Automatic iTerm2 preset switching on MacOS

auto_switch_theme.py

#!/usr/bin/env python3

import asyncio
import iterm2

THEME_LIGHT = "Tango Light"
THEME_DARK = "Tango Dark"


class AutoSwitchTheme:
    def __init__(self, connection, light="Light Background", dark="Dark Background"):
        self.connection = connection
        self.light = light
        self.dark = dark

    async def get_app(self):
        return await iterm2.async_get_app(self.connection)

    async def get_theme(self) -> str:
        parts = await (await self.get_app()).async_get_theme()
        if len(parts) <= 1:
            return parts[0]
        return ""

    async def set_color_preset(self, theme):
        preset = await iterm2.ColorPreset.async_get(
            self.connection, self.light if theme == "light" else self.dark
        )

        profiles = await iterm2.PartialProfile.async_query(self.connection)
        for partial in profiles:
            await (await partial.async_get_full_profile()).async_set_color_preset(
                preset
            )


async def quit(connection):
    while True:
        if not connection.websocket.open:
            exit(0)
        await asyncio.sleep(1)


async def main(connection):
    asyncio.ensure_future(quit(connection), loop=asyncio.get_event_loop())

    ast = AutoSwitchTheme(connection, THEME_LIGHT, THEME_DARK)
    await ast.set_color_preset(await ast.get_theme())

    async with iterm2.VariableMonitor(
        connection, iterm2.VariableScopes.APP, "effectiveTheme", None
    ) as mon:
        while True:
            # Block until theme changes
            theme = await mon.async_get()

            # Set preset if theme has changed
            await ast.set_color_preset(theme)


try:
    iterm2.run_forever(main)
except:
    print("Unable to connect on iTerm2 application")

Thanks @plivox, I've been using your script and it's worked well and, most importantly to me, behavesitself. (The previous auto-dark script I had been using spawned accumulating processes which consumed CPU and couldn't clean up.)

With this script, when dark mode is supposed to be active and I open a new terminal window, I may see a quick flash of white (light mode background) before it switches to black (dark mode); but that's a minor annoyance.

Thanks for the gist!

@SinisterStairs, with pleasure and thanks for the feedback.

@plivox I am having an issue where the script is running if I do it manually through the scripts menu, but even though it is here: $HOME/Library/Application Support/iTerm2/Scripts/AutoLaunch/auto_switch_theme.py - it doesn't seem to be running automatically. Do you have any idea what I might be doing wrong?

EDIT: Solved. You have to check "Enable Python API in Preferences"->General->Magic

@dasizeman, Yes, you have to activate the Python API in the preferences 👍

Thanks @plivox! Another thing I noticed is that was giving me trouble is that it doesn't seem to work with iTerm's minimal theme (which I really like 😢 ). Do you have any ideas if this is something we could improve on the script side or is it possibly an issue with the API being inconsistent for that theme?

Great stuff, and thanks for sharing your work! 🥇 👍

Just a small observation: THEME_LIGHT and THEME_DARK are actually used to select colour presets. What about renaming them to COLOUR_PRESET_LIGHT and COLOUR_PRESET_DARK?

Thanks @plivox! Another thing I noticed is that was giving me trouble is that it doesn't seem to work with iTerm's minimal theme (which I really like 😢 ). Do you have any ideas if this is something we could improve on the script side or is it possibly an issue with the API being inconsistent for that theme?

Same issue. When switch to compact theme all work fine.

Thanks for this!

Jazakallahu Khairan 💐❤️

Thanks for this one!!

Thank you all for your feedback. As @stefanwascoding writes, the latest beta (3.5) includes separate color settings.