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Debugging Python applications remotely

This Guide describes how to install and configure Visual Studio Code Insiders to accsess the Linux system remotely over ssh. Later on is shown how to use Visual Studio Code to remote debug Phyton applications.

Visual Studio Code is a code editor build by Microsoft. It is an universal binary application and runs on Windows, Linux and macOS. Visual Studio Code Insider is a special version and extended Visual Studio Code with advanced plugins. Only Visual Studio Code Insider allow a remote access via SSH to ARMv7A Linux-devices.

Visual Studio Code Insider does allow only SSH access with a SSH-Keygen. The key must be regenerated after every Board-, SD card or IP-Address switch.

The following step by step guide shows how to setup Visual Studio Code Insider for Python application remote development and debugging on Windows 10 PC.For other systems please follow Microsoft's instructions: Visual Studio Code Remote Development Troubleshooting Tips and Tricks (Chapter: Improving your security with a dedicated key)

With the following guide Microsoft describes the remote debugging function of Visual Studio Code Insider: Developing on Remote Machines using SSH and Visual Studio Code

I. Generation of the SSH Key with Windows 10

• Open the Windows "Command Prompt" (admin rights not requiered)
• Execute following Command inside the Windows Command Prompt:

1. Generate a new SSH Key
   • Windows stores the key inside following directory: C:\Users\<USER Name>\.ssh

   ssh-keygen -t rsa -b 4096

   
   • Always press ENTER (do not enter an extra password or an other name):
2. Set the IPv4 Address of the board

   SET REMOTEHOST=root@192.168.2.105

   • Here for example with the IP 192.168.2.105
3. Copy the generated SSH-Key via SSH to the board
   • After this command the rsYocto splash screen appears and the Linux system asks for the password: eit

   scp %USERPROFILE%\.ssh\id_rsa.pub %REMOTEHOST%:~/tmp.pub

4. Authenticate and activate the SSH key
   • Again, after this following command should the rsYocto splash screen appear and the linux system should ask for the password: eit

   ssh %REMOTEHOST% "mkdir -p ~/.ssh && chmod 700 ~/.ssh && cat ~/tmp.pub >>  ~/.ssh/authorized_keys && chmod 600 ~/.ssh/authorized_keys && rm -f ~/tmp.pub"

II. Installation of Visual Studio Code Insider and configuration of remote access

• Download and install the latest version of Visual Studio Code Insider: Download Visual Studio Code Insiders

• Follow the installation Instructions

• After a successful installation open Visual Studio Code Insider

• On the sidebar (toolbar on the left hand side) click the Extension-icon

• Search for the extension:"Remote Development" (by Microsoft) (Remote Development - Visual Studio Marketplace) and press the install-button to install this extension

  

• Restart Visual Studio Code Insider to accept the changes

• Click on the side bar "Remote Explorer"

• Choose in the Drop Down Menu "REMOTE EXPLORER" the SSH Target

• Move the mouse of the title "SSH TARGETS" and click on the gear-icon

  

• Select in the appeared Dropdown menu: "C:\Users<USER Name>.ssh\config"

  

• Configure the name and IPv4-Address by adding the following jason-configuration file (change the HostName with the IPv4-Address of your board):

Host rsYocto
    ForwardAgent yes
    HostName 192.168.2.105
    User root
    IdentityFile ~/.ssh/id_rsa

• Save and close this configuration file
• If a error occurred close and restart Visual Studio Code Insider and try it again

III. Connection of the rsYocto with Visual Studio Code Insider

• Open Visual Studio Code Insider

• Select on the side bar "Remote SSH"

• Under the tap "Connections" an entry with the name "rsYocto" apears

• Right click on this entry and choose "Connect Host in current Window"

  

  • The first attach attempt takes a little bit longer, because the Visual Studio downloads and install the Visual Studio Code Server
  • (Be sure that the board is connected to the internet)
  • In case that the connection to the board is established successfully a green icon with a connected symbol should appear

IV. Accessing the rootfs files remotely

• Visual Studio Code Insider can access the rootfs of the embedded Linux systems
• Some Python sample applications pre-installed on rsYocto
• Navigate on the Sidebar to "Explorer" click the blue "Open Folder"
• Visual Studio Code Insider should now ask for a remote directory to add
  • Default: "/home/root/" --> user root folder with the Python examples
  • Web sever: "/usr/share/apache2/default-site/htdocs" --> every file inside this folder will be accessible with a web browser
• Click okay

• Now the rootfs is accessible with the Visual Studio Code Insider File explorer

V. Preparing the Python remote development

• Select inside the sidebar "Extension"
• Choose the previously installed extension "Python" (by Microsoft)
• Press the green button "Install on SSH:rsYocto"

• With this input Visual Studio Code Server starts with the installation of the required remote python debugging components
• Press "reload required" to activate this changes

VI. Debugging Python Code remotely

• Open any pre-installed Python sample
• Navigate to the sidebar icon "Debug and Run" and click on the "Debug with Python" Button
• Choose in the Drop Down Menu "Python File"

• Or use following json-file to configure the debugger:

        {
        "version": "0.2.0",
        "configurations": [
              {
                  "type": "python",
                  "request": "launch",
                  "name": "Python curent file remotly",
                  "program": "${file}",
                  "console":"integratedTerminal"
              }
            ]
        }

• The remote Debugging should start

• If not: press the "Start Debugging" button or F5

• Now Visual Studio Code is configured to write and debug any python Code directly on the embedded Linux

  

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VII. Use of the Python Package Manager pip (PyPI)

• The pre-installed example "serialEchoDemo.py" requires the pySerial-module

• "rsYocto" has a full support for all Python pip versions

• Use the PiP Homepage to find a module

• Run following command to download and install this module with rsYocto:

  pip install "module_name"

• Now it is possible to use Python packages, whose are designed by a large community (e.g. Raspberry Pi-community), on a SoC-FPGA

• To show all pre-installed Python PiP packages

  pip list

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Example: Debugging the Python script "gsensorDemo.py" on a DE10 Standard Board

Continue with the next level: Analyzation of applications with ARM DS-5 Streamline