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Solve some issues pointed out by pylint in senza/traffic.py
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@jmcs
jmcs committed Jan 6, 2017
1 parent 5a9b882 commit 026a6ed
Showing 1 changed file with 43 additions and 22 deletions.
65 changes: 43 additions & 22 deletions senza/traffic.py
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@@ -1,3 +1,7 @@
"""
Functions related to Traffic management
"""

import collections
from json import JSONEncoder
from typing import Dict, Iterator
Expand Down Expand Up @@ -63,6 +67,9 @@ def get_weights(dns_names: list, identifier: str, all_identifiers) -> ({str: int


def calculate_new_weights(delta, identifier, known_record_weights, percentage):
"""
Calculates the new weights for the all the Route53 records
"""
new_record_weights = {}
deltas = {}
for i, w in known_record_weights.items():
Expand All @@ -88,8 +95,9 @@ def calculate_new_weights(delta, identifier, known_record_weights, percentage):
def compensate(calculation_error, compensations, identifier, new_record_weights, partial_count,
percentage, identifier_versions):
"""
Compensate for the rounding errors as well as for the fact, that we do not allow to bring down the minimal weights
lower then minimal possible value not to disable traffic from the minimally configured versions (1) and
Compensate for the rounding errors as well as for the fact, that we do not
allow to bring down the minimal weights lower then minimal possible value
not to disable traffic from the minimally configured versions (1) and
we do not allow to add any values to the already disabled versions (0).
"""
# distribute the error on the versions, other then the current one
Expand All @@ -103,11 +111,11 @@ def compensate(calculation_error, compensations, identifier, new_record_weights,
for i in sorted(new_record_weights.keys(), key=lambda x: identifier_versions[x], reverse=True):
if i == identifier:
continue
nw = new_record_weights[i] + part
if nw <= 0:
new_weight = new_record_weights[i] + part
if new_weight <= 0:
# do not remove the traffic from the minimal traffic versions
continue
new_record_weights[i] = nw
new_record_weights[i] = new_weight
calculation_error -= part
compensations[i] = part
if calculation_error == 0:
Expand All @@ -119,7 +127,7 @@ def compensate(calculation_error, compensations, identifier, new_record_weights,
warning(
("Changing given percentage from {} to {} " +
"because all other versions are already getting the possible minimum traffic").format(
percentage / PERCENT_RESOLUTION, adjusted_percentage / PERCENT_RESOLUTION))
percentage / PERCENT_RESOLUTION, adjusted_percentage / PERCENT_RESOLUTION))
percentage = adjusted_percentage
new_record_weights[identifier] = percentage
assert calculation_error == 0
Expand Down Expand Up @@ -200,8 +208,7 @@ def dump_traffic_changes(stack_name: str,
known_record_weights: {str: int},
new_record_weights: {str: int},
compensations: {str: int},
deltas: {str: int}
):
deltas: {str: int}):
"""
dump changes to the traffic settings for the given versions
"""
Expand Down Expand Up @@ -236,10 +243,12 @@ def dump_traffic_changes(stack_name: str,


def print_traffic_changes(message: list):
print_table('stack_name version identifier old_weight% delta compensation new_weight% current'.split(), message)
print_table(['stack_name', 'version', 'identifier', 'old_weight%',
'delta', 'compensation', 'new_weight%', 'current'], message)


class StackVersion(collections.namedtuple('StackVersion', 'name version domain lb_dns_name notification_arns')):
class StackVersion(collections.namedtuple('StackVersion',
'name version domain lb_dns_name notification_arns')):
@property
def identifier(self):
return '{}-{}'.format(self.name, self.version)
Expand Down Expand Up @@ -271,7 +280,9 @@ def get_stack_versions(stack_name: str, region: str) -> Iterator[StackVersion]:
elif res.resource_type == 'AWS::Route53::RecordSet':
if 'version' not in res.logical_id.lower():
domain.append(res.physical_resource_id)
yield StackVersion(stack_name, get_tag(details.tags, 'StackVersion'), domain, lb_dns_name, notification_arns)
yield StackVersion(stack_name,
get_tag(details.tags, 'StackVersion'),
domain, lb_dns_name, notification_arns)


def get_version(versions: list, version: str):
Expand All @@ -291,8 +302,7 @@ def get_records(domain: str):
while result['IsTruncated']:
recordfilter = {'HostedZoneId': hosted_zone.id,
'StartRecordName': result['NextRecordName'],
'StartRecordType': result['NextRecordType']
}
'StartRecordType': result['NextRecordType']}
if result.get('NextRecordIdentifier'):
recordfilter['StartRecordIdentifier'] = result.get('NextRecordIdentifier')

Expand All @@ -314,10 +324,13 @@ def print_version_traffic(stack_ref: StackReference, region):
raise click.UsageError('No stack version of "{}" found'.format(stack_ref.name))

if not version.domain:
raise click.UsageError('Stack {} version {} has no domain'.format(version.name, version.version))
raise click.UsageError('Stack {} version {} has '
'no domain'.format(version.name,
version.version))

known_record_weights, partial_count, partial_sum = get_weights(version.dns_name, version.identifier,
identifier_versions.keys())
known_record_weights, _, _ = get_weights(version.dns_name,
version.identifier,
identifier_versions.keys())

rows = [
{
Expand All @@ -344,16 +357,18 @@ def change_version_traffic(stack_ref: StackReference, percentage: float,
region: str):
versions = list(get_stack_versions(stack_ref.name, region))
arns = []
for v in versions:
arns = arns + v.notification_arns
for each_version in versions:
arns = arns + each_version.notification_arns
identifier_versions = collections.OrderedDict(
(version.identifier, version.version) for version in versions)
version = get_version(versions, stack_ref.version)

identifier = version.identifier

if not version.domain:
raise click.UsageError('Stack {} version {} has no domain'.format(version.name, version.version))
raise click.UsageError('Stack {} version {} has '
'no domain'.format(version.name,
version.version))

percentage = int(percentage * PERCENT_RESOLUTION)
known_record_weights, partial_count, partial_sum = get_weights(version.dns_name, identifier,
Expand All @@ -362,7 +377,8 @@ def change_version_traffic(stack_ref: StackReference, percentage: float,
if partial_count == 0 and percentage == 0:
# disable the last remaining version
new_record_weights = {i: 0 for i in known_record_weights.keys()}
message = 'DNS record "{dns_name}" will be removed from that stack'.format(dns_name=version.dns_name)
message = ('DNS record "{dns_name}" will be removed from that '
'stack'.format(dns_name=version.dns_name))
ok(msg=message)
else:
with Action('Calculating new weights..'):
Expand All @@ -375,7 +391,10 @@ def change_version_traffic(stack_ref: StackReference, percentage: float,
# will put the only last version to full traffic percentage
compensations[identifier] = FULL_PERCENTAGE - percentage
percentage = int(FULL_PERCENTAGE)
new_record_weights, deltas = calculate_new_weights(delta, identifier, known_record_weights, percentage)
new_record_weights, deltas = calculate_new_weights(delta,
identifier,
known_record_weights,
percentage)
total_weight = sum(new_record_weights.values())
calculation_error = FULL_PERCENTAGE - total_weight
if calculation_error and calculation_error < FULL_PERCENTAGE:
Expand All @@ -401,7 +420,9 @@ def inform_sns(arns: list, message: str, region):
sns_topics = set(arns)
sns = BotoClientProxy('sns', region_name=region)
for sns_topic in sns_topics:
sns.publish(TopicArn=sns_topic, Subject="SenzaTrafficRedirect", Message=jsonizer.encode((message)))
sns.publish(TopicArn=sns_topic,
Subject="SenzaTrafficRedirect",
Message=jsonizer.encode((message)))


def resolve_to_ip_addresses(dns_name: str) -> set:
Expand Down

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