Is it possible to query an Amazon RDS instance directly from API Gateway?

Question

I'm new to API Gateway, and as far I have tried is a really powerful tool. For the project I'm working right now we are using a PostgreSQL instance in RDS. I've seen that is possible to access directly to DynamoDB tables from API Gateway, so I was wondering if is there a way to do so for relational databases. So I created a resource with a GET method and configure it to connect to my database, but I wasn't sure if I used the right parameters:

Provided information about the target backend

So I wasn't sure about the arguments in each setting's field. In AWS Subdomain I wrote the public URL as if I was connecting me from my pgAdmin client (no port cause the full structure was not accepted, so I know I'm doing something bad). Before that I tried using the ARN of my RDS resource, but an this error appeared:

AWS ARN for integration must contains path or action

For execution role I created one with the policies to access my Postgres resource.

Reading RDS documentation I found out that is possible to use the Query API from RDS using the HTTP verb GET or POST and a Query parameter named Action, so I tried to figure out how to place my query statement in this way:

HTTP Query-based requests

But when I test the method, this is the Response Body:

{
  "message": "AWS ARN for integration contains invalid action"
}

And this is these are the Logs:

Execution log for request test-request
Sat Mar 19 15:27:17 UTC 2016 : Execution failed: AWS ARN for integration contains invalid action
Sat Mar 19 15:27:17 UTC 2016 : Method completed with status: 400

I know I'm doing a lot of things wrong, so does anybody knows if this is actually possible and how to do it, cause I haven't found any detailed tutorial yet.

Answer 1

No this isn't possible. The API Gateway service proxy will only proxy calls to the AWS API. The RDS API only allows you to do things like create a database, delete a database, take snapshots, etc. It doesn't allow you to connect and run queries against the database.

You should look into pointing API Gateway at a Lambda function that has the ability to connect to your RDS database and run queries.