Skip to content

Remote access - GUI

The script livestream_gui.py is meant to build an easy controllable interface to start and stop the livestream. Furthermore it also displays the most common errors that occur on the livestream.py script is running.

Code Description

The first thing that the code does is to check wheter the interface is already running or not. This check is done by checking wether a lockfile exists or not. When it doesn't exist it is created to prevent from opening more than one Interface.

Afterwards a window with an interface is created with the Tkinter library. The interface displays the status of the livestream, a button to start or stop the livestream and it shows errors that occur on the RaspberryPi. All this functions are controlled over SSH with the Paramiko library.

Status display

To get the status of the livetsream the following comamnd is executed in the terminal of the RaspberryPi over SSH.

command = f"ps aux | grep {script_name}"

Start and Stop Button

The following commands are executed to start and stop the livestream.

Start command

command = "source /home/pi/docs/halpha/venv/bin/activate && python /home/pi/docs/halpha/sun_catching/livestream.py"
This activates the virtual environement and executes the desired script

Stop command

ssh.exec_command(f"pkill -f 'python /home/pi/docs/halpha/sun_catching/livestream.py'")
This simply kills all processes assigned to the livestream.py script.

Error handling

To handle the errors that occur in the livetsream.py script they are written into a logfile on the RaspberryPi. This file can then be read over an SFTP connection with the RaspberryPi with the following structure. 

    with sftp.file("/home/pi/docs/halpha/sun_catching/error_log.txt", 'r') as file:
        file_contents = file.read()
    error_status.config(text = file_contents)

Installation

To use this interface on a remote machine Python should be installed on the remote machine and the following librarys have to be installed over pip:

  • Paramiko
  • Tkinter

Python script

The python script can be found here.