Remove the emergency alerts canary

See https://github.com/alphagov/notifications-broadcasts-infra/pull/197
for why we no longer need this and we get to delete some code!

app/celery/scheduled_tasks.py

@@ -1,4 +1,3 @@
-import uuid
 from datetime import datetime, timedelta
 
 from flask import current_app
@@ -6,7 +5,7 @@ from notifications_utils.statsd_decorators import statsd
 from sqlalchemy import between
 from sqlalchemy.exc import SQLAlchemyError
 
-from app import cbc_proxy_client, notify_celery, zendesk_client
+from app import notify_celery, zendesk_client
 from app.celery.broadcast_message_tasks import trigger_link_test
 from app.celery.letters_pdf_tasks import get_pdf_for_templated_letter
 from app.celery.tasks import (
@@ -316,15 +315,6 @@ def check_for_services_with_high_failure_rates_or_sending_to_tv_numbers():
             )
 
 
-@notify_celery.task(name='send-canary-to-cbc-proxy')
-def send_canary_to_cbc_proxy():
-    if current_app.config['CBC_PROXY_ENABLED']:
-        identifier = str(uuid.uuid4())
-        message = f"Sending a canary message to CBC proxy with ID {identifier}"
-        current_app.logger.info(message)
-        cbc_proxy_client.get_proxy('canary').send_canary(identifier)
-
-
 @notify_celery.task(name='trigger-link-tests')
 def trigger_link_tests():
     if current_app.config['CBC_PROXY_ENABLED']:

app/clients/cbc_proxy.py

@@ -48,7 +48,6 @@ class CBCProxyClient:
 
     def get_proxy(self, provider):
         proxy_classes = {
-            'canary': CBCProxyCanary,
             BroadcastProvider.EE: CBCProxyEE,
             BroadcastProvider.THREE: CBCProxyThree,
             BroadcastProvider.O2: CBCProxyO2,
@@ -81,12 +80,6 @@ class CBCProxyClientBase(ABC):
     def __init__(self, lambda_client):
         self._lambda_client = lambda_client
 
-    def send_canary(
-        self,
-        identifier,
-    ):
-        pass
-
     def send_link_test(
         self,
         identifier,
@@ -162,26 +155,6 @@ class CBCProxyClientBase(ABC):
         return self.LANGUAGE_ENGLISH
 
 
-class CBCProxyCanary(CBCProxyClientBase):
-    """
-    The canary is a lambda which tests notify's connectivity to the Cell Broadcast AWS infrastructure. It calls the
-    canary, a specific lambda that does not open a vpn or connect to a provider but just responds from within AWS.
-    """
-    lambda_name = 'canary'
-    # we don't need a failover lambda for the canary as it doesn't actually make calls out to a CBC
-    # so we just reuse the normal one in case of a failover scenario
-    failover_lambda_name = 'canary'
-
-    LANGUAGE_ENGLISH = None
-    LANGUAGE_WELSH = None
-
-    def send_canary(
-        self,
-        identifier,
-    ):
-        self._invoke_lambda(self.lambda_name, payload={'identifier': identifier})
-
-
 class CBCProxyOne2ManyClient(CBCProxyClientBase):
     LANGUAGE_ENGLISH = 'en-GB'
     LANGUAGE_WELSH = 'cy-GB'

app/config.py

@@ -317,11 +317,6 @@ class Config(object):
             'schedule': crontab(hour=23, minute=00),
             'options': {'queue': QueueNames.PERIODIC}
         },
-        'send-canary-to-cbc-proxy': {
-            'task': 'send-canary-to-cbc-proxy',
-            'schedule': timedelta(minutes=5),
-            'options': {'queue': QueueNames.PERIODIC}
-        },
         'trigger-link-tests': {
             'task': 'trigger-link-tests',
             'schedule': timedelta(minutes=15),