Feature 07: Deployment, identity and backups (#75)

Co-authored-by: dev_agent <dev_agent@cubecraftlabs.com>

deploy/systemd/mealquest-firewall.service

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+# Applies the MealQuest DOCKER-USER rules (/usr/local/sbin/mealquest-firewall).
+#
+# PartOf= re-runs this unit whenever docker.service is stopped or restarted,
+# and WantedBy=docker.service starts it whenever docker.service starts. Both
+# are one-way: a failure here fails this unit visibly and never fails
+# docker.service.
+#
+# Start MealQuest only after this unit has succeeded:
+#   systemctl start mealquest-firewall && docker compose up -d
+[Unit]
+Description=Restrict MealQuest port 8090 to Traefik (DOCKER-USER)
+After=docker.service
+Requires=docker.service
+PartOf=docker.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/usr/local/sbin/mealquest-firewall
+
+[Install]
+WantedBy=multi-user.target docker.service

deploy/systemd/mealquest-firewall.sh

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+#!/bin/sh
+# Restrict the MealQuest published host port (10.60.1.14:8090) to Traefik
+# (10.60.1.33) and the Docker host itself (10.60.1.14); drop every other
+# source.
+#
+# DOCKER-USER runs after Docker's DNAT, so the destination there is the
+# container address and port, not the published ones. Match the original
+# destination address and port with conntrack instead of -d/--dport.
+#
+# The rules must sit at the top of DOCKER-USER, ahead of any other project's
+# rules (an earlier RETURN or DROP would decide MealQuest traffic first).
+# The port is never left open while the rules are updated:
+#
+#   1. If the chain already starts with exactly the three rules below and
+#      holds no other mealquest-firewall rule, change nothing.
+#   2. Otherwise insert the DROP at position 1 first, so the port is closed
+#      to every source (including Traefik, briefly) from here on.
+#   3. Delete every other rule tagged mealquest-firewall, by rule number,
+#      highest first.
+#   4. Insert the two RETURN rules above the DROP.
+#
+# Re-runs leave the same ordered rules at positions 1-3 and no duplicates.
+# Installed as /usr/local/sbin/mealquest-firewall.
+set -eu
+
+chain=DOCKER-USER
+tag="-m comment --comment mealquest-firewall"
+match="-m conntrack --ctorigdst 10.60.1.14 --ctorigdstport 8090 --ctdir ORIGINAL"
+
+# The three rules as iptables -S prints them, in their required order.
+want="-A $chain -s 10.60.1.33/32 $match $tag -j RETURN
+-A $chain -s 10.60.1.14/32 $match $tag -j RETURN
+-A $chain $match $tag -j DROP"
+
+rules=$(iptables -w -S "$chain" | grep -e '^-A ' || true)
+head=$(printf '%s\n' "$rules" | head -n 3)
+tagged=$(printf '%s\n' "$rules" | grep -c -e '--comment mealquest-firewall ' || true)
+if [ "$head" = "$want" ] && [ "$tagged" -eq 3 ]; then
+	exit 0
+fi
+
+iptables -w -I "$chain" 1 $match $tag -j DROP
+
+iptables -w -S "$chain" | grep -e '^-A ' |
+	awk '/--comment mealquest-firewall / { print NR }' |
+	sort -rn | while read -r num; do
+	if [ "$num" -ne 1 ]; then
+		iptables -w -D "$chain" "$num"
+	fi
+done
+
+iptables -w -I "$chain" 1 -s 10.60.1.14/32 $match $tag -j RETURN
+iptables -w -I "$chain" 1 -s 10.60.1.33/32 $match $tag -j RETURN

deploy/systemd/mealquest-media-backup.service

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+# Runs the nightly MealQuest media backup (/usr/local/sbin/mealquest-media-backup).
+# Triggered by mealquest-media-backup.timer; run by hand with
+#   systemctl start mealquest-media-backup
+# and read the result with
+#   journalctl -u mealquest-media-backup
+#
+# The script runs as the app's user (10001, host user "mealquest") with no
+# capabilities. systemd, as root, only bind-mounts the data volume's root
+# (a root-owned path the app cannot replace) read-only at
+# /run/mealquest-data and copies the NAS key into the credentials directory.
+[Unit]
+Description=Back up MealQuest media to the Synology NAS
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=oneshot
+ExecStart=/usr/local/sbin/mealquest-media-backup
+User=mealquest
+Group=mealquest
+LoadCredential=nas_key:/home/overseer/mealquest/deploy/secrets/litestream_key
+BindReadOnlyPaths=/var/lib/docker/volumes/mealquest-data/_data:/run/mealquest-data
+ProtectSystem=strict
+ProtectHome=yes
+PrivateTmp=yes
+PrivateDevices=yes
+NoNewPrivileges=yes
+CapabilityBoundingSet=
+RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX

deploy/systemd/mealquest-media-backup.sh

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+#!/bin/sh
+# Nightly copy of the MealQuest media directory (recipe and dinner photos)
+# to the Synology NAS. The database itself is replicated continuously by
+# Litestream; this covers the files beside it.
+#
+# Runs as the unprivileged app user (10001, host user "mealquest"), never
+# root: mealquest-media-backup.service bind-mounts the data volume
+# read-only at /run/mealquest-data and hands the NAS key in as a systemd
+# credential. Anything the app could plant in the volume is therefore read
+# with the app's own permissions only.
+#
+# The script changes into the media directory and checks that the physical
+# path is the expected one, so a media path that is a symlink is refused.
+# rsync then copies "./" — the directory the shell is already in — so
+# swapping the path afterwards cannot redirect it. Symlinks inside the
+# directory are copied as links (-a), never followed.
+#
+# The media directory is created at deploy time (deploy/RUNBOOK.md). If it
+# is missing the job fails; it is never treated as "nothing to back up".
+#
+# rsync mirrors into .../mealquest-backups/media/ only: the target ends in
+# a slash, so --delete removes files from that directory and nothing
+# outside it. Re-runs transfer only what changed. Output goes to the
+# journal via mealquest-media-backup.service.
+set -eu
+
+src=/run/mealquest-data/media
+dest=joshua@10.60.1.50:/volume1/homes/Joshua/mealquest-backups/media/
+key=$CREDENTIALS_DIRECTORY/nas_key
+known_hosts=/etc/mealquest/known_hosts
+
+if ! cd "$src"; then
+	echo "mealquest-media-backup: media directory $src is missing" >&2
+	exit 1
+fi
+if [ "$(pwd -P)" != "$src" ]; then
+	echo "mealquest-media-backup: $src is a symlink to $(pwd -P); refusing to back it up" >&2
+	exit 1
+fi
+
+rsync -a --delete --stats \
+	-e "ssh -F none -i $key -o IdentitiesOnly=yes -o BatchMode=yes -o UserKnownHostsFile=$known_hosts -o GlobalKnownHostsFile=/dev/null -o StrictHostKeyChecking=yes" \
+	./ "$dest"
+echo "mealquest-media-backup: synced $src to $dest as uid $(id -u)"

deploy/systemd/mealquest-media-backup.timer

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+# Nightly trigger for mealquest-media-backup.service. Persistent= runs a
+# missed backup at the next boot.
+[Unit]
+Description=Nightly MealQuest media backup
+
+[Timer]
+OnCalendar=*-*-* 03:30:00
+Persistent=true
+
+[Install]
+WantedBy=timers.target

deploy/systemd/mealquest.service

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+# Owns the MealQuest compose stack (deploy/compose.yaml). The services use
+# restart: "no", so Docker never starts them on its own; this unit is the
+# only start path.
+#
+# Requires= and After=mealquest-firewall.service start the stack only after
+# the DOCKER-USER rules are applied, and not at all if that unit fails.
+# PartOf=docker.service propagates a Docker stop or restart here, so a
+# Docker restart re-applies the firewall before the stack comes back.
+[Unit]
+Description=MealQuest compose stack
+Requires=mealquest-firewall.service
+After=mealquest-firewall.service docker.service
+PartOf=docker.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/usr/bin/docker compose -f /home/overseer/mealquest/deploy/compose.yaml up -d
+ExecStop=/usr/bin/docker compose -f /home/overseer/mealquest/deploy/compose.yaml down
+
+[Install]
+WantedBy=multi-user.target