+211

tools/sway-spawn-workspace/daemon.py

View file Reviewed

··· 1 1 + #!/usr/bin/env python3 2 2 + """Place new sway windows on the workspace of the process that spawned them. 3 3 + 4 4 + Sway maps a new view onto the *currently focused* workspace. That is wrong 5 5 + whenever the spawning process lives elsewhere: a build finishing in a terminal 6 6 + on workspace "strom" pops its window onto whatever workspace happens to be 7 7 + focused at that moment. 8 8 + 9 9 + This daemon subscribes to sway's window::new events and resolves the workspace 10 10 + of the spawning process by walking /proc PPid links until it hits a pid that 11 11 + already owns a window. Terminals here exec tmux, which breaks the ppid chain at 12 12 + the (session-global) tmux server, so the walk also hops tmux pane -> session -> 13 13 + attached client pid and continues from there. 14 14 + 15 15 + Windows whose ancestry cannot be resolved (systemd user services, dbus 16 16 + activation, single-process multi-window apps like Firefox) keep sway's default 17 17 + behaviour. 18 18 + """ 19 19 + 20 20 + from __future__ import annotations 21 21 + 22 22 + import json 23 23 + import subprocess 24 24 + import sys 25 25 + from collections.abc import Iterator 26 26 + from typing import Any 27 27 + 28 28 + # Sway's hidden scratchpad workspace; views parked there must never be moved, 29 29 + # and a view living there is not a placement hint for anything else. 30 30 + SCRATCHPAD = "__i3_scratch" 31 31 + 32 32 + 33 33 + def run(args: list[str]) -> str | None: 34 34 + """Run a command, returning its stdout, or None when it failed.""" 35 35 + try: 36 36 + proc = subprocess.run(args, capture_output=True, text=True, check=False) 37 37 + except OSError as e: 38 38 + print(f"failed to run {args[0]}: {e}", file=sys.stderr) 39 39 + return None 40 40 + if proc.returncode != 0: 41 41 + return None 42 42 + return proc.stdout 43 43 + 44 44 + 45 45 + def swaymsg_json(*args: str) -> Any: 46 46 + """Query sway IPC, returning the parsed reply or None.""" 47 47 + out = run(["swaymsg", "-r", "-t", *args]) 48 48 + if out is None: 49 49 + return None 50 50 + try: 51 51 + return json.loads(out) 52 52 + except json.JSONDecodeError as e: 53 53 + print(f"failed to parse sway reply: {e}", file=sys.stderr) 54 54 + return None 55 55 + 56 56 + 57 57 + def iter_views( 58 58 + node: dict[str, Any], workspace: str | None 59 59 + ) -> Iterator[tuple[str, int, int]]: 60 60 + """Yield (workspace name, container id, pid) for every view in the tree.""" 61 61 + if node.get("type") == "workspace": 62 62 + workspace = node.get("name") 63 63 + pid = node.get("pid") 64 64 + if pid is not None and workspace is not None: 65 65 + yield workspace, int(node["id"]), int(pid) 66 66 + for key in ("nodes", "floating_nodes"): 67 67 + for child in node.get(key, []): 68 68 + yield from iter_views(child, workspace) 69 69 + 70 70 + 71 71 + def parent_pid(pid: int) -> int | None: 72 72 + """Read PPid from /proc, or None if the process is gone.""" 73 73 + try: 74 74 + with open(f"/proc/{pid}/status", encoding="utf-8") as f: 75 75 + for line in f: 76 76 + if line.startswith("PPid:"): 77 77 + return int(line.split()[1]) 78 78 + except (OSError, ValueError): 79 79 + return None 80 80 + return None 81 81 + 82 82 + 83 83 + def tmux_hops() -> dict[int, list[int]]: 84 84 + """Map each tmux pane's root pid to the pids of its session's clients. 85 85 + 86 86 + A process started inside a pane has that pane's root pid as an ancestor, 87 87 + but its ppid chain leads to the tmux server, not to the terminal window. 88 88 + The attached client processes are children of that terminal, so they are 89 89 + where the walk has to continue. 90 90 + """ 91 91 + panes = run(["tmux", "list-panes", "-a", "-F", "#{pane_pid} #{session_id}"]) 92 92 + clients = run(["tmux", "list-clients", "-F", "#{client_pid} #{session_id}"]) 93 93 + if not panes or not clients: 94 94 + return {} 95 95 + session_clients: dict[str, list[int]] = {} 96 96 + for line in clients.splitlines(): 97 97 + pid, _, session = line.partition(" ") 98 98 + try: 99 99 + session_clients.setdefault(session, []).append(int(pid)) 100 100 + except ValueError: 101 101 + continue 102 102 + hops: dict[int, list[int]] = {} 103 103 + for line in panes.splitlines(): 104 104 + pid, _, session = line.partition(" ") 105 105 + try: 106 106 + hops[int(pid)] = session_clients.get(session, []) 107 107 + except ValueError: 108 108 + continue 109 109 + return hops 110 110 + 111 111 + 112 112 + def resolve_workspace( 113 113 + pid: int, 114 114 + pid_workspaces: dict[int, str], 115 115 + hops: dict[int, list[int]], 116 116 + visited: set[int], 117 117 + ) -> str | None: 118 118 + """Find the workspace of the nearest ancestor process that owns a window.""" 119 119 + current: int | None = pid 120 120 + while current is not None and current > 1: 121 121 + if current in visited: 122 122 + return None 123 123 + visited.add(current) 124 124 + workspace = pid_workspaces.get(current) 125 125 + if workspace is not None: 126 126 + return workspace 127 127 + for client in hops.get(current, []): 128 128 + workspace = resolve_workspace(client, pid_workspaces, hops, visited) 129 129 + if workspace is not None: 130 130 + return workspace 131 131 + current = parent_pid(current) 132 132 + return None 133 133 + 134 134 + 135 135 + def quote(name: str) -> str: 136 136 + """Quote a workspace name for a sway command.""" 137 137 + escaped = name.replace("\\", "\\\\").replace('"', '\\"') 138 138 + return f'"{escaped}"' 139 139 + 140 140 + 141 141 + def handle_new_window(container_id: int, pid: int) -> None: 142 142 + """Move a freshly mapped view to the workspace of its spawning process.""" 143 143 + tree = swaymsg_json("get_tree") 144 144 + if tree is None: 145 145 + return 146 146 + 147 147 + origin: str | None = None 148 148 + pid_workspaces: dict[int, str] = {} 149 149 + for workspace, view_id, view_pid in iter_views(tree, None): 150 150 + if view_id == container_id: 151 151 + origin = workspace 152 152 + continue 153 153 + # Views of the same process are no hint: a single-process multi-window 154 154 + # app (Firefox) would drag every new window to an unrelated workspace. 155 155 + if view_pid == pid or workspace.startswith(SCRATCHPAD): 156 156 + continue 157 157 + pid_workspaces.setdefault(view_pid, workspace) 158 158 + 159 159 + if origin is None or origin.startswith(SCRATCHPAD): 160 160 + # Window already closed again, or parked in the scratchpad by a 161 161 + # for_window rule (the workspace-manager Firefox anchor). 162 162 + return 163 163 + 164 164 + target = resolve_workspace(pid, pid_workspaces, tmux_hops(), set()) 165 165 + if target is None or target == origin: 166 166 + return 167 167 + 168 168 + print( 169 169 + f"moving container {container_id} (pid {pid}): {origin} -> {target}", 170 170 + file=sys.stderr, 171 171 + ) 172 172 + run( 173 173 + [ 174 174 + "swaymsg", 175 175 + "--", 176 176 + f"[con_id={container_id}] move container to workspace {quote(target)}", 177 177 + ] 178 178 + ) 179 179 + 180 180 + 181 181 + def main() -> int: 182 182 + """Subscribe to sway window events and place new windows.""" 183 183 + proc = subprocess.Popen( 184 184 + ["swaymsg", "-t", "subscribe", "-m", '["window"]'], 185 185 + stdout=subprocess.PIPE, 186 186 + text=True, 187 187 + ) 188 188 + if proc.stdout is None: 189 189 + print("no stdout from swaymsg subscribe", file=sys.stderr) 190 190 + return 1 191 191 + 192 192 + for line in proc.stdout: 193 193 + try: 194 194 + event: dict[str, Any] = json.loads(line) 195 195 + except json.JSONDecodeError as e: 196 196 + print(f"failed to parse sway event: {e}", file=sys.stderr) 197 197 + continue 198 198 + if event.get("change") != "new": 199 199 + continue 200 200 + container: dict[str, Any] = event.get("container") or {} 201 201 + pid = container.get("pid") 202 202 + container_id = container.get("id") 203 203 + if pid is None or container_id is None: 204 204 + continue 205 205 + handle_new_window(int(container_id), int(pid)) 206 206 + 207 207 + return proc.wait() 208 208 + 209 209 + 210 210 + if __name__ == "__main__": 211 211 + sys.exit(main())

+38

tools/sway-spawn-workspace/flake-module.nix

View file Reviewed

··· 1 1 + { ... }: 2 2 + { 3 3 + perSystem = 4 4 + { pkgs, ... }: 5 5 + let 6 6 + python = pkgs.python3; 7 7 + in 8 8 + { 9 9 + packages.sway-spawn-workspace = pkgs.stdenv.mkDerivation { 10 10 + pname = "sway-spawn-workspace"; 11 11 + version = "0.1.0"; 12 12 + src = ./.; 13 13 + nativeBuildInputs = [ 14 14 + pkgs.makeWrapper 15 15 + pkgs.ruff 16 16 + python.pkgs.mypy 17 17 + ]; 18 18 + doCheck = true; 19 19 + checkPhase = '' 20 20 + runHook preCheck 21 21 + ruff check daemon.py 22 22 + ruff format --check daemon.py 23 23 + mypy --strict daemon.py 24 24 + runHook postCheck 25 25 + ''; 26 26 + installPhase = '' 27 27 + runHook preInstall 28 28 + mkdir -p $out/bin 29 29 + cp daemon.py $out/bin/sway-spawn-workspace 30 30 + chmod +x $out/bin/sway-spawn-workspace 31 31 + wrapProgram $out/bin/sway-spawn-workspace \ 32 32 + --prefix PATH : ${python}/bin:${pkgs.sway}/bin:${pkgs.tmux}/bin 33 33 + runHook postInstall 34 34 + ''; 35 35 + meta.mainProgram = "sway-spawn-workspace"; 36 36 + }; 37 37 + }; 38 38 + }

+15

2configs/desktops/sway/default.nix

View file Reviewed

··· 93 93 }; 94 94 }; 95 95 96 96 + # Keep new windows on the workspace of the process that spawned them instead 97 97 + # of the focused one (sway only tracks this for its own `exec`, and only for 98 98 + # 60s). 99 99 + systemd.user.services.sway-spawn-workspace = { 100 100 + description = "Place new windows on their spawning process's workspace"; 101 101 + partOf = [ "sway-session.target" ]; 102 102 + wantedBy = [ "sway-session.target" ]; 103 103 + serviceConfig = { 104 104 + Type = "simple"; 105 105 + ExecStart = lib.getExe self.packages.${pkgs.system}.sway-spawn-workspace; 106 106 + Restart = "on-failure"; 107 107 + RestartSec = 2; 108 108 + }; 109 109 + }; 110 110 + 96 111 # Inhibit idle when audio is playing (prevents suspend during calls/music) 97 112 systemd.user.services.sway-audio-idle-inhibit = { 98 113 description = "Inhibit idle when audio is playing";