Linux 應用程式開發入門
我會實現一個守護程序,從這個程式你將瞭解,Linux 應用程式開發基本流程
我們將實現一個遠端shell的功能,可以通過tcp協議,執行遠端機器上的命令或shell指令碼
通過這個命令可以實現批量操作,管理上千臺伺服器。需要發揮你的想象力,靈活使用它。
寫這個指令碼,我是為了替代SSH遠端操作,因為SSH不能控制執行命令,操作風險大,也不安全。
程式還不完善,還需要很多後續改進工作,比如通過SSL建立Socket連結,使用者認證,ACL訪問控制等等.
目錄
- 1. 環境
- 2. nodekeeper 主程式
- 2.1. 幫助資訊
- 2.2. 引數處理
- 2.3. 後臺執行
- 2.4. 日誌記錄
- 2.5. 多執行緒
- 3. 配置檔案
- 4. init.d 指令碼
- 4.1. start/stop
- 4.2. service start/stop
1. 環境
OS: Ubuntu 11.10
Python: 3.2.2
程式目錄: /srv/nodekeeper
目錄與相關檔案
$ cd /srv $ find nodekeeper | grep -v .svn nodekeeper nodekeeper/nodekeeper.ubuntu nodekeeper/nodekeeper.cenos nodekeeper/etc nodekeeper/etc/commands.cfg nodekeeper/etc/protocol.cfg nodekeeper/bin nodekeeper/bin/nodekeeper nodekeeper/bin/console
2. nodekeeper 主程式
$ cat nodekeeper/bin/nodekeeper #!/usr/bin/env python3 #/bin/env python3 #-*- coding: utf-8 -*- ############################################## # Home : http://netkiller.sf.net # Author: Neo <[email protected]> ############################################## import asyncore, asynchat, socket, threading import subprocess, os, sys, getopt, configparser, logging import string, re from multiprocessing import Process class Backend(asyncore.dispatcher): queue = [] def __init__(self, host, port,config): asyncore.dispatcher.__init__(self) self.host = host self.port = port self.config = config self.create_socket(socket.AF_INET, socket.SOCK_STREAM) self.bind((host,port)) self.listen(10) try: cfg = Protocol(config['protocol'], self.host) #self.protocols = cfg.items(self.host) self.protocols = cfg.all() self.sections = cfg.sections() except configparser.NoSectionError as err: print("Error: %s %s" %(err, config['protocol'])) sys.exit(2) try: logging.basicConfig(level=logging.NOTSET, format='%(asctime)s %(levelname)-8s %(message)s', datefmt='%Y-%m-%d %H:%M:%S', filename=config['logfile'], filemode='a') self.logging = logging.getLogger() #self.logging.debug('Test') except AttributeError as err: print("Error: %s %s" %(err, config['logfile'])) sys.exit(2) def handle_accept (self): conn, addr = self.accept() self.queue.append(addr) request_handler(conn, self) def handle_connect(self): pass def handle_expt(self): self.close() def handle_close(self): self.close() class request_handler(asynchat.async_chat): def __init__(self, sock, resource): asynchat.async_chat.__init__(self, sock=sock) self.sessions = resource self.buffer = b'' self.set_terminator(b"rn") self.logging = resource.logging self.protocols = resource.protocols self.sections = resource.sections self.host = self.sessions.host def handle_connect(self): # connection succeeded #self.logging.info('') pass def handle_expt(self): # connection failed self.close() def collect_incoming_data(self, data): """Buffer the data""" #self.buffer.append(data) self.buffer = data def found_terminator(self): try: buffer = bytes.decode(self.buffer) except UnicodeDecodeError: print("rnError: ",err) buffer = '' try: execute = re.split(' ', buffer) command = execute[0] parameter = ' '.join( execute[1:]) response = b'' screen = '' if self.buffer == b'quit' or self.buffer == b'exit' : self.push(b'shutdown!!!rn') self.close_when_done() elif self.buffer == b'help' or self.buffer == b'?': screen = "Help may be requested at any point in a command by entering a question mark '?' or 'help'. the help list will be showing the available options.rn" for cmd,v in self.protocols : screen += cmd + "rn" elif self.buffer == b'sections' : for sect in self.sections : screen += sect + "rn" elif self.buffer == b'help.html' : for cmd,v in self.protocols : screen += '<a href="?host='+self.host+'&cmd='+cmd+'">'+ cmd +'</a><br />' + "rn" elif self.buffer == b'enable': self.prompt = b'#' elif self.buffer == b'end' or self.buffer == b'^z': self.prompt = b'>' else: proto = dict(self.protocols) if command in proto : run = proto[command] + ' ' + parameter screen = subprocess.getoutput(run) if screen : response = bytes(screen + "rn",'utf8') self.push(response) self.logging.info(bytes.decode(self.buffer)) self.buffer = b'' self.close_when_done() except : self.close_when_done() sys.exit(2) class Protocol(): config = None agreement = None def __init__(self,cfg = 'protocol.cfg',sections = ''): self.config = configparser.SafeConfigParser() self.config.read(cfg) #self.agreement = self.config.items('common') def sections(self): return self.config.sections() def items(self, sections): self.agreement = self.config.items(sections) return self.agreement def dicts(self): return dict(self.agreement) def all(self): self.agreement = [] for section in self.config.sections(): self.agreement += self.config.items(section) return self.agreement def main(): daemon = False host = 'localhost' port = 7800 pidfile = '' logfile = '' cfgfile = '' try: opts, args = getopt.getopt(sys.argv[1:], "h:p:d?v", [ "daemon","host=","port=", 'help',"h=","p=", "basedir=", "pidfile=", "config=", "protocol=", "logfile="]) if not opts : usage() sys.exit() for o, a in opts : if o in ('-?', '--help') : usage() sys.exit() elif o in ("-v", "--verbose"): usage() sys.exit() elif o in ("-d", "--daemon"): daemon = True elif o in ("-h", "--host"): host = a elif o in ("-p", "--port"): port = int(a) elif o in ("--basedir"): BASEDIR = a elif o in ("--pidfile"): pidfile = a elif o in ("--config"): cfgfile = a elif o in ("--protocol"): protocol = a elif o in ("--logfile"): logfile = a else: assert False, "unhandled option" except getopt.GetoptError as err: # print help information and exit: usage() sys.exit(2) try: if daemon : pid = os.fork() if pid > 0: #exit first parent sys.exit(0) myself = str(sys.argv[0].split('/')[-1:][0]) #pidfile = os.getpid() if not pidfile : pidfile = '/var/run/'+myself+'.pid' file = open(pidfile,'w') file.write(str(os.getpid())) file.close() if not cfgfile : cfgfile = ''+myself+'.cfg' if not logfile : logfile = '/var/log/'+myself+'.log' config = dict({'cfgfile':cfgfile, 'pidfile':pidfile, 'logfile':logfile, 'protocol':protocol}) Backend(host,port,config) asyncore.loop(timeout=30, use_poll=True) except socket.error as err: print("rnError: ",err) sys.exit(2) except IOError as err: print("rnError: ",err) sys.exit(2) def usage(): myself = str(sys.argv[0].split('/')[-1:][0]) print("Usage: %s -d -h <ip address> -p <7800>" % myself ); print("Development and deployment administration platform") print("rnMandatory arguments to long options are mandatory for short options too.") print("t-?, --help") print("t-v, --verbose") print("t-d, --daemon") print("t-h, --host tt(default localhost)") print("t-p, --port") print("t --config tt(default %s.cfg)" % myself) print("t --protocol tt(default %s.cfg)" % "protocol.cfg") print("t --pidfile tt(default /var/run/%s.pid)" % myself) print("t --logfile tt(default /var/log/%s.log)" % myself) print("rnExample:") print("t%s --daemon --host localhost --port 7800" % myself) print("t%s -d -h localhost -p 7800" % myself) print("rnSee http://netkiller.sf.net/ for updates, bug reports, and answers, rnif you have no web access, by sending email to Neo Chan<[email protected]>. ") # Exit status is 0 if OK, 1 if minor problems, 2 if serious trouble. if __name__ == '__main__': try: main() except KeyboardInterrupt: print ("Crtl+C Pressed. Shutting down.")
2.1. 幫助資訊
usage()
Usage: nodekeeper -d -h <ip address> -p <7800>
Development and deployment administration platform
Mandatory arguments to long options are mandatory for short options too.
-?, --help
-v, --verbose
-d, --daemon
-h, --host (default localhost)
-p, --port
--config (default nodekeeper.cfg)
--protocol (default protocol.cfg.cfg)
--pidfile (default /var/run/nodekeeper.pid)
--logfile (default /var/log/nodekeeper.log)
Example:
nodekeeper --daemon --host localhost --port 7800
nodekeeper -d -h localhost -p 7800
See http://netkiller.sf.net/ for updates, bug reports, and answers,
if you have no web access, by sending email to Neo Chan<[email protected]>.
2.2. 引數處理
getopt.getopt 實現Unix風格的命令引數,例如:
nodekeeper --daemon --host localhost --port 7800
--host localhost --port 7800 IP地址與埠引數
--daemon 引數實現後臺執行
具體實現程式碼
try:
opts, args = getopt.getopt(sys.argv[1:], "h:p:d?v", [ "daemon","host=","port=", 'help',"h=","p=", "basedir=", "pidfile=", "config=", "protocol=", "logfile="])
if not opts :
usage()
sys.exit()
for o, a in opts :
if o in ('-?', '--help') :
usage()
sys.exit()
elif o in ("-v", "--verbose"):
usage()
sys.exit()
elif o in ("-d", "--daemon"):
daemon = True
elif o in ("-h", "--host"):
host = a
elif o in ("-p", "--port"):
port = int(a)
elif o in ("--basedir"):
BASEDIR = a
elif o in ("--pidfile"):
pidfile = a
elif o in ("--config"):
cfgfile = a
elif o in ("--protocol"):
protocol = a
elif o in ("--logfile"):
logfile = a
else:
assert False, "unhandled option"
except getopt.GetoptError as err:
# print help information and exit:
usage()
sys.exit(2)
2.3. 後臺執行
--daemon 引數實現後臺執行,原理是首先通過os.fork()克隆一個程序,然後退出當前程序,克隆的新程序繼續執行
如果是Shell程式,你可使用“&”符號後臺執行,但作為一個應用程式,使用“&”顯得不專業。
具體實現的程式碼如下
if daemon :
pid = os.fork()
if pid > 0:
#exit first parent
sys.exit(0)
程式一旦進入後臺,當前程序即將關閉,所以你必須儲存PID,為後面的推出程式操作使用,這裡我們可以通過 --pidfile 指定一個pid檔案
2.4. 日誌記錄
程式一旦進入後臺,你只能通過ps,pstree, top 等命令檢視狀態,執行情況必須通過日誌的形式,打印出來
具體實現程式碼如下:
logging.basicConfig(level=logging.NOTSET,
format='%(asctime)s %(levelname)-8s %(message)s',
datefmt='%Y-%m-%d %H:%M:%S',
filename=config['logfile'],
filemode='a')
self.logging = logging.getLogger()
self.logging.debug('Test')
2.5. 多執行緒
繼承 asynchat.async_chat 實現多執行緒
class request_handler(asynchat.async_chat):
def __init__(self, sock, resource):
asynchat.async_chat.__init__(self, sock=sock)
連線數限制
self.listen(10)
可以將這個引數提出來,然後通過命令列設定。
nodekeeper --daemon --maxconn 100 --host localhost --port 7800
self.max_connect = maxconn
self.listen(self.max_connect)
3. 配置檔案
$ cat nodekeeper/etc/protocol.cfg
[system]
ls = ls
os.hosts = cat /etc/hosts
os.issue = cat /etc/issue
os.memory = free
os.who = who
os.harddisk = df -h
os.uptime = uptime
os.cpuinfo = cat /proc/cpuinfo
os.meminfo = cat /proc/meminfo
os.dmesg = dmesg
os.process = ps aux
os.summary = echo
network.status = netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'
network.netstat = netstat -nlp
network.ifconfig = ifconfig
network.route = ip route
[apache]
apache.start = /usr/local/apache/bin/apachectl start
apache.stop = /usr/local/apache/bin/apachectl stop
apache.restart = /usr/local/apache/bin/apachectl restart
apache.status = ps ax |grep httpd
apache.conf = cat /usr/local/apache/conf/httpd.conf
apache.conf.vhost = cat /usr/local/apache/conf/extra/httpd-vhosts.conf
apache.logs.now =
apache.logs.tail =
[resin]
resin.start = /usr/local/resin/bin/httpd.sh start
resin.stop = /usr/local/resin/bin/httpd.sh stop
resin.restart = /usr/local/resin/bin/httpd.sh restart
resin.status = /usr/local/resin/bin/httpd.sh status
resin.conf = cat /usr/local/resin/conf/resin.conf
[www]
www.list = ls -1 /www
www.permission = find /www -type d -exec chmod 755 {} ; find /www -type f -exec chmod 644 {} ;
www.permission.777 = chmod 777 -R /www/*
lamp.status = ps ax |grep -E "mysqld|httpd|resin"
[samba]
samba.start = /etc/init.d/smb start
samba.stop = /etc/init.d/smb stop
samba.restart = /etc/init.d/smb restart
samba.status = /etc/init.d/smb status
[mysql]
mysql.start = /etc/init.d/mysql start
mysql.stop = /etc/init.d/mysql stop
mysql.restart = /etc/init.d/mysql restart
[memcache]
memcache.start = /etc/init.d/memcache start
memcache.stop = /etc/init.d/memcache stop
memcache.restart = /etc/init.d/memcache restart
[vsftpd]
vsftpd.start = /etc/init.d/vsftpd start
vsftpd.stop = /etc/init.d/vsftpd stop
vsftpd.restart = /etc/init.d/vsftpd restart
vsftpd.status = /etc/init.d/vsftpd status
4. init.d 指令碼
Linux 所有守護程序都是用init.d下面的指令碼來管理
當人你也可以直接執行命令:
nodekeeper --daemon --host localhost --port 7800
但這樣只能算是一個半成品,也不夠專業,我們寫的是linux運用程式,必須遵循Linux規範,所有要實現一個init.d指令碼
$ cat nodekeeper
#! /bin/sh
### BEGIN INIT INFO
# Provides: nodekeeper
# Required-Start: $local_fs $remote_fs $network $syslog
# Required-Stop: $local_fs $remote_fs $network $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: starts the nodekeeper web server
# Description: starts nodekeeper using start-stop-daemon
### END INIT INFO
PATH=/srv/nodekeeper/bin:$PATH
DAEMON=/srv/nodekeeper/bin/nodekeeper
NAME=nodekeeper
DESC=nodekeeper
BASEDIR="/srv/nodekeeper"
HOST=$(ifconfig | grep 'inet addr:'| grep -v '127.0.0.1' | cut -d: -f2 | awk '{ print $1}'|head -n 1)
PORT=7800
CONFIG=$BASEDIR/etc/$NAME.cfg
LOGFILE=$BASEDIR/log/$NAME.log
PIDFILE=$BASEDIR/run/$NAME.pid
PIDFILE=/var/run/$NAME.pid
PROTOCOL=$BASEDIR/etc/protocol.cfg
DAEMON_OPTS="--daemon --host $HOST --port $PORT --config=$CONFIG --protocol=$PROTOCOL --pidfile=$PIDFILE --logfile=$LOGFILE"
test -x $DAEMON || exit 0
# Include nodekeeper defaults if available
if [ -f /etc/default/nodekeeper ] ; then
. /etc/default/nodekeeper
fi
set -e
. /lib/lsb/init-functions
#test_nodekeeper_config() {
# if $DAEMON -t $DAEMON_OPTS >/dev/null 2>&1
# then
# return 0
# else
# $DAEMON -t $DAEMON_OPTS
# return $?
# fi
#}
case "$1" in
start)
echo -n "Starting $DESC: "
start-stop-daemon --start --quiet --pidfile /var/run/$NAME.pid
--exec $DAEMON -- $DAEMON_OPTS || true
echo "$NAME."
;;
stop)
echo -n "Stopping $DESC: "
start-stop-daemon --stop --quiet --pidfile /var/run/$NAME.pid
--exec $DAEMON || true
echo "$NAME."
;;
restart|force-reload)
echo -n "Restarting $DESC: "
start-stop-daemon --stop --quiet --pidfile
/var/run/$NAME.pid --exec $DAEMON || true
sleep 1
start-stop-daemon --start --quiet --pidfile
/var/run/$NAME.pid --exec $DAEMON -- $DAEMON_OPTS || true
echo "$NAME."
;;
reload)
echo -n "Reloading $DESC configuration: "
start-stop-daemon --stop --signal HUP --quiet --pidfile /var/run/$NAME.pid
--exec $DAEMON || true
echo "$NAME."
;;
configtest)
echo -n "Testing $DESC configuration: "
if test_nodekeeper_config
then
echo "$NAME."
else
exit $?
fi
;;
status)
status_of_proc -p /var/run/$NAME.pid "$DAEMON" nodekeeper && exit 0 || exit $?
;;
*)
echo "Usage: $NAME {start|stop|restart|reload|force-reload|status|configtest}" >&2
exit 1
;;
esac
exit 0
我們將使用DAEMON_OPTS變數,提供所有需要的引數
DAEMON_OPTS="--daemon --host $HOST --port $PORT --config=$CONFIG --protocol=$PROTOCOL --pidfile=$PIDFILE --logfile=$LOGFILE"
4.1. start/stop
/etc/init.d/nodekeeper start
/etc/init.d/nodekeeper stop
4.2. service start/stop
service nodekeeper start
service nodekeeper stop