takeover-host

#!/usr/bin/env bash
set -euo pipefail

# Takeover script for NixOS hosts not yet managed by this flake
# Usage: ./takeover-host <FLAKE_HOSTNAME> <REMOTE_SSH_ADDR> [--no-switch]

if [ "$#" -lt 2 ]; then
    echo "Usage: $0 <FLAKE_HOSTNAME> <REMOTE_SSH_ADDR> [--no-switch]"
    echo "Example: $0 streambox root@192.168.1.100"
    exit 1
fi

FLAKE_HOSTNAME="$1"
REMOTE_SSH_ADDR="$2"
DO_SWITCH=true

if [ "${3:-}" == "--no-switch" ]; then
    DO_SWITCH=false
fi

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
cd "$SCRIPT_DIR"

echo "==> Building configuration for $FLAKE_HOSTNAME..."
# We use a temporary gcroat to prevent immediate garbage collection
mkdir -p .tmp/builds
OUT_LINK=".tmp/builds/$FLAKE_HOSTNAME"

nix build ".?submodules=1#nixosConfigurations.${FLAKE_HOSTNAME}.config.system.build.toplevel" \
    --out-link "$OUT_LINK"

CLOSURE=$(readlink -f "$OUT_LINK")

echo "==> Copying closure $CLOSURE to $REMOTE_SSH_ADDR..."
nix copy --to "ssh://${REMOTE_SSH_ADDR}" "$CLOSURE"

if [ "$DO_SWITCH" = true ]; then
    echo "==> Ensuring bootloader is ready on $REMOTE_SSH_ADDR..."
    # If using systemd-boot, we might need to install it first if it wasn't used before
    # We check if it's already installed, and if not, we try to install it.
    ssh "$REMOTE_SSH_ADDR" "sudo bootctl status >/dev/null 2>&1 || (echo 'Installing systemd-boot...' && sudo bootctl install --esp-path=/boot)" || true

    echo "==> Activating configuration on $REMOTE_SSH_ADDR..."
    # 1. Set the system profile to point to the new closure
    # 2. Run the activation script
    ssh "$REMOTE_SSH_ADDR" "sudo nix-env -p /nix/var/nix/profiles/system --set $CLOSURE && sudo $CLOSURE/bin/switch-to-configuration switch"
    echo "==> Success! Host $REMOTE_SSH_ADDR is now running the '$FLAKE_HOSTNAME' configuration."
else
    echo "==> Build and copy complete. To activate manually, run on the remote host:"
    echo "    sudo nix-env -p /nix/var/nix/profiles/system --set $CLOSURE"
    echo "    sudo $CLOSURE/bin/switch-to-configuration switch"
fi