1 files changed, 114 insertions, 0 deletions
diff --git a/azurelinuxagent/protocol/protocolFactory.py b/azurelinuxagent/protocol/protocolFactory.py
new file mode 100644
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+++ b/azurelinuxagent/protocol/protocolFactory.py
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+# Windows Azure Linux Agent
+#
+# Copyright 2014 Microsoft Corporation
+#
+# 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.
+#
+# Requires Python 2.4+ and Openssl 1.0+
+#
+import os
+import traceback
+import threading
+import azurelinuxagent.logger as logger
+from azurelinuxagent.future import text
+import azurelinuxagent.utils.fileutil as fileutil
+from azurelinuxagent.utils.osutil import OSUTIL
+from azurelinuxagent.protocol.common import *
+from azurelinuxagent.protocol.v1 import WireProtocol
+from azurelinuxagent.protocol.v2 import MetadataProtocol
+
+WIRE_SERVER_ADDR_FILE_NAME = "WireServer"
+
+def get_wire_protocol_endpoint():
+    path = os.path.join(OSUTIL.get_lib_dir(), WIRE_SERVER_ADDR_FILE_NAME)
+    try:
+        endpoint = fileutil.read_file(path)
+    except IOError as e:
+        raise ProtocolNotFound("Wire server endpoint not found: {0}".format(e))
+
+    if endpoint is None:
+        raise ProtocolNotFound("Wire server endpoint is None")
+
+    return endpoint
+
+def detect_wire_protocol():
+    endpoint = get_wire_protocol_endpoint()
+
+    OSUTIL.gen_transport_cert()
+    protocol = WireProtocol(endpoint)
+    protocol.initialize()
+    logger.info("Protocol V1 found.")
+    return protocol
+
+def detect_metadata_protocol():
+    protocol = MetadataProtocol()
+    protocol.initialize()
+
+    logger.info("Protocol V2 found.")
+    return protocol
+
+def detect_available_protocols(prob_funcs=[detect_wire_protocol, 
+                                           detect_metadata_protocol]):
+    available_protocols = []
+    for probe_func in prob_funcs:
+        try:
+            protocol = probe_func()
+            available_protocols.append(protocol)
+        except ProtocolNotFound as e:
+            logger.info(text(e))
+    return available_protocols
+
+def detect_default_protocol():
+    logger.info("Detect default protocol.")
+    available_protocols = detect_available_protocols()
+    return choose_default_protocol(available_protocols)
+
+def choose_default_protocol(protocols):
+    if len(protocols) > 0:
+        return protocols[0]
+    else:
+        raise ProtocolNotFound("No available protocol detected.")
+
+def get_wire_protocol():
+    endpoint = get_wire_protocol_endpoint()
+    return WireProtocol(endpoint)
+
+def get_metadata_protocol():
+    return MetadataProtocol()
+
+def get_available_protocols(getters=[get_wire_protocol, get_metadata_protocol]):
+    available_protocols = []
+    for getter in getters:
+        try:
+            protocol = getter()
+            available_protocols.append(protocol)
+        except ProtocolNotFound as e:
+            logger.info(text(e))
+    return available_protocols
+
+class ProtocolFactory(object):
+    def __init__(self):
+        self._protocol = None
+        self._lock = threading.Lock()
+
+    def get_default_protocol(self):
+        if self._protocol is None:
+            self._lock.acquire()
+            if self._protocol is None:
+                available_protocols = get_available_protocols()
+                self._protocol = choose_default_protocol(available_protocols)
+            self._lock.release()
+
+        return self._protocol
+
+FACTORY = ProtocolFactory()