Event stream IPC

[YaLTeR]

Some basic scaffolding for an event stream IPC.

1. Changed the client to read only a single line worth of response.

   This mirrors how the server works, and will be necessary to tell apart further messages. Events will arrive at one per line.

2. Added Request::EventStream that replies with Response::Handled and then proceeds to write one Event per line as they occur.

3. Events will be designed in such a way that the initial burst will synchronize the current state to the client, then subsequent events will modify that state in a consistent way. E.g. the initial burst of events will create all current outputs and workspaces.

4. Compositor-side, event stream clients have a buffer of events for sending. If this buffer runs too large (the client hanged and isn't reading), this client will be dropped. This is kinda similar to what Wayland itself does.

The events are all subject to change until this PR is merged. Currently only the WindowFocused is actually implemented, and I'm planning to change its type too.

[SidharthArya]

Hi, when is this planned to be merged?
Can pick up other tasks (except WindowFocused) if needed ?
Would love to see WorkspaceFocused, MonitorFocused, WorkspaceAdded and MonitorAdded.

[YaLTeR]

No plan yet, this is just scaffolding for now. It's in a too early of a state to get help from others on specific tasks.

[jakesarjeant]

No plan yet, this is just scaffolding for now. It's in a too early of a state to get help from others on specific tasks.

Has that changed yet? I'd be happy to pick up some work too if needed

[YaLTeR]

I was fairly busy with uni; I think I am about to have sorted most of it out though so I will look into this more soon.

[YaLTeR]

Update, I did some more sketching out. Now, the following events are implemented: WorkspacesChanged, WorkspaceSwitched, KeyboardLayoutsChanged, KeyboardLayoutSwitched.

I was able to make a Waybar workspace indicator with the following Python script:

#!/usr/bin/python3

import json
import os
import sys
from socket import AF_UNIX, SHUT_WR, socket

niri_socket = socket(AF_UNIX)
niri_socket.connect(os.environ["NIRI_SOCKET"])
file = niri_socket.makefile("rw")

file.write('"EventStream"')
file.flush()
niri_socket.shutdown(SHUT_WR)

output = None
if len(sys.argv) > 1:
    output = sys.argv[1]

workspaces = {}


def print_workspaces():
    vals = workspaces.values()
    if output is not None:
        vals = filter(lambda ws: ws["output"] == output, vals)

    vals = sorted(vals, key=lambda ws: ws["idx"])
    text = "\n".join(("󰪥" if ws["is_active"] else "󰄰" for ws in vals))
    print(json.dumps({"text": text}), flush=True)


for line in file:
    event = json.loads(line)

    if changed := event.get("WorkspacesChanged"):
        workspaces = {ws["id"]: ws for ws in changed["workspaces"]}
        print_workspaces()
    elif switched := event.get("WorkspaceSwitched"):
        for ws in workspaces.values():
            if ws["output"] == switched["output"]:
                ws["is_active"] = ws["id"] == switched["id"]
        print_workspaces()

(Note the \n: my bar is vertical, so it uses newlines.)

And this is the custom module setup:

    "custom/workspaces": {
        "exec": "~/source/py/niri-ipc/workspaces.py \"$WAYBAR_OUTPUT_NAME\"",
        "return-type": "json"
    },

[YaLTeR]

I started implementing built-in support in Waybar using this event stream draft PR. You can try my fork here: https://github.com/YaLTeR/Waybar/tree/niri

niri-waybar-workspaces.mp4

So far I added niri/workspaces and niri/language with configuration roughly matching some subset of the same from sway/ and hyprland/.

[YaLTeR]

Pushed a breaking change to the IPC to differentiate between active and focused workspaces, Waybar fork also updated. New Python script:

#!/usr/bin/python3

import json
import os
import sys
from socket import AF_UNIX, SHUT_WR, socket

niri_socket = socket(AF_UNIX)
niri_socket.connect(os.environ["NIRI_SOCKET"])
file = niri_socket.makefile("rw")

file.write('"EventStream"')
file.flush()
niri_socket.shutdown(SHUT_WR)

output = None
if len(sys.argv) > 1:
    output = sys.argv[1]

workspaces = {}


def print_workspaces():
    vals = workspaces.values()
    if output is not None:
        vals = filter(lambda ws: ws["output"] == output, vals)

    vals = sorted(vals, key=lambda ws: ws["idx"])
    text = "\n".join(("󰪥" if ws["is_active"] else "󰄰" for ws in vals))
    print(json.dumps({"text": text}), flush=True)


for line in file:
    event = json.loads(line)

    if changed := event.get("WorkspacesChanged"):
        workspaces = {ws["id"]: ws for ws in changed["workspaces"]}
        print_workspaces()
    elif focused := event.get("WorkspaceFocused"):
        ws_output = workspaces[focused["id"]]["output"]
        for ws in workspaces.values():
            got_focused = ws["id"] == focused["id"]
            if ws["output"] == ws_output:
                ws["is_active"] = got_focused
            ws["is_focused"] = got_focused
        print_workspaces()
    elif activated := event.get("WorkspaceActivated"):
        ws_output = workspaces[activated["id"]]["output"]
        for ws in workspaces.values():
            if ws["output"] == ws_output:
                ws["is_active"] = ws["id"] == activated["id"]
        print_workspaces()

[YaLTeR]

Pushed another breaking change, along with an implementation of Window events:

• WorkspaceActiveWindowChanged
• WindowsChanged
• WindowOpenedOrChanged
• WindowClosed
• WindowFocusChanged

Waybar fork is updated to use this, and also I implemented a niri/window module similar to hyprland/window.

This completes my sketching so far; I'm fairly sure that this is enough IPC to cover the remaining window icon support in the workspaces Waybar module (I'm too lazy to implement that), and anything past that should be fairly straightforward to add without breaking changes.

That said, I'd like others to take a look at this before merging, give it a try with Waybar or by implementing their own scripts, in case I missed something important.

Newest Python workspaces script:

#!/usr/bin/python3

import json
import os
import sys
from socket import AF_UNIX, SHUT_WR, socket

niri_socket = socket(AF_UNIX)
niri_socket.connect(os.environ["NIRI_SOCKET"])
file = niri_socket.makefile("rw")

file.write('"EventStream"')
file.flush()
niri_socket.shutdown(SHUT_WR)

output = None
if len(sys.argv) > 1:
    output = sys.argv[1]

workspaces = {}


def print_workspaces():
    vals = workspaces.values()
    if output is not None:
        vals = filter(lambda ws: ws["output"] == output, vals)

    vals = sorted(vals, key=lambda ws: ws["idx"])
    text = "\n".join(("󰪥" if ws["is_active"] else "󰄰" for ws in vals))
    print(json.dumps({"text": text}), flush=True)


for line in file:
    event = json.loads(line)

    if changed := event.get("WorkspacesChanged"):
        workspaces = {ws["id"]: ws for ws in changed["workspaces"]}
        print_workspaces()
    elif activated := event.get("WorkspaceActivated"):
        focused = activated["focused"]
        ws_output = workspaces[activated["id"]]["output"]
        for ws in workspaces.values():
            got_activated = ws["id"] == activated["id"]
            if ws["output"] == ws_output:
                ws["is_active"] = got_activated
            if focused:
                ws["is_focused"] = got_activated
        print_workspaces()