cron - 使用 Upstart 代替 cron

Question

我可以使用 Upstart 来按计划运行任务吗？

现在我的 crontab 中有这个任务:

0 3 * * * /usr/bin/node ~/update.js
0 9 * * * /usr/bin/node ~/update.js
0 12 * * * /usr/bin/node ~/update.js
0 15 * * * /usr/bin/node ~/update.js

我如何通过 Upstart 运行此任务？是否可以？

Answer 1

这是使用 bash 对类似 cron 的行为的一种非常幼稚的实现:

description "cron-like naive backup service"
author "Reut Sharabani"

stop on [016] or backup-stop

start on backup-start or filesystem

# restart for 20 times, every 5 seconds, if crashes
respawn
respawn limit 20 5

script
    # actual backup 
    logger "starting backup"

    # folder to back-up to
    BKP_FOLDER="/home/XXXX/YYYY/backups"

    # backups log file
    LOG_FILE="/home/XXXX/YYYY/backups.log"  

    # logger "entering backup loop"
    while true
    do

        # verify log file exists
        if [ ! -e "$LOG_FILE" ]
        then
            logger "log file for backup service did not exist, creating one in "$LOG_FILE
            echo "Backup logs: " > $LOG_FILE
        fi
        # verify destination folder exist
        if [ ! -d "$BKP_FOLDER" ]
        then
            logger "Backup service folder did not exist, creating it in "$BKP_FOLDER
            mkdir $BKP_FOLDER
        fi


        # logger "checking last backup"

        # generate current backup, makes backups daily
        # (if we changed to +%M-%d-%m-%y it'd be per minute...)
        current_bkp="`date +%d-%m-%Y`"

        # generate last backed-up file
        last_bkp=`tail -1 $LOG_FILE`

        # check if this file wasn't already backed-up
        logger "checking $current_bkp against last status: $last_bkp"

        if [ "$last_bkp" = "$current_bkp finished" ]
        then
            logger "date $current_bkp already backed up!"
            # check for existing backup every hour
            sleep 600
        else

            # make sure a backup process isn't currently working!
            # a backup process is any process zipping into XXXX for the matter...
            if [ "`pgrep -f 'zip.*XXXX'`" = '' ]
            then
                # no process is running, back things up
                echo "$current_bkp started" >> $LOG_FILE
                logger $current_bkp" is being backed up..."
                # zip all folders in this list, array definition
                # does not work in upstart for some reason...
                zip -r $BKP_FOLDER"/"$current_bkp".zip" '/home/.../CENSORED' '/home/.../CENSORED' '/home/.../CENSORED'
                echo "$current_bkp finished" >> $LOG_FILE
                logger "date $current_bkp backed up!"

            else
                # backup process is still running, do nothing
                logger "Backup stopped because process $BKP_PROC was already backing up things..."
                logger "process info:"
                logger "`ps aux | grep $BKP_PROC | grep zip`"
            fi

        fi
    done
end script

此示例是每天的，但可以使用 date 轻松更改为您想要的任何基础。命令。

确保使用相关的等待时间。我使用十分钟进行每日备份，这足以满足我的需要(应该在午夜后几分钟开始备份)。

不要忘记您可以使用 rsync，这是我最初使用的(但 zip 更适合我的需求，因为我想保留单个备份的历史记录)

祝你好运! :-)