terom@5: """
terom@5:     Invoke external commands.
terom@72: 
terom@72:     XXX: replace with pvl.invoke
terom@5: """
terom@5: 
terom@5: import subprocess
terom@5: import logging
terom@5: 
terom@5: log = logging.getLogger('pvl.backup.invoke')
terom@5: 
terom@68: SUDO = '/usr/bin/sudo'
terom@68: 
terom@5: class InvokeError (Exception) :
terom@5:     def __init__ (self, cmd, exit) :
terom@5:         self.cmd = cmd
terom@5:         self.exit = exit
terom@5: 
terom@5:     def __str__ (self) :
terom@5:         return "{cmd} failed: {exit}".format(cmd=self.cmd, exit=self.exit)
terom@5: 
terom@68: def invoke (cmd, args, data=None, sudo=False) :
terom@5:     """
terom@5:         Invoke a command directly.
terom@5:         
terom@5:         data:       data to pass in on stdin, returning stdout.
terom@5:                     if given as False, passes through our process stdin/out
terom@68:         sudo:       exec using sudo
terom@5: 
terom@5:         Doesn't give any data on stdin, and keeps process stderr.
terom@5:         Returns stdout.
terom@5:     """
terom@5:     
terom@68:     log.debug("{sudo}{cmd} {args}".format(sudo=('sudo ' if sudo else ''), cmd=cmd, args=' '.join(args)))
terom@5: 
terom@5:     if data is False :
terom@5:         # keep process stdin/out
terom@5:         io = None
terom@5:     else :
terom@5:         io = subprocess.PIPE
terom@5: 
terom@68:     args = [cmd] + args
terom@68: 
terom@68:     if sudo :
terom@68:         args = [SUDO] + args
terom@68: 
terom@68:     p = subprocess.Popen(args, stdin=io, stdout=io)
terom@5: 
terom@5:     # get output
terom@5:     stdout, stderr = p.communicate(input=data)
terom@5: 
terom@5:     if p.returncode :
terom@5:         # failed
terom@5:         raise InvokeError(cmd, p.returncode)
terom@5: 
terom@5:     return stdout
terom@5: 
terom@12: def process_opt (opt, value) :
terom@12:     """
terom@12:         Mangle from python keyword-argument dict format to command-line option tuple format.
terom@12: 
terom@12:         >>> process_opt('foo', True)
terom@12:         ('--foo',)
terom@12:         >>> process_opt('foo', 2)
terom@12:         ('--foo', '2')
terom@12:         >>> process_opt('foo', 'bar')
terom@12:         ('--foo', 'bar')
terom@12:         >>> process_opt('foo_bar', 'asdf')
terom@12:         ('--foo-bar', 'asdf')
terom@12: 
terom@27:         # empty
terom@27:         >>> process_opt('foo', False)
terom@27:         ()
terom@27:         >>> process_opt('foo', None)
terom@27:         ()
terom@12:         >>> process_opt('bar', '')
terom@27:         ()
terom@12: 
terom@12:         Returns a tuple of argv items.
terom@12:     """
terom@12: 
terom@12:     # mangle opt
terom@12:     opt = '--' + opt.replace('_', '-')
terom@12: 
terom@12:     if value is True :
terom@12:         # flag opt
terom@12:         return (opt, )
terom@12: 
terom@27:     elif not value :
terom@12:         # flag opt / omit
terom@12:         return ( )
terom@12: 
terom@12:     else :
terom@12:         # as-is
terom@12:         return (opt, str(value))
terom@12: 
terom@5: def optargs (*args, **kwargs) :
terom@5:     """
terom@5:         Convert args/options into command-line format
terom@5:     """
terom@5: 
terom@12:     ## opts
terom@5:     # process
terom@12:     opts = [process_opt(opt, value) for opt, value in kwargs.iteritems()]
terom@5: 
terom@5:     # flatten
terom@5:     opts = [str(opt_part) for opt_parts in opts for opt_part in opt_parts if opt_part]
terom@5: 
terom@12:     ## args
terom@5:     args = [str(arg) for arg in args if arg]
terom@5: 
terom@5:     return opts + args
terom@5:  
terom@5: def command (cmd, *args, **opts) :
terom@5:     """
terom@5:         Invoke a command with options/arguments, given via Python arguments/keyword arguments.
terom@5: 
terom@5:         Return stdout.
terom@5:     """
terom@5:     
terom@5:     log.debug("{cmd} {opts} {args}".format(cmd=cmd, args=args, opts=opts))
terom@5: 
terom@5:     # invoke
terom@5:     return invoke(cmd, optargs(*args, **opts))
terom@12: 
terom@12: if __name__ == '__main__':
terom@12:     import doctest
terom@12:     doctest.testmod()
terom@12: