OpenStack Study: correlation_id.py

**** CubicPower OpenStack Study ****

# Copyright (c) 2013 Rackspace Hosting

# All Rights Reserved.

#

# Licensed under the Apache License, Version 2.0 (the "License"); you may

# not use this file except in compliance with the License. You may obtain

# a copy of the License at

#

# http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT

# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the

# License for the specific language governing permissions and limitations

# under the License.

"""Middleware that attaches a correlation id to WSGI request"""

import uuid

from neutron.openstack.common.middleware import base

**** CubicPower OpenStack Study ****

class CorrelationIdMiddleware(base.Middleware):

**** CubicPower OpenStack Study ****

    def process_request(self, req):

        correlation_id = (req.headers.get("X_CORRELATION_ID") or

                          str(uuid.uuid4()))

        req.headers['X_CORRELATION_ID'] = correlation_id