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  • Supervisor使用教程

    在项目中,经常有脚本需要常驻运行的需求。以PHP脚本为例,最简单的方式是:

    $ nohup php cli.php &
    

    这样能保证当前终端被关闭或者按CRTL+C后,脚本仍在后台运行。但是没法保证脚本异常后自动重启等。

    Supervisor 是用Python开发的一套通用的进程管理程序,能将一个普通的命令行进程变为后台daemon,并监控进程状态,异常退出时能自动重启。

    官网介绍:http://supervisord.org/

    本文所用环境:

    • CentOS release 6.8 (Final)
    • Python 2.6.6
    • pip 7.1.0 from /usr/lib/python2.6/site-packages (python 2.6)
    • supervisor 3.3.4

    安装

    平台要求

    引自官网(http://supervisord.org/introduction.html#platform-requirements):

    Supervisor已经过测试,可以在Linux(Ubuntu 9.10),Mac OS X(10.4 / 10.5 / 10.6)和Solaris(10 for Intel)和FreeBSD 6.1上运行。它可能在大多数UNIX系统上都能正常工作。在任何版本的Windows下,Supervisor 都不会运行。Supervisor 可以使用Python 2.4或更高版本,但不能在任何版本的Python 3下使用。

    我使用的环境:

    $ python -V
    Python 2.6.6
    

    安装

    安装方法有:
    1、easy_install 安装(需安装有pip):

    $ easy_install supervisor
    

    2、pip 安装(需安装有pip,推荐):

    $ pip install supervisor
    

    3、Debian / Ubuntu可以直接通过apt安装:

    $ apt-get install supervisor
    

    本文测试的时候是使用pip安装的。其它方式未做测试。

    安装后配置文件生成:

    1、通过easy_install或pip安装后,需要运行

    $ mkdir /etc/supervisor
    $ echo_supervisord_conf > /etc/supervisor/supervisord.conf
    

    生成配置文件。

    2、使用apt-get安装后,supervisor的主配置文件在:

    /etc/supervisor/supervisord.conf 
    

    supervisor的配置文件默认是不全的。子进程配置文件在:

    /etc/supervisor/conf.d/*.conf
    

    启动supervisor

    我们先修改supervisord.conf最后的[include]部分配置:

    [include]
    files = /etc/supervisor/conf.d/*.conf
    

    这样就可以支持子配置文件,而不用改动主配置文件。

    启动方法一般有:

    1、使用 pip或者easy_install 安装的supervisor则:

    $ supervisord 
    

    即可运行。

    supervisor 默认在以下路径查找配置文件:/usr/etc/supervisord.conf, /usr/supervisord.conf, supervisord.conf, etc/supervisord.conf, /etc/supervisord.conf, /etc/supervisor/supervisord.conf

    如需指定主配置文件,则需要使用-c参数:

    $ supervisord -c /etc/supervisor/supervisord.conf
    

    查看安装的版本:

    $ supervisord -v
    3.3.4
    

    然后查看supervisor的状态:

    $ supervisorctl  status
    

    注: supervisord是主进程,supervisorctl是给守护进程发送命令的客户端工具。

    2、使用 apt-get 安装的supervisor直接可以通过

    $ /etc/init.d/supervisor start
    

    运行。

    使用示例

    我们以简单的 /tmp/echo_time.sh 为例:

    #/bin/bash
    
    while true; do
        echo `date +%Y-%m-%d,%H:%m:%s`
        sleep 2
    done
    

    /etc/supervisor/conf.d/新增子进程配置文件 echo_time.conf

    [program:echo_time]
    command=sh /tmp/echo_time.sh
    priority=999                ; the relative start priority (default 999)
    autostart=true              ; start at supervisord start (default: true)
    autorestart=true            ; retstart at unexpected quit (default: true)
    startsecs=10                ; number of secs prog must stay running (def. 10)
    startretries=3              ; max # of serial start failures (default 3)
    exitcodes=0,2               ; 'expected' exit codes for process (default 0,2)
    stopsignal=QUIT             ; signal used to kill process (default TERM)
    stopwaitsecs=10             ; max num secs to wait before SIGKILL (default 10)
    user=root                 ; setuid to this UNIX account to run the program
    log_stdout=true
    log_stderr=true             ; if true, log program stderr (def false)
    logfile=/tmp/echo_time.log
    logfile_maxbytes=1MB        ; max # logfile bytes b4 rotation (default 50MB)
    logfile_backups=10          ; # of logfile backups (default 10)
    stdout_logfile_maxbytes=20MB  ; stdout 日志文件大小,默认 50MB
    stdout_logfile_backups=20     ; stdout 日志文件备份数
    stdout_logfile=/tmp/echo_time.stdout.log
    

    然后启动程序:

    $ supervisorctl reread
    $ supervisorctl update
    

    这两个命令分别代表重新读取配置、更新子进程组。执行update后输出:

    echo_time: added process group
    

    这样刚才添加的echo_time脚本就常驻运行起来了。可以通过日志查看运行情况:

    $ tail -f /tmp/echo_time.stdout.log
    2018-12-22,14:12:1545459550
    2018-12-22,14:12:1545459552
    2018-12-22,14:12:1545459554
    

    也可以使用supervisorctl status查看子进程运行情况:

    $ supervisorctl  status
    echo_time                        RUNNING   pid 28206, uptime 0:00:11
    

    配置文件

    主配置

    主配置文件名: supervisord.conf

    可以通过运行echo_supervisord_conf获得。这个配置文件一般情况下不需要更改,除了最后的[include]部分,其余保持默认即可。

    [unix_http_server]
    file=/tmp/supervisor.sock   ; the path to the socket file
    ;chmod=0700                 ; socket file mode (default 0700)
    ;chown=nobody:nogroup       ; socket file uid:gid owner
    ;username=user              ; default is no username (open server)
    ;password=123               ; default is no password (open server)
    
    ;[inet_http_server]         ; 配置web后台
    ;port=127.0.0.1:9001        ; 指定ip_address:port, 使用 *:port 监听所有 IP
    ;username=user              ; 默认没有用户名 (open server)
    ;password=123               ; 默认没有密码 (open server)
    
    [supervisord]
    logfile=/tmp/supervisord.log ; 日志文件; 默认 $CWD/supervisord.log
    logfile_maxbytes=50MB        ; 日志文件最大大小; 默认 50MB
    logfile_backups=10           ; # of main logfile backups; 0 means none, default 10
    loglevel=info                ; log level; default info; others: debug,warn,trace
    pidfile=/tmp/supervisord.pid ; pid文件
    nodaemon=false               ; 是否运行在前台; 默认是后台
    minfds=1024                  ; min. avail startup file descriptors; default 1024
    minprocs=200                 ; min. avail process descriptors;default 200
    ;umask=022                   ; process file creation umask; default 022
    ;user=chrism                 ; default is current user, required if root
    ;identifier=supervisor       ; supervisord identifier, default is 'supervisor'
    ;directory=/tmp              ; default is not to cd during start
    ;nocleanup=true              ; don't clean up tempfiles at start; default false
    ;childlogdir=/tmp            ; 'AUTO' child log dir, default $TEMP
    ;environment=KEY="value"     ; key value pairs to add to environment
    ;strip_ansi=false            ; strip ansi escape codes in logs; def. false
    
    ; The rpcinterface:supervisor section must remain in the config file for
    ; RPC (supervisorctl/web interface) to work.  Additional interfaces may be
    ; added by defining them in separate [rpcinterface:x] sections.
    
    [rpcinterface:supervisor]
    supervisor.rpcinterface_factory = supervisor.rpcinterface:make_main_rpcinterface
    
    ; 配置 supervisorctl 
    ; configure it match the settings in either the unix_http_server
    ; or inet_http_server section.
    
    [supervisorctl]
    serverurl=unix:///tmp/supervisor.sock ; use a unix:// URL  for a unix socket
    ;serverurl=http://127.0.0.1:9001 ; use an http:// url to specify an inet socket
    ;username=chris              ; should be same as in [*_http_server] if set
    ;password=123                ; should be same as in [*_http_server] if set
    ;prompt=mysupervisor         ; cmd line prompt (default "supervisor")
    ;history_file=~/.sc_history  ; use readline history if available
    
    ; 下面是子进程配置文件示例
    ; Create one or more 'real' program: sections to be able to control them under
    ; supervisor.
    
    ;[program:theprogramname]
    ;command=/bin/cat              ; the program (relative uses PATH, can take args)
    ;process_name=%(program_name)s ; process_name expr (default %(program_name)s)
    ;numprocs=1                    ; number of processes copies to start (def 1)
    ;directory=/tmp                ; directory to cwd to before exec (def no cwd)
    ;umask=022                     ; umask for process (default None)
    ;priority=999                  ; the relative start priority (default 999)
    ;autostart=true                ; start at supervisord start (default: true)
    ;startsecs=1                   ; # of secs prog must stay up to be running (def. 1)
    ;startretries=3                ; max # of serial start failures when starting (default 3)
    ;autorestart=unexpected        ; when to restart if exited after running (def: unexpected)
    ;exitcodes=0,2                 ; 'expected' exit codes used with autorestart (default 0,2)
    ;stopsignal=QUIT               ; signal used to kill process (default TERM)
    ;stopwaitsecs=10               ; max num secs to wait b4 SIGKILL (default 10)
    ;stopasgroup=false             ; send stop signal to the UNIX process group (default false)
    ;killasgroup=false             ; SIGKILL the UNIX process group (def false)
    ;user=chrism                   ; setuid to this UNIX account to run the program
    ;redirect_stderr=true          ; redirect proc stderr to stdout (default false)
    ;stdout_logfile=/a/path        ; stdout log path, NONE for none; default AUTO
    ;stdout_logfile_maxbytes=1MB   ; max # logfile bytes b4 rotation (default 50MB)
    ;stdout_logfile_backups=10     ; # of stdout logfile backups (0 means none, default 10)
    ;stdout_capture_maxbytes=1MB   ; number of bytes in 'capturemode' (default 0)
    ;stdout_events_enabled=false   ; emit events on stdout writes (default false)
    ;stderr_logfile=/a/path        ; stderr log path, NONE for none; default AUTO
    ;stderr_logfile_maxbytes=1MB   ; max # logfile bytes b4 rotation (default 50MB)
    ;stderr_logfile_backups=10     ; # of stderr logfile backups (0 means none, default 10)
    ;stderr_capture_maxbytes=1MB   ; number of bytes in 'capturemode' (default 0)
    ;stderr_events_enabled=false   ; emit events on stderr writes (default false)
    ;environment=A="1",B="2"       ; process environment additions (def no adds)
    ;serverurl=AUTO                ; override serverurl computation (childutils)
    
    ; The sample eventlistener section below shows all possible eventlistener
    ; subsection values.  Create one or more 'real' eventlistener: sections to be
    ; able to handle event notifications sent by supervisord.
    
    ;[eventlistener:theeventlistenername]
    ;command=/bin/eventlistener    ; the program (relative uses PATH, can take args)
    ;process_name=%(program_name)s ; process_name expr (default %(program_name)s)
    ;numprocs=1                    ; number of processes copies to start (def 1)
    ;events=EVENT                  ; event notif. types to subscribe to (req'd)
    ;buffer_size=10                ; event buffer queue size (default 10)
    ;directory=/tmp                ; directory to cwd to before exec (def no cwd)
    ;umask=022                     ; umask for process (default None)
    ;priority=-1                   ; the relative start priority (default -1)
    ;autostart=true                ; start at supervisord start (default: true)
    ;startsecs=1                   ; # of secs prog must stay up to be running (def. 1)
    ;startretries=3                ; max # of serial start failures when starting (default 3)
    ;autorestart=unexpected        ; autorestart if exited after running (def: unexpected)
    ;exitcodes=0,2                 ; 'expected' exit codes used with autorestart (default 0,2)
    ;stopsignal=QUIT               ; signal used to kill process (default TERM)
    ;stopwaitsecs=10               ; max num secs to wait b4 SIGKILL (default 10)
    ;stopasgroup=false             ; send stop signal to the UNIX process group (default false)
    ;killasgroup=false             ; SIGKILL the UNIX process group (def false)
    ;user=chrism                   ; setuid to this UNIX account to run the program
    ;redirect_stderr=false         ; redirect_stderr=true is not allowed for eventlisteners
    ;stdout_logfile=/a/path        ; stdout log path, NONE for none; default AUTO
    ;stdout_logfile_maxbytes=1MB   ; max # logfile bytes b4 rotation (default 50MB)
    ;stdout_logfile_backups=10     ; # of stdout logfile backups (0 means none, default 10)
    ;stdout_events_enabled=false   ; emit events on stdout writes (default false)
    ;stderr_logfile=/a/path        ; stderr log path, NONE for none; default AUTO
    ;stderr_logfile_maxbytes=1MB   ; max # logfile bytes b4 rotation (default 50MB)
    ;stderr_logfile_backups=10     ; # of stderr logfile backups (0 means none, default 10)
    ;stderr_events_enabled=false   ; emit events on stderr writes (default false)
    ;environment=A="1",B="2"       ; process environment additions
    ;serverurl=AUTO                ; override serverurl computation (childutils)
    
    ; The sample group section below shows all possible group values.  Create one
    ; or more 'real' group: sections to create "heterogeneous" process groups.
    
    ;[group:thegroupname]
    ;programs=progname1,progname2  ; each refers to 'x' in [program:x] definitions
    ;priority=999                  ; the relative start priority (default 999)
    
    ; 配置include files
    ; The [include] section can just contain the "files" setting.  This
    ; setting can list multiple files (separated by whitespace or
    ; newlines).  It can also contain wildcards.  The filenames are
    ; interpreted as relative to this file.  Included files *cannot*
    ; include files themselves.
    
    [include]  
    ; .ini和.conf都支持
    files = relative/directory/*.ini
    

    子进程配置文件

    一般放在:/etc/supervisor/conf.d/目录 。一个脚本对应一个配置文件。

    配置说明:

    ;*为必须填写项
    ;*[program:应用名称]
    [program:cat]
    
    ;*命令路径,如果使用python启动的程序应该为 python /home/test.py, 
    ;不建议放入/home/user/, 对于非user用户一般情况下是不能访问
    command=/bin/cat
    
    ;当numprocs为1时,process_name=%(program_name)s;
    当numprocs>=2时,%(program_name)s_%(process_num)02d
    process_name=%(program_name)s
    
    ;进程数量
    numprocs=1
    
    ;执行目录,若有/home/supervisor_test/test1.py
    ;将directory设置成/home/supervisor_test
    ;则command只需设置成python test1.py
    ;否则command必须设置成绝对执行目录
    directory=/tmp
    
    ;掩码:--- -w- -w-, 转换后rwx r-x w-x
    umask=022
    
    ;优先级,值越高,最后启动,最先被关闭,默认值999
    priority=999
    
    ;如果是true,当supervisor启动时,程序将会自动启动
    autostart=true
    
    ;*自动重启
    autorestart=true
    
    ;启动延时执行,默认1秒
    startsecs=10
    
    ;启动尝试次数,默认3次
    startretries=3
    
    ;当退出码是0,2时,执行重启,默认值0,2
    exitcodes=0,2
    
    ;停止信号,默认TERM
    ;中断:INT(类似于Ctrl+C)(kill -INT pid),退出后会将写文件或日志(推荐)
    ;终止:TERM(kill -TERM pid)
    ;挂起:HUP(kill -HUP pid),注意与Ctrl+Z/kill -stop pid不同
    ;从容停止:QUIT(kill -QUIT pid)
    ;KILL, USR1, USR2其他见命令(kill -l),说明1
    stopsignal=TERM
    
    stopwaitsecs=10
    
    ;*以root用户执行
    user=root
    
    ;重定向
    redirect_stderr=false
    
    stdout_logfile=/a/path
    stdout_logfile_maxbytes=1MB
    stdout_logfile_backups=10
    stdout_capture_maxbytes=1MB
    stderr_logfile=/a/path
    stderr_logfile_maxbytes=1MB
    stderr_logfile_backups=10
    stderr_capture_maxbytes=1MB
    
    ;环境变量设置
    environment=A="1",B="2"
    
    serverurl=AUTO
    

    简化模板

    [program:echo_time]
    command=sh /tmp/echo_time.sh
    autostart=true
    autorestart=true
    startsecs=10
    startretries=3 
    exitcodes=0,2
    stopsignal=QUIT
    stopwaitsecs=10
    user=root
    log_stdout=true
    log_stderr=true
    logfile=/tmp/echo_time.log
    logfile_maxbytes=1MB
    logfile_backups=10 
    stdout_logfile_maxbytes=20MB 
    stdout_logfile_backups=20 
    stdout_logfile=/tmp/echo_time.stdout.log
    

    如果上面的模板里增加下面两句:

    process_name=%(process_num)02d
    numprocs=3
    

    执行supervisorctl update后会启动三个进程:

    $ supervisorctl status
    echo_time:00     RUNNING   pid 26762, uptime 2:06:12
    echo_time:01     RUNNING   pid 26866, uptime 2:06:02
    echo_time:02     RUNNING   pid 27975, uptime 2:05:52
    

    这对于需要多进程消费的场景非常有用。


    防盗版声明:本文系原创文章,发布于公众号飞鸿影的博客(fhyblog)及博客园,转载需作者同意。


    命令行程序

    supervisord

    supervisord 是主进程。

    通过supervisord -h可以查看帮助说明。示例:

    -c/--configuration FILENAME ;指定配置文件
    -n/--nodaemon ;运行在前台(调试用)
    -v/--version ;打印版本信息
    
    -u/--user USER ;以指定用户(或用户ID)运行
    -m/--umask UMASK ;指定子进程的umask,默认是022
    -l/--logfile FILENAME ;指定日志文件
    -e/--loglevel LEVEL ;指定日志级别
    

    supervisorctl

    supervisorctl 是客户端程序,用于向supervisord发起命令。

    通过supervisorctl -h可以查看帮助说明。我们主要关心的是其action命令:

    $ supervisorctl  help
    
    default commands (type help <topic>):
    =====================================
    add    exit      open  reload  restart   start   tail   
    avail  fg        pid   remove  shutdown  status  update 
    clear  maintail  quit  reread  signal    stop    version
    

    这些命令对于控制子进程非常重要。示例:

    reread ;重新加载配置文件
    update ;将配置文件里新增的子进程加入进程组,如果设置了autostart=true则会启动新新增的子进程
    status ;查看所有进程状态
    status <name> ;查看指定进程状态
    start all; 启动所有子进程
    start <name>; 启动指定子进程
    restart all; 重启所有子进程
    restart <name>; 重启指定子进程
    stop all; 停止所有子进程
    stop <name>; 停止指定子进程
    reload ;重启supervisord
    add <name>; 添加子进程到进程组
    reomve <name>; 从进程组移除子进程,需要先stop。注意:移除后,需要使用reread和update才能重新运行该进程
    

    supervisord 有进程组(process group)的概念:只有子进程在进程组,才能被运行。

    supervisorctl也支持交互式命令行:

    $ supervisorctl
    echo_time                        RUNNING   pid 27188, uptime 0:05:09
    supervisor> version
    3.3.4
    supervisor> 
    

    web界面操作

    需要开启supervisord.conf注释掉的这4行:

    [inet_http_server]         ; inet (TCP) server disabled by default
    port=127.0.0.1:9001        ; ip_address:port specifier, *:port for all iface
    username=user              ; default is no username (open server)
    password=123               ; default is no password (open server)
    

    端口默认是监听127.0.0.1:9001,这里方便测试,修改为:

    port=*:9001 
    

    然后重启主进程supervisord:

    $ supervisorctl reload
    

    浏览器访问:http://myip:9001 ,输入用户名、密码后,即可看到web页面:

    注意:如果修改配置文件时,[inet_http_server] 这一行被注释,会导致不仅web需要认证,命令行使用supervisorctl也需要认证,这时候就需要在交互式命令行里输入用户名、密码才能进行下一步的操作。

    其它问题

    1、Centos6 docker环境没有pip

    解决方案:需要先安装扩展源EPEL。

    EPEL(http://fedoraproject.org/wiki/EPEL) 是由 Fedora 社区打造,为 RHEL 及衍生发行版如 CentOS、Scientific Linux 等提供高质量软件包的项目。

    首先安装epel扩展源:

    $ yum -y install epel-release
    

    然后再安装pip

    $ yum -y install python-pip
    

    查看版本:

    $ pip -V
    pip 7.1.0 from /usr/lib/python2.6/site-packages (python 2.6)
    

    参考:https://www.cnblogs.com/saolv/p/6963314.html

    2、Centos6环境安装supervisor后,执行:

    $ supervisor -V
    

    出现:

    Traceback (most recent call last):
      File "/usr/bin/echo_supervisord_conf", line 5, in <module>
        from pkg_resources import load_entry_point
      File "/usr/lib/python2.6/site-packages/setuptools-0.6c11-py2.6.egg/pkg_resources.py", line 2603, in <module>
      File "/usr/lib/python2.6/site-packages/setuptools-0.6c11-py2.6.egg/pkg_resources.py", line 666, in require
      File "/usr/lib/python2.6/site-packages/setuptools-0.6c11-py2.6.egg/pkg_resources.py", line 565, in resolve
    pkg_resources.DistributionNotFound: meld3>=0.6.5
    

    原因:pip安装的meld3不可用,手动安装。

    wget https://pypi.python.org/packages/source/m/meld3/meld3-1.0.2.tar.gz
    tar -zxf meld3-1.0.2.tar.gz
    cd meld3-1.0.2
    python setup.py install
    

    感谢https://www.cnblogs.com/hubery/p/5653007.html 文章提供的方法!这个问题困扰了好久,github页面(https://github.com/Supervisor/meld3/issues/23)提供的解决方案都不可行,反而导致pip都不能用了。

    3、因参考github里meld3解决方案导致pip不可用:

    Traceback (most recent call last):
      File "/usr/bin/pip", line 5, in <module>
        from pkg_resources import load_entry_point
      File "/usr/lib/python2.6/site-packages/pkg_resources/__init__.py", line 957, in <module>
        class Environment:
      File "/usr/lib/python2.6/site-packages/pkg_resources/__init__.py", line 961, in Environment
        self, search_path=None, platform=get_supported_platform(),
      File "/usr/lib/python2.6/site-packages/pkg_resources/__init__.py", line 188, in get_supported_platform
        plat = get_build_platform()
      File "/usr/lib/python2.6/site-packages/pkg_resources/__init__.py", line 391, in get_build_platform
        from sysconfig import get_platform
    ImportError: No module named sysconfig
    

    解决方案:删除/site-packages下面的包,重新安装python-setuptools:

    rm -rf /usr/lib/python2.6/site-packages/pkg_resources*
    yum reinstall python-setuptools
    

    参考:https://stackoverflow.com/questions/50742538/importerror-no-module-named-sysconfig-cant-get-pip-working

    4、输入supervisord 命令后报错:

    Traceback (most recent call last):
      File "/usr/local/bin/supervisord", line 6, in <module>
        from pkg_resources import load_entry_point
      File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3019, in <module>
        @_call_aside
      File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3003, in _call_aside
        f(*args, **kwargs)
      File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3032, in _initialize_master_working_set
        working_set = WorkingSet._build_master()
      File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 655, in _build_master
        ws.require(__requires__)
      File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 963, in require
        needed = self.resolve(parse_requirements(requirements))
      File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 849, in resolve
        raise DistributionNotFound(req, requirers)
    pkg_resources.DistributionNotFound: The 'supervisor==3.2.0' distribution was not found and is required by the application
    
    

    解决:

    1、查找supervisord在哪

    whereis supervisord
    

    supervisord: /usr/local/bin/supervisord

    2、执行

    rm -rf /usr/local/bin/supervisord
    

    原因是supervisor 正常被卸载,supervisord 并没有被正常卸载。

    也可以指定错误版本重新安装:

    pip install supervisor==3.2.0
    

    详情:https://hooklife.me/linux/Supervisor在deepin安装、卸载与使用/

    参考

    1、Supervisor: A Process Control System — Supervisor 3.3.4 documentation
    http://supervisord.org/index.html
    2、进程管理supervisor的简单说明 - jyzhou - 博客园
    https://www.cnblogs.com/zhoujinyi/p/6073705.html
    3、DevOps
    https://mp.weixin.qq.com/s/mqrkAEaGFKJy-4PQadJJ9w?
    4、supervisor使用 - 回首郑板桥 - 博客园
    https://www.cnblogs.com/hubery/p/5653007.html

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  • 原文地址:https://www.cnblogs.com/52fhy/p/10161253.html
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