begin work on the agent

.gitignore

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+*.py[co]
+bin/*
+lib/*
+include/*
+local/*
+

Makefile

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+default:
+	pyflakes teeth/
+	pep8 --max-line-length=119 teeth/

teeth/agent/protocol.py

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+"""
+Copyright 2013 Rackspace, 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 simplejson as json
+import uuid
+
+from twisted.protocols.basic import LineReceiver
+from twisted.internet.defer import maybeDeferred
+from twisted.internet import defer
+
+
+DEFAULT_PROTOCOL_VERSION = 'v1'
+
+
+class TeethAgentProtocol(LineReceiver):
+    def __init__(self, encoder):
+        self.encoder = encoder
+        self.handlers = {}
+        self.pending_command_deferreds = {}
+
+    def lineReceived(self, line):
+        line = line.strip()
+        if not line:
+            return
+
+        message = json.loads(line)
+        if 'method' in message:
+            self.handle_command(message)
+        elif 'result' in message:
+            self.handle_response(message)
+
+    def send_command(self, command):
+        message_id = str(uuid.uuid4())
+        d = defer.Deferred()
+        self.pending_command_deferreds[message_id] = d
+        self.sendLine(self.encoder.encode({
+            'id': message_id,
+            'version': DEFAULT_PROTOCOL_VERSION,
+            'method': command['method'],
+            'args': command.get('args', []),
+            'kwargs': command.get('kwargs', {}),
+        }))
+        return d
+
+    def handle_command(self, message):
+        message_id = message['id']
+        version = message['version']
+        args = message.get('args', [])
+        kwargs = message.get('kwargs', {})
+        d = maybeDeferred(self.handlers[version][message['method']], *args, **kwargs)
+        d.addCallback(self.send_response, version, message_id)
+
+    def send_response(self, result, version, message_id):
+        self.sendLine(self.encoder.encode({
+            'id': message_id,
+            'version': version,
+            'result': result,
+        }))
+
+    def handle_response(self, message):
+        d = self.pending_command_deferreds.pop(message['id'])
+        error = message.get('error', None)
+        if error:
+            d.errback(error)
+        else:
+            d.callback(message.get('result', None))