fix

code/ddns-lambda.py

@@ -73,7 +73,7 @@
 LOGGER = logging.getLogger()
 account_id = None
 region = None
-VERSION = '1.2.0b73'
+VERSION = '1.2.0b74'
 
 # Read Env variables
 DEBUG_LOG_LEVEL = os.environ.get('DebugLogLevel', 'INFO')
@@ -306,6 +306,20 @@ def lambda_handler(
     dns_data_tuple = namedtuple('DnsData', dns_data_fields)
 
     caller_response = []
+# if not an ec2 start or stop, skip processing, send SNS, and exit
+    action = evaluate_event_action(event)
+    if not action:
+        caller_response.append(f"Event structure not an aws.ec2 event, exiting")
+        if SNS_ENABLE:
+            sns_msg = {}
+            sns_msg['account_id'] = account_id
+            sns_msg['region'] = event['region']
+            sns_msg['event'] = str(event)
+            sns_msg['context'] = str(context)
+            sns_msg['message'] = caller_response[-1]
+            publish_to_sns(sns_client, json.dumps(sns_msg))
+        return caller_response
+
     # Checking to make sure there is a dynamodb table named in the Env Variable
     tables = list_tables(dynamodb_client)
 
@@ -3229,13 +3243,38 @@ def discover_emr_master(tags):
     -  emr:elasticmapreduce:instance-group-role == MASTER
 
     :param dict tags: dict of tag
-    :return (bool,str): Tuple containing is_master (is an EMR node and is the master), and the cluster_id if it's a cluster
+    :return (bool,str): Tuple containing is_master (is an EMR node and is the master), and the cluster_id if it's a cluster.  cluster_id will be empty if not a cluster.
     """
 
     cluster_id = tags.get('aws:elasticmapreduce:job-flow-id', '')
     is_master = tags.get('aws:elasticmapreduce:instance-group-role', '') == 'MASTER'
 
-    return (is_master and cluster_id != '', cluster_id)
+    is_cluster = cluster_id != ''
+    LOGGER.debug(
+        f"discover_emr: is_cluster {is_cluster}, is_master {is_master}, cluster_id {cluster_id}")
+    return (is_master and is_cluster, cluster_id)
+
+
+def evaluate_event_action(event):
+  """
+  This takes the EventBridge event and returns a DNS action to take (ADD|REMOVE) based on running or not-running (stopping, terminating). If not an ec2 event, it returns None.
+
+  :param dict(str) event: Event dict from handler
+  :return str: DNS action, either ADD (to create records) or REMOVE (to delete records)
+  e_source = event['source']
+  action=None
+  try:
+    if e_source=='aws.ec2':
+      e_instance_id = event['detail']['instance-id']
+      e_state = event['detail']['state']
+      action="ADD" if e_state == "running" else "DELETE"
+      LOGGER.info(f"event_action ** {action} ** instance_id {instance_id} instance_state {e_state}")
+    else:
+      LOGGER.info(f"event_action unrecognized source {e_source}")
+  except:
+      LOGGER.error(f"event_action event structure cannot be parsed {lineno()}")
+  return action
+
 
 ##
 # aws: elasticmapreduce: job - flow - id        j - 8O514K6HPIYZ