ansible/get_url

#!/usr/bin/python

# (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/>.
#
# Synopsis:
#        ansible -m get_url -a "url=http://some.place/some.file dest=/tmp/file"
#
# Arguments:
#    url=                (mandatory, no default)
#    dest=                (mandatory, no default)
#        if dest= is a file, url is copied to that file
#        if dest= is a directory, determine name from url= and store it in dest/
#    mode, owner, group, ... from the "file" module are also supported
#
# Playbook:
#   The dest=<directory> feature lets you do this in a Playbook:
#
#          - name: Grab a bunch of jQuery stuff
#            action: get_url url=http://code.jquery.com/$item  dest=${jquery_directory} mode=0444
#            with_items:
#            - jquery.min.js
#            - mobile/latest/jquery.mobile.min.js
#            - ui/jquery-ui-git.css
#
# TODO:
#    timeout=
#    Support gzip compression? 
#        http://www.diveintopython.net/http_web_services/gzip_compression.html

import sys
import os
import shlex
import shutil
import syslog
import datetime
import tempfile

try:
    from hashlib import md5 as _md5
except ImportError: 
    from md5 import md5 as _md5

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

# ==============================================================
# support

def md5(filename):
    ''' Return MD5 hex digest of local file, or None if file is not present. '''
    if not os.path.exists(filename):
        return None
    digest = _md5()
    blocksize = 64 * 1024
    infile = open(filename, 'rb')
    block = infile.read(blocksize)
    while block:
        digest.update(block)
        block = infile.read(blocksize)
    infile.close()
    return digest.hexdigest()

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

def url_filename(url):
    return os.path.basename(urlparse.urlsplit(url)[2])

def url_do_get(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 = {}
    info['url'] = url
    r = None

    if dest:
        if os.path.isdir(dest):
            destpath = "%s/%s" % (dest, url_filename(url))
        else:
            destpath = dest
    else:
        destpath = url_filename(url)

    info['destpath'] = destpath

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

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

    try:
        r = urllib2.urlopen(request)

        dinfo = dict(r.info())
        for x in dinfo:
             info[x] = dinfo[x]

        info['msg'] = "OK %s octets" % r.headers.get('Content-Length', 'unknown')
        info['status'] = 200
    except urllib2.HTTPError as e:
        # Must not fail_json() here so caller can handle HTTP 304 unmodified
        info['msg'] = "%s" % e
        info['status'] = e.code
        return r, info
    except urllib2.URLError as e:
        if 'code' in e:
            co = e.code
        else:
            co = -1
        resp = "%s" % e
        module.fail_json(msg="Request failed", status_code=co, response=resp)

    return r, info

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

    req, info = url_do_get(url, dest)

    # TODO: should really handle 304, but how? src file could exist (and be
    #       newer) but be empty ...

    if info['status'] == 304:
        module.exit_json(url=url, dest=info.get('destpath', dest), changed=False, msg=info.get('msg', ''))

    # We have the data. Create a temporary file and copy content into that
    # to do the MD5-thing

    if info['status'] == 200:
        destpath = info['destpath']

        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
    else:
        module.fail_json(msg="Request failed", status_code=info['status'], response=info['msg'], url=url)

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

def main():
    global module
    module = AnsibleModule(
        argument_spec = dict(
            url = dict(required=True),
            dest = dict(required=True),
        )
    )
    
    url = module.params.get('url', '')
    dest = module.params.get('dest', '')
    
    if url == "":
        module.fail_json(msg="url= URL missing")
    if dest == "":
        module.fail_json(msg="dest= missing")
    
    dest = os.path.expanduser(dest)
    
    if not HAS_URLLIB2:
        module.fail_json(msg="urllib2 is not installed")
    if not HAS_URLPARSE:
        module.fail_json(msg="urlparse is not installed")
    
    
    # Here we go... if this succeeds, tmpsrc is the name of a temporary file
    # containing slurped content. If it fails, we've already raised an error
    # to Ansible
    
    tmpsrc, info = url_get(url, dest)
    
    md5sum_src = None
    
    dest = info.get('destpath', None)
    
    # 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 = md5(tmpsrc)
    
    
    md5sum_dest = None
    # 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 = 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:
        # was os.system("cp %s %s" % (src, 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
    
    # Mission complete
    
    os.remove(tmpsrc)
    module.exit_json(url=url, dest=dest, src=tmpsrc,
        md5sum=md5sum_src, changed=changed, msg=info.get('msg', ''),
        daisychain="file")

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

main()