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# vi: ts=4 expandtab
#
# Copyright (C) 2012 Canonical Ltd.
# Copyright (C) 2012 Hewlett-Packard Development Company, L.P.
# Copyright (C) 2012 Yahoo! Inc.
#
# Author: Scott Moser <scott.moser@canonical.com>
# Author: Juerg Haefliger <juerg.haefliger@hp.com>
# Author: Joshua Harlow <harlowja@yahoo-inc.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3, as
# published by the Free Software Foundation.
#
# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
import time
import requests
from requests import exceptions
from urlparse import urlparse
from cloudinit import log as logging
from cloudinit import version
LOG = logging.getLogger(__name__)
# Check if requests has ssl support (added in requests >= 0.8.8)
SSL_ENABLED = False
CONFIG_ENABLED = False # This was added in 0.7
try:
import pkg_resources
from distutils.version import LooseVersion
_REQ = pkg_resources.get_distribution('requests')
_REQ_VER = LooseVersion(_REQ.version)
if _REQ_VER >= LooseVersion('0.8.8'):
SSL_ENABLED = True
if _REQ_VER >= LooseVersion('0.7.0'):
CONFIG_ENABLED = True
except:
pass
class UrlResponse(object):
def __init__(self, status_code, contents=None, headers=None):
self._status_code = status_code
self._contents = contents
self._headers = headers
@property
def code(self):
return self._status_code
@property
def contents(self):
return self._contents
@property
def headers(self):
return self._headers
def __str__(self):
if not self.contents:
return ''
else:
return str(self.contents)
def ok(self, redirects_ok=False):
upper = 300
if redirects_ok:
upper = 400
if self.code >= 200 and self.code < upper:
return True
else:
return False
def readurl(url, data=None, timeout=None, retries=0,
headers=None, ssl_details=None, check_status=True):
req_args = {
'url': url,
}
if urlparse(url).scheme == 'https' and ssl_details:
if not SSL_ENABLED:
LOG.warn("SSL is not enabled, cert. verification can not occur!")
else:
if 'ca_certs' in ssl_details and ssl_details['ca_certs']:
req_args['verify'] = ssl_details['ca_certs']
else:
req_args['verify'] = True
if 'cert_file' in ssl_details and 'key_file' in ssl_details:
req_args['cert'] = [ssl_details['cert_file'],
ssl_details['key_file']]
req_args['allow_redirects'] = False
req_args['method'] = 'GET'
if timeout is not None:
req_args['timeout'] = max(float(timeout), 0)
if data:
req_args['method'] = 'POST'
# It doesn't seem like config
# was added in older library versions, thus we
# need to manually do the retries if it wasn't
manual_tries = 1
if CONFIG_ENABLED:
req_config = {}
req_config['store_cookies'] = False
if retries:
req_config['max_retries'] = max(int(retries), 0)
req_args['config'] = req_config
else:
if retries:
manual_tries = max(int(retries) + 1, 1)
if not headers:
headers = {
'User-Agent': 'Cloud-Init/%s' % (version.version_string()),
}
req_args['headers'] = headers
LOG.debug("Attempting to open '%s' with %s configuration", url, req_args)
if data:
# Do this after the log (it might be large)
req_args['data'] = data
last_excp = []
for _i in range(0, manual_tries):
try:
r = requests.request(**req_args)
if check_status:
r.raise_for_status()
except exceptions.RequestException as e:
last_excp = [e]
if last_excp:
raise last_excp[-1]
return UrlResponse(r.status_code, r.content, r.headers)
def wait_for_url(urls, max_wait=None, timeout=None,
status_cb=None, headers_cb=None, sleep_time=1,
exception_cb=None):
"""
urls: a list of urls to try
max_wait: roughly the maximum time to wait before giving up
The max time is *actually* len(urls)*timeout as each url will
be tried once and given the timeout provided.
timeout: the timeout provided to urlopen
status_cb: call method with string message when a url is not available
headers_cb: call method with single argument of url to get headers
for request.
exception_cb: call method with 2 arguments 'msg' (per status_cb) and
'exception', the exception that occurred.
the idea of this routine is to wait for the EC2 metdata service to
come up. On both Eucalyptus and EC2 we have seen the case where
the instance hit the MD before the MD service was up. EC2 seems
to have permenantely fixed this, though.
In openstack, the metadata service might be painfully slow, and
unable to avoid hitting a timeout of even up to 10 seconds or more
(LP: #894279) for a simple GET.
Offset those needs with the need to not hang forever (and block boot)
on a system where cloud-init is configured to look for EC2 Metadata
service but is not going to find one. It is possible that the instance
data host (169.254.169.254) may be firewalled off Entirely for a sytem,
meaning that the connection will block forever unless a timeout is set.
"""
start_time = time.time()
def log_status_cb(msg, exc=None):
LOG.debug(msg)
if status_cb is None:
status_cb = log_status_cb
def timeup(max_wait, start_time):
return ((max_wait <= 0 or max_wait is None) or
(time.time() - start_time > max_wait))
loop_n = 0
while True:
sleep_time = int(loop_n / 5) + 1
for url in urls:
now = time.time()
if loop_n != 0:
if timeup(max_wait, start_time):
break
if timeout and (now + timeout > (start_time + max_wait)):
# shorten timeout to not run way over max_time
timeout = int((start_time + max_wait) - now)
reason = ""
try:
if headers_cb is not None:
headers = headers_cb(url)
else:
headers = {}
resp = readurl(url, headers=headers, timeout=timeout,
check_status=False)
if not resp.contents:
reason = "empty response [%s]" % (resp.code)
e = ValueError(reason)
elif not resp.ok():
reason = "bad status code [%s]" % (resp.code)
e = ValueError(reason)
else:
return url
except exceptions.RequestException as e:
reason = "request error [%s]" % e
except Exception as e:
reason = "unexpected error [%s]" % e
time_taken = int(time.time() - start_time)
status_msg = "Calling '%s' failed [%s/%ss]: %s" % (url,
time_taken,
max_wait, reason)
status_cb(status_msg)
if exception_cb:
exception_cb(msg=status_msg, exception=e)
if timeup(max_wait, start_time):
break
loop_n = loop_n + 1
LOG.debug("Please wait %s seconds while we wait to try again",
sleep_time)
time.sleep(sleep_time)
return False
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