This document summarizes eProsima's RPC over DDS solution for building remote procedure calls between applications using the Real-Time Innovation's Connext DDS middleware. It presents the architecture of RPC over DDS, which uses request and reply topics to enable communication between client and service applications. It also provides an example demonstrating how to define a Calculator interface using OMG IDL, generate interface support code, and implement a client and server to make remote calls for multiplication and division.

1. eProsima RPC over DDS
for RTI Connext DDS
Connext Conference, London 2015
15/10/2015
Jaime Martin Losa
CTO eProsima
JaimeMartin@eProsima.com
+34 607 91 37 45 www.eProsima.com

2. Old solution: Manual
2
Struct FunRequest {
RequestID;
RequestParameter1;
/* ... */
RequestParameterN;
};
Struct FunReply {
RequestID;
ReplyResult1;
/* ... */
ReplyResultN;
};

3. RPC over DDS Standard: Automatic
3
interface MyInterface {
funReturnValueType Fun(in MyTypeI1 m1,in MyTypeI2 m2,...,
out MyTypeO1 n1, out MyTypeO2 n2,...,
inout MyType1 l1,inout MyType2 l2 );
/* ... */
};

4. Architecture
Request Topic
Reply Topic
ClientApp
Publisher Subscriber
STUB
Requester
ServiceApp
Publisher Subscriber
Skeleton
Replier
Resource Aware
Dispatching Agent
Global Data Space
4

5. Definition of the
Services

6. Definition of the services
 OMG IDL 3.5 + DDS-XTYPES is used
– “Any” and “valuetype” not part of DDS-XTYPES
 Exceptions supported
 Atributes in the interfaces ignored
 Oneway invocations supported throught the IDL
oneway keyword
6

7. eProsima RPC over DDS
for RTI Connext DDS

8. eProsima RPC over DDS Features
 Open Source: LGPL – Published on GitHub
 Windows and Linux support (32 and 64 bits)
 Project and makefile generation for VS2010-3 &
gcc 4.x
 Synchronous, asynchronous and one way
operations
 Different Server threading models
 100% Standard: ISO C++ and OMG DDS
 Comprehensive documentation

9. eProsima RPC over DDS
 Available on:
– eProsima.com web site:
 http://www.eprosima.com/index.php/products-all/eprosima-
rpc-over-dds-all
– eProsima GitHub:
 https://github.com/eprosima

10. Example

11. Hands On: Calculator
 Create Calculator.idl
 Generate Interface Support :
///////////////////////////
// Connext Con Example //
///////////////////////////
exception divideByZeroEx{
long count;
};
interface Calculator {
float multiply(in float a,in float b);
float divide(in float a,in float b) raises(divideByZeroEx);
};
rpcddsgen -ppDisable -example x64Win64VS2013 Calculator.idl

12. Hands On: Calculator
 Edit the Example: CalculatorClientExample.cxx
// Call to remote procedures
try
{
return_ = proxy->multiply(16, 2); // multiply
std::cout << return_ << std::endl;
return_ = proxy->divide(16, 2); // divide
std::cout << return_ << std::endl;
return_ = proxy->divide(16, 0); // user exception
std::cout << return_ << std::endl;
}
catch (divideByZeroEx &ex)
{
std::cout << "divideByZeroEx" << std::endl;
}
catch (SystemException &ex)
{
std::cout << "System Exception:" << std::endl;
}

13. Hands On: Calculator
 Edit the CalculatorServerImplExample.cxx
DDS_Float CalculatorServerImplExample::multiply
(/*in*/ DDS_Float a, /*in*/ DDS_Float b)
{
DDS_Float return_ = a*b;
return return_;
}
DDS_Float CalculatorServerImplExample::divide
(/*in*/ DDS_Float a, /*in*/ DDS_Float b)
{
DDS_Float return_ = 0.0;
if (b == 0) {
throw divideByZeroEx();
}
return_ = a / b;
return return_;
}

14. Thank you!
Jaime Martin Losa
CTO eProsima
JaimeMartin@eProsima.com
+34 607 91 37 45 www.eProsima.com