Automatic load for librdkafka libraries not working in NetFramework projects with 2.6.0

[dmalanij]

Description

When using the libraries in Net 4.8 project (in particular a WebAPI), as of 2.6.0 the initialization of the Confluent.Kafka.Impl.Librdkafka initialization fails with a DllNotFoundException and the message:

Failed to load the librdkafka native library.

How to reproduce

In a NetFramework project, reference to the latest version of the Confluent.Kafka package; as soon as the runtime reaches the Kafka initialization (ie: using the ProducerBuilder<,>) the exception is thrown even if the redist assemblies are in place (in particular in the bin\librdkafka as the librdkafka.redist package targets take care of).

Root cause Analysis

I believe that the problem is hapenning because 2.6.0 has not included the target for net462; therefore the initialization goes through the netstandard variation without the automatic path resolution that is present for the cases of net462.

Workaround

This can be avoided by simply including a call to Library.Load(path) where path contains the location for the librdkafka.dll (which in case can be ripped of inspired by the logic used by the implementation of the LoadNetFrameworkDelegates.

[UBSaxo]

We face same blocking issue. I cloned Confluent.Kafka and could easily reproduce it simply by changing the target framework of Confluent.Kafka.UnitTests test project to net48 and then loads of tests fail with the DllNotFoundException.

[anchitj]

Can you try with 2.6.1? We've added back net462

[dmalanij]

Can you try with 2.6.1? We've added back net462

I'll give it a try as soon as I can, right now we're in the final stage of our release cycle so the dependencies are fixed.
Cheers

[UBSaxo]

I have validated this by running your own unit tests against net48 and that works. With 2.6.0 that failed.

I would still love to see your automated tests extended to also cover NET Framework to avoid this mistake from repeating itself in future.

[samuelburnett]

I am still encountering this issue. I have a NET Framework 4.8 project that references 2.6.1 and receive the following error at runtime:
Error while loading librdkafka.dll or its dependencies from C:\PATH_TO_PROJECT\bin\Debug\librdkafka.dll.

No issue in my NET 6 project referencing 2.6.1.

[dmalanij]

Can you try with 2.6.1? We've added back net462

Finally we were able to do the update and, same as @UBSaxo, the code is working fine now with 2.6.1.