1 files changed, 75 insertions, 0 deletions
diff --git a/app/discover/events/event_metadata_parser.py b/app/discover/events/event_metadata_parser.py
new file mode 100644
index 0000000..5d09376
--- /dev/null
+++ b/app/discover/events/event_metadata_parser.py
@@ -0,0 +1,75 @@
+###############################################################################
+# Copyright (c) 2017 Koren Lev (Cisco Systems), Yaron Yogev (Cisco Systems)   #
+# and others                                                                  #
+#                                                                             #
+# All rights reserved. This program and the accompanying materials            #
+# are made available under the terms of the Apache License, Version 2.0       #
+# which accompanies this distribution, and is available at                    #
+# http://www.apache.org/licenses/LICENSE-2.0                                  #
+###############################################################################
+from typing import List, Tuple
+
+from utils.metadata_parser import MetadataParser
+
+
+class EventMetadataParser(MetadataParser):
+
+    HANDLERS_PACKAGE = 'handlers_package'
+    QUEUES = 'queues'
+    EVENT_HANDLERS = 'event_handlers'
+
+    REQUIRED_EXPORTS = [HANDLERS_PACKAGE, EVENT_HANDLERS]
+
+    def __init__(self):
+        super().__init__()
+        self.handlers_package = None
+        self.queues = []
+        self.event_handlers = []
+
+    def get_required_fields(self) -> list:
+        return self.REQUIRED_EXPORTS
+
+    def validate_metadata(self, metadata: dict) -> bool:
+        super().validate_metadata(metadata)
+
+        package = metadata.get(self.HANDLERS_PACKAGE)
+        if not package or not isinstance(package, str):
+            self.add_error("Handlers package '{}' is invalid".format(package))
+
+        event_handlers = metadata.get(self.EVENT_HANDLERS)
+        if not event_handlers or not isinstance(event_handlers, dict):
+            self.add_error("Event handlers attribute is invalid or empty"
+                           "(should be a non-empty dict)")
+
+        return len(self.errors) == 0
+
+    def _finalize_parsing(self, metadata):
+        handlers_package = metadata[self.HANDLERS_PACKAGE]
+        queues = metadata.get(self.QUEUES, None)
+        event_handlers = metadata[self.EVENT_HANDLERS]
+
+        # Convert variables to EventHandler-friendly format
+        self.handlers_package = handlers_package
+
+        try:
+            if queues and isinstance(queues, list):
+                self.queues = [{"queue": q["queue"],
+                                "exchange": q["exchange"]}
+                               for q in queues]
+        except KeyError:
+            self.add_error("Queues variable has invalid format")
+            return
+
+        self.event_handlers = event_handlers
+
+    def parse_metadata_file(self, file_path: str) -> dict:
+        metadata = super().parse_metadata_file(file_path)
+        self._finalize_parsing(metadata)
+        super().check_errors()
+        return metadata
+
+
+def parse_metadata_file(file_path: str):
+    parser = EventMetadataParser()
+    parser.parse_metadata_file(file_path)
+    return parser.handlers_package, parser.queues, parser.event_handlers