ansible/mount

#!/usr/bin/python

# (c) 2012, Red Hat, inc
# Written by Seth Vidal
# based on the mount modules from salt and puppet
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.

try:
    import json
except ImportError:
    import simplejson as json
import os
import os.path
import shlex
import subprocess
import sys
import syslog


#mount module - mount fs and define in fstab
#usage:
# mount name=mountpoint, src=device_to_be_mounted fstype=fstype opts=mount_opts, dump=0 passno=0 state=[present|absent|mounted|unmounted] 
# absent == remove from fstab and unmounted
# present == add to fstab, do not change mount state
# mounted == add to fstab if not there and make sure it is mounted
# unmounted == do not change fstab state, but unmount

def exit_json(rc=0, **kwargs):
    print json.dumps(kwargs)
    sys.exit(rc)

def fail_json(**kwargs):
    kwargs['failed'] = True
    exit_json(rc=1, **kwargs)

def write_fstab(lines, dest):

    fs_w = open(dest, 'w')
    for l in lines:
        fs_w.write(l)

    fs_w.flush()
    fs_w.close()

def set_mount(**kwargs):
    "set/change a mount point location in fstab"
    # kwargs: name, src, fstype, opts, dump, passno, state, fstab=/etc/fstab
    args = { 'opts':'defaults',
             'dump':'0',
             'passno':'0',
             'fstab':'/etc/fstab' }
    args.update(kwargs)

    new_line = '%(src)s %(name)s %(fstype)s %(opts)s %(dump)s %(passno)s\n' 

    to_write = []
    exists = False
    changed = False
    for line in open(args['fstab'], 'r').readlines():
        if not line.strip():
             to_write.append(line)
             continue
        if line.strip().startswith('#'):
            to_write.append(line)
            continue
        if len(line.split()) != 6:
            # not sure what this is or why it is here
            # but it is not our fault so leave it be
            to_write.append(line)
            continue
        
        ld = {}
        ld['src'], ld['name'], ld['fstype'], ld['opts'], ld['dump'], ld['passno']  = line.split()

        if ld['name'] != args['name']:
            to_write.append(line)
            continue

        # it exists - now see if what we have is different
        exists = True
        for t in ('src', 'fstype','opts', 'dump', 'passno'):
            if ld[t] != args[t]:
                changed = True
                ld[t] = args[t]

        if changed:
             to_write.append(new_line % ld)
        else:
             to_write.append(line)
         
    
    if not exists:
        to_write.append(new_line % args)
        changed = True
    
    if changed:
        write_fstab(to_write, args['fstab'])

    return (args['name'], changed)
            

def unset_mount(**kwargs):
    "remove a mount point from fstab"
    # kwargs: name, src, fstype, opts, dump, passno, state, fstab=/etc/fstab
    args = { 'opts':'default',
             'dump':'0',
             'passno':'0',
             'fstab':'/etc/fstab' }
    args.update(kwargs)

    to_write = []
    changed = False
    for line in open(args['fstab'], 'r').readlines():
        if not line.strip():
             to_write.append(line)
             continue
        if line.strip().startswith('#'):
            to_write.append(line)
            continue
        if len(line.split()) != 6:
            # not sure what this is or why it is here
            # but it is not our fault so leave it be
            to_write.append(line)
            continue
        
        ld = {}
        ld['src'], ld['name'], ld['fstype'], ld['opts'], ld['dump'], ld['passno']  = line.split()

        if ld['name'] != args['name']:
            to_write.append(line)
            continue

        # if we got here we found a match - continue and mark changed
        changed = True

    if changed:
        write_fstab(to_write, args['fstab'])

    return (args['name'], changed)

     
def mount(**kwargs):
    "mount up a path or remount if needed"
    name = kwargs['name']
    if os.path.ismount(name):
        cmd = ['/bin/mount', '-o', 'remount', name]
    else:
        cmd = ['/bin/mount', name ]

    call = subprocess.Popen(cmd, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    out, err = call.communicate()
    if call.returncode == 0:
        return 0, ''
    else:
        return call.rc, out+err

def umount(**kwargs):
    "unmount a path"
    cmd = ['/bin/umount', name]

    call = subprocess.Popen(cmd, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    out, err = call.communicate()
    if call.returncode == 0:
        return 0, ''
    else:
        return call.rc, out+err

argfile = sys.argv[1]
args    = open(argfile, 'r').read()
items   = shlex.split(args)
syslog.openlog('ansible-%s' % os.path.basename(__file__))
syslog.syslog(syslog.LOG_NOTICE, 'Invoked with %s' % args)

if not len(items):
    fail_json(msg='the module requires arguments -a')
    sys.exit(1)

params = {}
for x in items:
    (k, v) = x.split("=",1)
    params[k] = v

state      = params.get('state',None)
name       = params.get('name', None)
opts       = params.get('opts', None)
passno     = params.get('passno', None)
dump       = params.get('dump', None)
src        = params.get('src', None)
fstype     = params.get('fstype', None)
fstab      = params.get('fstab', None)


if state not in [ 'present', 'absent', 'mounted', 'unmounted' ]:
    fail_json(msg='invalid state')

if not name:
    fail_json(msg='no name option given')

if not src:
    fail_json(msg='no src option given')

if not fstype:
    fail_json(msg='no fstype option given')


changed = False
rc = 0
args = {'name':name,
        'src':src,
        'fstype':fstype }
if passno is not None:
    args['passno'] = passno
if opts is not None:
    args['opts'] = opts
if dump is not None:
    args['dump'] = dump
if fstab is not None:
    args['fstab'] = fstab


# absent == remove from fstab and unmounted
# unmounted == do not change fstab state, but unmount
# present == add to fstab, do not change mount state
# mounted == add to fstab if not there and make sure it is mounted, if it has changed in fstab then remount it


if state == 'absent':
    name, changed = unset_mount(**args)
    if changed:
        if os.path.ismount(name):
            res,msg  = umount(**args)
            if res:
                fail_json(msg="Error unmounting %s: %s" % (name, msg))

        if os.path.exists(name):
            try:
                os.rmdir(name)
            except (OSError, IOError), e:
                fail_json(msg="Error rmdir %s: %s" % (name, str(e)))

    exit_json(changed=changed, **args)


if state == 'unmounted':
    if os.path.ismount(name):
        res,msg  = umount(**args)
        if res:
            fail_json(msg="Error unmounting %s: %s" % (name, msg))
        changed = True

    exit_json(changed=changed, **args)

    

if state in ['mounted', 'present']:
    name, changed = set_mount(**args)
    if state == 'mounted':
        if not os.path.exists(name):
            try:
                os.makedirs(name)
            except (OSError, IOError), e:
                fail_json(msg="Error making dir %s: %s" % (name, str(e)))

        res = 0
        if os.path.ismount(name):
            if changed:
                res,msg = mount(**args)
        else:
            changed = True
            res,msg = mount(**args)

        if res:
            fail_json(msg="Error mounting %s: %s" % (name, msg))


    exit_json(changed=changed, **args)

fail_json(msg='Unexpected position reached')
sys.exit(0)