Debug .NET apps on ARM single-board computers

Grein
07/31/2024

Debugging .NET apps running on ARM-based SBCs like Raspberry Pi presents a unique challenge. If desired, you can install Visual Studio Code and the .NET SDK on the device and develop locally. However, the device's performance is such that coding and debugging locally is not ideal. Additionally, the Visual Studio Code extension for C# is not compatible with 32-bit ARM operating systems. Consequently, functionality like IntelliSense and debugging in Visual Studio Code on ARM devices is only supported in 64-bit systems.

For these reasons, it's strongly recommended that you develop your app on a development computer and then deploy the app to the device for remote debugging. If you wish to develop and debug locally on the device, the following is required:

A 64-bit OS with a desktop environment, such as Raspberry Pi OS (64-bit).
Visual Studio Code with the C# extension.
- Disable the hardware acceleration.
.NET SDK 6.0 or later.
- Install using the dotnet-install script as in a framework-dependent deployment. Be sure to add a DOTNET_ROOT environment variable and add the .dotnet directory to $PATH.

The rest of this article describes how to debug .NET apps on single-board computers remotely from a development computer.

Important

As of this writing, remotely debugging .NET 7 apps in linux-arm environments is unreliable and may cause the process to exit prematurely. This issue is under investigation. .NET 6 apps that target linux-arm and .NET 7 apps that target linux-arm64 are unaffected.

Debug from Visual Studio Code (cross-platform)

Debugging .NET on single-board computers from Visual Studio Code requires configuration steps on the SBC and in the project's launch.json file.

Enable SSH on the SBC

SSH is required for remote debugging. To enable SSH on Raspberry Pi, refer to Enable SSH in the Raspberry Pi documentation. Ensure that you have configured passwordless SSH.

Important

This example requires you to configure passwordless SSH on your device, as OpenSSH doesn't support passing passwords on the command line. If you need to use a password, consider substituting the Plink tool for ssh.

Install the Visual Studio Remote Debugger on the SBC

Within a Bash console on the SBC (either in a local session or via SSH), run the following command. This command downloads and installs the Visual Studio Remote Debugger on the device:

curl -sSL https://aka.ms/getvsdbgsh | /bin/sh /dev/stdin -v latest -l ~/vsdbg

Set up launch.json in Visual Studio Code

On the development computer, add a launch configuration to the project's launch.json. If the project doesn't have a launch.json file, add one by switching to the Run tab, selecting create a launch.json file, and selecting .NET or .NET Core in the dialog.

The new configuration in launch.json should look similar to one of the following:

Self-contained
Framework-dependent

"configurations": [
    {
        "name": ".NET Remote Launch - Self-contained",
        "type": "coreclr",
        "request": "launch",
        "program": "~/sample/sample",
        "args": [],
        "cwd": "~/sample",
        "stopAtEntry": false,
        "console": "internalConsole",
        "pipeTransport": {
            "pipeCwd": "${workspaceRoot}",
            "pipeProgram": "ssh",
            "pipeArgs": [
                "pi@raspberrypi"
            ],
            "debuggerPath": "~/vsdbg/vsdbg"
        }
    },

Notice the following:

program is the executable file created by dotnet publish.
cwd is the working directory to use when launching the app on the device.
pipeProgram is the path to an SSH client on the local machine.
pipeArgs are the parameters to be passed to the SSH client. Be sure to specify the password parameter, as well as the pi user in the format <user>@<hostname>.

"configurations": [
    {
        "name": ".NET Remote Launch - Framework-dependent",
        "type": "coreclr",
        "request": "launch",
        "program": "~/dotnet/dotnet",
        "args": ["~/sample/sample.dll"],
        "cwd": "~/sample",
        "justMyCode": false,
        "stopAtEntry": false,
        "console": "internalConsole",
        "pipeTransport": {
            "pipeCwd": "${workspaceRoot}",
            "pipeProgram": "ssh",
            "pipeArgs": [
                "pi@raspberrypi"
            ],
            "debuggerPath": "~/vsdbg/vsdbg"
            }
        },

Notice the following:

program is the path to the .NET runtime on the device.
args is the path to the assembly to debug on the device.
cwd is the working directory to use when launching the app on the device.
justMyCode is set to false to ensure that the debugger breaks on breakpoints in the app's code.
pipeProgram is the path to an SSH client on the local machine.
pipeArgs are the parameters to be passed to the SSH client. Be sure to specify the password parameter, as well as the pi user in the format <user>@<hostname>.

Deploy the app

Deploy the app as described in Deploy .NET apps to ARM single-board computers. Ensure the deployment path is the same path specified in the cwd parameter in the launch.json configuration.

Launch the debugger

In Visual Studio Code, on the Run and Debug tab, select the configuration you added to launch.json and select Start Debugging. The app launches on the device. The debugger may be used to set breakpoints, inspect locals, and more.

Debug from Visual Studio on Windows

Visual Studio can debug .NET apps on remote devices via SSH. No specialized configuration is required on the device. For details on using Visual Studio to debug .NET remotely, see Remote debug .NET on Linux using SSH.

Be sure to select the dotnet process if you're debugging a framework-dependent deployment. Otherwise, the process will be named the same as the app's executable.

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