Migrating from Nx Metadata SDK 5.1 to 6.0 — Concerns & Questions

Answered

Subramanian

September 26, 2025 05:41

I'm currently evaluating the transition from Nx Metadata SDK 5.1 to 6.0 for a real-time object detection pipeline integrated with Nx Witness. I’ve been using JSON-based metadata injection via HTTP POST and plugin-side logic, but I understand that SDK 6.0 introduces Protocol Buffers and gRPC streaming.

Here are some specific concerns I’d love input on:

 

 1. Metadata Format Migration

• How painful is the switch from JSON to protobuf in practice?
• Are there official .proto definitions for common object/event types, or do we need to define our own?
• Any tips for converting existing nlohmann::json C++ logic to protobuf?

 

 2. Injection Mechanism Changes

• Is gRPC now the preferred method for metadata injection, or can we still use HTTP POST for backward compatibility?
• For plugin-side injection, what’s the recommended way to stream protobuf metadata into the server?

 

 3. Plugin Architecture

• Are there major changes in plugin registration or lifecycle management?
• Any gotchas when adapting existing C++ plugins to the new SDK headers and protobuf dependencies?

 

 4. Deployment & Compatibility

• Is SDK 6.0 backward-compatible with Nx Witness 5.x clients?
• Any known issues with ARM builds or edge deployment workflows?

 

 Bonus: Testing & Debugging

• What tools or strategies do you use to validate protobuf metadata injection?
• Any sample plugins or test harnesses for 6.0 that helped you get started?

 

Would really appreciate any insights, migration tips, or sample code. Thanks in advance!

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• 

  Ichiro

  • Network Optix team

  October 09, 2025 02:56

  Hi Subramanian, 

   

  1. Metadata Format Migration

  • How challenging is the transition from JSON to Protobuf in practice?
  • Are official .proto definitions available for common object/event types, or is custom definition required?
  • Do you have any recommendations for converting existing nlohmann::json C++ logic to Protobuf?

  Currently, we do not utilize gRPC or Protocol Buffers. Our analytics API, for example, expects JSON, as do all other endpoints we are aware of. Therefore, we are unable to provide answers to these questions as these technologies are not integrated into our product.

  2. Injection Mechanism Changes

  • Is gRPC now the preferred method for metadata injection, or is HTTP POST still supported for backward compatibility?
  • For plugin-side injection, what is the recommended approach for streaming Protobuf metadata to the server?

  We currently use JSON-RPC and do not employ gRPC or Protobuf. Both HTTP and JSON-RPC are supported in parallel, ensuring no backward compatibility concerns.

   

  3. Plugin Architecture

  • Are there significant changes in plugin registration or lifecycle management?

  As far as we know, there are no major changes. Please refer to the release notes for further details: https://meta.nxvms.com/download/other/betas#6.1.0.41495

  • Are there any known difficulties when adapting existing C++ plugins to the new SDK headers and Protobuf dependencies?

  Again, as we do not use Protobuf, we cannot provide an answer to this question.

   

  4. Deployment & Compatibility

  • Is SDK 6.0 backward-compatible with Nx Witness 5.x clients?

  In general, backward compatibility is possible. However, if you are developing with SDK 6.0, some features may not be available on older clients. It is generally not straightforward to expect a newer SDK version to support new features on an older client version. Therefore, while generally compatible, this is not an ideal solution.

  Additionally, please note that troubleshooting plugin issues developed with SDK 6.0 on a 5.x client is not supported. As a guideline, we strongly recommend using the same version of the SDK and Desktop Client in all cases to ensure proper compatibility and support.

  • Are there any known issues with ARM builds or edge deployment workflows?

  No, there are no known issues.

   

  5. Testing & Debugging

  • What tools or strategies are used to validate Protobuf metadata injection?
  • Are there any sample plugins or test harnesses for 6.0 that would be helpful for getting started?

  We do not use gRPC or Protobuf.

  • Are insights, migration tips, sample code, online meetings, or educational resources available and required?

  Samples are available within the MetaSDK, which also provides STUB samples for various usages.

   

  We are unsure where you obtained information regarding these changes, as there appears to be a misunderstanding, or significant clarification is required for such an assumption. To reiterate, we do not currently utilize gRPC or Protobuf.

   

  Hope this helps.
  Thanks.

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