KbankGetUser Lambda Function

Quick Reference

• Function Name: payment3-kbank-get-user-${BRANCH}
• Handler: queryuser.lambda_handler
• Runtime: Python 3.12 (Docker Image)
• Trigger: API Gateway (GET /kbank/user)
• Template.yaml: Lines 581-607

Function Overview

The KbankGetUser function queries KBank user mappings from KBankUserMappingTable. It retrieves the KBank user ID for a given Villa user ID. This function is exposed via API Gateway for external queries.

Entry Point

File: functions/kbankuser/queryuser.py
Handler: lambda_handler(event, context)

def lambda_handler(event, context):
    try:
        # Extract request body
        params = event.get("queryStringParameters", {})
        print(f"Request params: {json.dumps(params, indent=2)}")

        # Required fields
        required_fields = ["user_id"]
        for field in required_fields:
            if field not in params:
                return {
                    "statusCode": 400,
                    "body": json.dumps({"error": f"Missing required field: {field}"}),
                }

        user_id = params["user_id"]
        print(f"User ID: {user_id}")

        # Check if user already exists in DynamoDB
        existing_user = get_user_from_dynamodb(user_id)
        print(f"Existing user: {existing_user}")
        if not existing_user:
            return {
                "statusCode": 404,
                "body": json.dumps(
                    {
                        "message": "User doesnt exist",
                    }
                ),
            }

        return {
            "statusCode": 200,
            "body": json.dumps(
                {
                    "user_id": user_id,
                    "kbank_id": existing_user.kbank_id,
                }
            ),
        }

    except Exception as e:
        print(f"Error in lambda_handler: {str(e)}")
        sentry_sdk.capture_exception(e)
        return {
            "statusCode": 500,
            "body": json.dumps({"error": "Internal server error", "details": str(e)}),
        }

Event Structure

API Gateway Event

Path: GET /kbank/user?user_id={user_id}
Auth: NONE (public endpoint)

Query Parameters:

• user_id - Villa user ID (required)

Response (Success):

{
  "statusCode": 200,
  "body": "{\"user_id\": \"...\", \"kbank_id\": \"...\"}"
}

Response (Not Found):

{
  "statusCode": 404,
  "body": "{\"message\": \"User doesnt exist\"}"
}

DynamoDB Tables

KBankUserMappingTable

Table Name: payment3-kbank-user-mapping-{BRANCH}
Region: ap-southeast-1

Query Pattern:

from src.kbankUserMappingTable import KBankUserMappingTable

# Get most recent user record
users = list(
    KBankUserMappingTable.query(
        user_id,
        scan_index_forward=False,  # Most recent first
        limit=1
    )
)
if users:
    kbank_id = users[0].kbank_id

Processing Flow

1. Parse Query Parameters: Extract user_id from queryStringParameters
2. Validate Input: Check user_id is present
3. Query DynamoDB: Query KBankUserMappingTable by user_id
4. Return Response: Return kbank_id or 404 if not found

Error Handling

Missing user_id: Returns 400 error

User Not Found: Returns 404 error

Other Errors: Returns 500 error, logged to Sentry

IAM Policies

From template.yaml (lines 588-592):

• LambdaInvokePolicy for get-apikey-master
• DynamoDBReadPolicy for KBankUserMappingTable

Dependencies

• KBankUserMappingTable - User mappings (read)

Related Functions

• KBankCreateUser - Creates KBank user mappings

References

• Template.yaml: Lines 581-607
• Related Functions: KBankCreateUser