path: root/source_control/git.py

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

# (c) 2012, Michael DeHaan <michael.dehaan@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/>.

DOCUMENTATION = '''
---
module: git
author:
    - "Ansible Core Team"
    - "Michael DeHaan"
version_added: "0.0.1"
short_description: Deploy software (or files) from git checkouts
description:
    - Manage I(git) checkouts of repositories to deploy files or software.
options:
    repo:
        required: true
        aliases: [ name ]
        description:
            - git, SSH, or HTTP(S) protocol address of the git repository.
    dest:
        required: true
        description:
            - Absolute path of where the repository should be checked out to.
              This parameter is required, unless C(clone) is set to C(no)
              This change was made in version 1.8.3. Prior to this version,
              the C(dest) parameter was always required.
    version:
        required: false
        default: "HEAD"
        description:
            - What version of the repository to check out.  This can be the
              the literal string C(HEAD), a branch name, a tag name.
              It can also be a I(SHA-1) hash, in which case C(refspec) needs
              to be specified if the given revision is not already available.
    accept_hostkey:
        required: false
        default: "no"
        choices: [ "yes", "no" ]
        version_added: "1.5"
        description:
            - if C(yes), adds the hostkey for the repo url if not already
              added. If ssh_opts contains "-o StrictHostKeyChecking=no",
              this parameter is ignored.
    ssh_opts:
        required: false
        default: None
        version_added: "1.5"
        description:
            - Creates a wrapper script and exports the path as GIT_SSH
              which git then automatically uses to override ssh arguments.
              An example value could be "-o StrictHostKeyChecking=no"
    key_file:
        required: false
        default: None
        version_added: "1.5"
        description:
            - Specify an optional private key file to use for the checkout.
    reference:
        required: false
        default: null
        version_added: "1.4"
        description:
            - Reference repository (see "git clone --reference ...")
    remote:
        required: false
        default: "origin"
        description:
            - Name of the remote.
    refspec:
        required: false
        default: null
        version_added: "1.9"
        description:
            - Add an additional refspec to be fetched.
              If version is set to a I(SHA-1) not reachable from any branch
              or tag, this option may be necessary to specify the ref containing
              the I(SHA-1).
              Uses the same syntax as the 'git fetch' command.
              An example value could be "refs/meta/config".
    force:
        required: false
        default: "no"
        choices: [ "yes", "no" ]
        version_added: "0.7"
        description:
            - If C(yes), any modified files in the working
              repository will be discarded.  Prior to 0.7, this was always
              'yes' and could not be disabled.  Prior to 1.9, the default was
              `yes`
    depth:
        required: false
        default: null
        version_added: "1.2"
        description:
            - Create a shallow clone with a history truncated to the specified
              number or revisions. The minimum possible value is C(1), otherwise
              ignored. Needs I(git>=1.9.1) to work correctly.
    clone:
        required: false
        default: "yes"
        choices: [ "yes", "no" ]
        version_added: "1.9"
        description:
            - If C(no), do not clone the repository if it does not exist locally
    update:
        required: false
        default: "yes"
        choices: [ "yes", "no" ]
        version_added: "1.2"
        description:
            - If C(no), do not retrieve new revisions from the origin repository
    executable:
        required: false
        default: null
        version_added: "1.4"
        description:
            - Path to git executable to use. If not supplied,
              the normal mechanism for resolving binary paths will be used.
    bare:
        required: false
        default: "no"
        choices: [ "yes", "no" ]
        version_added: "1.4"
        description:
            - if C(yes), repository will be created as a bare repo, otherwise
              it will be a standard repo with a workspace.
    umask:
        required: false
        default: null
        version_added: "2.2"
        description:
            - The umask to set before doing any checkouts, or any other
              repository maintenance.

    recursive:
        required: false
        default: "yes"
        choices: [ "yes", "no" ]
        version_added: "1.6"
        description:
            - if C(no), repository will be cloned without the --recursive
              option, skipping sub-modules.

    track_submodules:
        required: false
        default: "no"
        choices: ["yes", "no"]
        version_added: "1.8"
        description:
            - if C(yes), submodules will track the latest commit on their
              master branch (or other branch specified in .gitmodules).  If
              C(no), submodules will be kept at the revision specified by the
              main project. This is equivalent to specifying the --remote flag
              to git submodule update.

    verify_commit:
        required: false
        default: "no"
        choices: ["yes", "no"]
        version_added: "2.0"
        description:
            - if C(yes), when cloning or checking out a C(version) verify the
              signature of a GPG signed commit. This requires C(git) version>=2.1.0
              to be installed. The commit MUST be signed and the public key MUST
              be trusted in the GPG trustdb.

requirements:
    - git>=1.7.1 (the command line tool)

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.  To avoid this prompt,
      one solution is to use the option accept_hostkey. Another solution is to
      add the remote host public key in C(/etc/ssh/ssh_known_hosts) before calling
      the git module, with the following command: ssh-keyscan -H remote_host.com >> /etc/ssh/ssh_known_hosts."
'''

EXAMPLES = '''
# Example git checkout from Ansible Playbooks
- git:
    repo: git://foosball.example.org/path/to/repo.git
    dest: /srv/checkout
    version: release-0.22

# Example read-write git checkout from github
- git:
    repo: ssh://git@github.com/mylogin/hello.git
    dest: /home/mylogin/hello

# Example just ensuring the repo checkout exists
- git:
    repo: git://foosball.example.org/path/to/repo.git
    dest: /srv/checkout
    update: no

# Example just get information about the repository whether or not it has
# already been cloned locally.
- git:
    repo: git://foosball.example.org/path/to/repo.git
    dest: /srv/checkout
    clone: no
    update: no

# Example checkout a github repo and use refspec to fetch all pull requests
- git:
    repo: https://github.com/ansible/ansible-examples.git
    dest: /src/ansible-examples
    refspec: '+refs/pull/*:refs/heads/*'
'''

import os
import re
import shlex
import stat
import sys
import tempfile
from distutils.version import LooseVersion

from ansible.module_utils.basic import AnsibleModule, get_module_path
from ansible.module_utils.known_hosts import add_git_host_key
from ansible.module_utils.six import b, string_types
from ansible.module_utils._text import to_native


def head_splitter(headfile, remote, module=None, fail_on_error=False):
    '''Extract the head reference'''
    # https://github.com/ansible/ansible-modules-core/pull/907

    res = None
    if os.path.exists(headfile):
        rawdata = None
        try:
            f = open(headfile, 'r')
            rawdata = f.readline()
            f.close()
        except:
            if fail_on_error and module:
                module.fail_json(msg="Unable to read %s" % headfile)
        if rawdata:
            try:
                rawdata = rawdata.replace('refs/remotes/%s' % remote, '', 1)
                refparts = rawdata.split(' ')
                newref = refparts[-1]
                nrefparts = newref.split('/',2)
                res = nrefparts[-1].rstrip('\n')
            except:
                if fail_on_error and module:
                    module.fail_json(msg="Unable to split head from '%s'" % rawdata)
    return res


def unfrackgitpath(path):
    # copied from ansible.utils.path
    return os.path.normpath(os.path.realpath(os.path.expanduser(os.path.expandvars(path))))

def get_submodule_update_params(module, git_path, cwd):

    #or: git submodule [--quiet] update [--init] [-N|--no-fetch]
    #[-f|--force] [--rebase] [--reference <repository>] [--merge]
    #[--recursive] [--] [<path>...]

    params = []

    # run a bad submodule command to get valid params
    cmd = "%s submodule update --help" % (git_path)
    rc, stdout, stderr = module.run_command(cmd, cwd=cwd)
    lines = stderr.split('\n')
    update_line = None
    for line in lines:
        if 'git submodule [--quiet] update ' in line:
            update_line = line
    if update_line:
        update_line = update_line.replace('[','')
        update_line = update_line.replace(']','')
        update_line = update_line.replace('|',' ')
        parts = shlex.split(update_line)
        for part in parts:
            if part.startswith('--'):
                part = part.replace('--', '')
                params.append(part)

    return params

def write_ssh_wrapper():
    module_dir = get_module_path()
    try:
        # make sure we have full permission to the module_dir, which
        # may not be the case if we're sudo'ing to a non-root user
        if os.access(module_dir, os.W_OK|os.R_OK|os.X_OK):
            fd, wrapper_path = tempfile.mkstemp(prefix=module_dir + '/')
        else:
            raise OSError
    except (IOError, OSError):
        fd, wrapper_path = tempfile.mkstemp()
    fh = os.fdopen(fd, 'w+b')
    template = """#!/bin/sh
if [ -z "$GIT_SSH_OPTS" ]; then
    BASEOPTS=""
else
    BASEOPTS=$GIT_SSH_OPTS
fi

if [ -z "$GIT_KEY" ]; then
    ssh $BASEOPTS "$@"
else
    ssh -i "$GIT_KEY" -o IdentitiesOnly=yes $BASEOPTS "$@"
fi
"""
    fh.write(template)
    fh.close()
    st = os.stat(wrapper_path)
    os.chmod(wrapper_path, st.st_mode | stat.S_IEXEC)
    return wrapper_path

def set_git_ssh(ssh_wrapper, key_file, ssh_opts):

    if os.environ.get("GIT_SSH"):
        del os.environ["GIT_SSH"]
    os.environ["GIT_SSH"] = ssh_wrapper

    if os.environ.get("GIT_KEY"):
        del os.environ["GIT_KEY"]

    if key_file:
        os.environ["GIT_KEY"] = key_file

    if os.environ.get("GIT_SSH_OPTS"):
        del os.environ["GIT_SSH_OPTS"]

    if ssh_opts:
        os.environ["GIT_SSH_OPTS"] = ssh_opts

def get_version(module, git_path, dest, ref="HEAD"):
    ''' samples the version of the git repo '''

    cmd = "%s rev-parse %s" % (git_path, ref)
    rc, stdout, stderr = module.run_command(cmd, cwd=dest)
    sha = to_native(stdout).rstrip('\n')
    return sha

def get_submodule_versions(git_path, module, dest, version='HEAD'):
    cmd = [git_path, 'submodule', 'foreach', git_path, 'rev-parse', version]
    (rc, out, err) = module.run_command(cmd, cwd=dest)
    if rc != 0:
        module.fail_json(msg='Unable to determine hashes of submodules', stdout=out, stderr=err, rc=rc)
    submodules = {}
    subm_name = None
    for line in out.splitlines():
        if line.startswith("Entering '"):
            subm_name = line[10:-1]
        elif len(line.strip()) == 40:
            if subm_name is None:
                module.fail_json()
            submodules[subm_name] = line.strip()
            subm_name = None
        else:
            module.fail_json(msg='Unable to parse submodule hash line: %s' % line.strip())
    if subm_name is not None:
        module.fail_json(msg='Unable to find hash for submodule: %s' % subm_name)

    return submodules

def clone(git_path, module, repo, dest, remote, depth, version, bare,
          reference, refspec, verify_commit):
    ''' makes a new git repo if it does not already exist '''

    dest_dirname = os.path.dirname(dest)
    try:
        os.makedirs(dest_dirname)
    except:
        pass
    cmd = [ git_path, 'clone' ]

    if bare:
        cmd.append('--bare')
    else:
        cmd.extend([ '--origin', remote ])
    if depth:
        if version == 'HEAD' \
           or refspec  \
           or is_remote_branch(git_path, module, dest, repo, version) \
           or is_remote_tag(git_path, module, dest, repo, version):
            # only use depth if the remote opject is branch or tag (i.e. fetchable)
            cmd.extend([ '--depth', str(depth) ])
    if reference:
        cmd.extend([ '--reference', str(reference) ])
    cmd.extend([ repo, dest ])
    module.run_command(cmd, check_rc=True, cwd=dest_dirname)
    if bare:
        if remote != 'origin':
            module.run_command([git_path, 'remote', 'add', remote, repo], check_rc=True, cwd=dest)

    if refspec:
        cmd = [git_path, 'fetch']
        if depth:
            cmd.extend([ '--depth', str(depth) ])
        cmd.extend([remote, refspec])
        module.run_command(cmd, check_rc=True, cwd=dest)

    if verify_commit:
        verify_commit_sign(git_path, module, dest, version)

def has_local_mods(module, git_path, dest, bare):
    if bare:
        return False

    cmd = "%s status --porcelain" % (git_path)
    rc, stdout, stderr = module.run_command(cmd, cwd=dest)
    lines = stdout.splitlines()
    lines = list(filter(lambda c: not re.search('^\\?\\?.*$', c), lines))

    return len(lines) > 0

def reset(git_path, module, dest):
    '''
    Resets the index and working tree to HEAD.
    Discards any changes to tracked files in working
    tree since that commit.
    '''
    cmd = "%s reset --hard HEAD" % (git_path,)
    return module.run_command(cmd, check_rc=True, cwd=dest)

def get_diff(module, git_path, dest, repo, remote, depth, bare, before, after):
    ''' Return the difference between 2 versions '''
    if before is None:
        return { 'prepared': '>> Newly checked out %s' % after }
    elif before != after:
        # Ensure we have the object we are referring to during git diff !
        git_version_used = git_version(git_path, module)
        fetch(git_path, module, repo, dest, after, remote, depth, bare, '', git_version_used)
        cmd = '%s diff %s %s' % (git_path, before, after)
        (rc, out, err) = module.run_command(cmd, cwd=dest)
        if rc == 0 and out:
            return { 'prepared': out }
        elif rc == 0:
            return { 'prepared': '>> No visual differences between %s and %s' % (before, after) }
        elif err:
            return { 'prepared': '>> Failed to get proper diff between %s and %s:\n>> %s' % (before, after, err) }
        else:
            return { 'prepared': '>> Failed to get proper diff between %s and %s' % (before, after) }
    return {}

def get_remote_head(git_path, module, dest, version, remote, bare):
    cloning = False
    cwd = None
    tag = False
    if remote == module.params['repo']:
        cloning = True
    else:
        cwd = dest
    if version == 'HEAD':
        if cloning:
            # cloning the repo, just get the remote's HEAD version
            cmd = '%s ls-remote %s -h HEAD' % (git_path, remote)
        else:
            head_branch = get_head_branch(git_path, module, dest, remote, bare)
            cmd = '%s ls-remote %s -h refs/heads/%s' % (git_path, remote, head_branch)
    elif is_remote_branch(git_path, module, dest, remote, version):
        cmd = '%s ls-remote %s -h refs/heads/%s' % (git_path, remote, version)
    elif is_remote_tag(git_path, module, dest, remote, version):
        tag = True
        cmd = '%s ls-remote %s -t refs/tags/%s*' % (git_path, remote, version)
    else:
        # appears to be a sha1.  return as-is since it appears
        # cannot check for a specific sha1 on remote
        return version
    (rc, out, err) = module.run_command(cmd, check_rc=True, cwd=cwd)
    if len(out) < 1:
        module.fail_json(msg="Could not determine remote revision for %s" % version, stdout=out, stderr=err, rc=rc)

    out = to_native(out)

    if tag:
        # Find the dereferenced tag if this is an annotated tag.
        for tag in out.split('\n'):
            if tag.endswith(version + '^{}'):
                out = tag
                break
            elif tag.endswith(version):
                out = tag

    rev = out.split()[0]
    return rev

def is_remote_tag(git_path, module, dest, remote, version):
    cmd = '%s ls-remote %s -t refs/tags/%s' % (git_path, remote, version)
    (rc, out, err) = module.run_command(cmd, check_rc=True, cwd=dest)
    if to_native(version, errors='surrogate_or_strict') in out:
        return True
    else:
        return False

def get_branches(git_path, module, dest):
    branches = []
    cmd = '%s branch --no-color -a' % (git_path,)
    (rc, out, err) = module.run_command(cmd, cwd=dest)
    if rc != 0:
        module.fail_json(msg="Could not determine branch data - received %s" % out, stdout=out, stderr=err)
    for line in out.split('\n'):
        if line.strip():
            branches.append(line.strip())
    return branches

def get_tags(git_path, module, dest):
    tags = []
    cmd = '%s tag' % (git_path,)
    (rc, out, err) = module.run_command(cmd, cwd=dest)
    if rc != 0:
        module.fail_json(msg="Could not determine tag data - received %s" % out, stdout=out, stderr=err)
    for line in to_native(out).split('\n'):
        if line.strip():
            tags.append(line.strip())
    return tags

def is_remote_branch(git_path, module, dest, remote, version):
    cmd = '%s ls-remote %s -h refs/heads/%s' % (git_path, remote, version)
    (rc, out, err) = module.run_command(cmd, check_rc=True, cwd=dest)
    if to_native(version, errors='surrogate_or_strict') in out:
        return True
    else:
        return False

def is_local_branch(git_path, module, dest, branch):
    branches = get_branches(git_path, module, dest)
    lbranch = '%s' % branch
    if lbranch in branches:
        return True
    elif '* %s' % branch in branches:
        return True
    else:
        return False

def is_not_a_branch(git_path, module, dest):
    branches = get_branches(git_path, module, dest)
    for branch in branches:
        if branch.startswith('* ') and ('no branch' in branch or 'detached from' in branch):
            return True
    return False

def get_head_branch(git_path, module, dest, remote, bare=False):
    '''
    Determine what branch HEAD is associated with.  This is partly
    taken from lib/ansible/utils/__init__.py.  It finds the correct
    path to .git/HEAD and reads from that file the branch that HEAD is
    associated with.  In the case of a detached HEAD, this will look
    up the branch in .git/refs/remotes/<remote>/HEAD.
    '''
    if bare:
        repo_path = dest
    else:
        repo_path = os.path.join(dest, '.git')
    # Check if the .git is a file. If it is a file, it means that we are in a submodule structure.
    if os.path.isfile(repo_path):
        try:
            git_conf = open(repo_path, 'rb')
            for line in git_conf:
                config_val = line.split(b(':'), 1)
                if config_val[0].strip() == b('gitdir'):
                    gitdir = to_native(config_val[1].strip(), errors='surrogate_or_strict')
                    break
            else:
                # No repo path found
                return ''

            # There is a possibility the .git file to have an absolute path.
            if os.path.isabs(gitdir):
                repo_path = gitdir
            else:
                repo_path = os.path.join(repo_path.split('.git')[0], gitdir)
        except (IOError, AttributeError):
            # No repo path found
            return ''
    # Read .git/HEAD for the name of the branch.
    # If we're in a detached HEAD state, look up the branch associated with
    # the remote HEAD in .git/refs/remotes/<remote>/HEAD
    headfile = os.path.join(repo_path, "HEAD")
    if is_not_a_branch(git_path, module, dest):
        headfile = os.path.join(repo_path, 'refs', 'remotes', remote, 'HEAD')
    branch = head_splitter(headfile, remote, module=module, fail_on_error=True)
    return branch

def get_remote_url(git_path, module, dest, remote):
    '''Return URL of remote source for repo.'''
    command = [git_path, 'ls-remote', '--get-url', remote]
    (rc, out, err) = module.run_command(command, cwd=dest)
    if rc != 0:
        # There was an issue getting remote URL, most likely
        # command is not available in this version of Git.
        return None
    return to_native(out).rstrip('\n')

def set_remote_url(git_path, module, repo, dest, remote):
    ''' updates repo from remote sources '''
    # Return if remote URL isn't changing.
    remote_url = get_remote_url(git_path, module, dest, remote)
    if remote_url == repo or remote_url == unfrackgitpath(repo):
        return False

    command = [git_path, 'remote', 'set-url', remote, repo]
    (rc, out, err) = module.run_command(command, cwd=dest)
    if rc != 0:
        label = "set a new url %s for %s" % (repo, remote)
        module.fail_json(msg="Failed to %s: %s %s" % (label, out, err))

    # Return False if remote_url is None to maintain previous behavior
    # for Git versions prior to 1.7.5 that lack required functionality.
    return remote_url is not None

def fetch(git_path, module, repo, dest, version, remote, depth, bare, refspec, git_version_used):
    ''' updates repo from remote sources '''
    set_remote_url(git_path, module, repo, dest, remote)
    commands = []

    fetch_str = 'download remote objects and refs'
    fetch_cmd = [git_path, 'fetch']

    refspecs = []
    if depth:
        # try to find the minimal set of refs we need to fetch to get a
        # successful checkout
        currenthead = get_head_branch(git_path, module, dest, remote)
        if refspec:
            refspecs.append(refspec)
        elif version == 'HEAD':
            refspecs.append(currenthead)
        elif is_remote_branch(git_path, module, dest, repo, version):
            if currenthead != version:
                # this workaround is only needed for older git versions
                # 1.8.3 is broken, 1.9.x works
                # ensure that remote branch is available as both local and remote ref
                refspecs.append('+refs/heads/%s:refs/heads/%s' % (version, version))
                refspecs.append('+refs/heads/%s:refs/remotes/%s/%s' % (version, remote, version))
            else:
                refspecs.append(version)
        elif is_remote_tag(git_path, module, dest, repo, version):
            refspecs.append('+refs/tags/'+version+':refs/tags/'+version)
        if refspecs:
            # if refspecs is empty, i.e. version is neither heads nor tags
            # assume it is a version hash
            # fall back to a full clone, otherwise we might not be able to checkout
            # version
            fetch_cmd.extend(['--depth', str(depth)])

    if not depth or not refspecs:
        # don't try to be minimalistic but do a full clone
        # also do this if depth is given, but version is something that can't be fetched directly
        if bare:
            refspecs = ['+refs/heads/*:refs/heads/*', '+refs/tags/*:refs/tags/*']
        else:
            # ensure all tags are fetched
            if git_version_used >= LooseVersion('1.9'):
                fetch_cmd.append('--tags')
            else:
                # old git versions have a bug in --tags that prevents updating existing tags
                commands.append((fetch_str, fetch_cmd + [remote]))
                refspecs = ['+refs/tags/*:refs/tags/*']
        if refspec:
            refspecs.append(refspec)
    fetch_cmd.extend([remote])

    commands.append((fetch_str, fetch_cmd + refspecs))

    for (label,command) in commands:
        (rc,out,err) = module.run_command(command, cwd=dest)
        if rc != 0:
            module.fail_json(msg="Failed to %s: %s %s" % (label, out, err), cmd=command)

def submodules_fetch(git_path, module, remote, track_submodules, dest):
    changed = False

    if not os.path.exists(os.path.join(dest, '.gitmodules')):
        # no submodules
        return changed

    gitmodules_file = open(os.path.join(dest, '.gitmodules'), 'r')
    for line in gitmodules_file:
        # Check for new submodules
        if not changed and line.strip().startswith('path'):
            path = line.split('=', 1)[1].strip()
            # Check that dest/path/.git exists
            if not os.path.exists(os.path.join(dest, path, '.git')):
                changed = True

        # add the submodule repo's hostkey
        if line.strip().startswith('url'):
            repo = line.split('=', 1)[1].strip()
            if module.params['ssh_opts'] is not None:
                if "-o StrictHostKeyChecking=no" not in module.params['ssh_opts']:
                    add_git_host_key(module, repo, accept_hostkey=module.params['accept_hostkey'])
            else:
                add_git_host_key(module, repo, accept_hostkey=module.params['accept_hostkey'])

    # Check for updates to existing modules
    if not changed:
        # Fetch updates
        begin = get_submodule_versions(git_path, module, dest)
        cmd = [git_path, 'submodule', 'foreach', git_path, 'fetch']
        (rc, out, err) = module.run_command(cmd, check_rc=True, cwd=dest)
        if rc != 0:
            module.fail_json(msg="Failed to fetch submodules: %s" % out + err)

        if track_submodules:
            # Compare against submodule HEAD
            ### FIXME: determine this from .gitmodules
            version = 'master'
            after = get_submodule_versions(git_path, module, dest, '%s/%s'
                    % (remote, version))
            if begin != after:
                changed = True
        else:
            # Compare against the superproject's expectation
            cmd = [git_path, 'submodule', 'status']
            (rc, out, err) = module.run_command(cmd, check_rc=True, cwd=dest)
            if rc != 0:
                module.fail_json(msg='Failed to retrieve submodule status: %s' % out + err)
            for line in out.splitlines():
                if line[0] != ' ':
                    changed = True
                    break
    return changed

def submodule_update(git_path, module, dest, track_submodules, force=False):
    ''' init and update any submodules '''

    # get the valid submodule params
    params = get_submodule_update_params(module, git_path, dest)

    # skip submodule commands if .gitmodules is not present
    if not os.path.exists(os.path.join(dest, '.gitmodules')):
        return (0, '', '')
    cmd = [ git_path, 'submodule', 'sync' ]
    (rc, out, err) = module.run_command(cmd, check_rc=True, cwd=dest)
    if 'remote' in params and track_submodules:
        cmd = [ git_path, 'submodule', 'update', '--init', '--recursive' ,'--remote' ]
    else:
        cmd = [ git_path, 'submodule', 'update', '--init', '--recursive' ]
    if force:
        cmd.append('--force')
    (rc, out, err) = module.run_command(cmd, cwd=dest)
    if rc != 0:
        module.fail_json(msg="Failed to init/update submodules: %s" % out + err)
    return (rc, out, err)

def set_remote_branch(git_path, module, dest, remote, version, depth):
    """set refs for the remote branch version

    This assumes the branch does not yet exist locally and is therefore also not checked out.
    Can't use git remote set-branches, as it is not available in git 1.7.1 (centos6)
    """

    branchref = "+refs/heads/%s:refs/heads/%s" % (version, version)
    branchref += ' +refs/heads/%s:refs/remotes/%s/%s' % (version, remote, version)
    cmd = "%s fetch --depth=%s %s %s" % (git_path, depth, remote, branchref)
    (rc, out, err) = module.run_command(cmd, cwd=dest)
    if rc != 0:
        module.fail_json(msg="Failed to fetch branch from remote: %s" % version, stdout=out, stderr=err, rc=rc)

def switch_version(git_path, module, dest, remote, version, verify_commit, depth):
    cmd = ''
    if version == 'HEAD':
        branch = get_head_branch(git_path, module, dest, remote)
        (rc, out, err) = module.run_command("%s checkout --force %s" % (git_path, branch), cwd=dest)
        if rc != 0:
            module.fail_json(msg="Failed to checkout branch %s" % branch,
                             stdout=out, stderr=err, rc=rc)
        cmd = "%s reset --hard %s" % (git_path, remote)
    else:
        # FIXME check for local_branch first, should have been fetched already
        if is_remote_branch(git_path, module, dest, remote, version):
            if depth and not is_local_branch(git_path, module, dest, version):
                # git clone --depth implies --single-branch, which makes
                # the checkout fail if the version changes
                # fetch the remote branch, to be able to check it out next
                set_remote_branch(git_path, module, dest, remote, version, depth)
            if not is_local_branch(git_path, module, dest, version):
                cmd = "%s checkout --track -b %s %s/%s" % (git_path, version, remote, version)
            else:
                (rc, out, err) = module.run_command("%s checkout --force %s" % (git_path, version), cwd=dest)
                if rc != 0:
                    module.fail_json(msg="Failed to checkout branch %s" % version,
                                     stdout=out, stderr=err, rc=rc)
                cmd = "%s reset --hard %s/%s" % (git_path, remote, version)
        else:
            cmd = "%s checkout --force %s" % (git_path, version)
    (rc, out1, err1) = module.run_command(cmd, cwd=dest)
    if rc != 0:
        if version != 'HEAD':
            module.fail_json(msg="Failed to checkout %s" % (version),
                             stdout=out1, stderr=err1, rc=rc, cmd=cmd)
        else:
            module.fail_json(msg="Failed to checkout branch %s" % (branch),
                             stdout=out1, stderr=err1, rc=rc, cmd=cmd)

    if verify_commit:
        verify_commit_sign(git_path, module, dest, version)

    return (rc, out1, err1)


def verify_commit_sign(git_path, module, dest, version):
    if version in get_tags(git_path, module, dest):
        git_sub = "verify-tag"
    else:
        git_sub = "verify-commit"
    cmd = "%s %s %s" % (git_path, git_sub, version)
    (rc, out, err) = module.run_command(cmd, cwd=dest)
    if rc != 0:
        module.fail_json(msg='Failed to verify GPG signature of commit/tag "%s"' % version, stdout=out, stderr=err, rc=rc)
    return (rc, out, err)


def git_version(git_path, module):
    """return the installed version of git"""
    cmd = "%s --version" % git_path
    (rc, out, err) = module.run_command(cmd)
    if rc != 0:
        # one could fail_json here, but the version info is not that important, so let's try to fail only on actual git commands
        return None
    rematch = re.search('git version (.*)$', to_native(out))
    if not rematch:
        return None
    return LooseVersion(rematch.groups()[0])


# ===========================================

def main():
    module = AnsibleModule(
        argument_spec = dict(
            dest=dict(type='path'),
            repo=dict(required=True, aliases=['name']),
            version=dict(default='HEAD'),
            remote=dict(default='origin'),
            refspec=dict(default=None),
            reference=dict(default=None),
            force=dict(default='no', type='bool'),
            depth=dict(default=None, type='int'),
            clone=dict(default='yes', type='bool'),
            update=dict(default='yes', type='bool'),
            verify_commit=dict(default='no', type='bool'),
            accept_hostkey=dict(default='no', type='bool'),
            key_file=dict(default=None, type='path', required=False),
            ssh_opts=dict(default=None, required=False),
            executable=dict(default=None, type='path'),
            bare=dict(default='no', type='bool'),
            recursive=dict(default='yes', type='bool'),
            track_submodules=dict(default='no', type='bool'),
            umask=dict(default=None, type='raw'),
        ),
        supports_check_mode=True
    )

    dest      = module.params['dest']
    repo      = module.params['repo']
    version   = module.params['version']
    remote    = module.params['remote']
    refspec   = module.params['refspec']
    force     = module.params['force']
    depth     = module.params['depth']
    update    = module.params['update']
    allow_clone = module.params['clone']
    bare      = module.params['bare']
    verify_commit = module.params['verify_commit']
    reference = module.params['reference']
    git_path  = module.params['executable'] or module.get_bin_path('git', True)
    key_file  = module.params['key_file']
    ssh_opts  = module.params['ssh_opts']
    umask  = module.params['umask']

    result = dict( warnings=list() )

    # evaluate and set the umask before doing anything else
    if umask is not None:
        if not isinstance(umask, string_types):
            module.fail_json(msg="umask must be defined as a quoted octal integer")
        try:
            umask = int(umask, 8)
        except:
            module.fail_json(msg="umask must be an octal integer",
                             details=str(sys.exc_info()[1]))
        os.umask(umask)

    # Certain features such as depth require a file:/// protocol for path based urls
    # so force a protocal here ...
    if repo.startswith('/'):
        repo = 'file://' + repo

    # We screenscrape a huge amount of git commands so use C locale anytime we
    # call run_command()
    module.run_command_environ_update = dict(LANG='C', LC_ALL='C', LC_MESSAGES='C', LC_CTYPE='C')

    gitconfig = None
    if not dest and allow_clone:
        module.fail_json(msg="the destination directory must be specified unless clone=no")
    elif dest:
        dest = os.path.abspath(dest)
        if bare:
            gitconfig = os.path.join(dest, 'config')
        else:
            gitconfig = os.path.join(dest, '.git', 'config')

    # create a wrapper script and export
    # GIT_SSH=<path> as an environment variable
    # for git to use the wrapper script
    ssh_wrapper = None
    if key_file or ssh_opts:
        ssh_wrapper = write_ssh_wrapper()
        set_git_ssh(ssh_wrapper, key_file, ssh_opts)
        module.add_cleanup_file(path=ssh_wrapper)

    # add the git repo's hostkey
    if module.params['ssh_opts'] is not None:
        if "-o StrictHostKeyChecking=no" not in module.params['ssh_opts']:
            add_git_host_key(module, repo, accept_hostkey=module.params['accept_hostkey'])
    else:
        add_git_host_key(module, repo, accept_hostkey=module.params['accept_hostkey'])
    git_version_used = git_version(git_path, module)

    if depth is not None and git_version_used < LooseVersion('1.9.1'):
        result['warnings'].append("Your git version is too old to fully support the depth argument. Falling back to full checkouts.")
        depth = None

    recursive = module.params['recursive']
    track_submodules = module.params['track_submodules']

    result.update(before=None)
    local_mods = False
    need_fetch = True
    if (dest and not os.path.exists(gitconfig)) or (not dest and not allow_clone):
        # if there is no git configuration, do a clone operation unless:
        # * the user requested no clone (they just want info)
        # * we're doing a check mode test
        # In those cases we do an ls-remote
        if module.check_mode or not allow_clone:
            remote_head = get_remote_head(git_path, module, dest, version, repo, bare)
            result.update(changed=True, after=remote_head)
            if module._diff:
                diff = get_diff(module, git_path, dest, repo, remote, depth, bare, result['before'], result['after'])
                if diff:
                    result['diff'] = diff
            module.exit_json(**result)
        # there's no git config, so clone
        clone(git_path, module, repo, dest, remote, depth, version, bare, reference, refspec, verify_commit)
        need_fetch = False
    elif not update:
        # Just return having found a repo already in the dest path
        # this does no checking that the repo is the actual repo
        # requested.
        result['before'] = get_version(module, git_path, dest)
        result.update(changed=False, after=result['before'])
        module.exit_json(**result)
    else:
        # else do a pull
        local_mods = has_local_mods(module, git_path, dest, bare)
        result['before'] = get_version(module, git_path, dest)
        if local_mods:
            # failure should happen regardless of check mode
            if not force:
                module.fail_json(msg="Local modifications exist in repository (force=no).", **result)
            # if force and in non-check mode, do a reset
            if not module.check_mode:
                reset(git_path, module, dest)

        # exit if already at desired sha version
        if module.check_mode:
            remote_url = get_remote_url(git_path, module, dest, remote)
            remote_url_changed = remote_url and remote_url != repo and remote_url != unfrackgitpath(repo)
        else:
            remote_url_changed = set_remote_url(git_path, module, repo, dest, remote)
        result.update(remote_url_changed=remote_url_changed)

        if need_fetch:
            if module.check_mode:
                remote_head = get_remote_head(git_path, module, dest, version, remote, bare)
                result.update(changed=(result['before'] != remote_head), after=remote_head)
                # FIXME: This diff should fail since the new remote_head is not fetched yet?!
                if module._diff:
                    diff = get_diff(module, git_path, dest, repo, remote, depth, bare, result['before'], result['after'])
                    if diff:
                        result['diff'] = diff
                module.exit_json(**result)
            else:
                fetch(git_path, module, repo, dest, version, remote, depth, bare, refspec, git_version_used)

        result['after'] = get_version(module, git_path, dest)

        if result['before'] == result['after']:
            if local_mods:
                result.update(changed=True, after=remote_head, msg='Local modifications exist')
                # no diff, since the repo didn't change
                module.exit_json(**result)

    # switch to version specified regardless of whether
    # we got new revisions from the repository
    if not bare:
        switch_version(git_path, module, dest, remote, version, verify_commit, depth)

    # Deal with submodules
    submodules_updated = False
    if recursive and not bare:
        submodules_updated = submodules_fetch(git_path, module, remote, track_submodules, dest)
        if submodules_updated:
            result.update(submodules_changed=submodules_updated)

            if module.check_mode:
                result.update(changed=True, after=remote_head)
                module.exit_json(**result)

            # Switch to version specified
            submodule_update(git_path, module, dest, track_submodules, force=force)

    # determine if we changed anything
    result['after'] = get_version(module, git_path, dest)

    result.update(changed=False)
    if result['before'] != result['after'] or local_mods or submodules_updated or remote_url_changed:
        result.update(changed=True)
        if module._diff:
            diff = get_diff(module, git_path, dest, repo, remote, depth, bare, result['before'], result['after'])
            if diff:
                result['diff'] = diff

    # cleanup the wrapper script
    if ssh_wrapper:
        try:
            os.remove(ssh_wrapper)
        except OSError:
            # No need to fail if the file already doesn't exist
            pass

    module.exit_json(**result)


if __name__ == '__main__':
    main()