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https://github.com/GSA/notifications-api.git
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9da8e54d69
We will need a lambda to failover to if the first lambda fails. This isn't so much a case of the lambda itself failing, as it is a cross availability zone resource automatically, it's more in case something in the networking goes down in our AZ and therefore the lambda can't call out to the CBC. In this case, we will be able to swap to using the second AZ by calling the second lambda.
279 lines
8.0 KiB
Python
279 lines
8.0 KiB
Python
import json
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from abc import ABC, abstractmethod
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import boto3
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from flask import current_app
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from notifications_utils.template import non_gsm_characters
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from app.config import BroadcastProvider
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from app.utils import DATETIME_FORMAT, format_sequential_number
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# The variable names in this file have specific meaning in a CAP message
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#
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# identifier is a unique field for each CAP message
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#
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# headline is a field which we are not sure if we will use
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#
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# description is the body of the message
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# areas is a list of dicts, with the following items
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# * description is a string which populates the areaDesc field
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# * polygon is a list of lat/long pairs
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#
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# previous_provider_messages is a list of previous events (models.py::BroadcastProviderMessage)
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# ie a Cancel message would have a unique event but have the event of
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# the preceeding Alert message in the previous_provider_messages field
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class CBCProxyException(Exception):
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pass
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class CBCProxyClient:
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_lambda_client = None
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def init_app(self, app):
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if app.config.get('CBC_PROXY_ENABLED'):
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self._lambda_client = boto3.client(
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'lambda',
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region_name='eu-west-2',
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aws_access_key_id=app.config['CBC_PROXY_AWS_ACCESS_KEY_ID'],
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aws_secret_access_key=app.config['CBC_PROXY_AWS_SECRET_ACCESS_KEY'],
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)
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def get_proxy(self, provider):
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proxy_classes = {
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'canary': CBCProxyCanary,
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BroadcastProvider.EE: CBCProxyEE,
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BroadcastProvider.VODAFONE: CBCProxyVodafone,
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}
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return proxy_classes[provider](self._lambda_client)
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class CBCProxyClientBase(ABC):
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@property
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@abstractmethod
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def lambda_name(self):
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pass
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@property
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@abstractmethod
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def failover_lambda_name(self):
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pass
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@property
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@abstractmethod
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def LANGUAGE_ENGLISH(self):
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pass
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@property
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@abstractmethod
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def LANGUAGE_WELSH(self):
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pass
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def __init__(self, lambda_client):
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self._lambda_client = lambda_client
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def send_canary(
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self,
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identifier,
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):
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pass
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def send_link_test(
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self,
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identifier,
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sequential_number
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):
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pass
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def create_and_send_broadcast(
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self, identifier, headline, description, areas, sent, expires, message_number=None
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):
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pass
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# We have not implementated updating a broadcast
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def update_and_send_broadcast(
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self,
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identifier, previous_provider_messages, headline, description, areas,
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sent, expires, message_number=None
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):
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pass
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# We have not implemented cancelling a broadcast
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def cancel_broadcast(
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self,
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identifier, previous_provider_messages, headline, description, areas,
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sent, expires, message_number=None
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):
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pass
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def _invoke_lambda_with_failover(self, payload):
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payload_bytes = bytes(json.dumps(payload), encoding='utf8')
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result = self._invoke_lambda(self.lambda_name, payload_bytes)
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if 'FunctionError' in result:
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raise CBCProxyException('Function exited with unhandled exception')
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return result
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def _invoke_lambda(self, lambda_name, payload_bytes):
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result = self._lambda_client.invoke(
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FunctionName=lambda_name,
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InvocationType='RequestResponse',
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Payload=payload_bytes,
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)
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if result['StatusCode'] > 299:
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raise CBCProxyException('Could not invoke lambda')
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return result
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def infer_language_from(self, content):
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if non_gsm_characters(content):
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return self.LANGUAGE_WELSH
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return self.LANGUAGE_ENGLISH
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class CBCProxyCanary(CBCProxyClientBase):
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"""
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The canary is a lambda which tests notify's connectivity to the Cell Broadcast AWS infrastructure. It calls the
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canary, a specific lambda that does not open a vpn or connect to a provider but just responds from within AWS.
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"""
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lambda_name = 'canary'
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# we don't need a failover lambda for the canary as it doesn't actually make calls out to a CBC
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# so we just reuse the normal one in case of a failover scenario
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failover_lambda_name = 'canary'
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LANGUAGE_ENGLISH = None
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LANGUAGE_WELSH = None
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def send_canary(
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self,
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identifier,
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):
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self._invoke_lambda_with_failover(payload={'identifier': identifier})
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class CBCProxyEE(CBCProxyClientBase):
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lambda_name = 'bt-ee-1-proxy'
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failover_lambda_name = 'bt-ee-2-proxy'
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LANGUAGE_ENGLISH = 'en-GB'
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LANGUAGE_WELSH = 'cy-GB'
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def send_link_test(
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self,
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identifier,
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sequential_number=None,
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):
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"""
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link test - open up a connection to a specific provider, and send them an xml payload with a <msgType> of
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test.
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"""
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payload = {
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'message_type': 'test',
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'identifier': identifier,
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'message_format': 'cap'
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}
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self._invoke_lambda_with_failover(payload=payload)
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def create_and_send_broadcast(
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self, identifier, headline, description, areas, sent, expires, message_number=None
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):
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payload = {
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'message_type': 'alert',
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'identifier': identifier,
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'message_format': 'cap',
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'headline': headline,
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'description': description,
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'areas': areas,
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'sent': sent,
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'expires': expires,
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'language': self.infer_language_from(description),
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}
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self._invoke_lambda_with_failover(payload=payload)
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def cancel_broadcast(
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self,
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identifier, previous_provider_messages,
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sent, message_number=None
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):
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payload = {
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'message_type': 'cancel',
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'identifier': identifier,
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'message_format': 'cap',
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"references": [
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{
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"message_id": str(message.id),
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"sent": message.created_at.strftime(DATETIME_FORMAT)
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} for message in previous_provider_messages
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],
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'sent': sent,
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}
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self._invoke_lambda_with_failover(payload=payload)
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class CBCProxyVodafone(CBCProxyClientBase):
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lambda_name = 'vodafone-1-proxy'
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failover_lambda_name = 'vodafone-2-proxy'
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LANGUAGE_ENGLISH = 'English'
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LANGUAGE_WELSH = 'Welsh'
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def send_link_test(
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self,
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identifier,
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sequential_number,
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):
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"""
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link test - open up a connection to a specific provider, and send them an xml payload with a <msgType> of
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test.
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"""
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payload = {
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'message_type': 'test',
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'identifier': identifier,
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'message_number': sequential_number,
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'message_format': 'ibag'
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}
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self._invoke_lambda_with_failover(payload=payload)
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def create_and_send_broadcast(
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self, identifier, message_number, headline, description, areas, sent, expires,
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):
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payload = {
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'message_type': 'alert',
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'identifier': identifier,
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'message_number': message_number,
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'message_format': 'ibag',
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'headline': headline,
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'description': description,
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'areas': areas,
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'sent': sent,
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'expires': expires,
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'language': self.infer_language_from(description),
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}
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self._invoke_lambda_with_failover(payload=payload)
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def cancel_broadcast(
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self, identifier, previous_provider_messages, sent, message_number
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):
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payload = {
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'message_type': 'cancel',
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'identifier': identifier,
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'message_number': message_number,
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'message_format': 'ibag',
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"references": [
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{
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"message_id": str(message.id),
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"message_number": format_sequential_number(message.message_number),
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"sent": message.created_at.strftime(DATETIME_FORMAT)
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} for message in previous_provider_messages
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],
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'sent': sent,
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}
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self._invoke_lambda_with_failover(payload=payload)
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