ansible/library/get_url

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

# (c) 2012, Jan-Piet Mens <jpmens () 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/>.
#
# see examples/playbooks/get_url.yml

import shutil
import datetime
import tempfile

DOCUMENTATION = '''
---
module: get_url
short_description: Downloads files from HTTP, HTTPS, or FTP to node
description:
     - Downloads files from HTTP, HTTPS, or FTP to the remote server. The remote
       server must have direct access to the remote resource.
version_added: "0.6"
options:
  url:
    description:
      - HTTP, HTTPS, or FTP URL
    required: true
    default: null
    aliases: []
  dest:
    description:
      - absolute path of where to download the file to.
      - If I(dest) is a directory, the basename of the file on the remote server will be used. If a directory, I(thirsty=yes) must also be set.
    required: true
    default: null
  thirsty:
    description:
      - if C(yes), will download the file every time and replace the
        file if the contents change. if C(no), the file will only be downloaded if
        the destination does not exist. Generally should be C(yes) only for small
        local files. prior to 0.6, acts if C(yes) by default.
    version_added: "0.7"
    required: false
    choices: [ "yes", "no" ]
    default: "no"
  others:
    description:
      - all arguments accepted by the M(file) module also work here
    required: false
examples:
   - code: get_url url=http://example.com/path/file.conf dest=/etc/foo.conf mode=0440
     description: Obtain and install config file
notes:
    - This module doesn't support proxies or passwords.
    - Also see the M(template) module.
# informational: requirements for nodes
requirements: [ urllib2, urlparse ]
'''

HAS_URLLIB2=True
try:
    import urllib2
except ImportError:
    HAS_URLLIB2=False
HAS_URLPARSE=True

try:
    import urlparse
    import socket
except ImportError:
    HAS_URLPARSE=False

# ==============================================================
# url handling

def url_filename(url):
    fn = os.path.basename(urlparse.urlsplit(url)[2])
    if fn == '':
        return 'index.html'
    return fn

def url_do_get(module, url, dest):
    """
    Get url and return request and info
    Credits: http://stackoverflow.com/questions/7006574/how-to-download-file-from-ftp
    """

    USERAGENT = 'ansible-httpget'
    info = dict(url=url)
    r = None
    actualdest = None

    if os.path.isdir(dest):
        urlfilename = url_filename(url)
        actualdest = "%s/%s" % (dest, urlfilename)
        module.params['path'] = actualdest
    else:
        actualdest = dest
    info['daisychain_args'] = module.params
    info['daisychain_args']['state'] = 'file'
    info['daisychain_args']['dest'] = actualdest
    info['actualdest'] = actualdest

    request = urllib2.Request(url)
    request.add_header('User-agent', USERAGENT)

    if os.path.exists(actualdest):
        t = datetime.datetime.utcfromtimestamp(os.path.getmtime(actualdest))
        tstamp = t.strftime('%a, %d %b %Y %H:%M:%S +0000')
        request.add_header('If-Modified-Since', tstamp)

    try:
        r = urllib2.urlopen(request)
        info.update(r.info())
        info.update(dict(msg="OK (%s bytes)" % r.headers.get('Content-Length', 'unknown'), status=200))
    except urllib2.HTTPError, e:
        # Must not fail_json() here so caller can handle HTTP 304 unmodified
        info.update(dict(msg=str(e), status=e.code))
        return r, info
    except urllib2.URLError, e:
        code = getattr(e, 'code', -1)
        module.fail_json(msg="Request failed: %s" % str(e), status_code=code)

    return r, info

def url_get(module, url, dest):
    """
    Download url and store at dest.
    If dest is a directory, determine filename from url.
    Return (tempfile, info about the request)
    """

    req, info = url_do_get(module, url, dest)

    # TODO: should really handle 304, but how? src file could exist (and be newer) but empty
    if info['status'] == 304:
        module.exit_json(url=url, dest=info.get('actualdest', dest), changed=False, msg=info.get('msg', ''))

    # create a temporary file and copy content to do md5-based replacement
    if info['status'] != 200:
        module.fail_json(msg="Request failed", status_code=info['status'], response=info['msg'], url=url)
    actualdest = info['actualdest']

    fd, tempname = tempfile.mkstemp()
    f = os.fdopen(fd, 'wb')
    try:
        shutil.copyfileobj(req, f)
    except Exception, err:
        os.remove(tempname)
        module.fail_json(msg="failed to create temporary content file: %s" % str(err))
    f.close()
    req.close()
    return tempname, info

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

def main():

    # does this really happen on non-ancient python?
    if not HAS_URLLIB2:
        module.fail_json(msg="urllib2 is not installed")
    if not HAS_URLPARSE:
        module.fail_json(msg="urlparse is not installed")

    module = AnsibleModule(
        # not checking because of daisy chain to file module
        check_invalid_arguments = False,
        argument_spec = dict(
            url = dict(required=True),
            dest = dict(required=True),
            thirsty = dict(default='no', choices=BOOLEANS)
        )
    )

    url  = module.params['url']
    dest = os.path.expanduser(module.params['dest'])
    thirsty = module.boolean(module.params['thirsty'])

    if not thirsty:
        if os.path.isdir(dest):
            module.fail_json(msg="non-thirsty mode needs a filename for a destination, not a directory")
        if os.path.exists(dest):
            module.exit_json(msg="file already exists", dest=dest, url=url, changed=False)

    # download to tmpsrc
    tmpsrc, info = url_get(module, url, dest)
    md5sum_src   = None
    md5sum_dest  = None
    dest         = info['actualdest']

    # raise an error if there is no tmpsrc file
    if not os.path.exists(tmpsrc):
        os.remove(tmpsrc)
        module.fail_json(msg="Request failed", status_code=info['status'], response=info['msg'])
    if not os.access(tmpsrc, os.R_OK):
        os.remove(tmpsrc)
        module.fail_json( msg="Source %s not readable" % (tmpsrc))
    md5sum_src = module.md5(tmpsrc)

    # check if there is no dest file
    if os.path.exists(dest):
        # raise an error if copy has no permission on dest
        if not os.access(dest, os.W_OK):
            os.remove(tmpsrc)
            module.fail_json( msg="Destination %s not writable" % (dest))
        if not os.access(dest, os.R_OK):
            os.remove(tmpsrc)
            module.fail_json( msg="Destination %s not readable" % (dest))
        md5sum_dest = module.md5(dest)
    else:
        if not os.access(os.path.dirname(dest), os.W_OK):
            os.remove(tmpsrc)
            module.fail_json( msg="Destination %s not writable" % (os.path.dirname(dest)))

    if md5sum_src != md5sum_dest:
        try:
            shutil.copyfile(tmpsrc, dest)
        except Exception, err:
            os.remove(tmpsrc)
            module.fail_json(msg="failed to copy %s to %s: %s" % (tmpsrc, dest, str(err)))
        changed = True
    else:
        changed = False

    os.remove(tmpsrc)

    # Mission complete
    module.exit_json(url=url, dest=dest, src=tmpsrc, md5sum=md5sum_src,
        changed=changed, msg=info.get('msg',''),
        daisychain="file", daisychain_args=info.get('daisychain_args',''))

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