fix aggregation_job

1. change the pattern to `"yyyy-MM-dd''T''HH:mm:ss.SSS''Z''"`
2. change event_timestamp col name to event_time to match schema

The above changes make the aggregation job work.

Author: divakaivan

bootcamp/materials/4-apache-flink-training/src/job/aggregation_job.py

@@ -49,16 +49,16 @@ def create_processed_events_source_kafka(t_env):
     kafka_key = os.environ.get("KAFKA_WEB_TRAFFIC_KEY", "")
     kafka_secret = os.environ.get("KAFKA_WEB_TRAFFIC_SECRET", "")
     table_name = "process_events_kafka"
-    pattern = "yyyy-MM-dd HH:mm:ss"
+    pattern = "yyyy-MM-dd''T''HH:mm:ss.SSS''Z''"
     sink_ddl = f"""
         CREATE TABLE {table_name} (
             ip VARCHAR,
-            event_timestamp VARCHAR,
+            event_time VARCHAR,
             referrer VARCHAR,
             host VARCHAR,
             url VARCHAR,
             geodata VARCHAR,
-            window_timestamp AS TO_TIMESTAMP(event_timestamp, '{pattern}'),
+            window_timestamp AS TO_TIMESTAMP(event_time, '{pattern}'),
             WATERMARK FOR window_timestamp AS window_timestamp - INTERVAL '15' SECOND
         ) WITH (
              'connector' = 'kafka',