Trace Debugging for Eclipse eCAL™ 🐛

This is a contribution challenge. The goal is to add trace debugging to Eclipse eCAL™ using Open Telemetry.

📚 About

Eclipse eCAL is a publish subscribe Middleware with the main focus on research and development of autonomous driving algorithms.

• A Publisher publishes data to a topic, identified by a name.
• A Subscriber subscribes to a topic, identified by a name. When it received data, it calls a callback function.

In a 1:1 connection, that looks like follows:

As you can think, with more nodes, it is getting complicated! Especially, when a callback is still running while new data is being published, that data has to be dropped.

Let's look at another example:

The PubSub2 node may now ask:

Why wasn't I informed about msg A? 🤔

Well, nobody knows, because the charts you are seeing above don't exist, yet. 😣

Debugging this inter-process time-related behavior is hard. You cannot use traditional debuggers like gdb, as that would modify the behavior That's why we want to add trace debugging to eCAL.

🎯 Goal

The goal is to know: What is happening when? And why?

• When was the data published?
• How long did it take to transmit the data?
• How long did the callback need to process the data?
• Who triggered the callback?

OpenTelemetry is a library that can be used to generate traces at runtime without actually debugging and/or stopping the process. These traces can be visualized using a tool like Jaeger:

💡 Need to know

• C++
• CMake

We recommend using Windows or Linux. MacOS may work too, but eCAL is poorly tested on that OS.

👨‍🏫 Hack-Coaches

• Kerstin Keller
• Florian Reimold
• Kristof Hannemann
• Rex Schilasky

🛠 Template Setup

1. Checkout eCAL

   git clone https://github.com/eclipse-ecal/ecal.git
   cd ecal
   git submodule init
   git submodule update

2. CMake and build a minimalistic eCAL configuration

   mkdir _build
   cd _build
   
   cmake .. -DBUILD_APPS=OFF -DHAS_QT5=OFF -DHAS_HDF5=OFF -DECAL_THIRDPARTY_BUILD_FINEFTP=OFF -DECAL_THIRDPARTY_BUILD_CURL=OFF -DECAL_THIRDPARTY_BUILD_HDF5=OFF -DECAL_THIRDPARTY_BUILD_QWT=OFF -DCMAKE_BUILD_TYPE=Debug
   
   cmake --build . --config Debug

3. Start Samples

   • Start ecal_sample_person_snd and ecal_sample_person_rec from the _build/bin/ directory:

     

4. Add Open Telementry

   • Well, you are on your own on this one, but we are here to help! 😊

👀 All necessary links

Eclipse eCAL:

• 🏠 Homepage: http://ecal.io
• 👨‍💻 GH Repository: https://github.com/eclipse-ecal/ecal
• 💡 How to compile eCAL: https://eclipse-ecal.github.io/ecal/development/building_ecal_from_source.html

Open Telemetry

• = Library for generating traces
• 🏠 Homepage: https://opentelemetry.io/
• 👨‍💻 GH Repository: https://github.com/open-telemetry/opentelemetry-cpp
• 💡 Open Telemetry in C++: https://opentelemetry.io/docs/demo/services/currency/

Jaeger:

• = Viewer for OpenTelemetry data:
• 🏠 Homepage: https://www.jaegertracing.io/