Implemented lookback-window-start option #192

docs/configuration_options.rst

@@ -72,6 +72,7 @@ num-read-checks-before-scale-down          ``int``  1             Force Dynamic
 num-write-checks-before-scale-down         ``int``  1             Force Dynamic DynamoDB to have `x` consecutive positive results before scaling writes down (`1` means scale down immediately)
 num-read-checks-reset-percent              ``int``  0             Set a read consumption percentage when the `num-read-checks-before-scale-down` count should be reset. This option is optional, even if you use the `num-read-checks-before-scale-down` feature
 num-write-checks-reset-percent             ``int``  0             Set a write consumption percentage when the `num-write-checks-before-scale-down` count should be reset. This option is optional, even if you use the `num-write-checks-before-scale-down` feature
+lookback-window-start                      ``int``  15            Dynamic DynamoDB fetches data from CloudWatch in a window that streches between ``now()-15`` and ``now()-10`` minutes. If you want to look at slightly newer data, change this value. Please note that it might not be set to less than 5 minutes (as CloudWatch data for DynamoDB is updated every 5 minutes).
 maintenance-windows                        ``str``                Force Dynamic DynamoDB to operate within maintenance windows. E.g. ``22:00-23:59,00:00-06:00``
 enable-reads-up-scaling                    ``bool`` ``true``      Turn on or off of up scaling of read capacity
 enable-reads-down-scaling                  ``bool`` ``true``      Turn on or off of down scaling of read capacity

dynamic_dynamodb/config/__init__.py

@@ -64,6 +64,7 @@
         'allow_scaling_down_reads_on_0_percent': False,
         'allow_scaling_down_writes_on_0_percent': False,
         'always_decrease_rw_together': False,
+        'lookback-window-start': 15,
         'maintenance_windows': None,
         'sns_topic_arn': None,
         'sns_message_types': []
@@ -104,6 +105,7 @@
         'allow_scaling_down_reads_on_0_percent': False,
         'allow_scaling_down_writes_on_0_percent': False,
         'always_decrease_rw_together': False,
+        'lookback-window-start': 15,
         'maintenance_windows': None,
         'sns_topic_arn': None,
         'sns_message_types': []

dynamic_dynamodb/config/config_file_parser.py

@@ -221,6 +221,12 @@
         'option': 'writes-lower-alarm-threshold',
         'required': False,
         'type': 'int'
+    },
+    {
+        'key': 'lookback_window_start',
+        'option': 'lookback-window-start',
+        'required': False,
+        'type': 'int'
     }
 ]
 

dynamic_dynamodb/core/gsi.py

@@ -164,12 +164,16 @@ def __ensure_provisioning_reads(
 
     update_needed = False
     try:
+        lookback_window_start = get_gsi_option(
+            table_key, gsi_key, 'lookback-window-start')
         current_read_units = dynamodb.get_provisioned_gsi_read_units(
             table_name, gsi_name)
         consumed_read_units_percent = \
-            gsi_stats.get_consumed_read_units_percent(table_name, gsi_name)
+            gsi_stats.get_consumed_read_units_percent(
+                table_name, gsi_name, lookback_window_start)
         throttled_read_count = \
-            gsi_stats.get_throttled_read_event_count(table_name, gsi_name)
+            gsi_stats.get_throttled_read_event_count(
+                table_name, gsi_name, lookback_window_start)
         reads_upper_threshold = \
             get_gsi_option(table_key, gsi_key, 'reads_upper_threshold')
         reads_lower_threshold = \
@@ -365,12 +369,16 @@ def __ensure_provisioning_writes(
 
     update_needed = False
     try:
+        lookback_window_start = get_gsi_option(
+            table_key, gsi_key, 'lookback-window-start')
         current_write_units = dynamodb.get_provisioned_gsi_write_units(
             table_name, gsi_name)
         consumed_write_units_percent = \
-            gsi_stats.get_consumed_write_units_percent(table_name, gsi_name)
+            gsi_stats.get_consumed_write_units_percent(
+                table_name, gsi_name, lookback_window_start)
         throttled_write_count = \
-            gsi_stats.get_throttled_write_event_count(table_name, gsi_name)
+            gsi_stats.get_throttled_write_event_count(
+                table_name, gsi_name, lookback_window_start)
         writes_upper_threshold = \
             get_gsi_option(table_key, gsi_key, 'writes_upper_threshold')
         writes_lower_threshold = \

dynamic_dynamodb/core/table.py

@@ -139,12 +139,16 @@ def __ensure_provisioning_reads(table_name, key_name, num_consec_read_checks):
 
     update_needed = False
     try:
+        lookback_window_start = get_table_option(
+            table_name, 'lookback-window-start')
         current_read_units = dynamodb.get_provisioned_table_read_units(
             table_name)
         consumed_read_units_percent = \
-            table_stats.get_consumed_read_units_percent(table_name)
+            table_stats.get_consumed_read_units_percent(
+                table_name, lookback_window_start)
         throttled_read_count = \
-            table_stats.get_throttled_read_event_count(table_name)
+            table_stats.get_throttled_read_event_count(
+                table_name, lookback_window_start)
         reads_upper_threshold = \
             get_table_option(key_name, 'reads_upper_threshold')
         reads_lower_threshold = \
@@ -320,12 +324,16 @@ def __ensure_provisioning_writes(
 
     update_needed = False
     try:
+        lookback_window_start = get_table_option(
+            table_name, 'lookback-window-start')
         current_write_units = dynamodb.get_provisioned_table_write_units(
             table_name)
         consumed_write_units_percent = \
-            table_stats.get_consumed_write_units_percent(table_name)
+            table_stats.get_consumed_write_units_percent(
+                table_name, lookback_window_start)
         throttled_write_count = \
-            table_stats.get_throttled_write_event_count(table_name)
+            table_stats.get_throttled_write_event_count(
+                table_name, lookback_window_start)
         writes_upper_threshold = \
             get_table_option(key_name, 'writes_upper_threshold')
         writes_lower_threshold = \