notification service initial

README.md

@@ -184,7 +184,9 @@ Kernel       7.2.11-arch1-1
 Last update  2026-10-22 13:43
 ```
 
-The kernel comes from Arch, so it's shown separately. If a newer kernel is waiting for a reboot, "version" says so.
+The kernel comes from Arch, so it's shown separately. If a newer kernel is waiting for a reboot, "version" says so. It also tells you if a newer version of CoreDesktop is available.
+
+You don't have to check by hand: a few minutes after you log in, and every few hours after that, CoreDesktop checks for a new version and shows a notification if there is one. Click it to run "update" in a terminal, or dismiss it. Once dismissed, you won't be notified again until there's an even newer version.
 
 ### Sibling projects
 

install.sh

@@ -190,6 +190,10 @@ bash ~/.local/share/coredesktop/system/nvidia.sh
 echo "Configuring the shell..."
 bash ~/.local/share/coredesktop/shell/setup.sh
 
+# Notify in GNOME when a new version of CoreDesktop is available
+echo "Configuring update notifications..."
+bash ~/.local/share/coredesktop/system/update-notify.sh
+
 # Apply GNOME dconf settings only if the settings file has changed since last run
 bash ~/.local/share/coredesktop/gnome/apply-gnome-settings.sh
 

system/systemd/coredesktop-update-check.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=Notify when a new version of CoreDesktop is available
+# Notifications need a desktop session to show in
+ConditionEnvironment=|WAYLAND_DISPLAY
+ConditionEnvironment=|DISPLAY
+
+[Service]
+# Not oneshot: the script waits, without a time limit, for the notification
+# to be clicked or dismissed
+Type=simple
+ExecStart=%h/.local/share/coredesktop/system/update-check

system/systemd/coredesktop-update-check.timer

@@ -0,0 +1,11 @@
+[Unit]
+Description=Check for a new version of CoreDesktop every few hours
+
+[Timer]
+OnStartupSec=5min
+# Counted from when the last check finished, so a notification left open for
+# hours doesn't have another check queued up behind it
+OnUnitInactiveSec=4h
+
+[Install]
+WantedBy=timers.target

system/update-check

@@ -0,0 +1,52 @@
+#!/bin/bash
+#
+# Purpose : Show a GNOME notification when a newer CoreDesktop is available.
+#           Clicking it (or its "Update now" button) runs update in a terminal.
+#           Run by coredesktop-update-check.timer (see system/update-notify.sh).
+
+# Wrapped in { ...; exit; } so bash reads the whole script up front; update
+# replaces this file (git pull) while the notification is waiting for a click.
+{
+
+# The newest version the user has been told about. Dismissing a notification
+# means not hearing about that version again, only about a newer one.
+NOTIFIED="$HOME/.local/state/coredesktop/update-notified"
+
+latest="$("$HOME/.local/bin/version" --check)" || exit 0
+[ "$(cat "$NOTIFIED" 2> /dev/null)" = "$latest" ] && exit 0
+
+# Waits until the notification is clicked or dismissed, then prints the action
+# ("default" is a click on the notification itself, empty if dismissed)
+action="$(notify-send --wait \
+  --app-name=CoreDesktop \
+  --icon=software-update-available \
+  --action=default=Update \
+  --action=update="Update now" \
+  "CoreDesktop update available" \
+  "Version $latest is ready. Click to run update.")" || exit 0
+
+mkdir -p "$(dirname "$NOTIFIED")"
+echo "$latest" > "$NOTIFIED"
+
+[ "$action" = "default" ] || [ "$action" = "update" ] || exit 0
+
+# Open the first terminal found. bash -i reads ~/.bashrc, as if the user had
+# typed update themselves, and the window stays open to show how it went.
+run_update=(bash -ic 'update; echo; read -rp "Press Enter to close this window."')
+if command -v xdg-terminal-exec &> /dev/null; then
+  terminal=(xdg-terminal-exec)
+elif command -v kgx &> /dev/null; then
+  terminal=(kgx --)
+elif command -v ghostty &> /dev/null; then
+  terminal=(ghostty -e)
+elif command -v kitty &> /dev/null; then
+  terminal=(kitty)
+else
+  notify-send --app-name=CoreDesktop "No terminal found" "Open a terminal and run update."
+  exit 1
+fi
+
+# Run the terminal as its own unit: when this service exits, systemd stops
+# everything still running in it, which would close the terminal mid-update
+exec systemd-run --user --quiet --collect -- "${terminal[@]}" "${run_update[@]}"
+}

system/update-notify.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+#
+# Purpose : Install and enable the timer that checks for a new version of
+#           CoreDesktop and shows a GNOME notification (system/update-check).
+#           Run by install.sh and on every update (updates.d/16-update-notify.sh)
+#           so changes to the units reach existing machines.
+
+set -e
+
+COREDESKTOP="$HOME/.local/share/coredesktop"
+UNITS="$HOME/.config/systemd/user"
+
+mkdir -p "$UNITS"
+cp "$COREDESKTOP"/system/systemd/coredesktop-update-check.{service,timer} "$UNITS/"
+systemctl --user daemon-reload
+systemctl --user enable --now coredesktop-update-check.timer

updates.d/16-update-notify.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+COREDESKTOP="$HOME/.local/share/coredesktop"
+
+run_update() {
+  bash "$COREDESKTOP/system/update-notify.sh"
+}

version

@@ -6,6 +6,9 @@
 # the local checkout is on, plus the short hash to tell same-day commits apart,
 # e.g. 2026.10.22 (c5f0651). The kernel is shown separately because it comes
 # from Arch, not CoreDesktop.
+#
+# version --check prints the newer version and exits 0 if one is available,
+# exits 1 if this machine is up to date, or 2 if it couldn't check.
 
 COREDESKTOP="$HOME/.local/share/coredesktop"
 
@@ -13,16 +16,40 @@ source "$COREDESKTOP/utils.sh"
 
 if ! git -C "$COREDESKTOP" rev-parse --git-dir &> /dev/null; then
   echo "CoreDesktop isn't installed in $COREDESKTOP."
-  exit 1
+  exit 2
 fi
 
-version="$(git -C "$COREDESKTOP" log -1 --format='%cd (%h)' --date=format:%Y.%m.%d)"
+# Version string for a commit, e.g. 2026.10.22 (c5f0651)
+describe() {
+  git -C "$COREDESKTOP" log -1 --format='%cd (%h)' --date=format:%Y.%m.%d "$1"
+}
+
+# Print the newer version if the remote has commits this checkout doesn't.
+# Returns 1 if up to date, 2 if the remote couldn't be reached.
+newer_version() {
+  GIT_TERMINAL_PROMPT=0 timeout 30 git -C "$COREDESKTOP" fetch --quiet &> /dev/null || return 2
+  local behind
+  behind="$(git -C "$COREDESKTOP" rev-list --count 'HEAD..@{upstream}' 2> /dev/null)" || return 2
+  (( behind > 0 )) || return 1
+  describe '@{upstream}'
+}
+
+if [ "$1" = "--check" ]; then
+  newer_version
+  exit
+fi
+
+version="$(describe HEAD)"
 
 # Local edits to the checkout mean this isn't exactly the version above
 if [ -n "$(git -C "$COREDESKTOP" status --porcelain --untracked-files=no)" ]; then
   version="$version, modified"
 fi
 
+if latest="$(newer_version)"; then
+  version="$version, $latest is available (run update)"
+fi
+
 kernel="$(uname -r)"
 # If the running kernel's modules are gone, a newer kernel was installed
 if [ ! -d "/usr/lib/modules/$kernel" ]; then