As your Node.js applications become more complex, you may find the need to utilize child processes to perform computationally intensive tasks or execute external commands. While this allows for better utilization of system resources, it also introduces the challenge of monitoring the CPU and memory usage of these child processes.
In this article, we will explore how to monitor the CPU and memory usage of child processes in Node.js using the built-in child_process module and external tools like pidusage and pm2.
Table of Contents
- Using the child_process Module
- Monitoring CPU Usage
- Monitoring Memory Usage
- External Tools
- Conclusion
- References
Using the child_process Module
The child_process module in Node.js provides a way to spawn additional processes outside of the main Node.js event loop. By utilizing the exec, execFile, or spawn methods, you can create child processes to perform various tasks.
To monitor the CPU and memory usage of these child processes, you can leverage the pid (Process ID) returned by the spawn method.
Monitoring CPU Usage
To monitor the CPU usage of a child process, you can use the pidusage module. This module provides an easy way to retrieve the CPU usage of a process using its PID.
Here’s an example of how to use pidusage to monitor the CPU usage of a child process:
const { spawn } = require('child_process');
const pidusage = require('pidusage');
const child = spawn('your-command');
// Get the PID of the child process
const pid = child.pid;
// Monitor the CPU usage every second
setInterval(() => {
pidusage.stat(pid, (err, stat) => {
if (err) {
console.error(err);
} else {
console.log(`CPU usage: ${stat.cpu}%`);
}
});
}, 1000);
In this example, we spawn a child process using the spawn method and obtain its PID. We then use pidusage to retrieve the CPU usage of the child process every second.
Monitoring Memory Usage
Similarly, you can monitor the memory usage of a child process using the pidusage module. The pidusage module provides a memory property in the stat object, which represents the memory usage of a process in bytes.
Here’s an example of how to use pidusage to monitor the memory usage of a child process:
const { spawn } = require('child_process');
const pidusage = require('pidusage');
const child = spawn('your-command');
// Get the PID of the child process
const pid = child.pid;
// Monitor the memory usage every second
setInterval(() => {
pidusage.stat(pid, (err, stat) => {
if (err) {
console.error(err);
} else {
console.log(`Memory usage: ${Math.round(stat.memory / 1024 / 1024)} MB`);
}
});
}, 1000);
In this example, we spawn a child process and retrieve its PID. We then use pidusage to retrieve the memory usage of the child process every second. We convert the memory usage from bytes to megabytes for better readability.
External Tools
Apart from using the pidusage module, you can also utilize external tools like pm2 to monitor the CPU and memory usage of child processes in Node.js. pm2 is a process manager for Node.js applications that provides powerful monitoring capabilities.
To monitor child processes using pm2, you can simply start your child process with pm2 and use the pm2 monit command to view the CPU and memory usage in real-time.
Conclusion
Monitoring the CPU and memory usage of child processes in Node.js is crucial when dealing with computationally intensive tasks or external commands. By leveraging the child_process module and external tools like pidusage and pm2, you can keep track of the resource usage of your child processes.
Remember to analyze the monitoring data and make necessary optimizations to ensure optimal performance and resource utilization.