Cron 作业作为脚本运行正常，但不是 @reboot

Question

我正在无头远程 Ubuntu (v20.04.3) 上运行 Django (v3.1.7) 应用程序，我希望使用 crontab 在重新启动时启动该应用程序。下面的脚本可以从命令行运行。我已经在这里crontabs-reboot-only-works-for-root 和链接的建议，但仍然没有发现问题。我添加了日志记录（参见下面的*.log），但没有得到任何有用的输出。

编辑：test 屏幕在命令行和重新启动时都有效。 django 和 streaming 屏幕在重新启动时不起作用。使用which python3 检查 python 可执行文件返回/usr/bin/python3。所以在我看来，我拥有reboot.sh 和cron 的正确权限应该能够在crontab 文件中的PATH= 中找到python3。

/home/myapp/reboot.sh

#!/bin/bash
echo "$(date) Starting reboot.sh"

start_django () {
   echo "$(date) Entering start_django"
   screen -S django -dm bash -c 'cd /home/myapp && /usr/local/bin/gunicorn myapp.wsgi:application --bind 0.0.0.0:8000' > /home/myapp/django_cron.log 2>&1 
   sleep 1
   echo "$(date) Exiting start_django"
}

start_stream () {
   echo "$(date) Entering start_stream"
   screen -S streaming -dm bash -c 'cd /home/myapp/data_api && python3 api_stream_client.py' > /home/myapp/stream_cron.log 2>&1
   sleep 1
   echo "$(date) Exiting start_stream"
}

start_test () {
  echo "$(date) Entering start_test"
  screen -S testa -dm bash -c 'cd /home/myapp && exec bash' > /home/myapp/test_cron.log 2>&1
  sleep 1
  echo "$(date) Exiting start_test"
}


if screen -list | grep -q "No Sockets found"; then
    echo "$(date) No screens available"
    echo "$(date) Starting test"
    start_test
    echo "$(date) Starting django"
    start_django
    echo "$(date) Starting stream"
    start_stream
else
    if screen -list | grep -q "django"; then
        echo "$(date) django exists"
    else
        echo "$(date) django does not exist - starting now"
        start_django
    fi

    if screen -list | grep -q "streaming"; then
        echo "$(date) stream exists"
    else
        echo "$(date) stream does not exist - starting now"
        start_stream
    fi

    if screen -list | grep -q "test"; then
        echo "$(date) test exists"
    else
        echo "$(date) test does not exist - starting now"
        start_test
    fi
fi

contab -l

# m h  dom mon dow   command
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
@reboot sleep 60 && /home/myapp/reboot.sh > /home/myapp/cron.log 2>&1

/var/log/cron.log

Jan 28 15:21:44 localhost systemd-timesyncd[637]: Network configuration changed, trying to establish connection.
Jan 28 15:21:44 localhost cron[814]: (CRON) INFO (pidfile fd = 3)
Jan 28 15:21:44 localhost cron[814]: (CRON) INFO (Running @reboot jobs)
Jan 28 15:21:44 localhost CRON[824]: (root) CMD (sleep 60 && /home/financialdashboard/reboot.sh > /home/financialdashboard/cron.log 2>&1)
Jan 28 15:21:46 localhost systemd-timesyncd[637]: Network configuration changed, trying to establish connection.
Jan 28 15:21:50 localhost systemd-timesyncd[637]: Network configuration changed, trying to establish connection.
Jan 28 15:21:55 localhost systemd-timesyncd[637]: Network configuration changed, trying to establish connection.
Jan 28 15:21:55 localhost systemd-timesyncd[637]: Initial synchronization to time server [2001:67c:1560:8003::c7]:123 (ntp.ubuntu.com).

/home/myapp/cron.log

Fri Jan 28 15:22:44 UTC 2022 Starting reboot.sh
Fri Jan 28 15:22:44 UTC 2022 No screens available
Fri Jan 28 15:22:44 UTC 2022 Starting test
Fri Jan 28 15:22:44 UTC 2022 Entering start_test
Fri Jan 28 15:22:45 UTC 2022 Exiting start_test
Fri Jan 28 15:22:45 UTC 2022 Starting django
Fri Jan 28 15:22:45 UTC 2022 Entering start_django
Fri Jan 28 15:22:46 UTC 2022 Exiting start_django
Fri Jan 28 15:22:46 UTC 2022 Starting stream
Fri Jan 28 15:22:46 UTC 2022 Entering start_stream
Fri Jan 28 15:22:47 UTC 2022 Exiting start_stream

django_cron.log、stream_cron.log 和 test_cron.log 都是空的

Answer 1

建议修复您的crontab -l

# m h  dom mon dow   command
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
@reboot /usr/bin/sleep 60 && /home/myapp/reboot.sh > /home/myapp/cron.log 2>&1

建议修复您的/home/myapp/reboot.sh

在第二行注入source /home/myapp/.bash_profile。

sed -i "2i source /home/myapp/.bash_profile" /home/myapp/reboot.sh

Answer 2

已修复：django 和 streaming 屏幕依赖于一些未使用 cron 加载的环境变量。请参阅此处where-can-i-set-environment-variables-that-crontab-will-use 了解更多详情。

通过关注gnu-screen-logtstamp-string 和save-screen-program-output-to-a-file，我能够在屏幕上进行日志记录。

我更新的 /home/myapp/reboot.sh：

#!/bin/bash
SHELL=/bin/bash

echo "$(date) Starting reboot.sh"

# Load environment variables
source /etc/profile.d/env.sh

start_django () {
    echo "$(date) Entering start_django"
    screen -c /home/myapp/django_cron_log.conf -L -S django -dm bash -c 'cd /home/myapp && /usr/local/bin/gunicorn myapp.wsgi:application --bind 0.0.0.0:8000'
    echo "$(date) Exiting start_django"
}

start_stream () {
    echo "$(date) Entering start_stream"
    screen -c /home/myapp/stream_cron_log.conf -L -S streaming -dm bash -c 'cd /home/myapp/data_api && python3 api_stream_client.py && exec bash'
    echo "$(date) Exiting start_stream"
}

if screen -list | grep -q "No Sockets found"; then
    echo "$(date) No screens available"

    echo "$(date) Starting django"
    start_django

    echo "$(date) Starting stream"
    start_stream
else
    if screen -list | grep -q "django"; then
        echo "$(date) django exists; not starting django"
    else
        echo "$(date) django does not exist - starting now"
        start_django
    fi

    if screen -list | grep -q "streaming"; then
        echo "$(date) stream exists; not starting stream"
    else
        echo "$(date) stream does not exist - starting now"
        start_stream
    fi
fi

screen 中的 -c /home/myapp/*_cron_log.conf -L 将被删除以用于生产。