Publish/Subscribe issue with mixed RCF versions
Posted: Wed Aug 17, 2022 12:47 pm
Hello,
here is an issue with using RCF publish/subscribe with different RCF versions.
Publishing an event from a publisher (v3.2) to a subscriber (v2.2) is somehow silently swallowed. Nothing happens on subscriber side, no event is received and no error is thrown on either subscriber or publisher side.
Situation:
By setting the RCF_LOG to level 4 the following output is made on subscriber side:
To compare here is the output from RCF v2.2 only:
With a patch the interface name was again send to the subscriber. And the event was received and processed again there.
Here is the content of the patch:
Is there any other way, supported by the public RCF API, to ensure compatibility between those publisher and subscriber?
Kind regards
Falk
[Edit: patch with with deeper context created]
here is an issue with using RCF publish/subscribe with different RCF versions.
Publishing an event from a publisher (v3.2) to a subscriber (v2.2) is somehow silently swallowed. Nothing happens on subscriber side, no event is received and no error is thrown on either subscriber or publisher side.
Situation:
- Publisher works with RCF v3.2
Subscriber works with RCF 2.2
Runtime version is set to 12 (RCF v2.2) on publisher side
Code: Select all
pubPtr->publish().getClientStub().setRuntimeVersion(12);
Comparing to the output of a communication between RCF v2.2-only publisher and subscriber the empty field r.mSubInterface stands out.RcfServer.cpp(568): [Thread: 6264][Time: 45953] RcfServer - received request. [Args: this=0000000002652F80, mRequest=(r.mToken = ( id = 0 ))(r.mSubInterface = )(r.mFnId = 0)(r.mSerializationProtocol = 1)(r.mMarshalingProtocol = 1)(r.mOneway = 1)(r.mClose = 0)(r.mService = )(r.mRuntimeVersion = 13)(r.mPingBackIntervalMs = 0)(r.mArchiveVersion = 0), ]
To compare here is the output from RCF v2.2 only:
Looking into the relevant code locations for this field some comments hints that this field is no longer used in RCF 3(.2).RcfServer.cpp(568): [Thread: 4388][Time: 265812] RcfServer - received request. [Args: this=00000000030F40F0, mRequest=(r.mToken = ( id = 0 ))(r.mSubInterface = I_Publish)(r.mFnId = 0)(r.mSerializationProtocol = 1)(r.mMarshalingProtocol = 1)(r.mOneway = 1)(r.mClose = 0)(r.mService = )(r.mRuntimeVersion = 12)(r.mPingBackIntervalMs = 0)(r.mArchiveVersion = 0), ]
With a patch the interface name was again send to the subscriber. And the event was received and processed again there.
Here is the content of the patch:
Code: Select all
diff -U 3 src/RCF/MethodInvocation.cpp src/RCF/MethodInvocation.cpp
--- src/RCF/MethodInvocation.cpp Sun Jul 12 14:15:49 2020
+++ src/RCF/MethodInvocation.cpp Wed Aug 17 13:44:11 2022
@@ -403,7 +403,8 @@
const std::string EmptyString;
- ByteBuffer MethodInvocationRequest::encodeRequestHeader()
+ ByteBuffer MethodInvocationRequest::encodeRequestHeader(
+ const std::string &subInterface)
{
RCF_ASSERT(!mVecPtr || mVecPtr.unique());
if (!mVecPtr)
@@ -454,7 +455,7 @@
SF::encodeInt(0, *mVecPtr, pos);
// mSubInterface - unused
- SF::encodeString(EmptyString, *mVecPtr, pos);
+ SF::encodeString(subInterface, *mVecPtr, pos);
SF::encodeInt(mFnId, *mVecPtr, pos);
SF::encodeInt(mSerializationProtocol, *mVecPtr, pos);
diff -U 3 src/RCF/Marshal.cpp src/RCF/Marshal.cpp
--- src/RCF/Marshal.cpp Sun Jul 12 14:15:49 2020
+++ src/RCF/Marshal.cpp Wed Aug 17 09:37:34 2022
@@ -132,10 +132,14 @@
::RCF::CurrentClientStubSentry sentry(*this);
+ std::string interfaceName; // needed for backward compatibility
+ if (mRequest.mOneway && mRequest.mRuntimeVersion == 12)
+ interfaceName = mInterfaceName;
+
mOut.reset(
getSerializationProtocol(),
32,
- mRequest.encodeRequestHeader(),
+ mRequest.encodeRequestHeader(interfaceName),
mRuntimeVersion,
mArchiveVersion,
mEnableSfPointerTracking);
diff -U 3 include/RCF/MethodInvocation.hpp include/RCF/MethodInvocation.hpp
--- include/RCF/MethodInvocation.hpp Sun Jul 12 14:15:49 2020
+++ include/RCF/MethodInvocation.hpp Wed Aug 17 09:31:08 2022
@@ -122,7 +122,7 @@
void setService(const std::string &service);
int getPingBackIntervalMs();
- ByteBuffer encodeRequestHeader();
+ ByteBuffer encodeRequestHeader(const std::string &subInterface);
void encodeRequest(
const std::vector<ByteBuffer> & buffers,
Kind regards
Falk
[Edit: patch with with deeper context created]