ubuntu-18.04 设置开机启动python脚本

开机启动折腾了好久，搞定开机启动但是启动python项目时又遇到问题搞了半天。

一、配置开机启动
ubuntu-18.04没有rc.local，不能通过rc.local来设置开机启动脚本，可以自己建一个。

1. 建立rc-local.service文件
   sudo vi /etc/systemd/system/rc-local.service
   然后将下面内容复制进去

   [Unit]
   Description=/etc/rc.local Compatibility
   ConditionPathExists=/etc/rc.local
    
   [Service]
   Type=forking
   ExecStart=/etc/rc.local start
   TimeoutSec=0
   StandardOutput=tty
   RemainAfterExit=yes
   SysVStartPriority=99
    
   [Install]
   WantedBy=multi-user.target
   

2. 创建文件rc.local
   sudo vi /etc/rc.local
   然后将下面内容复制进去

   #!/bin/sh -e
   #
   # rc.local
   #
   # This script is executed at the end of each multiuser runlevel.
   # Make sure that the script will "exit 0" on success or any other
   # value on error.
   #
   # In order to enable or disable this script just change the execution
   # bits.
   #
   # By default this script does nothing.
   #后台启动python工程，结果重定向到log.txt
   /usr/bin/nohup /usr/bin/python start_person.py > log.txt 2>&1 &
   exit 0
   

3. 给rc.local加上权限

   sudo chmod +x /etc/rc.local
   

4. 重启看看日志就可以.

二、解决python启动无法导入第三方模块问题

1. 看日志发现导入模块失败，但是本地直接执行脚本没有任何问题
   如 ImportError: No module named torch

2. 分析
   1）在本地进入python交互环境，查看python搜索路径

   nvidia@nvidia-desktop:~/data/projects/dt_product$ python
   Python 2.7.15+ (default, Nov 27 2018, 23:36:35)
   [GCC 7.3.0] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> import sys
   >>> sys.path
   ['', '/home/nvidia/.local/lib/python2.7/site-packages', '/home/nvidia/data/projects/dt_product', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-aarch64-linux-gnu', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/gtk-2.0']
   >>>
   

   2）新建一个python脚本设置为开机启动，在此脚本中获取python搜索路径

   !test.py
   
   import sys
   print sys.path
   

   重新启动环境查看启动重定向得日志 log.txt ：

   ['/home/nvidia/data/projects/dt_product', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-aarch64-linux-gnu', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/gtk-2.0']
   

   对比发现少了一个路径：'/home/nvidia/.local/lib/python2.7/site-packages',环境上看此路径为无法import 包得安装路径；应该是安装这些包时留的坑。

3. 解决
   一种是安装时注意下路径，一种是把这个路径加到环境变量中。
   加入环境变量网上搜有几种，但是试了都不行，因为启动python项目时改环境变量未生效，所以最简单得就是在启动python项目前加入该变量。

   打开刚才创建得启动python项目得文件，启动前加入环境变量

   sudo vi /etc/rc.local
   

   #!/bin/sh -e
   #
   # rc.local
   #
   # This script is executed at the end of each multiuser runlevel.
   # Make sure that the script will "exit 0" on success or any other
   # value on error.
   #
   # In order to enable or disable this script just change the execution
   # bits.
   #
   # By default this script does nothing.
   
   #加入环境变量
   export PYTHONPATH=/home/nvidia/.local/lib/python2.7/site-packages:$PYTHONPATH
   
   #后台启动python工程，结果重定向到log.txt
   /usr/bin/nohup /usr/bin/python start_person.py > log.txt 2>&1 &
   exit 0
   

   重启再查看日志是否启动。