# 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 # Author: Juerg Haefliger # Author: Joshua Harlow # # 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 . import httplib import time import requests from requests import exceptions from urlparse import (urlparse, urlunparse) from cloudinit import log as logging from cloudinit import version LOG = logging.getLogger(__name__) NOT_FOUND = httplib.NOT_FOUND # Check if requests has ssl support (added in requests >= 0.8.8) SSL_ENABLED = False CONFIG_ENABLED = False # This was added in 0.7 (but taken out in >=1.0) try: from distutils.version import LooseVersion import pkg_resources _REQ = pkg_resources.get_distribution('requests') _REQ_VER = LooseVersion(_REQ.version) # pylint: disable=E1103 if _REQ_VER >= LooseVersion('0.8.8'): SSL_ENABLED = True if _REQ_VER >= LooseVersion('0.7.0') and _REQ_VER < LooseVersion('1.0.0'): CONFIG_ENABLED = True except: pass def _cleanurl(url): parsed_url = list(urlparse(url, scheme='http')) # pylint: disable=E1123 if not parsed_url[1] and parsed_url[2]: # Swap these since this seems to be a common # occurrence when given urls like 'www.google.com' parsed_url[1] = parsed_url[2] parsed_url[2] = '' return urlunparse(parsed_url) # Made to have same accessors as UrlResponse so that the # read_file_or_url can return this or that object and the # 'user' of those objects will not need to know the difference. class StringResponse(object): def __init__(self, contents, code=200): self.code = code self.headers = {} self.contents = contents self.url = None def ok(self, *args, **kwargs): # pylint: disable=W0613 if self.code != 200: return False return True def __str__(self): return self.contents class FileResponse(StringResponse): def __init__(self, path, contents, code=200): StringResponse.__init__(self, contents, code=code) self.url = path class UrlResponse(object): def __init__(self, response): self._response = response @property def contents(self): return self._response.content @property def url(self): return self._response.url 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 @property def headers(self): return self._response.headers @property def code(self): return self._response.status_code def __str__(self): return self.contents class UrlError(IOError): def __init__(self, cause, code=None, headers=None): IOError.__init__(self, str(cause)) self.cause = cause self.code = code self.headers = headers if self.headers is None: self.headers = {} def readurl(url, data=None, timeout=None, retries=0, sec_between=1, headers=None, headers_cb=None, ssl_details=None, check_status=True, allow_redirects=True, exception_cb=None): url = _cleanurl(url) req_args = { 'url': url, } scheme = urlparse(url).scheme # pylint: disable=E1101 if 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']] elif 'cert_file' in ssl_details: req_args['cert'] = str(ssl_details['cert_file']) req_args['allow_redirects'] = allow_redirects 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 (or newer ones either), thus we # need to manually do the retries if it wasn't... if CONFIG_ENABLED: req_config = { 'store_cookies': False, } # Don't use the retry support built-in # since it doesn't allow for 'sleep_times' # in between tries.... # if retries: # req_config['max_retries'] = max(int(retries), 0) req_args['config'] = req_config manual_tries = 1 if retries: manual_tries = max(int(retries) + 1, 1) if not headers: headers = { 'User-Agent': 'Cloud-Init/%s' % (version.version_string()), } if not headers_cb: def _cb(url): return headers headers_cb = _cb if data: # Do this after the log (it might be large) req_args['data'] = data if sec_between is None: sec_between = -1 excps = [] # Handle retrying ourselves since the built-in support # doesn't handle sleeping between tries... for i in range(0, manual_tries): req_args['headers'] = headers_cb(url) filtered_req_args = {} for (k, v) in req_args.items(): if k == 'data': continue filtered_req_args[k] = v try: LOG.debug("[%s/%s] open '%s' with %s configuration", i, manual_tries, url, filtered_req_args) r = requests.request(**req_args) if check_status: r.raise_for_status() # pylint: disable=E1103 LOG.debug("Read from %s (%s, %sb) after %s attempts", url, r.status_code, len(r.content), # pylint: disable=E1103 (i + 1)) # Doesn't seem like we can make it use a different # subclass for responses, so add our own backward-compat # attrs return UrlResponse(r) except exceptions.RequestException as e: if (isinstance(e, (exceptions.HTTPError)) and hasattr(e, 'response') # This appeared in v 0.10.8 and hasattr(e.response, 'status_code')): excps.append(UrlError(e, code=e.response.status_code, headers=e.response.headers)) else: excps.append(UrlError(e)) if SSL_ENABLED and isinstance(e, exceptions.SSLError): # ssl exceptions are not going to get fixed by waiting a # few seconds break if exception_cb and not exception_cb(filtered_req_args, excps[-1]): break if i + 1 < manual_tries and sec_between > 0: LOG.debug("Please wait %s seconds while we wait to try again", sec_between) time.sleep(sec_between) if excps: raise excps[-1] return None # Should throw before this... 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 = "" e = None try: if headers_cb is not None: headers = headers_cb(url) else: headers = {} response = readurl(url, headers=headers, timeout=timeout, check_status=False) if not response.contents: reason = "empty response [%s]" % (response.code) e = UrlError(ValueError(reason), code=response.code, headers=response.headers) elif not response.ok(): reason = "bad status code [%s]" % (response.code) e = UrlError(ValueError(reason), code=response.code, headers=response.headers) else: return url except UrlError 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: # This can be used to alter the headers that will be sent # in the future, for example this is what the MAAS datasource # does. 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