[Q&A] Best way for debug nvflare application

[tommasofavaron1]

Python version (python3 -V)

310

NVFlare version (python3 -m pip list | grep "nvflare")

2.5.1

NVFlare branch (if running examples, please use the branch that corresponds to the NVFlare version, git branch)

2.5

Operating system

Ubunto 22

Have you successfully run any of the following examples?

• hello-numpy-sag with simulator
• hello-pt with simulator
• hello-numpy-sag with POC
• hello-pt with POC

Please describe your question

I am trying to debug an NVFlare application with my personal code using the simulator:

simulator = SimulatorRunner(
    job_folder="my_first_job",
    workspace="workspace",
    clients="client1",
    n_clients=1,
    threads=1,
    max_clients=1,
)
run_status = simulator.run()

The problem I encounter is that when I launch the simulator, I cannot debug the "custom code" because NVFlare creates a clone in the specified workspace for each run of the simulator and so debugger not connect.
Can you suggest a way to easily debug situations like this? Or I'm doing something wrong?

[chesterxgchen]

I think you can debug it, just need to set the debugger for it @yhwen can you help for some pointer, as you have done so many times.

For myself, I found the easiest way to debug just few print statements without debugger.

[mbujo]

Hey,
I have exactly the same setup and problem.
Any solution yet?

[yhwen]

Sorry for delaying the response on this.

If you are using the PyCharm, for debugging the application in Simulator mode, you can add your application's "custom" folder as 'Sources Root". Then the Simulator run will stop the execution for server or the client when hitting the breakpoint. And you will be able to fully make use of the debug functions.

If you want to debug with the full Server / Client POC mode, you can start your server and client in Debug sessions separately. For server, using the script parameters like this "-m Server_Folder -s fed_server.json --set secure_train=true config_folder=config". and for client like "-m Client_Folder -s fed_client.json --set secure_train=true uid=client1 config_folder=config". Then you can add breakpoints and fully debug your server and client Apps.

[mbujo]

Thanks for the prompt help, and helping to find a solution via pathMappings.
I solved it now by just adapting my launch.json file and doing pathMappings between the original and the NVFlare-copied file. This is my launch.json:

{
    "version": "0.2.0",
    "configurations": [
      {
        "name": "Run KMeans Job",
        "type": "python",
        "request": "launch",
        "program": "${workspaceFolder}/src/kmeans_job.py",
        "console": "integratedTerminal",
        "args": [
          "--workspace_dir", "/tmp/nvflare/workspace/works/kmeans",
          "--job_dir", "/tmp/nvflare/workspace/jobs/kmeans",
          "--client_data_paths",
          "/som/path/to/data.csv,/another/path/to/data.csv",
          "--num_rounds", "5",
          "--valid_frac", "1.0"
        ],
        "justMyCode": false,
        "pathMappings": [
            {
            "localRoot": "${workspaceFolder}/src/modules",
            "remoteRoot": "/tmp/nvflare/workspace/works/kmeans/sklearn_kmeans_1_clients/site-1/simulate_job/app_site-1/custom/modules"
            }
        ]
      }
    ]
  }