Source code for oio.common.client
# Copyright (C) 2015-2017 OpenIO SAS, as part of OpenIO SDS
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 3.0 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library.
from oio.common.green import sleep
from oio.common.logger import get_logger
from oio.common.configuration import load_namespace_conf, validate_service_conf
from oio.api.base import HttpApi
from oio.common.exceptions import Conflict, OioException, ServiceBusy
from random import randrange
REQUEST_ATTEMPTS = 1
[docs]class ProxyClient(HttpApi):
"""
Client directed towards oio-proxy, with logging facility
"""
_slot_time = 0.5
def __init__(self, conf, request_prefix="",
no_ns_in_url=False, endpoint=None,
request_attempts=REQUEST_ATTEMPTS,
logger=None, **kwargs):
"""
:param request_prefix: text to insert in between endpoint and
requested URL
:type request_prefix: `str`
:param no_ns_in_url: do not insert namespace name between endpoint
and `request_prefix`
:type no_ns_in_url: `bool`
:param request_attempts: number of attempts for the request in case of
error 503
:raise oio.common.exceptions.ServiceBusy: if all attempts fail
"""
assert request_attempts > 0
validate_service_conf(conf)
self.ns = conf.get('namespace')
self.conf = conf
self.logger = logger or get_logger(conf)
if not endpoint:
endpoint = self.conf.get('proxyd_url', None)
ep_parts = list()
if endpoint:
self.proxy_netloc = endpoint.lstrip("http://")
else:
ns_conf = load_namespace_conf(self.ns)
self.proxy_netloc = ns_conf.get('proxy')
ep_parts.append("http:/")
ep_parts.append(self.proxy_netloc)
ep_parts.append("v3.0")
if not no_ns_in_url:
ep_parts.append(self.ns)
if request_prefix:
ep_parts.append(request_prefix.lstrip('/'))
self._request_attempts = request_attempts
super(ProxyClient, self).__init__(
endpoint='/'.join(ep_parts), service_type='proxy', **kwargs)
def _direct_request(self, method, url, headers=None, request_attempts=None,
**kwargs):
if not request_attempts:
request_attempts = self._request_attempts
if request_attempts <= 0:
raise OioException("Negative request attempts: %d"
% request_attempts)
if kwargs.get("autocreate"):
if not headers:
headers = dict()
headers["X-oio-action-mode"] = "autocreate"
kwargs = kwargs.copy()
kwargs.pop("autocreate")
for i in range(request_attempts):
try:
return super(ProxyClient, self)._direct_request(
method, url, headers=headers, **kwargs)
except ServiceBusy:
if i >= request_attempts - 1:
raise
# retry with exponential backoff
ProxyClient._exp_sleep(i + 1)
except Conflict:
if i > 0 and method == 'POST':
# We were retrying a POST operation, it's highly probable
# that the original operation succeeded after we timed
# out. So we consider this a success and don't raise
# the exception.
return None, None
raise
@staticmethod
def _exp_sleep(attempts):
"""Sleep an exponential amount of time derived from `attempts`."""
limit = pow(2, attempts)
k = randrange(limit)
sleep(k * ProxyClient._slot_time)