total memory, free memory, available memory, memory used for buffers and caching, and swap space details. Values are converted from kilobytes (KB) to megabytes (MB) for better readability.
const memoryInfo = Deno.systemMemoryInfo();
console.log("System Memory Info:");
console.log(`Total Memory: ${memoryInfo.total / 1024 / 1024} MB`);
console.log(`Free Memory: ${memoryInfo.free / 1024 / 1024} MB`);
console.log(`Available Memory: ${memoryInfo.available / 1024 / 1024} MB`);
console.log(`Buffers: ${memoryInfo.buffers / 1024 / 1024} MB`);
console.log(`Cached: ${memoryInfo.cached / 1024 / 1024} MB`);
console.log(`Swap Total: ${memoryInfo.swapTotal / 1024 / 1024} MB`);
console.log(`Swap Free: ${memoryInfo.swapFree / 1024 / 1024} MB`);Load averages indicate the average number of active processes over these time periods, providing insights into the system's CPU load and overall activity.
const loadAvg = Deno.loadavg();
console.log("Load Averages:");
console.log(`1 Minute Load Average: ${loadAvg[0]}`);
console.log(`5 Minute Load Average: ${loadAvg[1]}`);
console.log(`15 Minute Load Average: ${loadAvg[2]}`);Get memory usage details such as external memory, resident set size (RSS), total heap size, and heap used.
const memoryUsage = Deno.memoryUsage();
console.log("Memory Usage:");
console.log(`External: ${memoryUsage.external / 1024 / 1024} MB`);
console.log(`RSS: ${memoryUsage.rss / 1024 / 1024} MB`);
console.log(`Heap Total: ${memoryUsage.heapTotal / 1024 / 1024} MB`);
console.log(`Heap Used: ${memoryUsage.heapUsed / 1024 / 1024} MB`);Run this example locally using the Deno CLI:
deno run --allow-sys https://docs.deno.com/examples/scripts/reading_system_metrics.ts