def get_consumed_read_units_percent(table_name, gsi_name, time_frame=300):
""" Returns the number of consumed read units in percent
:type table_name: str
:param table_name: Name of the DynamoDB table
:type gsi_name: str
:param gsi_name: Name of the GSI
:type time_frame: int
:param time_frame: How many seconds to look at
:returns: int -- Number of consumed reads
"""
metrics = __get_aws_metric(
table_name, gsi_name, time_frame, 'ConsumedReadCapacityUnits')
if metrics:
consumed_read_units = int(
math.ceil(float(metrics[0]['Sum'])/float(time_frame)))
else:
consumed_read_units = 0
try:
consumed_read_units_percent = int(
math.ceil(
float(consumed_read_units) /
float(dynamodb.get_provisioned_gsi_read_units(
table_name, gsi_name)) * 100))
except JSONResponseError:
raise
logger.info('{0} - GSI: {1} - Consumed read units: {2:d}%'.format(
table_name, gsi_name, consumed_read_units_percent))
return consumed_read_units_percent
def get_consumed_read_units_percent(table_name, gsi_name, time_frame=300):
""" Returns the number of consumed read units in percent
:type table_name: str
:param table_name: Name of the DynamoDB table
:type gsi_name: str
:param gsi_name: Name of the GSI
:type time_frame: int
:param time_frame: How many seconds to look at
:returns: int -- Number of consumed reads
"""
metrics = cloudwatch_connection.get_metric_statistics(
period=time_frame,
start_time=datetime.utcnow()-timedelta(minutes=10, seconds=time_frame),
end_time=datetime.utcnow()-timedelta(minutes=10),
metric_name='ConsumedReadCapacityUnits',
namespace='AWS/DynamoDB',
statistics=['Sum'],
dimensions={
'TableName': table_name,
'GlobalSecondaryIndexName': gsi_name
},
unit='Count')
if metrics:
consumed_read_units = int(
math.ceil(float(metrics[0]['Sum'])/float(time_frame)))
else:
consumed_read_units = 0
consumed_read_units_percent = int(
math.ceil(
float(consumed_read_units) /
float(dynamodb.get_provisioned_gsi_read_units(
table_name, gsi_name)) * 100))
logger.info('{0} - GSI: {1} - Consumed read units: {2:d}%'.format(
table_name, gsi_name, consumed_read_units_percent))
return consumed_read_units_percent
def __update_throughput(
table_name, table_key, gsi_name, gsi_key, read_units, write_units):
""" Update throughput on the GSI
:type table_name: str
:param table_name: Name of the DynamoDB table
:type table_key: str
:param table_key: Table configuration option key name
:type gsi_name: str
:param gsi_name: Name of the GSI
:type gsi_key: str
:param gsi_key: Configuration option key name
:type read_units: int
:param read_units: New read unit provisioning
:type write_units: int
:param write_units: New write unit provisioning
"""
try:
current_ru = dynamodb.get_provisioned_gsi_read_units(
table_name, gsi_name)
current_wu = dynamodb.get_provisioned_gsi_write_units(
table_name, gsi_name)
except JSONResponseError:
raise
# Check that we are in the right time frame
if get_gsi_option(table_key, gsi_key, 'maintenance_windows'):
if (not __is_maintenance_window(table_name, gsi_name, get_gsi_option(
table_key, gsi_key, 'maintenance_windows'))):
logger.warning(
'{0} - GSI: {1} - '
'Current time is outside maintenance window'.format(
table_name,
gsi_name))
return
else:
logger.info(
'{0} - GSI: {1} - '
'Current time is within maintenance window'.format(
table_name,
gsi_name))
# Check table status
try:
gsi_status = dynamodb.get_gsi_status(table_name, gsi_name)
except JSONResponseError:
raise
logger.debug('{0} - GSI: {1} - GSI status is {2}'.format(
table_name, gsi_name, gsi_status))
if gsi_status != 'ACTIVE':
logger.warning(
'{0} - GSI: {1} - Not performing throughput changes when GSI '
'status is {2}'.format(table_name, gsi_name, gsi_status))
return
# If this setting is True, we will only scale down when
# BOTH reads AND writes are low
if get_gsi_option(table_key, gsi_key, 'always_decrease_rw_together'):
read_units, write_units = __calculate_always_decrease_rw_values(
table_name,
gsi_name,
read_units,
current_ru,
write_units,
current_wu)
if read_units == current_ru and write_units == current_wu:
logger.info('{0} - GSI: {1} - No changes to perform'.format(
table_name, gsi_name))
return
if not get_global_option('dry_run'):
dynamodb.update_gsi_provisioning(
table_name,
table_key,
gsi_name,
gsi_key,
int(read_units),
int(write_units))
logger.info(
'{0} - GSI: {1} - '
'Provisioning updated to {2} reads and {3} writes'.format(
table_name,
gsi_name,
read_units,
write_units))
def __ensure_provisioning_reads(table_name, table_key, gsi_name, gsi_key):
""" Ensure that provisioning is correct
:type table_name: str
:param table_name: Name of the DynamoDB table
:type table_key: str
:param table_key: Table configuration option key name
:type gsi_name: str
:param gsi_name: Name of the GSI
:type gsi_key: str
:param gsi_key: Configuration option key name
:returns: (bool, int) -- update_needed, updated_read_units
"""
if not get_gsi_option(table_key, gsi_key, 'enable_reads_autoscaling'):
logger.info(
'{0} - GSI: {1} - '
'Autoscaling of reads has been disabled'.format(
table_name, gsi_name))
return False, dynamodb.get_provisioned_gsi_read_units(
table_name, gsi_name)
update_needed = False
try:
updated_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)
throttled_read_count = \
gsi_stats.get_throttled_read_event_count(table_name, gsi_name)
reads_upper_threshold = \
get_gsi_option(table_key, gsi_key, 'reads_upper_threshold')
reads_lower_threshold = \
get_gsi_option(table_key, gsi_key, 'reads_lower_threshold')
increase_reads_unit = \
get_gsi_option(table_key, gsi_key, 'increase_reads_unit')
decrease_reads_unit = \
get_gsi_option(table_key, gsi_key, 'decrease_reads_unit')
increase_reads_with = \
get_gsi_option(table_key, gsi_key, 'increase_reads_with')
decrease_reads_with = \
get_gsi_option(table_key, gsi_key, 'decrease_reads_with')
throttled_reads_upper_threshold = \
get_gsi_option(
table_key, gsi_key, 'throttled_reads_upper_threshold')
max_provisioned_reads = \
get_gsi_option(table_key, gsi_key, 'max_provisioned_reads')
except JSONResponseError:
raise
except BotoServerError:
raise
if (consumed_read_units_percent == 0 and not
get_gsi_option(
table_key,
gsi_key,
'allow_scaling_down_reads_on_0_percent')):
logger.info(
'{0} - GSI: {1} - '
'Scaling down reads is not done when usage is at 0%'.format(
table_name, gsi_name))
elif consumed_read_units_percent >= reads_upper_threshold:
if increase_reads_unit == 'percent':
updated_provisioning = calculators.increase_reads_in_percent(
updated_read_units,
increase_reads_with,
table_name,
table_key,
gsi_name,
gsi_key,)
else:
updated_provisioning = calculators.increase_reads_in_units(
updated_read_units,
increase_reads_with,
table_name,
table_key,
gsi_name,
gsi_key)
if updated_read_units != updated_provisioning:
update_needed = True
updated_read_units = updated_provisioning
elif throttled_read_count > throttled_reads_upper_threshold:
if throttled_reads_upper_threshold > 0:
if increase_reads_unit == 'percent':
updated_provisioning = calculators.increase_reads_in_percent(
updated_read_units,
increase_reads_with,
table_name,
table_key,
gsi_name,
gsi_key,)
else:
updated_provisioning = calculators.increase_reads_in_units(
updated_read_units,
increase_reads_with,
table_name,
table_key,
gsi_name,
gsi_key)
if updated_read_units != updated_provisioning:
update_needed = True
updated_read_units = updated_provisioning
elif consumed_read_units_percent <= reads_lower_threshold:
if decrease_reads_unit == 'percent':
updated_provisioning = calculators.decrease_reads_in_percent(
updated_read_units,
decrease_reads_with,
table_name,
table_key,
gsi_name,
gsi_key)
else:
updated_provisioning = calculators.decrease_reads_in_units(
updated_read_units,
decrease_reads_with,
table_name,
table_key,
gsi_name,
gsi_key)
if updated_read_units != updated_provisioning:
update_needed = True
updated_read_units = updated_provisioning
if max_provisioned_reads:
if int(updated_read_units) > int(max_provisioned_reads):
update_needed = True
updated_read_units = int(max_provisioned_reads)
logger.info(
'Will not increase writes over gsi-max-provisioned-reads '
'limit ({0} writes)'.format(updated_read_units))
return update_needed, int(updated_read_units)
