homelab/netbird/setup.sh

#!/usr/bin/env bash
# Prepare local Compose configuration without replacing existing credentials.
set -euo pipefail
cd "$(dirname "${BASH_SOURCE[0]}")"
umask 077
if [ ! -f .env ]; then
  cp .env.example .env
fi

if grep -q '^NETBIRD_PROXY_SUBNET=auto$' .env; then
  subnet="$(docker network inspect proxy --format '{{range .IPAM.Config}}{{println .Subnet}}{{end}}' | awk '/^[0-9]+\./ { print; exit }')"
  if [ -z "$subnet" ]; then
    echo "No IPv4 subnet found on the Docker proxy network. Set NETBIRD_PROXY_SUBNET in .env." >&2
    exit 1
  fi
  # The detected value must be safe to substitute into the env file.
  if [[ ! "$subnet" =~ ^[0-9.]+/[0-9]+$ ]]; then
    echo "Unexpected Docker network subnet: $subnet" >&2
    exit 1
  fi
  sed -i "s|^NETBIRD_PROXY_SUBNET=auto$|NETBIRD_PROXY_SUBNET=$subnet|" .env
fi

mkdir -p secrets
chmod 700 secrets
for name in relay-auth-secret datastore-encryption-key; do
  path="secrets/$name"
  if [ -e "$path" ]; then
    if [ ! -s "$path" ]; then
      echo "Existing secret is empty: $path. Restore it before continuing." >&2
      exit 1
    fi
  else
    openssl rand -base64 32 >"$path"
  fi
  chmod 600 "$path"
done
printf '%s\n' 'Local files are ready. Review .env, then run docker compose config --quiet.'