Merge "Add a base transport class"

marconiclient/errors.py

@@ -0,0 +1,19 @@
+# Copyright 2013 Red Hat, Inc.
+#
+#    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.
+
+__all__ = ['MarconiError']
+
+
+class MarconiError(Exception):
+    """Base class for errors."""

marconiclient/transport/__init__.py

@@ -0,0 +1,67 @@
+# Copyright (c) 2013 Red Hat, Inc.
+#
+# 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.
+
+import six
+from six.moves.urllib import parse
+from stevedore import driver
+
+from marconiclient import errors
+
+
+class DriverLoadFailure(errors.MarconiError):
+    """Raised if a transport driver can't be loaded."""
+
+    def __init__(self, driver, ex):
+        msg = 'Failed to load transport driver "%s": %s' % (driver, ex)
+        super(DriverLoadFailure, self).__init__(msg)
+        self.driver = driver
+        self.ex = ex
+
+
+def get_transport(conf, url_or_request, module='queues'):
+    """Gets a transport for a given url.
+
+    An example transport URL might be::
+
+        zmq://example.org:8888/v1/
+
+    :param conf: the user configuration
+    :type conf: cfg.ConfigOpts
+    :param url_or_request: a transport URL
+    :type url_or_request: `six.string_types` or
+        `marconiclient.transport.request.Request`
+    :param module: Module the target transport belongs to.
+    :type module: str
+
+    :returns: A `Transport` instance.
+    :rtype: `marconiclient.transport.Transport`
+    """
+
+    url = url_or_request
+    if not isinstance(url_or_request, six.string_types):
+        url = url_or_request.endpoint
+
+    parsed = parse.urlparse(url)
+
+    try:
+        namespace = 'marconiclient.{0}.transport'.format(module)
+        mgr = driver.DriverManager(namespace,
+                                   parsed.scheme,
+                                   invoke_on_load=True,
+                                   invoke_args=[conf])
+    except RuntimeError as ex:
+        raise DriverLoadFailure(parsed.scheme, ex)
+
+    return mgr.driver

marconiclient/transport/base.py

@@ -0,0 +1,33 @@
+# Copyright (c) 2013 Red Hat, Inc.
+#
+# 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.
+
+import abc
+
+import six
+
+
+@six.add_metaclass(abc.ABCMeta)
+class Transport(object):
+
+    def __init__(self, conf):
+        self.conf = conf
+
+    @abc.abstractmethod
+    def send(self, request):
+        """Returns the response.
+
+        :returns: The final response
+        :rtype: `marconiclient.transport.response.Response`
+        """

marconiclient/transport/response.py

@@ -0,0 +1,37 @@
+# Copyright (c) 2013 Red Hat, Inc.
+#
+# 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.
+
+
+class Response(object):
+    """Common response class for Marconiclient.
+
+    All `marconiclient.transport.base.Transport` implementations
+    will return this to the higher level API which will then build
+    an object out of it.
+
+    :param request: The request sent to the server.
+    :type: `marconiclient.transport.request.Request`
+    :param content: Response's content
+    :type: `six.string_types`
+    :param headers: Optional headers returned in the response.
+    :type: dict
+    """
+
+    __slots__ = ('request', 'content', 'headers')
+
+    def __init__(self, request, content, headers=None):
+        self.request = request
+        self.content = content
+        self.headers = headers or {}

requirements.txt

@@ -1,5 +1,6 @@
 pbr>=0.5.21,<1.0
 six>=1.3.0
+stevedore>=0.10
 
 python-keystoneclient