#!/usr/bin/python

import routefs
from routes import Mapper

from syslog import *
from time import time

from invirt import database
from invirt.config import structs as config

class RemConfFS(routefs.RouteFS):
	"""
	RemConfFS creates a filesytem for configuring remctl, like this:
	/
	|-- acl
	|   |-- machine1
	|   ...
	|   `-- machinen
	`-- conf
        
	The machine list and the acls are drawn from a database.
	"""
	
	def __init__(self, *args, **kw):
		"""Initialize the filesystem and set it to allow_other access besides
		the user who mounts the filesystem (i.e. root)
		"""
		super(RemConfFS, self).__init__(*args, **kw)
		self.lasttime = time()
		self.fuse_args.add("allow_other", True)
		
		openlog('invirt-remconffs ', LOG_PID, LOG_DAEMON)
		
		syslog(LOG_DEBUG, 'Init complete.')
        
        def make_map(self):
                m = Mapper()
                m.connect('', controller='getroot')
                m.connect('acl', controller='getmachines')
                m.connect('acl/:machine', controller='getacl')
                m.connect('conf', controller='getconf')
                return m
        
        def getroot(self, **kw):
                return ['acl', 'conf']
        
	def getacl(self, machine, **kw):
		"""Build the ACL file for a machine
		"""
		machine = database.Machine.query().filter_by(name=machine).one()
		users = [acl.user for acl in machine.acl]
		return "\n".join(map(self.userToPrinc, users)
				 + ['include /etc/remctl/acl/web',
				    ''])
        
	def getconf(self, **kw):
		"""Build the master conf file, with all machines
		"""
		return '\n'.join("control %s /usr/sbin/invirt-remote-proxy-control"
				 " /etc/remctl/remconffs/acl/%s"
				 % (machine_name, machine_name)
				 for machine_name in self.getmachines())+'\n'
	
	def getmachines(self, **kw):
		"""Get the list of VMs in the database, clearing the cache if it's 
		older than 15 seconds"""
		if time() - self.lasttime > 15:
			self.lasttime = time()
			database.clear_cache()
		return [machine.name for machine in database.session.query(database.Machine).all()]
        
	def userToPrinc(self, user):
		"""Convert Kerberos v4-style names to v5-style and append a default
		realm if none is specified
		"""
		if '@' in user:
			(princ, realm) = user.split('@')
		else:
			princ = user
			realm = config.authn[0].realm
		
		return princ.replace('.', '/') + '@' + realm

if __name__ == '__main__':
	database.connect()
        routefs.main(RemConfFS)
