Describe a DynamoDB table using Apache Camel

Question

I am trying to use the Apache Camel aws2 DyanamoDB component. In that there is a operation DescribeTable . I was trying that out.I have a camel rest API like so ->

.post("dynamodb-describe-table")
.route()
.process(new Processor(){

    @Override
    public void process(Exchange exchange) throws Exception {
        exchange.getIn().setHeader("CamelAwsDdbTableName", "user");
    }
    
})
.toD("aws2-ddb://user?accessKey=insert&secretKey=insert&region=us-east-1&operation=DescribeTable")
.endRest();

This operation is run successfully but the response is null. Why is this happening?

Answer 1

Operation DescribeTable does not return body. All attributes are returned in form of Message headers. All headers returned by this operation are listed in AWS DynamoDB documentation .

You have many options to create body, eg. with MVEL:

.transform().mvel("{" +
  "'tableSize': exchange.in.headers.CamelAwsDdbTableSize," +
  "'status': 'exchange.in.headers.CamelAwsDdbTableStatus'" +
"}")

Or Processor :

.process( exchange ->
    exchange.getIn().setBody(
            new HashMap<String, Object>(){{
                put("tableSize", exchange.getMessage().getHeader("CamelAwsDdbTableSize"));
                put("status", exchange.getMessage().getHeader("CamelAwsDdbTableStatus"));
                // ...
            }}
    )
)

Between your toD() and endRest() .

---

BTW I don't see any dynamic part in your URI, you should be able to use just to() , which i generally faster.