Adding lambda recon function

Used by PubSub mechanism

src/cct_recon/alerts-recon.py

@@ -0,0 +1,112 @@
+import copy
+import json
+
+import boto3
+
+PREV_SUFFIX = ".prev"
+V1_ALERTS_PREFIX = 'alerts/'
+V1_1_ALERTS_PREFIX = 'v1.1/service-alert/'
+V1_2_ALERTS_PREFIX = 'v1.2/service-alert/'
+SNS_ARN = "arn:aws:sns:af-south-1:566800947500:service-alerts"
+
+s3 = boto3.client('s3')
+sns = boto3.client('sns')
+
+
+def lambda_handler(event, context):
+    # extracting S3 details from triggering event
+    record, *_ = event['Records']
+    s3_event = record['s3']
+    bucket_name = s3_event['bucket']['name']
+    object_name = s3_event['object']['key']
+    print(f"{object_name=}")
+
+    # Fetching file from S3
+    service_alerts_response = s3.get_object(Bucket=bucket_name, Key=object_name)
+    service_alerts_data = json.load(service_alerts_response['Body'])
+
+    # Fetching old data from S3
+    old_object_name = object_name + PREV_SUFFIX
+    old_service_alerts_response = s3.get_object(Bucket=bucket_name, Key=old_object_name)
+    old_service_alerts_data = json.load(old_service_alerts_response['Body'])
+
+    # Creating set of old ID-Status pairs
+    old_ids = set([
+        f'{old_service_alert["Id"]}-{old_service_alert["status"]}'
+        for old_service_alert in old_service_alerts_data
+    ])
+
+    # Creating list of new service alerts
+    new_service_alerts = [
+        service_alert
+        for service_alert in service_alerts_data
+        if f'{service_alert["Id"]}-{service_alert["status"]}' not in old_ids
+    ]
+    print(f"{len(old_ids)=}, {len(new_service_alerts)=}")
+
+    for service_alert in new_service_alerts:
+        print(f"Writing {service_alert['Id']} to S3")
+        # V1 alert
+        v1_service_alert = copy.deepcopy(service_alert)
+        del v1_service_alert['geospatial_footprint']
+        del v1_service_alert['area_type']
+
+        response = s3.put_object(
+            Body=json.dumps(v1_service_alert),
+            Bucket=bucket_name,
+            Key=V1_ALERTS_PREFIX + str(service_alert["Id"]) + ".json",
+            ContentType='application/json'
+        )
+
+        v1_1_service_alert = copy.deepcopy(service_alert)
+        del v1_1_service_alert['status']
+
+        # V1.1 alert
+        response = s3.put_object(
+            Body=json.dumps(v1_1_service_alert),
+            Bucket=bucket_name,
+            Key=V1_1_ALERTS_PREFIX + str(service_alert["Id"]),
+            ContentType='application/json'
+        )
+
+        # V1.2 alert
+        response = s3.put_object(
+            Body=json.dumps(service_alert),
+            Bucket=bucket_name,
+            Key=V1_2_ALERTS_PREFIX + str(service_alert["Id"]),
+            ContentType='application/json'
+        )
+
+    new_service_alert_ids = [
+        {"Id": service_alert["Id"]}
+        for service_alert in new_service_alerts
+    ]
+
+    # Publishing new service alerts to SNS
+    if len(new_service_alert_ids):
+        print("Publishing to SNS!")
+        response = sns.publish(
+            TopicArn=SNS_ARN,
+            Subject=f"New or updated Service Alerts!",
+            Message=json.dumps(new_service_alert_ids)
+        )
+
+    # Creating stripped down version of service alerts list for dedupping
+    current_service_alerts = [
+        {"Id": service_alert["Id"], "status": service_alert["status"]}
+        for service_alert in service_alerts_data
+    ]
+    current_service_alerts_json = json.dumps(current_service_alerts)
+
+    # Writing back to S3 bucket
+    s3.put_object(
+        Body=current_service_alerts_json,
+        Bucket=bucket_name,
+        Key=object_name + PREV_SUFFIX,
+        ContentType='application/json'
+    )
+
+    return {
+        'statusCode': 200,
+        'body': current_service_alerts_json
+    }