I'm having an issue when calling a GET REST (Regional) API which then invokes DynamoDB Scan API to get all the items of a table called City-Temperature.
As a request parameter, I'm adding only 'tablename' since it's required to call DynamoDB:Scan API. But on testing the API, I'm getting a 400 status from DynamoDB with error as follows:
{
"__type": "com.amazon.coral.validate#ValidationException",
"message": "1 validation error detected: Value null at 'tableName' failed to satisfy constraint: Member must not be null"
}
For simplicity, the dynamoDB table "City-Temperature" contains five items with each item 'City' (primary key - String) containing a single attribute (string) "Temperature".
My steps to generate API Service Proxy:
- Created a new REST API.
- Created a resource named "get-cities-temp"
- Created a child resource named 'table-name' with path {tablename}
- Created a GET method to child resource with:
- Integration-type: AWS Service
- Region: Same as DynamoDB region
- Service: DynamoDB
- Action: Scan
- HTTP Method: POST (since all requests to DynamoDB are made using POST)
- Execution role ARN: (Assumed role created for API-Gateway and attached a policy which allows only single action "DynamoDB:Scan" with a resource ARN pointing to DyanmoDB "City-Temperature" table.
- In Integration-Method pane, I kept the 'Content-handling' to 'passthrough', and added Mapping Template with content-type 'application/json' to transform request with single param 'tablename' to be DynamoDB compatible as follows:
To add here: 'Request Body Passthrough' is set to 'When there are no templates defined (recommended)'
{
"tableName": "$input.params('tablename')"
}
Finally, in test section, I add tablename=City-Temperature as a query string to pass in table's name for Scan API and hit 'Test'. But an error as mentioned above is being thrown in response.
Update:
In logs, it looks like request body after transformation is being properly converted:
{ "tablename": "City-Temperature" }. But yet, same error as above
