Files
Classroom_Desktop/scripts/classroom-parent-call
T
ekklesiaandClaude Opus 5 34fd02e08f feat: give every room the broker, one scale, and its own panel back
Little Waders took the Plasma build and reported what a container
cannot. A disc player on a machine with no optical drive, a clock nobody
at the back of the room could read, a browser at half the size of the
panel around it, and Parent Call with no broker to call.

The broker is the same for every classroom, so it is a default now and
not something to fill in room by room. classroom-migrate brings an
existing room to the same place without touching its name, its username
or its password, and Parent Call distinguishes a broker it cannot reach
from one that was never set up: those send somebody to look at
completely different things.

The disc player's detection was right and ran too late — alongside the
session rather than before it, and the panel is built from the layout the
moment a session starts. It runs before the display manager now, and
again from udev when a drive is plugged in.

UI_SCALE had a ceiling of 1.5, which cannot express a 4K television; a
clock pinned at 15 points, which is the same size at every scale; and a
browser that was never told the number at all. All three are fixed and
the room doubles together at 200%.

This also brings 0.1.47's work into the repository, where it had only
ever existed in a build directory under /tmp: the hidden display dialog,
its authenticated writer, the polkit action, and the church's own
wallpaper. One piece of it is deliberately left out. The custom volume
display needed a shell package of our own, and with one selected
plasmashell builds no panel at all — measured twice, with that build's
own files, on a classroom that deletes its panel configuration at every
login by design.

The lab connected to the real church broker the moment the package
defaulted to it. Nothing was left behind, which was checked, but the
guard that should have stopped it had never worked: it used iptables,
which the lab image does not have, and probed with /dev/tcp under dash,
where that always fails. Both reported success.

Co-Authored-By: Claude Opus 5 <[email protected]>
2026-09-12 19:05:09 -05:00

766 lines
26 KiB
Python
Executable File

#!/usr/bin/env python3
"""Ask the sanctuary to call a child's parent.
A quick action, not an application. The panel launches this, it puts one
small card on the screen, and it goes away again. Everything it knows
about the church end comes from the Parent Call coordinator's own MQTT
contract; see classroom_parent_call for the contract itself.
Why this is a separate process, and not a Plasma applet:
the panel is the only way a teacher has of getting anywhere, and a
broker library, a network timeout and a text entry have no business
living inside it. If this crashes, the bar is untouched and clicking
the button again starts a new one.
Two rules it will not bend:
* a teacher is never told a call succeeded unless the coordinator
said so, and the strongest thing the coordinator ever says is
"Sent to sanctuary" — never "displayed";
* nothing is published until the status topic for that request is
already subscribed, so an answer cannot arrive before anyone is
listening.
"""
import os
import sys
import threading
import time
import gi
gi.require_version("Gtk", "3.0")
# Gdk has to be pinned too. Without it PyGObject warns that it may load a
# different major version than Gtk, and the key constants this file
# compares against would then be somebody else's.
gi.require_version("Gdk", "3.0")
from gi.repository import Gdk, GLib, Gtk # noqa: E402
sys.path.insert(0, "/usr/local/lib/ekklesia-classroom")
sys.path.insert(
0,
os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "lib"),
)
import classroom_parent_call as contract # noqa: E402
from classroom_config import read_device_config # noqa: E402
from classroom_mqtt import room_name # noqa: E402
APP_ID = "classroom-parent-call"
# How long to wait for the broker before telling the teacher the church
# network cannot be reached. Short: a teacher standing at the machine
# would rather be told quickly than watch a spinner.
CONNECT_TIMEOUT = 5.0
# Retained topics arrive immediately after subscribing, or never. This is
# how long "never" takes to establish.
RETAINED_GRACE = 1.5
# The coordinator answers a request almost at once. Silence for this long
# means it did not hear us, which is not the same as a refusal and is not
# reported as one.
FIRST_STATUS_TIMEOUT = 8.0
# Once it has answered, it may legitimately take as long as its own
# request expiry to finish — an operator has to approve. Its REQUEST_TTL
# is 180s; this is that with room to spare.
OVERALL_TIMEOUT = 210.0
# Long enough for a teacher to read "Sent to sanctuary" and walk away.
CLOSE_AFTER_SUCCESS = 4.0
def load_colours():
"""The session's own palette, read from the colour scheme in use.
There is one set of design tokens in this classroom, and they live in
a Plasma colour scheme. Reading them here rather than repeating them
means this card follows classroom-theme light and dark without
knowing that either exists.
"""
palette = {
"window": "#141c20", "view": "#0f171a", "text": "#e6edef",
"dim": "#93a5aa", "accent": "#4fb3a8", "on_accent": "#0e1518",
"negative": "#e36a6a", "neutral": "#e0b15c", "positive": "#6fcf97",
"line": "#25333a",
}
scheme = "EkklesiaDark"
for path in (
os.path.expanduser("~/.config/kdeglobals"),
"/etc/ekklesia-classroom/xdg/kdeglobals",
"/etc/xdg/kdeglobals",
):
try:
with open(path, "r", encoding="utf-8") as handle:
section = None
for line in handle:
line = line.strip()
if line.startswith("["):
section = line
elif section and section.startswith("[General]") and \
line.startswith("ColorScheme="):
scheme = line.split("=", 1)[1].strip()
break
except OSError:
continue
else:
if scheme:
break
def rgb(value):
parts = [part.strip() for part in value.split(",")]
if len(parts) != 3:
return None
try:
return "#%02x%02x%02x" % tuple(int(part) for part in parts)
except ValueError:
return None
try:
with open(f"/usr/share/color-schemes/{scheme}.colors", "r",
encoding="utf-8") as handle:
group = None
for line in handle:
line = line.strip()
if line.startswith("["):
group = line
continue
if "=" not in line or group is None:
continue
key, value = (part.strip() for part in line.split("=", 1))
colour = rgb(value)
if colour is None:
continue
if group == "[Colors:Window]":
if key == "BackgroundNormal":
palette["window"] = colour
elif key == "ForegroundNormal":
palette["text"] = colour
elif key == "ForegroundInactive":
palette["dim"] = colour
elif key == "ForegroundNegative":
palette["negative"] = colour
elif key == "ForegroundNeutral":
palette["neutral"] = colour
elif key == "ForegroundPositive":
palette["positive"] = colour
elif key == "BackgroundAlternate":
palette["line"] = colour
elif group == "[Colors:View]" and key == "BackgroundNormal":
palette["view"] = colour
elif group == "[Colors:Selection]":
if key == "BackgroundNormal":
palette["accent"] = colour
elif key == "ForegroundNormal":
palette["on_accent"] = colour
except OSError:
pass
return palette
STYLE = """
* {{ font-family: "Noto Sans", "DejaVu Sans", sans-serif; }}
/* The card draws its own corners, so the window behind it is nothing at
all. Rounding a window any other way would mean asking the compositor
for something, and this one is ours to draw. */
window {{ background-color: transparent; }}
#card {{
background-color: {window};
border: 1px solid {line};
border-radius: 12px;
padding: 24px 26px 20px 26px;
margin: 10px;
}}
#title {{ color: {text}; font-size: 17px; font-weight: 600; }}
#room {{ color: {accent}; font-size: 13px; font-weight: 600;
letter-spacing: 0.06em; }}
#hint {{ color: {dim}; font-size: 12px; }}
#status {{ color: {text}; font-size: 15px; font-weight: 600; }}
#detail {{ color: {dim}; font-size: 12px; }}
#child {{ color: {dim}; font-size: 13px; }}
#status.good {{ color: {positive}; }}
#status.bad {{ color: {negative}; }}
#status.waiting {{ color: {neutral}; }}
entry {{
background-color: {view};
color: {text};
border: 1px solid {line};
border-radius: 8px;
padding: 10px 12px;
font-size: 16px;
caret-color: {accent};
}}
entry:focus {{ border-color: {accent}; }}
entry:disabled {{ color: {dim}; }}
button {{
border-radius: 8px;
padding: 9px 18px;
font-size: 14px;
font-weight: 600;
border: 1px solid {line};
background-image: none;
background-color: transparent;
color: {text};
}}
button:hover {{ background-color: {line}; }}
button#primary {{
background-color: {accent};
color: {on_accent};
border-color: {accent};
}}
/* Disabled has to read as "not yet", not as a broken button: the accent
drains out of it rather than the whole thing fading. */
button#primary:disabled {{
background-color: transparent;
color: {dim};
border-color: {line};
}}
"""
class Broker(threading.Thread):
"""The MQTT half, kept off the interface thread.
Every callback hands its result to GTK with GLib.idle_add and touches
no widget itself.
"""
def __init__(self, config, topics, on_event):
super().__init__(daemon=True)
self.config = config
self.topics = topics
self.on_event = on_event
self.client = None
self.request_id = None
self._pending = None
self._lock = threading.Lock()
# -- lifecycle -----------------------------------------------------
def run(self):
try:
import paho.mqtt.client as mqtt
except ImportError:
self.emit("broker", reachable=False, why="no broker library")
return
host = (self.config.get("MQTT_HOST") or "").strip()
if not host or (self.config.get("MQTT_ENABLED") or "").strip().lower() \
not in ("1", "true", "yes", "on"):
self.emit("broker", reachable=False, why="not configured")
return
try:
port = int((self.config.get("MQTT_PORT") or "1883").strip())
except ValueError:
port = 1883
# A clean session on purpose. Nothing from a previous connection
# may be redelivered: a parent call from last Sunday arriving now
# would be worse than one that was lost.
try:
client = mqtt.Client(
mqtt.CallbackAPIVersion.VERSION2,
client_id=f"classroom-parent-call-{os.getpid()}",
clean_session=True,
)
except (AttributeError, TypeError):
client = mqtt.Client(
client_id=f"classroom-parent-call-{os.getpid()}",
clean_session=True,
)
username = (self.config.get("MQTT_USERNAME") or "").strip()
if username:
client.username_pw_set(
username, (self.config.get("MQTT_PASSWORD") or "").strip() or None
)
client.on_connect = self._connected
client.on_message = self._message
client.on_disconnect = self._disconnected
self.client = client
try:
client.connect(host, port, keepalive=30)
except (OSError, ValueError) as error:
self.emit("broker", reachable=False, why=str(error))
return
client.loop_forever(retry_first_connection=False)
def stop(self):
client = self.client
if client is not None:
try:
client.disconnect()
except Exception:
pass
# -- callbacks -----------------------------------------------------
def _connected(self, client, userdata, flags, reason_code, properties=None):
if getattr(reason_code, "is_failure", False) or \
(isinstance(reason_code, int) and reason_code != 0):
self.emit("broker", reachable=False, why=f"refused ({reason_code})")
return
client.subscribe([(self.topics.mode, 1), (self.topics.coordinator, 1)])
self.emit("broker", reachable=True)
def _disconnected(self, client, userdata, *args):
self.emit("disconnected")
def _message(self, client, userdata, message):
if message.topic == self.topics.mode:
self.emit("mode", mode=contract.read_mode(message.payload))
elif message.topic == self.topics.coordinator:
self.emit("coordinator",
online=contract.read_coordinator(message.payload))
elif self.request_id and message.topic == self.topics.status(self.request_id):
update = contract.read_status(message.payload, self.request_id)
if update:
self.emit("status", update=update)
# -- sending -------------------------------------------------------
def send(self, request_id, room, child):
"""Subscribe first, publish second. Never the other way round."""
client = self.client
if client is None:
self.emit("send-failed", why="not connected")
return
with self._lock:
self.request_id = request_id
body = contract.request_payload(request_id, room, child)
import json
def after_subscribe(_client, _userdata, _mid, _codes, _properties=None):
# QoS 1 so the coordinator's answer is not lost on a flaky
# link, and never retained: a request is an event.
client.publish(self.topics.request, json.dumps(body), qos=1,
retain=False)
self.emit("published")
client.on_subscribe = after_subscribe
client.subscribe(self.topics.status(request_id), qos=1)
def emit(self, kind, **data):
GLib.idle_add(self.on_event, kind, data)
class ParentCall(Gtk.Window):
def __init__(self):
super().__init__(title="Parent Call")
self.config = read_device_config()
self.room = room_name(self.config)
self.topics = contract.Topics(
(self.config.get("PARENT_CALL_ROOT") or contract.DEFAULT_ROOT).strip()
)
self.mode = None
self.coordinator_online = False
self.broker_reachable = None
self.request_id = None
self.sent_at = None
self.settled = False
self.autosend = False
self._timers = []
self.set_decorated(False)
self.set_titlebar(Gtk.Box())
self.set_resizable(False)
self.set_default_size(460, -1)
# Deliberately not set_position(): a Wayland client cannot place
# itself, and asking for the centre put the card in the top-left
# corner instead. KWin centres it, because kwinrc already asks for
# every window to be centred — no rule of its own is needed, and
# the one that was written for it turned out to be doing nothing.
self.set_type_hint(Gdk.WindowTypeHint.DIALOG)
# Belt and braces with the window rule: whichever of the two KWin
# honours, the card must not end up behind the lesson a teacher
# was reading when they pressed the button.
self.set_keep_above(True)
screen = self.get_screen()
visual = screen.get_rgba_visual()
if visual is not None:
self.set_visual(visual)
self.set_app_paintable(True)
self._build()
self._apply_style()
self.connect("key-press-event", self._key)
self.connect("destroy", lambda *_: self._quit())
self.broker = Broker(self.config, self.topics, self._event)
self.broker.start()
self._after(CONNECT_TIMEOUT, self._connect_deadline)
# -- interface -----------------------------------------------------
def _build(self):
card = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=14)
card.set_name("card")
heading = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL, spacing=10)
title = Gtk.Label(label="Parent Call", xalign=0)
title.set_name("title")
heading.pack_start(title, False, False, 0)
# The room is stated, never asked. This machine already knows
# which room it is, and a teacher picking it from a list is a
# chance to pick the wrong one.
room = Gtk.Label(label=self.room.upper(), xalign=0)
room.set_name("room")
room.set_valign(Gtk.Align.CENTER)
heading.pack_end(room, False, False, 0)
card.pack_start(heading, False, False, 0)
self.hint = Gtk.Label(
label="Who should we call a parent for?", xalign=0)
self.hint.set_name("hint")
card.pack_start(self.hint, False, False, 0)
self.entry = Gtk.Entry()
self.entry.set_placeholder_text("Child's name")
self.entry.set_max_length(contract.MAX_CHILD)
self.entry.set_sensitive(False)
self.entry.connect("activate", lambda *_: self._send())
self.entry.connect("changed", lambda *_: self._refresh_button())
card.pack_start(self.entry, False, False, 0)
self.status = Gtk.Label(label="", xalign=0)
self.status.set_name("status")
self.status.set_line_wrap(True)
self.status.set_no_show_all(True)
card.pack_start(self.status, False, False, 0)
self.detail = Gtk.Label(label="", xalign=0)
self.detail.set_name("detail")
self.detail.set_line_wrap(True)
self.detail.set_no_show_all(True)
card.pack_start(self.detail, False, False, 0)
buttons = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL, spacing=10)
buttons.set_halign(Gtk.Align.END)
self.close_button = Gtk.Button(label="Close")
self.close_button.connect("clicked", lambda *_: self._quit())
buttons.pack_start(self.close_button, False, False, 0)
self.primary = Gtk.Button(label="Call parent")
self.primary.set_name("primary")
self.primary.set_sensitive(False)
self.primary.connect("clicked", lambda *_: self._send())
buttons.pack_start(self.primary, False, False, 0)
card.pack_start(buttons, False, False, 0)
card.set_size_request(440, -1)
self.add(card)
card.show_all()
self.entry.grab_focus()
self._set_status("Checking with the sanctuary…", tone=None)
def _apply_style(self):
css = Gtk.CssProvider()
css.load_from_data(STYLE.format(**load_colours()).encode("utf-8"))
Gtk.StyleContext.add_provider_for_screen(
self.get_screen(), css, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION
)
def _set_status(self, text, tone=None, detail=None):
style = self.status.get_style_context()
for name in ("good", "bad", "waiting"):
style.remove_class(name)
if tone:
style.add_class(tone)
self.status.set_text(text or "")
self.status.set_visible(bool(text))
self.detail.set_text(detail or "")
self.detail.set_visible(bool(detail))
def _refresh_button(self):
ready = (
self.request_id is None
and self.broker_reachable
and contract.clean_child(self.entry.get_text()) is not None
and contract.availability(
self.mode, self.coordinator_online, self.broker_reachable
)[0]
)
self.primary.set_sensitive(bool(ready))
def _unavailable(self, message):
self.settled = True
self.entry.set_sensitive(False)
self.primary.hide()
self.hint.hide()
self.entry.hide()
self.close_button.set_label("Close")
self._set_status(message, tone="bad")
# -- events --------------------------------------------------------
def _event(self, kind, data):
if kind == "broker":
self.broker_reachable = data.get("reachable")
if not self.broker_reachable:
# Why it is not there decides who the teacher should
# fetch, so the reason the broker thread already knows is
# carried through to the card rather than flattened.
self._unavailable(contract.broker_message(data.get("why")))
else:
self._after(RETAINED_GRACE, self._retained_deadline)
elif kind == "mode":
self.mode = data.get("mode")
self._settle()
elif kind == "coordinator":
self.coordinator_online = bool(data.get("online"))
self._settle()
elif kind == "status":
self._status_arrived(data["update"])
elif kind == "published":
self.sent_at = time.monotonic()
self._after(FIRST_STATUS_TIMEOUT, self._first_status_deadline)
elif kind == "send-failed":
self._set_status("The call was not sent", tone="bad",
detail="Press Call parent to try again.")
self.request_id = None
self._refresh_button()
return False
def _settle(self, final=False):
"""Decide what to offer, once the retained topics have spoken.
A negative is only ever reached with final=True. The mode and the
coordinator's availability are two separate retained messages and
they arrive in whichever order the broker sends them — deciding on
the first one told a teacher the sanctuary was down while the
message saying otherwise was still in flight. Measured, in the
lab, on a coordinator that was demonstrably up.
"""
if self.request_id is not None or self.settled:
return
can, why = contract.availability(
self.mode, self.coordinator_online, self.broker_reachable
)
if can:
self.entry.set_sensitive(True)
self.entry.grab_focus()
note = ("A volunteer will approve it first."
if self.mode == contract.MODE_APPROVAL else None)
self._set_status("", tone=None, detail=note)
self.settled = True
self._refresh_button()
if self.autosend:
self.autosend = False
GLib.timeout_add(300, lambda: (self._send(), False)[1])
elif final and why:
self._unavailable(why)
def _status_arrived(self, update):
self._set_status(
update["message"],
tone=("good" if update["good"]
else "bad" if update["terminal"]
else "waiting"),
detail=update.get("detail"),
)
if not update["terminal"]:
return
# Terminal: stop listening, as the coordinator's contract asks.
self.broker.request_id = None
if update["good"]:
self.close_button.hide()
self._after(CLOSE_AFTER_SUCCESS, self._quit)
else:
self.request_id = None
self.entry.set_sensitive(True)
self.entry.show()
self.hint.hide()
self.primary.set_label("Try again")
self.primary.show()
self._refresh_button()
# -- sending -------------------------------------------------------
def _send(self):
if self.request_id is not None:
return
child = contract.clean_child(self.entry.get_text())
if child is None:
self._set_status("Enter the child's name", tone="bad")
return
can, why = contract.availability(
self.mode, self.coordinator_online, self.broker_reachable
)
if not can:
self._unavailable(why or contract.WORDING[contract.UNAVAILABLE])
return
self.request_id = contract.new_request_id(self.room)
self.entry.set_sensitive(False)
self.primary.set_sensitive(False)
self.primary.hide()
self.hint.set_text(f"Calling a parent for {child}")
self.hint.show()
self._set_status("Sending", tone="waiting")
self.broker.send(self.request_id, self.room, child)
self._after(OVERALL_TIMEOUT, self._overall_deadline)
# -- deadlines -----------------------------------------------------
def _after(self, seconds, callback):
self._timers.append(GLib.timeout_add(int(seconds * 1000), callback))
def _connect_deadline(self):
if self.broker_reachable is None:
self._unavailable("Cannot reach the church network")
return False
def _retained_deadline(self):
# Retained topics arrive at once or not at all. Now that both have
# had their chance, a negative is safe to show.
self._settle(final=True)
if not self.settled:
self._unavailable("Parent Call has not been set up yet")
return False
def _first_status_deadline(self):
if self.request_id is not None and self.status.get_text() == "Sending":
# Silence is not a refusal, and is not reported as one.
self._set_status("No answer from the sanctuary", tone="bad",
detail="The call was not confirmed. "
"Press Try again, or ask for help.")
self.request_id = None
self.entry.set_sensitive(True)
self.primary.set_label("Try again")
self.primary.show()
self._refresh_button()
return False
def _overall_deadline(self):
if self.request_id is not None:
self._set_status("No answer from the sanctuary", tone="bad",
detail="The call was not confirmed.")
self.request_id = None
self.primary.set_label("Try again")
self.primary.show()
self._refresh_button()
return False
# -- leaving -------------------------------------------------------
def _key(self, _widget, event):
"""Escape leaves. Nothing else does.
Deliberately narrow: an earlier version compared against a Gdk
that had not been version-pinned, and in the lab an ordinary
letter closed the card.
"""
if event.keyval == Gdk.KEY_Escape and not event.state & (
Gdk.ModifierType.CONTROL_MASK | Gdk.ModifierType.MOD1_MASK
):
self._quit()
return True
return False
def _quit(self, *_):
for timer in self._timers:
GLib.source_remove(timer)
self._timers = []
self.broker.stop()
Gtk.main_quit()
return False
def main():
GLib.set_prgname(APP_ID)
GLib.set_application_name("Parent Call")
# --child fills the name in, and --send presses the button once the
# sanctuary has answered for whether it may be pressed. Only the lab
# uses them: there is no teacher-facing path to either, and neither
# can send a call the coordinator would not have accepted anyway.
child = None
autosend = "--send" in sys.argv
if "--child" in sys.argv:
index = sys.argv.index("--child") + 1
if index < len(sys.argv):
child = sys.argv[index]
window = ParentCall()
if child:
window.entry.set_text(child)
if autosend:
window.autosend = True
window.show()
Gtk.main()
return 0
if __name__ == "__main__":
sys.exit(main())