# -*- coding: utf-8 -*-
import os
import subprocess
import signal
import pwd
import sys
class MockLogger( object ):
'''模拟日志类。方便单元测试。'''
def __init__( self ):
self .info = self .error = self .critical = self .debug
def debug( self , msg):
print "LOGGER:" + msg
class Shell( object ):
'''完成Shell脚本的包装。
执行结果存放在Shell.ret_code, Shell.ret_info, Shell.err_info中
run()为普通调用,会等待shell命令返回。
run_background()为异步调用,会立刻返回,不等待shell命令完成
异步调用时,可以使用get_status()查询状态,或使用wait()进入阻塞状态,
等待shell执行完成。
异步调用时,使用kill()强行停止脚本后,仍然需要使用wait()等待真正退出。
TODO 未验证Shell命令含有超大结果输出时的情况。
'''
def __init__( self , cmd):
self .cmd = cmd # cmd包括命令和参数
self .ret_code = None
self .ret_info = None
self .err_info = None
#使用时可替换为具体的logger
self .logger = MockLogger()
def run_background( self ):
'''以非阻塞方式执行shell命令(Popen的默认方式)。
'''
self .logger.debug( "run %s" % self .cmd)
# Popen在要执行的命令不存在时会抛出OSError异常,但shell=True后,
# shell会处理命令不存在的错误,因此没有了OSError异常,故不用处理
self ._process = subprocess.Popen( self .cmd, shell = True ,
stdout = subprocess.PIPE, stderr = subprocess.PIPE) #非阻塞
def run( self ):
'''以阻塞方式执行shell命令。
'''
self .run_background()
self .wait()
def run_cmd( self , cmd):
'''直接执行某条命令。方便一个实例重复使用执行多条命令。
'''
self .cmd = cmd
self .run()
def wait( self ):
'''等待shell执行完成。
'''
self .logger.debug( "waiting %s" % self .cmd)
self .ret_info, self .err_info = self ._process.communicate() #阻塞
# returncode: A negative value -N indicates that the child was
# terminated by signal N
self .ret_code = self ._process.returncode
self .logger.debug( "waiting %s done. return code is %d" % ( self .cmd,
self .ret_code))
def get_status( self ):
'''获取脚本运行状态(RUNNING|FINISHED)
'''
retcode = self ._process.poll()
if retcode = = None :
status = "RUNNING"
else :
status = "FINISHED"
self .logger.debug( "%s status is %s" % ( self .cmd, status))
return status
# Python2.4的subprocess还没有send_signal,terminate,kill
# 所以这里要山寨一把,2.7可直接用self._process的kill()
def send_signal( self , sig):
self .logger.debug( "send signal %s to %s" % (sig, self .cmd))
os.kill( self ._process.pid, sig)
def terminate( self ):
self .send_signal(signal.SIGTERM)
def kill( self ):
self .send_signal(signal.SIGKILL)
def print_result( self ):
print "return code:" , self .ret_code
print "return info:" , self .ret_info
print " error info:" , self .err_info
class RemoteShell(Shell):
'''远程执行命令(ssh方式)。
XXX 含特殊字符的命令可能导致调用失效,如双引号,美元号$
NOTE 若cmd含有双引号,可使用RemoteShell2
'''
def __init__( self , cmd, ip):
ssh = ( "ssh -o PreferredAuthentications=publickey -o "
"StrictHostKeyChecking=no -o ConnectTimeout=10" )
# 不必检查IP有效性,也不必检查信任关系,有问题shell会报错
cmd = '%s %s "%s"' % (ssh, ip, cmd)
Shell.__init__( self , cmd)
class RemoteShell2(RemoteShell):
'''与RemoteShell相同,只是变换了引号。
'''
def __init__( self , cmd, ip):
RemoteShell.__init__( self , cmd, ip)
self .cmd = "%s %s '%s'" % (ssh, ip, cmd)
class SuShell(Shell):
'''切换用户执行命令(su方式)。
XXX 只适合使用root切换至其它用户。
因为其它切换用户后需要输入密码,这样程序会挂住。
XXX 含特殊字符的命令可能导致调用失效,如双引号,美元号$
NOTE 若cmd含有双引号,可使用SuShell2
'''
def __init__( self , cmd, user):
if os.getuid() ! = 0 : # 非root用户直接报错
raise Exception( 'SuShell must be called by root user!' )
cmd = 'su - %s -c "%s"' % (user, cmd)
Shell.__init__( self , cmd)
class SuShell2(SuShell):
'''与SuShell相同,只是变换了引号。
'''
def __init__( self , cmd, user):
SuShell.__init__( self , cmd, user)
self .cmd = "su - %s -c '%s'" % (user, cmd)
class SuShellDeprecated(Shell):
'''切换用户执行命令(setuid方式)。
执行的函数为run2,而不是run
XXX 以“不干净”的方式运行:仅切换用户和组,环境变量信息不变。
XXX 无法获取命令的ret_code, ret_info, err_info
XXX 只适合使用root切换至其它用户。
'''
def __init__( self , cmd, user):
self .user = user
Shell.__init__( self , cmd)
def run2( self ):
if os.getuid() ! = 0 : # 非root用户直接报错
raise Exception( 'SuShell2 must be called by root user!' )
child_pid = os.fork()
if child_pid = = 0 : # 子进程干活
uid, gid = pwd.getpwnam( self .user)[ 2 : 4 ]
os.setgid(gid) # 必须先设置组
os.setuid(uid)
self .run()
sys.exit( 0 ) # 子进程退出,防止继续执行其它代码
else : # 父进程等待子进程退出
os.waitpid(child_pid, 0 )
if __name__ = = "__main__" :
'''test code'''
# 1. test normal
sa = Shell( 'who' )
sa.run()
sa.print_result()
# 2. test stderr
sb = Shell( 'ls /export/dir_should_not_exists' )
sb.run()
sb.print_result()
# 3. test background
sc = Shell( 'sleep 1' )
sc.run_background()
print 'hello from parent process'
print "return code:" , sc.ret_code
print "status:" , sc.get_status()
sc.wait()
sc.print_result()
# 4. test kill
import time
sd = Shell( 'sleep 2' )
sd.run_background()
time.sleep( 1 )
sd.kill()
sd.wait() # NOTE, still need to wait
sd.print_result()
# 5. test multiple command and uncompleted command output
se = Shell( 'pwd;sleep 1;pwd;pwd' )
se.run_background()
time.sleep( 1 )
se.kill()
se.wait() # NOTE, still need to wait
se.print_result()
# 6. test wrong command
sf = Shell( 'aaaaa' )
sf.run()
sf.print_result()
# 7. test instance reuse to run other command
sf.cmd = 'echo aaaaa'
sf.run()
sf.print_result()
sg = RemoteShell( 'pwd' , '127.0.0.1' )
sg.run()
sg.print_result()
# unreachable ip
sg2 = RemoteShell( 'pwd' , '17.0.0.1' )
sg2.run()
sg2.print_result()
# invalid ip
sg3 = RemoteShell( 'pwd' , '1711.0.0.1' )
sg3.run()
sg3.print_result()
# ip without trust relation
sg3 = RemoteShell( 'pwd' , '10.145.132.247' )
sg3.run()
sg3.print_result()
sh = SuShell( 'pwd' , 'ossuser' )
sh.run()
sh.print_result()
# wrong user
si = SuShell( 'pwd' , 'ossuser123' )
si.run()
si.print_result()
# user need password
si = SuShell( 'pwd' , 'root' )
si.run()
si.print_result()
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