Files
LLeMbas/deploy/install.sh
T
Homer 0ce8026bd2 A helper that would have deployed a channel nobody named
The channel is declared twice: in lembas.env, which this process reads and the
page prints, and baked into the systemd unit, which is what the helper actually
deploys. install.sh writes both together so they agree by construction -- and
the moment somebody edits one by hand they diverge, with the page naming one
channel down every card and the button deploying the other. Nothing anywhere
would have said so.

It cannot be collapsed to one place. Reading it from lembas.env at deploy time
would mean the service account decides what gets deployed, since it owns that
file -- and "the request carries no channel" is the property the whole design
rests on. So the two stay, and the marker file the page already reads to know
the helper exists now carries the channel it was installed with. A disagreement
is an alert.

Display only, deliberately: the service account can write that marker, so a
compromised process could lie about what the helper will do -- but not change
it, because the helper's own channel lives in /etc where that account cannot
reach. Lying about the channel is a much smaller thing than choosing it.

An empty marker -- every host installed before this -- reads as unknown rather
than as a mismatch. Claiming one would put a red alert on every existing host.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-06 21:44:35 +02:00

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#!/usr/bin/env bash
# Install LLeMbas as a system service behind nginx with a self-signed cert.
#
# Creates a dedicated service user, a virtualenv, a systemd unit and an nginx
# vhost. Idempotent: safe to re-run. To deploy new code afterwards use
# update.sh, which is what a `git push` should be followed by.
#
# Everything is configurable from the environment:
#
# SITE_HOST=chat.example ./deploy/install.sh # vhost name
# APP_PORT=8080 # loopback port
# PREFIX=/srv/lembas # install root
# HOME_DIR=/home/lembas # service user's home
# REPO_URL=... # defaults to this checkout's origin
#
# PREFIX defaults to a bind mount of HOME_DIR rather than living directly under
# /srv, because on many machines the root filesystem is small and the venv plus
# database belong on the larger /home volume. Set PREFIX=HOME_DIR to skip that.
set -euo pipefail
HERE="$(dirname "$(readlink -f "$0")")"
SITE_HOST="${SITE_HOST:-lembas.local}"
APP_PORT="${APP_PORT:-8080}"
SERVICE_USER="${SERVICE_USER:-lembas}"
HOME_DIR="${HOME_DIR:-/home/lembas}"
PREFIX="${PREFIX:-/srv/lembas}"
BRANCH="${LEMBAS_BRANCH:-main}"
# Which channel this host follows: `stable` (the newest release tag) or `edge`
# (the branch tip). Stable by default, because a branch tip is not a release --
# following one means deploying whatever was pushed five minutes ago, which is
# right for whoever builds this and wrong for whoever runs it.
CHANNEL="${LEMBAS_CHANNEL:-stable}"
# Whether to install the units that let the web interface update this host.
# Off, and off on a re-run that does not ask for it: it grants anybody who can
# administer the web UI the ability to deploy the branch, as root. See the
# "Updating from the web interface" section of deploy/README.md.
INSTALL_UPDATE_HELPER="${INSTALL_UPDATE_HELPER:-0}"
# Default to wherever this checkout came from, so a fork deploys itself.
REPO_URL="${REPO_URL:-$(git -C "$HERE" remote get-url origin 2>/dev/null || true)}"
APP="$PREFIX/app"
VENV="$PREFIX/venv"
ENV_FILE="$PREFIX/lembas.env"
if [[ -z "$REPO_URL" ]]; then
echo "Could not determine REPO_URL. Set it explicitly." >&2
exit 1
fi
# The deployment clones as the service user, which has no SSH key and should not
# have one: a credential that can push to the repository, sitting on a box, to
# do a read-only job. Whoever runs this usually has an ssh:// origin because
# *they* push over SSH, so the default inherited from their checkout is the one
# thing that cannot work here.
#
# The clone would fail loudly anyway. Saying so first turns "Permission denied
# (publickey)" from the service user into a sentence that names the fix.
if [[ "$REPO_URL" == ssh://* || "$REPO_URL" == git@* ]]; then
echo "== repository ==" >&2
echo " $REPO_URL is an SSH URL, and $SERVICE_USER has no key." >&2
echo " Set an https URL, which is what a deployment should fetch over:" >&2
echo " REPO_URL=https://host/owner/repo.git $0" >&2
echo " (Or give $SERVICE_USER a read-only deploy key and re-run.)" >&2
exit 1
fi
echo "== plan =="
echo " host : https://$SITE_HOST -> 127.0.0.1:$APP_PORT"
echo " user : $SERVICE_USER ($HOME_DIR)"
echo " prefix : $PREFIX"
echo " repo : $REPO_URL ($BRANCH, $CHANNEL channel)"
if [[ "$INSTALL_UPDATE_HELPER" == "1" ]]; then
echo " updates : web interface may deploy $BRANCH as root (helper units)"
else
echo " updates : by hand only ($PREFIX/app/deploy/update.sh)"
fi
echo "== service user =="
# --system: no ageing, no mail spool. Home under /home, not /var/lib, so the
# venv and database sit on the larger volume.
if ! getent passwd "$SERVICE_USER" >/dev/null; then
sudo useradd --system --create-home --home-dir "$HOME_DIR" \
--shell /usr/bin/nologin --comment "LLeMbas" "$SERVICE_USER"
else
echo " user $SERVICE_USER already exists"
fi
sudo chmod 755 "$HOME_DIR"
if [[ "$PREFIX" != "$HOME_DIR" ]]; then
echo "== $PREFIX bind-mount onto $HOME_DIR =="
sudo mkdir -p "$PREFIX"
grep -q "^$HOME_DIR[[:space:]]" /etc/fstab \
|| echo "$HOME_DIR $PREFIX none bind 0 0" | sudo tee -a /etc/fstab >/dev/null
sudo systemctl daemon-reload
mountpoint -q "$PREFIX" || sudo mount "$PREFIX"
fi
echo "== checkout =="
if [[ ! -d "$APP/.git" ]]; then
sudo -u "$SERVICE_USER" git clone --branch "$BRANCH" "$REPO_URL" "$APP"
else
echo " already cloned; use update.sh to pull"
fi
echo "== virtualenv =="
if [[ ! -x "$VENV/bin/python" ]]; then
sudo -u "$SERVICE_USER" python -m venv "$VENV"
fi
sudo -u "$SERVICE_USER" "$VENV/bin/pip" install --quiet --upgrade pip
# The extras a deployment gets. `search` because DuckDuckGo is the default web
# search provider and is meant to need no setup; `ssh` because agent chats reach
# their machine over it and a deployment without it offers the feature with an
# install hint instead. Listed here AND in update.sh -- an extra added to only
# one of them means existing deployments silently miss it.
LEMBAS_EXTRAS="${LEMBAS_EXTRAS:-search,ssh}"
sudo -u "$SERVICE_USER" "$VENV/bin/pip" install --quiet -e "$APP[$LEMBAS_EXTRAS]"
echo "== environment =="
# Generated once and never regenerated: rotating LEMBAS_SECRET_KEY signs every
# user out AND makes the stored upstream API keys unreadable.
if [[ ! -f "$ENV_FILE" ]]; then
KEY=$("$VENV/bin/python" -c "import secrets; print(secrets.token_urlsafe(48))")
sudo tee "$ENV_FILE" >/dev/null <<EOF
# LLeMbas service environment. Generated by deploy/install.sh.
# LEMBAS_SECRET_KEY signs sessions and encrypts stored API keys.
# Changing it signs everyone out and makes stored API keys unreadable.
LEMBAS_SECRET_KEY=$KEY
LEMBAS_DATA_DIR=$PREFIX/data
# Loopback only: reachable through the nginx vhost, never directly.
LEMBAS_HOST=127.0.0.1
LEMBAS_PORT=$APP_PORT
LEMBAS_LOG_LEVEL=info
LEMBAS_ALLOW_SIGNUP=true
LEMBAS_DEFAULT_THEME=moria
# Which branch /admin/updates compares against. Deployment configuration, not
# an instance setting: it decides what code runs here, and a value a web
# administrator could edit would turn "you may deploy the branch" into "you may
# deploy anything".
LEMBAS_UPDATE_BRANCH=$BRANCH
# stable follows the newest release tag; edge follows the branch tip.
LEMBAS_UPDATE_CHANNEL=$CHANNEL
EOF
sudo chown "$SERVICE_USER:$SERVICE_USER" "$ENV_FILE"
sudo chmod 600 "$ENV_FILE"
echo " generated $ENV_FILE"
else
echo " $ENV_FILE exists, keeping it (and its secret key)"
fi
sudo install -d -o "$SERVICE_USER" -g "$SERVICE_USER" -m 750 "$PREFIX/data"
echo "== systemd unit =="
sed -e "s|__PREFIX__|$PREFIX|g" -e "s|__SERVICE_USER__|$SERVICE_USER|g" \
"$HERE/lembas.service" | sudo tee /etc/systemd/system/lembas.service >/dev/null
# Which version of the template this host is running. update.sh compares
# against it and says so when the template moves on, because the installed
# unit usually grows host-specific lines and cannot simply be overwritten.
sha256sum "$HERE/lembas.service" | cut -d' ' -f1 | sudo tee "$PREFIX/.unit-applied" >/dev/null
sudo systemctl daemon-reload
echo "== update helper =="
# Two units and a marker. The marker is what the web interface reads to decide
# whether to offer the button at all -- a file rather than `systemctl
# is-enabled`, because that would be a subprocess on every page render to answer
# a question that changes once.
UPDATE_MARKER="$PREFIX/data/.update-helper"
if [[ "$INSTALL_UPDATE_HELPER" == "1" ]]; then
for unit in lembas-update.path lembas-update.service; do
sed -e "s|__PREFIX__|$PREFIX|g" \
-e "s|__SERVICE_USER__|$SERVICE_USER|g" \
-e "s|__UPDATE_BRANCH__|$BRANCH|g" \
-e "s|__UPDATE_CHANNEL__|$CHANNEL|g" \
"$HERE/$unit" | sudo tee "/etc/systemd/system/$unit" >/dev/null
done
sudo systemctl daemon-reload
sudo systemctl enable --now lembas-update.path
# The channel goes *into* the marker, not just its existence. It is declared
# in two places -- the unit above and lembas.env -- and this is what lets the
# Updates page notice when somebody has edited one and not the other.
echo "$CHANNEL" | sudo tee "$UPDATE_MARKER" >/dev/null
sudo chown "$SERVICE_USER:$SERVICE_USER" "$UPDATE_MARKER"
echo " installed. The web interface can now deploy the $CHANNEL channel and restart."
else
# Removed rather than left, so turning it off is re-running without the flag
# rather than remembering three commands. The button then says so and prints
# the manual one, which is the honest degradation.
sudo systemctl disable --now lembas-update.path 2>/dev/null || true
sudo rm -f /etc/systemd/system/lembas-update.path \
/etc/systemd/system/lembas-update.service "$UPDATE_MARKER"
sudo systemctl daemon-reload
echo " not installed (INSTALL_UPDATE_HELPER=1 to allow updating from the web UI)"
fi
echo "== self-signed cert for $SITE_HOST =="
sudo mkdir -p /etc/nginx/ssl
if [[ ! -f "/etc/nginx/ssl/$SITE_HOST.crt" ]]; then
sudo openssl req -x509 -newkey rsa:2048 -nodes \
-keyout "/etc/nginx/ssl/$SITE_HOST.key" -out "/etc/nginx/ssl/$SITE_HOST.crt" \
-days 3650 -subj "/CN=$SITE_HOST" -addext "subjectAltName=DNS:$SITE_HOST"
sudo chmod 600 "/etc/nginx/ssl/$SITE_HOST.key"
sudo chmod 644 "/etc/nginx/ssl/$SITE_HOST.crt"
fi
echo "== nginx vhost =="
sed -e "s|__SITE_HOST__|$SITE_HOST|g" -e "s|__APP_PORT__|$APP_PORT|g" \
"$HERE/nginx-vhost.conf" | sudo tee "/etc/nginx/conf.d/$SITE_HOST.conf" >/dev/null
sudo nginx -t
sudo systemctl reload nginx
# What this host was installed with, so update.sh can name the vhost it should
# be comparing against and print a command that actually runs. Without it the
# drift check below could only say "something changed somewhere".
printf 'SITE_HOST=%s\nAPP_PORT=%s\n' "$SITE_HOST" "$APP_PORT" \
| sudo tee "$PREFIX/.deploy-env" >/dev/null
sha256sum "$HERE/nginx-vhost.conf" | cut -d' ' -f1 \
| sudo tee "$PREFIX/.vhost-applied" >/dev/null
echo "== local name resolution =="
# Only useful when the LAN's DNS does not already answer for this name.
if ! getent hosts "$SITE_HOST" >/dev/null; then
printf '127.0.0.1\t%s\n::1\t\t%s\n' "$SITE_HOST" "$SITE_HOST" | sudo tee -a /etc/hosts >/dev/null
echo " added $SITE_HOST to /etc/hosts"
else
echo " $SITE_HOST already resolves"
fi
echo "== enable service =="
sudo systemctl enable --now lembas
sleep 2
sudo systemctl --no-pager --lines=0 status lembas || true
echo
echo "LLeMbas is up at https://$SITE_HOST (self-signed cert; accept the warning)"
echo "Create the first account -- it becomes the administrator."