TUI freeze

[pom11]

Hello!
Given the following widget for displaying docker containers stats i found out that the TUI is freezing for about 2 seconds at a refresh_rate of 10 seconds. Is this normal behaviour or will be solved in future updates?

Note: Docker environment has 32CPU 64GB RAM and there where 10 containers running.

from python_on_whales import docker as pwhales

class DockerContainerStats(Widget):

	def __init__(self, refresh_rate: int) -> None:
		self.refresh_rate = refresh_rate
		super().__init__()

	mouse_over = Reactive(False)

	def on_mount(self):
		self.set_interval(self.refresh_rate, self.refresh)

	def getContainers(self) -> Table:

		containers = pwhales.stats()

		table = Table(show_header=False, show_lines=False, box=box.HEAVY)
		table.add_column("Container", no_wrap=False, justify="left") 
		table.add_column("Name", no_wrap=False, justify="left") 
		table.add_column("CPU %", no_wrap=False, justify="left") 
		table.add_column("MEM %", no_wrap=False, justify="left") 

		for c in containers:
			table.add_row('[bold cyan]'+str(c.container), '[bold cyan]'+str(c.container_name), '[bold cyan]'+str(c.cpu_percentage), '[bold cyan]'+str(c.memory_percentage) )
		return table

	def render(self):
		table = self.getContainers()
		return Static(renderable=table)

[willmcgugan]

Have you done any profiling? How long does stats take to run? And how big is the table?

In general, it's not a good idea to do more than return a renderable in your render method. i.e. have another interval or test to retrieve the data, which render returns.

[pom11]

3 seconds to display the TUI. The table has 4 columns with 10 rows (+ headers). The only profiling i can do during runtime is to watch the included time of TUI (header). I dont understand your recommendation, sorry. Should i add all the docker stats logic in App and pass them to the Widget as i did with refresh_rate interval?

[pom11]

3 seconds at startup of TUI. 2 seconds per refresh. In interpreter the containers = pwhales.stats() takes 2 seconds too. I thought the TUI wont freeze until refresh is done.
Didn't looked at the source code of textual but i think there is a await problem/misconfig.

[willmcgugan]

It's possible there is a performance issue in Rich or Textual, but it is unlikely. What is more likely is that your call to pwhales.stats() is going to the network and taking a while to return, during which time Textual is unable to update the screen.

You will likely need to run pwhales.stats in a thread. The concurrent.futures module can help you with this.

You can confirm this by timing how long the pwhales.stats call takes to execute. You could use self.log to write the times to the log file.

[pom11]

Understood. That would be a good update for Textual to use a thread for a widget by default. Thx for info. Will get back with updates

[kfmfe04]

If you do get this working with futures, please share your code. I'm curious as to what this pattern looks like in the context of Textual. Thank you!