ansible/library/lvol

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

# (c) 2013, Jeroen Hoekx <jeroen.hoekx@dsquare.be>
#
# 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/>.

DOCUMENTATION = '''
---
author: Jeroen Hoekx
module: lvol
short_description: Configure LVM logical volumes
description:
  - This module creates, removes or resizes logical volumes.
version_added: "1.1"
options:
  vg:
    description:
    - The volume group this logical volume is part of.
    required: true
  lv:
    description:
    - The name of the logical volume.
    required: true
  size:
    description:
    - The size of the logical volume in megabytes.
  state:
    choices: [ "present", "absent" ]
    default: present
    description:
    - Control if the logical volume exists.
    required: false
examples:
  - description: Create a logical volume of 512m.
    code: lvol vg=firefly lv=test size=512
  - description: Extend the logical volume to 1024m.
    code: lvol vg=firefly lv=test size=1024
  - description: Reduce the logical volume to 512m
    code: lvol vg=firefly lv=test size=512
  - description: Remove the logical volume.
    code: lvol vg=firefly lv=test state=absent
notes:
  - Filesystems on top of the volume are not resized.
'''

def parse_lvs(data):
    lvs = []
    for line in data.splitlines():
        parts = line.strip().split(';')
        lvs.append({
            'name': parts[0],
            'size': int(parts[1].split('.')[0]),
            'path': parts[2],
        })
    return lvs

def main():
    module = AnsibleModule(
        argument_spec = dict(
            vg=dict(required=True),
            lv=dict(required=True),
            size=dict(),
            state=dict(choices=["absent", "present"], default='present'),
        ),
        supports_check_mode=True,
    )

    vg = module.params['vg']
    lv = module.params['lv']
    size = module.params['size']
    state = module.params['state']

    if state=='present' and not size:
        module.fail_json(msg="No size given.")

    if size:
        size = int(size)

    rc,current_lvs,err = module.run_command("lvs --noheadings -o lv_name,size,lv_path --units m --separator ';' %s"%(vg))

    if rc != 0:
        module.fail_json(msg="Volume group %s does not exist."%vg, rc=rc, err=err)

    changed = False

    lvs = parse_lvs(current_lvs)

    for test_lv in lvs:
        if test_lv['name'] == lv:
            this_lv = test_lv
            break
    else:
        this_lv = None

    if this_lv is None:
        if state == 'present':
            ### create LV
            if module.check_mode:
                changed = True
            else:
                rc,_,err = module.run_command("lvcreate -n %s -L %sm %s"%(lv, size, vg))
                if rc == 0:
                    changed = True
                else:
                    module.fail_json(msg="Creating logical volume '%s' failed"%(lv), rc=rc, err=err)
    else:
        if state == 'absent':
            ### remove LV
            if module.check_mode:
                module.exit_json(changed=True)
            rc,_,err = module.run_command("lvremove --force %s"%(this_lv['path']))
            if rc == 0:
                module.exit_json(changed=True)
            else:
                module.fail_json(msg="Failed to remove logical volume %s"%(lv),rc=rc, err=err)
        ### resize LV
        tool = None
        if size > this_lv['size']:
            tool = 'lvextend'
        elif size < this_lv['size']:
            tool = 'lvreduce --force'

        if tool:
            if module.check_mode:
                changed = True
            else:
                rc,_,err = module.run_command("%s -L %sm %s"%(tool, size, this_lv['path']))
                if rc == 0:
                    changed = True
                else:
                    module.fail_json(msg="Unable to resize %s to %sm."%(lv,size),rc=rc,err=err)

    module.exit_json(changed=changed)

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