In website operation, the stability of services and the integrity of data are core elements.For an efficient content management system like AnQiCMS, which is developed based on the Go language, it is particularly important for it to 'gracefully shut down' rather than 'forcefully close'.This is not just about the standardization of technology, but it also directly affects the normal operation of the website, user experience, and the security of critical data.

Graceful shutdown: Why is it so important?

Imagine that you are busy editing an important article, or the user is browsing your product page.What might happen if the AnQiCMS process on the server is abruptly interrupted?

  • Data loss or damage:A database write operation that may not have completed can lead to inconsistent data, even corruption.
  • User experience interruption:Users visiting your website may encounter error pages or an unavailable service.
  • Resources could not be released:Database connections, file locks, and other resources may not have been closed properly, affecting the startup of subsequent services or causing resource leaks.
  • Incomplete log records:The important operation log may not be written in time, which may cause difficulties in subsequent fault troubleshooting.

Therefore, gracefully stopping AnQiCMS means that the system has enough time to complete the current tasks it is processing, save all unsaved data, release the occupied resources, and send a clear exit signal to the operating system, thus avoiding the above potential problems.

The operation mechanism and shutdown command of AnQiCMS

AnQiCMS as a Go language application typically runs as an independent process on the server and provides services to the outside through reverse proxies such as Nginx, Apache.The start and stop often depend on scripts or container management tools.

According to the documentation provided by AnQiCMS, in a Linux environment, we usually usestart.shandstop.shSuch scripts manage their lifecycle by default.start.shThe script will go throughnohup ... &The command starts the AnQiCMS process in the background and ensures it continues to run after the terminal closes.

# start.sh 脚本示例
#!/bin/bash
BINNAME=anqicms
BINPATH=/www/wwwroot/anqicms

exists=`ps -ef | grep '\<anqicms\>' |grep -v grep |wc -l`
if [ $exists -eq 0 ]; then
    echo "$BINNAME NOT running"
    cd $BINPATH && nohup $BINPATH/$BINNAME >> $BINPATH/running.log 2>&1 &
fi

However, it is worth noting that thestop.shscript examples usekill -9this mandatory shutdown command:

# stop.sh 脚本示例 (官方文档提供)
#!/bin/bash
BINNAME=anqicms
BINPATH="$( cd "$( dirname "$0"  )" && pwd  )"

exists=`ps -ef | grep '\<anqicms\>' |grep -v grep |awk '{printf $2}'`
if [ $exists -eq 0 ]; then
    echo "$BINNAME NOT running"
else
    echo "$BINNAME is running"
    kill -9 $exists # 这里是问题所在
    echo "$BINNAME is stop"
fi

kill -9(i.e.,)SIGKILLA "signal) is a "termination immediately" command, which will force the operating system to stop the target process immediately, giving the process no chance to clean up or save data.This is like suddenly cutting off the power, rather than going through a normal shutdown process.kill -9It is a last resort, but not an elegant choice for a healthy, normally responsive application.

Implement an elegant shutdown of AnQiCMS

Applications written in Go language usually can respondSIGTERMsignals (i.e.,killCommand default signal sent), thus executing cleanup logic and exiting gracefully.The update log of AnQiCMS mentioned 'elegant start and restart of the blog', which implies that the system has the ability to handle such signals.

In order for AnQiCMS to shut down gracefully, we should modifystop.shscripts, such askill -9tokill:

Modified afterstop.shscript examples

#!/bin/bash
### stop anqicms gracefully
# author fesion (modified for graceful shutdown)
# the bin name is anqicms
BINNAME=anqicms
BINPATH="$( cd "$( dirname "$0"  )" && pwd  )"

# 查找AnQiCMS进程的PID
PID=$(ps -ef | grep '\<'$BINNAME'\>' | grep -v grep | awk '{print $2}')

if [ -z "$PID" ]; then
    echo "$BINNAME NOT running"
else
    echo "$BINNAME is running with PID $PID"
    echo "Attempting graceful shutdown for $BINNAME..."
    kill "$PID" # 发送SIGTERM信号，允许进程自行清理
    
    # 等待进程退出，给AnQiCMS留出清理时间，例如10秒
    COUNT=0
    while kill -0 "$PID" 2>/dev/null; do
        if [ "$COUNT" -ge 10 ]; then # 如果10秒后进程仍未退出，则强制终止
            echo "Graceful shutdown failed, forcing $BINNAME to stop..."
            kill -9 "$PID"
            break
        fi
        sleep 1
        COUNT=$((COUNT+1))
    done
    echo "$BINNAME has stopped."
fi

Key modification point:

  1. kill "$PID"This will send to AnQiCMS process:SIGTERMSignal.If AnQiCMS handles this signal correctly internally, it will perform cleaning operations such as closing database connections, completing the current request, and saving session data, and then exit itself.
  2. Add wait and timeout mechanism:To ensure the process has time for cleanup, we have added a:whileWait in a loop for the process to exit.kill -0 "$PID"Can check if a process exists without sending an actual signal. If AnQiCMS does not exit gracefully within the set time (e.g., 10 seconds), we will then usekill -9Perform a forced termination to prevent process deadlock.

Graceful shutdown in Docker environment

If you are running AnQiCMS in a Docker environment (such as 1Panel, aaPanel, or manual Docker deployment), it is even simpler. Docker'sdocker stopThe command will default send to the container's main processSIGTERMsignals (i.e.,killcommand), and wait for a period of time (default is 10 seconds) for the application to exit itself. If the application does not exit within this time, Docker will sendSIGKILLsignals (i.e.,kill -9Termination forced.

This means that if your AnQiCMS Docker container is properly configured and the AnQiCMS application itself is responsiveSIGTERMsignals, then throughdocker stop [容器名或ID]Stopping the service is already a graceful way to do it.

Points to note in the Windows/MacOS environment

On desktop operating systems such as Windows or MacOS, manually 'end task' or 'force quit' applications using Task Manager or Activity Monitor essentially involveskill -9Similar, both are forced to terminate.Although Go programs can respond to certain signals on these systems, the graphical interface typically does not provide an 'graceful shutdown' option unless the application itself provides an internal exit button or API.For AnQiCMS, the risk of forced shutdown is relatively low when used as a test or development environment on desktop systems, but it is strongly recommended to use script management or Docker management under Linux in production environments.

Summary

Gracefully stopping AnQiCMS is a good operational practice, which can effectively protect data, enhance system stability, and optimize user experience. By means ofstop.shscript, make sure it points to the correct directory of the AnQiCMS executable file, and that the directory containskill -9withkilland with appropriate timeout mechanisms, we can ensure that the AnQiCMS process performs necessary cleanup before exiting. In the Docker environment,docker stopThe command itself provides this elegant way to stop the process. As a website operations expert, adopting these strategies will make your AnQiCMS project management more professional and reliable.

Common Questions (FAQ)

Why is it saidkill -9it is a forced shutdown, rather than an elegant shutdown? What are the dangers?

A1:kill -9is sentSIGKILLSignal, this is a mandatory command at the operating system level, which the process cannot catch or respond to. This means thatkill -9The process will immediately stop with no chance to perform cleanup operations, such as saving cache data, closing file handles, releasing network connections, and synchronizing database status, etc.This may result in data loss, file corruption, resource leakage, and incomplete or inconsistent system states, which is a high-risk operation in a production environment.

**Q2: If I modify thestop.shscript iskillWhat if AnQiCMS does not exit gracefully but remains in a deadlock state?