ansible/hg

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

# (c) 2013, Yeukhon Wong <yeukhon@acm.org>
#
# This module was originally inspired by Brad Olson's ansible-module-mercurial
# <https://github.com/bradobro/ansible-module-mercurial>.
#
# 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 shutil
import ConfigParser
from subprocess import Popen, PIPE

DOCUMENTATION = '''
---
module: hg
short_description: Manages Mercurial (hg) repositories.
description:
    - Manages Mercurial (hg) repositories. Supports SSH, HTTP/S and local address.
version_added: "1.0"
author: Yeukhon Wong
options:
    repo:
        description:
            - The repository address.
        required: true
        default: null
    dest:
        description:
            - Absolute path of where the repository should be cloned to.
        required: true
        default: null
    revision:
        description:
            - Equivalent C(-r) option in hg command, which can either be a changeset number or a branch
              name.
        required: false
        default: "default"
    force:
        description:
    	    - Discards uncommited changes. Runs C(hg update -c).
        required: false
        default: "yes"
        choices: [ "yes", "no" ]



notes:
    - If the task seems to be hanging, first verify remote host is in C(known_hosts).
      SSH will prompt user to authorize the first contact with a remote host. One solution is to add
      C(StrictHostKeyChecking no) in C(.ssh/config) which will accept and authorize the connection
      on behalf of the user. However, if you run as a different user such as setting sudo to True),
      for example, root will not look at the user .ssh/config setting.

requirements: [ ]
'''

def _set_hgrc(hgrc, vals):
    parser = ConfigParser.SafeConfigParser()
    parser.read(hgrc)

    # val is a list of triple-tuple of the form [(section, option, value),...]
    for each in vals:
        (section, option, value) = each
        if not parser.has_section(section):
            parser.add_section(section)
        parser.set(section, option, value)
    
    f = open(hgrc, 'w')
    parser.write(f)
    f.close()

def _undo_hgrc(hgrc, vals):
    parser = ConfigParser.SafeConfigParser()
    parser.read(hgrc)
     
    for each in vals:
        (section, option, value) = each
        if parser.has_section(section):
            parser.remove_option(section, option)

    f = open(hgrc, 'w')
    parser.write(f)
    f.close()

def _hg_command(module, args_list):
    (rc, out, err) = module.run_command(['hg'] + args_list)
    return (rc, out, err)

def determine_changed(module, before, after, expecting):
    """
    This compares the user supplied revision to the before
    and after revision (actually, id).
    
    get_revision calls hg id -b -i -t which returns the string
    "<changeset>[+] <branch_name> <tag>" and  we compare if
    expected revision (which could be changeset, 
    branch name) is part of the result string from hg id.
    """

    # some custom error messages
    err1 = "no changes found. You supplied %s but repo is \
currently at %s" %(expecting, after)

    err2 = "Unknown error. The state before operation was %s,\
after the operation was %s, but we were expecting \
%s as part of the state." %(before, after, expecting)

    # if before and after are equal, only two possible explainations
    # case one: when current working copy is already what user want
    # case two: when current working copy is ahead of what user want
    # in case two, hg will exist successfully although that contradict
    # user assumption. Therefore, alert the user by failing the task.
    if before == after and expecting in after:
        module.exit_json(changed=False, before=before, after=after)
    elif before == after and not expecting in after: # this is case two
        module.fail_json(msg=err2) 
    elif before != after and expecting in after: # updated to expecting
        module.exit_json(changed=True, before=before, after=after)
    else:
        module.fail_json(msg=err2)

def get_revision(module, dest):
    """
    hg id -b -i -t returns a string in the format:
       "<changeset>[+] <branch_name> <tag>" 
    This format lists the state of the current working copy,
    and indicates whether there are uncommitted changes by the
    plus sign. Otherwise, the sign is omitted.

    Read the full description via hg id --help
    """
    (rc, out, err) = _hg_command(module, ['id', '-b', '-i', '-t', '-R', dest])
    if rc != 0:
        module.fail_json(msg=err)
    else:
        return out.strip('\n')

def has_local_mods(module, dest):
    out = get_revision(module, dest)
    if '+' in out:
        return True
    else:
        return False

def hg_discard(module, dest, force):
    if not force and has_local_mods(module, dest):
        module.fail_json(msg="Respository has uncommited changes.")
    return _hg_command(module, ['update', '-C', '-R', dest])

def hg_purge(module, dest):
    hgrc = os.path.join(dest, '.hg/hgrc')
    purge_option = [('extensions', 'purge', '')]
    _set_hgrc(hgrc, purge_option)   # hg purge requires purge extension
    
    (rc, out, err) = _hg_command(module, ['purge', '-R', dest])
    if rc == 0:
        _undo_hgrc(hgrc, purge_option)
    else:
        module.fail_json(msg=err)

def hg_pull(module, dest, revision):
    return _hg_command(module, ['pull', '-r', revision, '-R', dest])

def hg_update(module, dest, revision):
    return _hg_command(module, ['update', '-R', dest])

def hg_clone(module, repo, dest, revision):
    return _hg_command(module, ['clone', repo, dest, '-r', revision])

def main():
    module = AnsibleModule(
        argument_spec = dict(
            repo = dict(required=True),	    
            dest = dict(required=True),
            revision = dict(default="default"),
            force = dict(default='yes', choices=['yes', 'no']),
            purge = dict(default='no', choices=['yes', 'no'])
        ),
    )
    repo = module.params['repo']
    dest = module.params['dest']
    revision = module.params['revision']
    force = module.boolean(module.params['force'])
    purge = module.boolean(module.params['purge'])
    hgrc = os.path.join(dest, '.hg/hgrc')
    
    # If there is no hgrc file, then assume repo is absent
    # and perform clone. Otherwise, perform pull and update.
    if not os.path.exists(hgrc):
        before = ''
        (rc, out, err) = hg_clone(module, repo, dest, revision)
        if rc != 0:
            module.fail_json(msg=err)
        after = get_revision(module, dest)
        determine_changed(module, before, after, revision)
    else:
        # get the current state before doing pulling
        before = get_revision(module, dest)

        # calls hg update -C and abort when uncommited changes
        # are present if force=no
        (rc, out, err) = hg_discard(module, dest, force)
        if rc != 0:
            module.fail_json(msg=err)
        
        if purge:
            hg_purge(module, dest)

        (rc, out, err) = hg_pull(module, dest, revision)
        if rc != 0:
            module.fail_json(msg=err)

        (rc, out, err) = hg_update(module, dest, revision)
        if rc != 0:
            module.fail_json(msg=err)

        after = get_revision(module, dest)
        determine_changed(module, before, after, revision)

# include magic from lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()