How to Build a Robust Init Script for a Swoole Mail Server on Linux

Many services like nginx, MySQL, and php‑fpm provide init scripts for start/stop/restart, but Swoole services often lack such management and are manually killed. This article shares a method to create a comprehensive init script for a Swoole‑based mail server (zmail_server), enabling start, stop, force‑quit, restart, reload, reloadtask, and status commands.

Goal

Implement basic start|stop|force-quit|restart|reload|reloadtask|status commands.

Idea

Set process names for master and manager processes using swoole_set_process_name, then retrieve their PIDs by searching the process list, allowing various control actions.

Key Points

Assume the service name is zmail_server (see https://github.com/shenzhe/zmail).

1. In the onStart callback, set the master process name.

swoole_set_process_name('zmail_server running tcp://0.0.0.0:9501 master:' . $server->master_pid);

2. In the onManagerStart callback, set the manager process name.

swoole_set_process_name('zmail_server manager:' . $server->manager_id);

Full Script (modify as needed)

#!/bin/sh
### BEGIN INIT INFO
# Provides:          mail_server
# Required-Start:    $remote_fs $network
# Required-Stop:     $remote_fs $network
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: starts mail_server
# Description:      starts the PHP FastCGI Process Manager daemon
### END INIT INFO

PHP_BIN=/usr/local/php/bin/php
SERVER_PATH=/home/jing.wang/mail

getMasterPid() {
    PID=`/bin/ps axu|grep zmail_server|grep master|awk '{print $2}'`
    echo $PID
}
getManagerPid() {
    MID=`/bin/ps axu|grep zmail_server|grep manager|awk '{print $2}'`
    echo $MID
}
case "$1" in
    start)
        PID=`getMasterPid`
        if [ -n "$PID" ]; then
            echo -n "mail server is running"
            exit 1
        fi
        echo -n "Starting mail server "
        $PHP_BIN $SERVER_PATH/webroot/main.php default
        echo " done"
        ;;
    stop)
        PID=`getMasterPid`
        if [ -z "$PID" ]; then
            echo -n "mail server is not running"
            exit 1
        fi
        echo -n "Gracefully shutting down mail server "
        kill $PID
        echo " done"
        ;;
    status)
        PID=`getMasterPid`
        if [ -n "$PID" ]; then
            echo -n "mail server is running"
        else
            echo -n "mail server is not running"
        fi
        ;;
    force-quit)
        $0 stop
        ;;
    restart)
        $0 stop
        $0 start
        ;;
    reload)
        MID=`getManagerPid`
        if [ -z "$MID" ]; then
            echo -n "mail server is not running"
            exit 1
        fi
        echo -n "Reload service mail_server "
        kill -USR1 $MID
        echo " done"
        ;;
    reloadtask)
        MID=`getManagerPid`
        if [ -z "$MID" ]; then
            echo -n "mail server is not running"
            exit 1
        fi
        echo -n "Reload service mail_server"
        kill -USR2 $MID
        echo " done"
        ;;
    *)
        echo "Usage: $0 {start|stop|force-quit|restart|reload|reloadtask|status}"
        exit 1
        ;;
esac

Enable Autostart

Place the script at /etc/init.d/zmail_server.

Make it executable: chmod +x /etc/init.d/zmail_server.

Add to startup: chkconfig --add zmail_server.

Result

Run /etc/init.d/mail_server start and see the service start similarly to nginx/php-fpm.

Now the mail server can be managed like other Linux services.