PM2 常见命令

# config
pm2 ecosystem # create a configuration file
pm2 start ecosystem.config.js

# Restart application on changes
pm2 start env.js --watch --ignore-watch="node_modules"

# Fork mode
pm2 start app.js --name my-api # Name process

# Cluster mode
pm2 start app.js -i 0        # Will start maximum processes with LB depending on available CPUs
pm2 start app.js -i max      # Same as above, but deprecated.
pm2 scale app +3             # Scales `app` up by 3 workers
pm2 scale app 2              # Scales `app` up or down to 2 workers total

# Listing

pm2 list               # Display all processes status
pm2 jlist              # Print process list in raw JSON
pm2 prettylist         # Print process list in beautified JSON

pm2 describe 0         # Display all information about a specific process

pm2 monit              # Monitor all processes

# Logs

pm2 logs [--raw]       # Display all processes logs in streaming
pm2 flush              # Empty all log files
pm2 reloadLogs         # Reload all logs

# Actions

pm2 stop all           # Stop all processes
pm2 restart all        # Restart all processes

pm2 reload all         # Will 0s downtime reload (for NETWORKED apps)

pm2 stop 0             # Stop specific process id
pm2 restart 0          # Restart specific process id

pm2 delete 0           # Will remove process from pm2 list
pm2 delete all         # Will remove all processes from pm2 list

# Misc

pm2 reset <process>    # Reset meta data (restarted time...)
pm2 updatePM2          # Update in memory pm2
pm2 ping               # Ensure pm2 daemon has been launched
pm2 sendSignal SIGUSR2 my-app # Send system signal to script
pm2 start app.js --no-daemon
pm2 start app.js --no-vizion
pm2 start app.js --no-autorestart

cli

# cli
$ pm2 start bashscript.sh
$ pm2 start python-app.py --watch
$ pm2 start binary-file -- --port 1520

# Specify an app name
--name <app_name>

# Watch and Restart app when files change
--watch

# Set memory threshold for app reload
--max-memory-restart <200MB>

# Specify log file
--log <log_path>

# Pass extra arguments to the script
-- arg1 arg2 arg3

# Delay between automatic restarts
--restart-delay <delay in ms>

# Prefix logs with time
--time

# Do not auto restart app
--no-autorestart

# Specify cron for forced restart
--cron <cron_pattern>

# Attach to application log
--no-daemon

Node Cluster

const cluster = require('node:cluster')
const express = require('views/node/express')

if (cluster.isMaster) {
    // 下面调用了2次cluster.fork函数，意味着当我们在终端执行node index.js时，还会再额外执行2次index.js，
    // 只不过另外2次的cluster.isMaster设置为false
    cluster.fork()
    cluster.fork()
} else {
    const app = express()

    const doWork = (duration) => {
        const start = Date.now()
        while (Date.now() - start < duration) {}
    }
    app.get('/', (req, res) => {
        doWork(5000)
        res.send('Hi there')
    })
    app.get('/fast', (req, res) => {
        console.log('fast')
        res.send('This was fast!')
    })

    app.listen(3000)
}
// 代码中的 cluster.fork() 被调用了两次，这会创建两个子进程。当这两个子进程开始运行时，它们会共享同一个端口（3000）并监听相同的路由。
// 当一个请求进入主进程并匹配到 /fast 路由时，会触发对应的回调函数，打印出 "fast" 并发送响应。由于只有一个主进程在接收请求，因此 "fast" 只会被打印一次。
// 同一台机器创建多个主进程是没有意义的，因为共享计算资源；多个应用程序实例通常在不同的机器上运行，以实现负载均衡和高可用性