Initial commit of A1

[ric-plt/a1.git] / a1 / controller.py

diff --git a/a1/controller.py b/a1/controller.py
new file mode 100644 (file)
index 0000000..ca9618b
--- /dev/null
+++ b/a1/controller.py
@@ -0,0 +1,113 @@
+# ==================================================================================
+#       Copyright (c) 2019 Nokia
+#       Copyright (c) 2018-2019 AT&T Intellectual Property.
+#
+#   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.
+# ==================================================================================
+from flask import Response
+import connexion
+import json
+from a1 import get_module_logger
+from a1 import a1rmr, exceptions, utils
+
+
+logger = get_module_logger(__name__)
+
+
+def _get_needed_policy_info(policyname):
+    """
+    Get the needed info for a policy
+    """
+    # Currently we read the manifest on each call, which would seem to allow updating A1 in place. Revisit this?
+    manifest = utils.get_ric_manifest()
+    for m in manifest["controls"]:
+        if m["name"] == policyname:
+            schema = m["message_receives_payload_schema"] if "message_receives_payload_schema" in m else None
+            return (
+                utils.rmr_string_to_int(m["message_receives_rmr_type"]),
+                schema,
+                utils.rmr_string_to_int(m["message_sends_rmr_type"]),
+            )
+    raise exceptions.PolicyNotFound()
+
+
+def _try_func_return(func):
+    """
+    generic caller that returns the apporp http response if exceptions are raised
+    """
+    try:
+        return func()
+    except exceptions.PolicyNotFound as exc:
+        logger.exception(exc)
+        return "", 404
+    except exceptions.MissingManifest as exc:
+        logger.exception(exc)
+        return "A1 was unable to find the required RIC manifest. report this!", 500
+    except exceptions.MissingRmrString as exc:
+        logger.exception(exc)
+        return "A1 does not have a mapping for the desired rmr string. report this!", 500
+    except exceptions.MessageSendFailure as exc:
+        logger.exception(exc)
+        return "A1 was unable to send a needed message to a downstream subscriber", 504
+    except exceptions.ExpectedAckNotReceived as exc:
+        logger.exception(exc)
+        return "A1 was expecting an ACK back but it didn't receive one or didn't recieve the expected ACK", 504
+    except BaseException as exc:
+        # catch all, should never happen...
+        logger.exception(exc)
+        return Response(status=500)
+
+
+def _put_handler(policyname, data):
+    """
+    Handles policy put
+    """
+
+    mtype_send, schema, mtype_return = _get_needed_policy_info(policyname)
+
+    # validate the PUT against the schema, or if there is no shema, make sure the pUT is empty
+    if schema:
+        utils.validate_json(data, schema)
+    elif data != {}:
+        return "BODY SUPPLIED BUT POLICY HAS NO EXPECTED BODY", 400
+
+    # send rmr, wait for ACK
+    return_payload = a1rmr.send_ack_retry(json.dumps(data), message_type=mtype_send, expected_ack_message_type=mtype_return)
+
+    # right now it is assumed that xapps respond with JSON payloads
+    # it is further assumed that they include a field "status" and that the value "SUCCESS" indicates a good policy change
+    try:
+        rpj = json.loads(return_payload)
+        return (rpj, 200) if rpj["status"] == "SUCCESS" else ({"reason": "BAD STATUS", "return_payload": rpj}, 502)
+    except json.decoder.JSONDecodeError:
+        return {"reason": "NOT JSON", "return_payload": return_payload}, 502
+    except KeyError:
+        return {"reason": "NO STATUS", "return_payload": rpj}, 502
+
+
+# Public
+
+
+def put_handler(policyname):
+    """
+    Handles policy replacement
+    """
+    data = connexion.request.json
+    return _try_func_return(lambda: _put_handler(policyname, data))
+
+
+def get_handler(policyname):
+    """
+    Handles policy GET
+    """
+    return "", 501