[server]: Update punctuality_by_timestamp table

server/src/functions/update_average_punctuality/lambda_function.py

@@ -4,16 +4,20 @@ import requests
 import os
 from decimal import Decimal
 
+# Initialize DynamoDB resource
 dynamodb = boto3.resource("dynamodb")
-table = dynamodb.Table("punctuality_by_objectID")
+table_train = dynamodb.Table("punctuality_by_objectID")
+table_timestamp = dynamodb.Table("punctuality_by_timestamp")
+
 API_URL = "https://281bc6mcm5.execute-api.us-east-1.amazonaws.com/transient_data?objectType=IrishRailTrain"
 
 
 def fetch_train_data():
+    """Fetch train data from API."""
     try:
         response = requests.get(API_URL)
-        response.raise_for_status()  # Raise an error for bad status codes
-        if response.text.strip():  # Ensure response is not empty
+        response.raise_for_status()
+        if response.text.strip():
             return response.json()
         else:
             print("Error: Empty response from API")
@@ -27,8 +31,9 @@ def fetch_train_data():
 
 
 def update_punctuality(objectID, new_punctuality):
+    """Update punctuality data for a specific train."""
     new_punctuality = Decimal(str(new_punctuality))  # Ensure Decimal type for DynamoDB
-    response = table.get_item(Key={"objectID": objectID})
+    response = table_train.get_item(Key={"objectID": objectID})
     if "Item" in response:
         item = response["Item"]
         old_avg = Decimal(str(item["average_punctuality"]))
@@ -38,8 +43,8 @@ def update_punctuality(objectID, new_punctuality):
         new_avg = ((old_avg * count) + new_punctuality) / (count + 1)
         count += 1
 
-        # Update the DynamoDB table, renaming 'count' to avoid using a reserved keyword
-        table.update_item(
+        # Update the DynamoDB table, renaming 'count' to avoid reserved keyword issues
+        table_train.update_item(
             Key={"objectID": objectID},
             UpdateExpression="SET average_punctuality = :avg, #cnt = :cnt",
             ExpressionAttributeValues={":avg": new_avg, ":cnt": count},
@@ -47,22 +52,52 @@ def update_punctuality(objectID, new_punctuality):
         )
     else:
         # Insert new train punctuality record
-        table.put_item(
+        table_train.put_item(
             Item={"objectID": objectID, "average_punctuality": new_punctuality, "count": 1}
         )
 
 
+def update_punctuality_by_timestamp(timestamp, punctualities):
+    """Update the average punctuality for a given timestamp."""
+    if not punctualities:
+        return
+
+    avg_punctuality = sum(punctualities) / len(punctualities)
+
+    # Insert or update record in DynamoDB
+    table_timestamp.put_item(
+        Item={
+            "timestamp": timestamp,
+            "average_punctuality": avg_punctuality
+        }
+    )
+
+
 def lambda_handler(event, context):
+    """AWS Lambda handler."""
     train_data = fetch_train_data()
+
+    if not train_data:
+        return {"statusCode": 500, "body": json.dumps("No train data available")}
+
+    # Extract timestamp (assuming all records share the same timestamp)
+    timestamp = train_data[0].get("timestamp") if train_data else None
+    if not timestamp:
+        return {"statusCode": 500, "body": json.dumps("Missing timestamp in train data")}
+
+    punctualities = []
     for train in train_data:
         objectID = train.get("objectID")
         punctuality = int(train.get("trainPunctuality", 0))
 
         if objectID:
             update_punctuality(objectID, punctuality)
+            punctualities.append(punctuality)
+
+    # Update average punctuality for the timestamp
+    update_punctuality_by_timestamp(timestamp, punctualities)
 
     return {
         "statusCode": 200,
         "body": json.dumps("Punctuality data updated successfully")
     }
-