def _dispatch(self, alert, descriptor):
"""Send alert to an SNS topic
Args:
alert (Alert): Alert instance which triggered a rule
descriptor (str): Output descriptor
Returns:
bool: True if alert was sent successfully, False otherwise
"""
# SNS topics can only be accessed via their ARN
topic_name = self.config[self.__service__][descriptor]
topic_arn = 'arn:aws:sns:{}:{}:{}'.format(self.region, self.account_id, topic_name)
topic = boto3.resource('sns', region_name=self.region).Topic(topic_arn)
publication = compose_alert(alert, self, descriptor)
# Presentation defaults
default_subject = '{} triggered alert {}'.format(alert.rule_name, alert.alert_id)
default_message = json.dumps(publication, indent=2, sort_keys=True)
# Published presentation fields
# Subject must be < 100 characters long;
subject = elide_string_middle(publication.get('@aws-sns.topic', default_subject), 99)
message = publication.get('@aws-sns.message', default_message)
topic.publish(
Message=message,
Subject=subject
)
return True
def _standardize_custom_attachments(cls, custom_slack_attachments):
"""Supplies default fields to given attachments and validates their structure.
You can test out custom attachments using this tool:
https://api.slack.com/docs/messages/builder
When publishers provider custom slack attachments to the SlackOutput, it offers increased
flexibility, but requires more work. Publishers need to pay attention to the following:
- Slack requires escaping the characters: '&', '>' and '<'
- Slack messages have a limit of 4000 characters
- Individual slack messages support a maximum of 20 attachments
Args:
custom_slack_attachments (list): A list of dicts that is provided by the publisher.
Returns:
list: The value to the "attachments" Slack API argument
"""
attachments = []
for custom_slack_attachment in custom_slack_attachments:
attachment = cls._get_attachment_skeleton()
attachment.update(custom_slack_attachment)
# Enforce maximum text length; make sure to check size AFTER escaping in case
# extra escape characters pushes it over the limit
if len(attachment['text']) > cls.MAX_MESSAGE_SIZE:
LOGGER.warning(
'Custom attachment was truncated to length %d. Full message: %s',
cls.MAX_MESSAGE_SIZE,
attachment['text']
)
attachment['text'] = elide_string_middle(attachment['text'], cls.MAX_MESSAGE_SIZE)
attachments.append(attachment)
# Enforce maximum number of attachments
if len(attachments) >= cls.MAX_ATTACHMENTS:
LOGGER.warning(
'Message with %d custom attachments was truncated to %d attachments',
len(custom_slack_attachments),
cls.MAX_ATTACHMENTS
)
break
return attachments
def dispatch(self, **kwargs):
"""Send alert to an SNS topic"""
# SNS topics can only be accessed via their ARN
topic_name = self.config[self.__service__][kwargs['descriptor']]
topic_arn = 'arn:aws:sns:{}:{}:{}'.format(self.region, self.account_id,
topic_name)
topic = boto3.resource('sns', region_name=self.region).Topic(topic_arn)
alert = kwargs['alert']
response = topic.publish(
Message=json.dumps(alert, indent=2, sort_keys=True),
# Subject must be < 100 characters long
Subject=elide_string_middle(
'{} triggered alert {}'.format(kwargs['rule_name'],
alert['id']), 99))
return self._log_status(response, kwargs['descriptor'])
def test_elide_string_middle():
"""Alert Processor - Helpers - String Truncation"""
alphabet = 'abcdefghijklmnopqrstuvwxyz'
# String shortened
assert_equal('ab ... yz', elide_string_middle(alphabet, 10))
assert_equal('abcde ... vwxyz', elide_string_middle(alphabet, 15))
assert_equal('abcdefg ... tuvwxyz', elide_string_middle(alphabet, 20))
assert_equal('abcdefghij ... qrstuvwxyz',
elide_string_middle(alphabet, 25))
# String unchanged
assert_equal(alphabet, elide_string_middle(alphabet, 26))
assert_equal(alphabet, elide_string_middle(alphabet, 50))
def dispatch(self, alert, descriptor):
"""Send alert to an SNS topic
Args:
alert (Alert): Alert instance which triggered a rule
descriptor (str): Output descriptor
Returns:
bool: True if alert was sent successfully, False otherwise
"""
# SNS topics can only be accessed via their ARN
topic_name = self.config[self.__service__][descriptor]
topic_arn = 'arn:aws:sns:{}:{}:{}'.format(self.region, self.account_id, topic_name)
topic = boto3.resource('sns', region_name=self.region).Topic(topic_arn)
response = topic.publish(
Message=json.dumps(alert.output_dict(), indent=2, sort_keys=True),
# Subject must be < 100 characters long
Subject=elide_string_middle(
'{} triggered alert {}'.format(alert.rule_name, alert.alert_id), 99)
)
return self._log_status(response, descriptor)