Correct the lookup of the health endpoint to avoid caching when the lambda is warm.

Author: Graham Hargreaves

handler.py

@@ -18,22 +18,28 @@
     get_message_for_teams, get_org_message_for_teams, get_message_for_email, get_org_message_for_email, \
     get_org_message_for_eventbridge, get_message_for_eventbridge
 
-# query active health API endpoint
-health_dns = socket.gethostbyname_ex('global.health.amazonaws.com')
-(current_endpoint, global_endpoint, ip_endpoint) = health_dns
-health_active_list = current_endpoint.split('.')
-health_active_region = health_active_list[1]
-print("current health region: ", health_active_region)
-
-# create a boto3 health client w/ backoff/retry
-config = Config(
-    region_name=health_active_region,
-    retries=dict(
-        max_attempts=10  # org view apis have a lower tps than the single
-        # account apis so we need to use larger
-        # backoff/retry values than than the boto defaults
+
+boto3_config = None
+
+
+# Create a boto3 config object
+def create_boto3_config():
+    # query active health API endpoint
+    health_dns = socket.gethostbyname_ex('global.health.amazonaws.com')
+    (current_endpoint, global_endpoint, ip_endpoint) = health_dns
+    health_active_list = current_endpoint.split('.')
+    health_active_region = health_active_list[1]
+    print("current health region: ", health_active_region)
+    # create a boto3 health client w/ backoff/retry
+    return Config(
+        region_name=health_active_region,
+        retries=dict(
+            max_attempts=10  # org view apis have a lower tps than the single
+            # account apis so we need to use larger
+            # backoff/retry values than than the boto defaults
+        )
     )
-)
+
 
 # Get Account Name
 def get_account_name(account_id):
@@ -844,20 +850,22 @@ def get_sts_token(service):
         # create service client using the assumed role credentials, e.g. S3
         boto3_client = boto3.client(
           service,
-          config=config,
+          config=boto3_config,
           aws_access_key_id=ACCESS_KEY,
           aws_secret_access_key=SECRET_KEY,
           aws_session_token=SESSION_TOKEN,
         )
         print("Running in member account deployment mode")
     else:
-        boto3_client = boto3.client(service, config=config)
+        boto3_client = boto3.client(service, config=boto3_config)
         print("Running in management account deployment mode")
 
     return boto3_client
 
 def main(event, context):
     print("THANK YOU FOR CHOOSING AWS HEALTH AWARE!")
+    global boto3_config
+    boto3_config = create_boto3_config()
     health_client = get_sts_token('health')
     org_status = os.environ['ORG_STATUS']
     #str_ddb_format_sec = '%s'

requirements-dev.txt

@@ -0,0 +1,3 @@
+boto3==1.18.57
+pytest==6.2.5
+pytest-mock==3.6.1

test_create_boto3_config.py

@@ -0,0 +1,10 @@
+import handler
+import pytest
+
+
+@pytest.mark.parametrize('region', ['us-east-1', 'us-east-2'])
+def test_boto3_config_object(region, mocker):
+    """When the DNS record changes for the health API the config should be updated correctly"""
+    mock_gethostname = mocker.patch('handler.socket.gethostbyname_ex')
+    mock_gethostname.return_value = (f'health.{region}.amazonaws.com', ['global.health.amazonaws.com'], ['52.94.233.29'])
+    assert handler.create_boto3_config().region_name == region