How can I have a kivy app restart after downloading a new version of itself?
I'm developing a python GUI app that uses the kivy framework, I just added an auto-update feature to my app that securely downloads, verifies, and extracts a newer version of itself. After these upgrade steps are complete, I present the user with a modal dialog asking them to click a button to restart the app to the newer version.
How can I get that button to actually close the window and execute the new kivy app?
In python, you can use os.execv() to exit the current process and replace it with another execution.
The following commands demonstrate how to do this with kivy in Debian 10:
sudo apt-get -y install python3 python3-pip python3-virtualenv python3-setuptools
sudo dpkg -l | grep python
python3 -m virtualenv --python=python3.7 /tmp/virtualenv/kivy_test
/tmp/virtualenv/kivy_test/bin/python3 -m pip install --upgrade pip kivy
/tmp/virtualenv/kivy_test/bin/python3 -m pip list
source /tmp/virtualenv/kivy_test/bin/activate
tmpDir=`mktemp -d`
pushd "${tmpDir}"
cat << EOF > helloWorldOne.py
#!/usr/bin/env python3
import kivy, os
from kivy.app import App
from kivy.uix.label import Label
from kivy.clock import Clock
class MyApp(App):
def build(self):
Clock.schedule_once( self.restart, 1 )
return Label(text='Hello World One!')
def restart(self, dt):
os.execv( 'helloWorldTwo.py', ['helloWorldTwo.py'] )
if __name__ == '__main__':
MyApp().run()
EOF
cat << EOF > helloWorldTwo.py
#!/usr/bin/env python3
import kivy, os
from kivy.app import App
from kivy.uix.label import Label
from kivy.clock import Clock
class MyApp(App):
def build(self):
return Label(text='Hello World Two!')
if __name__ == '__main__':
MyApp().run()
EOF
chmod +x helloWorld*.py
./helloWorldOne.py
popd
When ./helloWorldOne.py is executed above, a window (the "old version") appears. After a 1 second delay, the restart() function is executed (which instead could be bound to a button)--which calls os.execv().
The helloWorldOne.py app window is closed and replaced with the helloWorldTwo.py app window.