ansible/library/mount

#!/usr/bin/python
# -*- coding: utf-8 -*-

# (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/>.

# 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 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 = dict(
        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 = dict(
        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.returncode, out+err

def umount(**kwargs):
    """ unmount a path """

    name = kwargs['name']
    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.returncode, out+err

def main():

    module = AnsibleModule(
        argument_spec = dict(
            state  = dict(required=True, choices=['present', 'absent', 'mounted', 'unmounted']),
            name   = dict(required=True),
            opts   = dict(default=None),
            passno = dict(default=None),
            dump   = dict(default=None),
            src    = dict(required=True),
            fstype = dict(required=True),
            fstab  = dict(default=None)
        )
    )

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

    state = module.params['state']
    name  = module.params['name']
    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)))

        module.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

        module.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))


        module.exit_json(changed=changed, **args)

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

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()