Add new config option use_aggregated_uve_db

    Provide an option to enable/disable serve UVE queries from the aggregated
    UVE db. In a scale setup, HA event (alarm-gen down), alarm-gen may take a
    long time to aggregate the UVEs depending on the number of UVEs, number
    of partitions it owns, etc., So, enabling this option would reduce the
    down time in case of HA events (collector down - time taken for generators
     to connect to the new collector and resync the UVEs, alarm-gen down - no
    impact on UVE queries, only the alarms would be reevaluated)

    This commit fix bug: legacy get_alarm do not use _usecache flag

    Closes-Bug: #1719236

Change-Id: I03dcee1a1b4103587197774cccd2901e4faa3a42

src/opserver/uveserver.py

@@ -358,15 +358,32 @@ def get_uve_regex(self, key):
     # end get_uve_regex
 
     def get_alarms(self, filters):
-        tables = filters.get('tablefilt')
+        tablesfilt = filters.get('tablefilt')
         kfilter = filters.get('kfilt')
         patterns = None
         if kfilter is not None:
             patterns = set()
             for filt in kfilter:
                 patterns.add(self.get_uve_regex(filt))
-
-        rsp = self._uvedbcache.get_uve_list(tables, filters, patterns, False)
+        if self._usecache:
+            rsp = self._uvedbcache.get_uve_list(tablesfilt, filters, patterns, False)
+        else:
+            tables = self.get_tables()
+            rsp = {}
+            uve_list = {}
+            for table in tables:
+                if tablesfilt is not None:
+                    if table not in tablesfilt:
+                        continue
+                uve_keys = self.get_uve_list(table, filters, False)
+                for uve_key in uve_keys:
+                    _,uve_val = self.get_uve(
+                        table + ':' + uve_key, True, filters)
+                    if uve_val == {}:
+                        continue
+                    else:
+                        uve_list[uve_key] = uve_val
+                rsp[table] = uve_list
         return rsp
     # end get_alarms