AWS API Gateway Input/Output Mapping

Question

I am sending a response from lambda to API gateway but api gateway always show status as 200 irrespective of error status received in response body from lambda function

Answer 1

I have below piece of code written in python:

import psycopg2
import json

db_endpoint = 'XYZ'
db_port = 5432
db_username = 'XYZ'
db_password = 'XYZ'
db_name = 'XYZ'

def lambda_handler(event, context):
    print("event is ----", event)
    project_id = event['project_id']
    identifier = 'IAM_USER'
    array_of_commands = None
    
    try:
        # Establish a connection to the database
        connection = psycopg2.connect(user=db_username, password=db_password, host=db_endpoint, database=db_name)
        
        try:
            # Create a cursor object to execute SQL queries
            with connection.cursor() as cursor:
                # Execute the SQL query
                query = f"SELECT value from project_datas where project_id = '{project_id}' and identifier= '{identifier}' "
                cursor.execute(query)
                
                # Fetch all the results
                results = cursor.fetchall()
                
                if results:
                    array_of_commands = results[0][0]['cred_value']
                    print("results-----", results)
                    print("array_of_commands-----", array_of_commands)
                else:
                    
                    # Return an error status code indicating no results found
                    response = {

                        'status': 404,
                        'headers': {
                            'Content-Type': 'application/json'
                        },
                        'body': 'No results found'
                    }
                    raise Exception(json.dumps(response))
        
        except psycopg2.Error as e:
            # Return an error status code and error message
            response = {
                'status': 500,
                'headers': {
                    'Content-Type': 'application/json'
                },
                'body': f"Error executing SQL query: {e}"
            }
        
        finally:
            # Close the cursor
            cursor.close()
    
    except psycopg2.Error as e:
        # Return an error status code and error message
        response = {
            'status': 500,
            'headers': {
                'Content-Type': 'application/json'
            },
            'body': f"Error connecting to the database: {e}"
        }
    
    finally:
        # Close the database connection
        if connection:
            connection.close()
    
    if array_of_commands is not None:
        # Return a success status code with the result
        response=array_of_commands
    
    return response

At API gateway, I have to perform 2 actions:-

1. Add status in Method Response
2. Integration Response

Click on Method Response

Click on Integration Response

Field Value Lambda Error Regex ."status": 404. Mapping Template $input.path('$.errorMessage')