assemble

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

# (c) 2012, Stephen Fromm <sfromm@gmail.com>
#
# 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/>.

import os
import os.path
import shutil
import tempfile

DOCUMENTATION = '''
---
module: assemble
short_description: Assembles a configuration file from fragments
description:
     - Assembles a configuration file from fragments. Often a particular
       program will take a single configuration file and does not support a
       C(conf.d) style structure where it is easy to build up the configuration
       from multiple sources. Assemble will take a directory of files that have
       already been transferred to the system, and concatenate them together to
       produce a destination file. Files are assembled in string sorting order.
       Puppet calls this idea I(fragments).
version_added: "0.5"
options:
  src:
    description:
      - An already existing directory full of source files.
    required: true
    default: null
    aliases: []
  dest:
    description:
      - A file to create using the concatenation of all of the source files.
    required: true
    default: null
  backup:
    description:
      - Create a backup file (if C(yes)), including the timestamp information so
        you can get the original file back if you somehow clobbered it
        incorrectly.
    required: false
    choices: [ "yes", "no" ]
    default: "no"
  others:
    description:
      - all arguments accepted by the M(file) module also work here
    required: false
examples:
   - code: "assemble: src=/etc/someapp/fragments dest=/etc/someapp/someapp.conf"
     description: "Example from Ansible Playbooks"
author: Stephen Fromm
'''

# ===========================================
# Support methods

def assemble_from_fragments(path):
    ''' assemble a file from a directory of fragments '''
    assembled = []
    for f in sorted(os.listdir(path)):
        fragment = "%s/%s" % (path, f)
        if os.path.isfile(fragment):
            assembled.append(file(fragment).read())
    return "".join(assembled)

def write_temp_file(data):
    fd, path = tempfile.mkstemp()
    os.write(fd, data)
    os.close(fd)
    return path

# ==============================================================
# main

def main():

    module = AnsibleModule(
        # not checking because of daisy chain to file module
        check_invalid_arguments = False,
        argument_spec = dict(
            src = dict(required=True),
            dest = dict(required=True),
            backup=dict(default=False, choices=BOOLEANS),
        )
    )

    changed=False
    pathmd5 = None
    destmd5 = None
    src = os.path.expanduser(module.params['src'])
    dest = os.path.expanduser(module.params['dest'])
    backup = module.boolean(module.params.get('backup', False))

    if not os.path.exists(src):
        module.fail_json(msg="Source (%s) does not exist" % src)

    if not os.path.isdir(src):
        module.fail_json(msg="Source (%s) is not a directory" % src)

    path = write_temp_file(assemble_from_fragments(src))
    pathmd5 = module.md5(path)

    if os.path.exists(dest):
        destmd5 = module.md5(dest)

    if pathmd5 != destmd5:
        if backup and destmd5 is not None:
            module.backup_local(dest)
        shutil.copy(path, dest)
        changed = True


    # Mission complete
    module.exit_json(src=src, dest=dest, md5sum=destmd5,
        changed=changed, msg="OK",
        daisychain="file", daisychain_args=module.params)

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

main()