Adds a developer interface with direct access to the internal inter-service APIs and a command-line tool based on reflection to interact with them.

Example output from command-line tool:

(.nova-venv)termie@preciousroy:p/nova/easy_api % ./bin/stack
usage: stack [options] <controller> <method> [arg1=value arg2=value]

  `stack help` should output the list of available controllers
  `stack <controller>` should output the available methods for that controller
  `stack help <controller>` should do the same
  `stack help <controller> <method>` should output info for a method

./bin/stack:
  -?,--[no]help: show this help
  --[no]helpshort: show usage only for this module
  --[no]helpxml: like --help, but generates XML output
  --host: Direct API host
    (default: '127.0.0.1')
  --port: Direct API host
    (default: '8001')
    (an integer)
  --project: Direct API project
    (default: 'proj1')
  --user: Direct API username
    (default: 'user1')

Available controllers:
   reflect   Reflection methods to list available methods.
   compute   API for interacting with the compute manager.

(.nova-venv)termie@preciousroy:p/nova/easy_api % ./bin/stack help reflect
Available methods for reflect:
   get_controllers   List available controllers.
   get_methods       List available methods.
   get_method_info   Get detailed information about a method.

(.nova-venv)termie@preciousroy:p/nova/easy_api % ./bin/stack help reflect get_method_info
get_method_info(method):

Get detailed information about a method.

(.nova-venv)termie@preciousroy:p/nova/easy_api % ./bin/stack reflect get_method_info method=/reflect/get_method_info
{u'args': [[u'method']],
 u'doc': u'Get detailed information about a method.',
 u'name': u'get_method_info',
 u'short_doc': u'Get detailed information about a method.'}

2 files changed, 262 insertions, 17 deletions

diff --git a/nova/api/direct.py b/nova/api/direct.py
new file mode 100644
index 000000000..81b3ae202
--- /dev/null
+++ b/nova/api/direct.py
@@ -0,0 +1,232 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2010 United States Government as represented by the
+# Administrator of the National Aeronautics and Space Administration.
+# 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.
+
+"""Public HTTP interface that allows services to self-register.
+
+The general flow of a request is:
+    - Request is parsed into WSGI bits.
+    - Some middleware checks authentication.
+    - Routing takes place based on the URL to find a controller.
+      (/controller/method)
+    - Parameters are parsed from the request and passed to a method on the
+      controller as keyword arguments.
+      - Optionally 'json' is decoded to provide all the parameters.
+    - Actual work is done and a result is returned.
+    - That result is turned into json and returned.
+
+"""
+
+import inspect
+import urllib
+
+import routes
+import webob
+
+from nova import context
+from nova import flags
+from nova import utils
+from nova import wsgi
+
+
+ROUTES = {}
+
+
+def register_service(path, handle):
+    ROUTES[path] = handle
+
+
+class Router(wsgi.Router):
+    def __init__(self, mapper=None):
+        if mapper is None:
+            mapper = routes.Mapper()
+
+        self._load_registered_routes(mapper)
+        super(Router, self).__init__(mapper=mapper)
+
+    def _load_registered_routes(self, mapper):
+        for route in ROUTES:
+            mapper.connect('/%s/{action}' % route,
+                           controller=ServiceWrapper(ROUTES[route]))
+
+
+class DelegatedAuthMiddleware(wsgi.Middleware):
+    def process_request(self, request):
+        os_user = request.headers['X-OpenStack-User']
+        os_project = request.headers['X-OpenStack-Project']
+        context_ref = context.RequestContext(user=os_user, project=os_project)
+        request.environ['openstack.context'] = context_ref
+
+
+class JsonParamsMiddleware(wsgi.Middleware):
+    def process_request(self, request):
+        if 'json' not in request.params:
+            return
+
+        params_json = request.params['json']
+        params_parsed = utils.loads(params_json)
+        params = {}
+        for k, v in params_parsed.iteritems():
+            if k in ('self', 'context'):
+                continue
+            if k.startswith('_'):
+                continue
+            params[k] = v
+
+        request.environ['openstack.params'] = params
+
+
+class PostParamsMiddleware(wsgi.Middleware):
+    def process_request(self, request):
+        params_parsed = request.params
+        params = {}
+        for k, v in params_parsed.iteritems():
+            if k in ('self', 'context'):
+                continue
+            if k.startswith('_'):
+                continue
+            params[k] = v
+
+        request.environ['openstack.params'] = params
+
+
+class Reflection(object):
+    """Reflection methods to list available methods."""
+    def __init__(self):
+        self._methods = {}
+        self._controllers = {}
+
+    def _gather_methods(self):
+        methods = {}
+        controllers = {}
+        for route, handler in ROUTES.iteritems():
+            controllers[route] = handler.__doc__.split('\n')[0]
+            for k in dir(handler):
+                if k.startswith('_'):
+                    continue
+                f = getattr(handler, k)
+                if not callable(f):
+                    continue
+
+                # bunch of ugly formatting stuff
+                argspec = inspect.getargspec(f)
+                args = [x for x in argspec[0]
+                        if x != 'self' and x != 'context']
+                defaults = argspec[3] and argspec[3] or []
+                args_r = list(reversed(args))
+                defaults_r = list(reversed(defaults))
+
+                args_out = []
+                while args_r:
+                    if defaults_r:
+                        args_out.append((args_r.pop(0),
+                                         repr(defaults_r.pop(0))))
+                    else:
+                        args_out.append((str(args_r.pop(0)),))
+
+                # if the method accepts keywords
+                if argspec[2]:
+                    args_out.insert(0, ('**%s' % argspec[2],))
+
+                methods['/%s/%s' % (route, k)] = {
+                        'short_doc': f.__doc__.split('\n')[0],
+                        'doc': f.__doc__,
+                        'name': k,
+                        'args': list(reversed(args_out))}
+
+        self._methods = methods
+        self._controllers = controllers
+
+    def get_controllers(self, context):
+        """List available controllers."""
+        if not self._controllers:
+            self._gather_methods()
+
+        return self._controllers
+
+    def get_methods(self, context):
+        """List available methods."""
+        if not self._methods:
+            self._gather_methods()
+
+        method_list = self._methods.keys()
+        method_list.sort()
+        methods = {}
+        for k in method_list:
+            methods[k] = self._methods[k]['short_doc']
+        return methods
+
+    def get_method_info(self, context, method):
+        """Get detailed information about a method."""
+        if not self._methods:
+            self._gather_methods()
+        return self._methods[method]
+
+
+class ServiceWrapper(wsgi.Controller):
+    def __init__(self, service_handle):
+        self.service_handle = service_handle
+
+    @webob.dec.wsgify
+    def __call__(self, req):
+        arg_dict = req.environ['wsgiorg.routing_args'][1]
+        action = arg_dict['action']
+        del arg_dict['action']
+
+        context = req.environ['openstack.context']
+        # allow middleware up the stack to override the params
+        params = {}
+        if 'openstack.params' in req.environ:
+            params = req.environ['openstack.params']
+
+        # TODO(termie): do some basic normalization on methods
+        method = getattr(self.service_handle, action)
+
+        result = method(context, **params)
+        if type(result) is dict or type(result) is list:
+            return self._serialize(result, req)
+        else:
+            return result
+
+
+class Proxy(object):
+    """Pretend a Direct API endpoint is an object."""
+    def __init__(self, app, prefix=None):
+        self.app = app
+        self.prefix = prefix
+
+    def __do_request(self, path, context, **kwargs):
+        req = webob.Request.blank(path)
+        req.method = 'POST'
+        req.body = urllib.urlencode({'json': utils.dumps(kwargs)})
+        req.environ['openstack.context'] = context
+        resp = req.get_response(self.app)
+        try:
+            return utils.loads(resp.body)
+        except Exception:
+            return resp.body
+
+    def __getattr__(self, key):
+        if self.prefix is None:
+            return self.__class__(self.app, prefix=key)
+
+        def _wrapper(context, **kwargs):
+            return self.__do_request('/%s/%s' % (self.prefix, key),
+                                     context,
+                                     **kwargs)
+        _wrapper.func_name = key
+        return _wrapper
diff --git a/nova/api/ec2/cloud.py b/nova/api/ec2/cloud.py
index fb7e6a59f..a1ae70fb0 100644
--- a/nova/api/ec2/cloud.py
+++ b/nova/api/ec2/cloud.py
@@ -92,8 +92,11 @@ class CloudController(object):
         self.image_service = utils.import_object(FLAGS.image_service)
         self.network_api = network.API()
         self.volume_api = volume.API()
-        self.compute_api = compute.API(self.image_service, self.network_api,
-                                       self.volume_api)
+        self.compute_api = compute.API(
+                network_api=self.network_api,
+                image_service=self.image_service,
+                volume_api=self.volume_api,
+                hostname_factory=id_to_ec2_id)
         self.setup()
 
     def __str__(self):
@@ -512,7 +515,8 @@ class CloudController(object):
         # instance_id is passed in as a list of instances
         ec2_id = instance_id[0]
         instance_id = ec2_id_to_id(ec2_id)
-        output = self.compute_api.get_console_output(context, instance_id)
+        output = self.compute_api.get_console_output(
+                context, instance_id=instance_id)
         now = datetime.datetime.utcnow()
         return {"InstanceId": ec2_id,
                 "Timestamp": now,
@@ -580,7 +584,7 @@ class CloudController(object):
 
     def delete_volume(self, context, volume_id, **kwargs):
         volume_id = ec2_id_to_id(volume_id)
-        self.volume_api.delete(context, volume_id)
+        self.volume_api.delete(context, volume_id=volume_id)
         return True
 
     def update_volume(self, context, volume_id, **kwargs):
@@ -597,9 +601,12 @@ class CloudController(object):
     def attach_volume(self, context, volume_id, instance_id, device, **kwargs):
         volume_id = ec2_id_to_id(volume_id)
         instance_id = ec2_id_to_id(instance_id)
-        LOG.audit(_("Attach volume %s to instacne %s at %s"), volume_id,
+        LOG.audit(_("Attach volume %s to instance %s at %s"), volume_id,
                   instance_id, device, context=context)
-        self.compute_api.attach_volume(context, instance_id, volume_id, device)
+        self.compute_api.attach_volume(context,
+                                       instance_id=instance_id,
+                                       volume_id=volume_id,
+                                       device=device)
         volume = self.volume_api.get(context, volume_id)
         return {'attachTime': volume['attach_time'],
                 'device': volume['mountpoint'],
@@ -612,7 +619,7 @@ class CloudController(object):
         volume_id = ec2_id_to_id(volume_id)
         LOG.audit(_("Detach volume %s"), volume_id, context=context)
         volume = self.volume_api.get(context, volume_id)
-        instance = self.compute_api.detach_volume(context, volume_id)
+        instance = self.compute_api.detach_volume(context, volume_id=volume_id)
         return {'attachTime': volume['attach_time'],
                 'device': volume['mountpoint'],
                 'instanceId': id_to_ec2_id(instance['id']),
@@ -643,6 +650,10 @@ class CloudController(object):
         return i[0]
 
     def _format_instances(self, context, instance_id=None, **kwargs):
+        # TODO(termie): this method is poorly named as its name does not imply
+        #               that it will be making a variety of database calls
+        #               rather than simply formatting a bunch of instances that
+        #               were handed to it
         reservations = {}
         # NOTE(vish): instance_id is an optional list of ids to filter by
         if instance_id:
@@ -743,7 +754,9 @@ class CloudController(object):
         LOG.audit(_("Associate address %s to instance %s"), public_ip,
                   instance_id, context=context)
         instance_id = ec2_id_to_id(instance_id)
-        self.compute_api.associate_floating_ip(context, instance_id, public_ip)
+        self.compute_api.associate_floating_ip(context,
+                                               instance_id=instance_id,
+                                               address=public_ip)
         return {'associateResponse': ["Address associated."]}
 
     def disassociate_address(self, context, public_ip, **kwargs):
@@ -754,8 +767,9 @@ class CloudController(object):
     def run_instances(self, context, **kwargs):
         max_count = int(kwargs.get('max_count', 1))
         instances = self.compute_api.create(context,
-            instance_types.get_by_type(kwargs.get('instance_type', None)),
-            kwargs['image_id'],
+            instance_type=instance_types.get_by_type(
+                kwargs.get('instance_type', None)),
+            image_id=kwargs['image_id'],
             min_count=int(kwargs.get('min_count', max_count)),
             max_count=max_count,
             kernel_id=kwargs.get('kernel_id', None),
@@ -766,8 +780,7 @@ class CloudController(object):
             user_data=kwargs.get('user_data'),
             security_group=kwargs.get('security_group'),
             availability_zone=kwargs.get('placement', {}).get(
-                                  'AvailabilityZone'),
-            generate_hostname=id_to_ec2_id)
+                                  'AvailabilityZone'))
         return self._format_run_instances(context,
                                           instances[0]['reservation_id'])
 
@@ -777,7 +790,7 @@ class CloudController(object):
         LOG.debug(_("Going to start terminating instances"))
         for ec2_id in instance_id:
             instance_id = ec2_id_to_id(ec2_id)
-            self.compute_api.delete(context, instance_id)
+            self.compute_api.delete(context, instance_id=instance_id)
         return True
 
     def reboot_instances(self, context, instance_id, **kwargs):
@@ -785,19 +798,19 @@ class CloudController(object):
         LOG.audit(_("Reboot instance %r"), instance_id, context=context)
         for ec2_id in instance_id:
             instance_id = ec2_id_to_id(ec2_id)
-            self.compute_api.reboot(context, instance_id)
+            self.compute_api.reboot(context, instance_id=instance_id)
         return True
 
     def rescue_instance(self, context, instance_id, **kwargs):
         """This is an extension to the normal ec2_api"""
         instance_id = ec2_id_to_id(instance_id)
-        self.compute_api.rescue(context, instance_id)
+        self.compute_api.rescue(context, instance_id=instance_id)
         return True
 
     def unrescue_instance(self, context, instance_id, **kwargs):
         """This is an extension to the normal ec2_api"""
         instance_id = ec2_id_to_id(instance_id)
-        self.compute_api.unrescue(context, instance_id)
+        self.compute_api.unrescue(context, instance_id=instance_id)
         return True
 
     def update_instance(self, context, ec2_id, **kwargs):
@@ -808,7 +821,7 @@ class CloudController(object):
                 changes[field] = kwargs[field]
         if changes:
             instance_id = ec2_id_to_id(ec2_id)
-            self.compute_api.update(context, instance_id, **kwargs)
+            self.compute_api.update(context, instance_id=instance_id, **kwargs)
         return True
 
     def describe_images(self, context, image_id=None, **kwargs):