Rust-Link/egg/with-sidecar.sh

#!/bin/sh
# with-sidecar.sh — start the rust-link sidecar beside a Rust server, then become the server.
#
# The egg's startup is this script followed by the game's own command line:
#
#   ./rust-link/with-sidecar.sh ./RustDedicated -batchmode …
#
# It ships in Rust-Link's release rather than inside the egg, so a fix here reaches a server at its
# next reinstall without anybody re-importing the egg (docs/modules/rust/PLAN.md §34.2.6, §34.4).
# The shape is docs/rust-link/INSTALL_RIG.md's, proven on the rigs; see that file for why each line
# that looks optional is not.
#
# POSIX sh and no jq: the game image (ghcr.io/pterodactyl/games:rust) has grep and sed, not jq.
#
# Deliberately NOT `set -e`. Every step before the last line is the bridge's, and the last line is
# the game's: nothing the bridge gets wrong — an unwritable log, a sidecar that will not start — may
# keep the server from booting. Each step reports its own failure and the script goes on to `exec`.

RL=/home/container/rust-link
mkdir -p "$RL" 2>/dev/null

export RUSTLINK_CONFIG="$RL/sidecar.toml"
# Fixed, and never a panel variable: the install script moves this directory aside around its own
# `rm -rf ${REMOVE_FILES}`, which is what keeps a wipe from reaching the store (§34.1).
export RUSTLINK_DB_PATH="$RL/rust-link.db"

# An EMPTY panel variable is exported as `VAR=""`. The sidecar treats that as unset, and so does
# this script, so a blank field always means "the default" (or, for the token, "the saved one").
for v in RUSTLINK_SERVER_ID RUSTLINK_WEB_TOKEN RUSTLINK_RETAIN_DAYS RUSTLINK_WEB_PORT RUSTLINK_GAME_BIND RUSTLINK_WEB_BIND; do
  eval "val=\${$v-}"
  if [ -z "$val" ]; then unset "$v"; fi
done

# The server id follows the PLUGIN's config once it exists. The plugin reads RUSTLINK_SERVER_ID only
# when it writes its first config; after that the file is canonical and the website locks it (D150).
# The sidecar refuses a plugin that names another server (D155), so a variable edited after the
# first boot would otherwise take the bridge down instead of changing nothing. Stock framework paths,
# the same ones the installer writes. `sed`, because the game image has no jq.
for f in /home/container/oxide/config/RunicGateway.json /home/container/carbon/configs/RunicGateway.json; do
  [ -f "$f" ] || continue
  ID="$(sed -n 's/^[[:space:]]*"ServerId":[[:space:]]*"\([^"]*\)".*$/\1/p' "$f" | head -n 1)"
  if [ -n "$ID" ]; then
    if [ -n "${RUSTLINK_SERVER_ID-}" ] && [ "$RUSTLINK_SERVER_ID" != "$ID" ]; then
      echo "[rust-link] RUSTLINK_SERVER_ID is '$RUSTLINK_SERVER_ID' but the plugin's config names '$ID'; using '$ID', the id the website knows. The variable is read once, at the first boot."
    fi
    export RUSTLINK_SERVER_ID="$ID"
  fi
  break
done

# The website-facing bind. Pterodactyl tells a container nothing about its extra allocations, so
# the port is typed into the egg, and it must be one of this server's allocations — a port that is
# not fails as a bind the website never reaches, which the lines below make visible (§34.1).
if [ -n "${RUSTLINK_WEB_PORT-}" ]; then
  export RUSTLINK_WEB_BIND="0.0.0.0:${RUSTLINK_WEB_PORT}"
fi

SIDECAR="$RL/rust-link-sidecar"
if [ ! -x "$SIDECAR" ]; then
  echo "[rust-link] $SIDECAR is missing - reinstall the server to fetch the bridge. Starting the game without it."
  exec "$@"
fi

# Provision first, so the token can be shown. `--print-config` resolves the configuration exactly as
# a start does, writing sidecar.toml with a generated token when there is none; the JSON it prints
# says whether it generated one on THIS call, which is what makes "print once" true (D152).
# Tracing is off on that path, so stdout is only the document. LD_PRELOAD is dropped for the
# sidecar in both calls: Carbon's entrypoint puts its Mono preloader in front of the whole startup.
if CFG="$(env -u LD_PRELOAD "$SIDECAR" --print-config 2>&1)"; then
  # The Nth `"key": "value"` line of the pretty-printed JSON. `bind` appears twice — game, then web.
  field() { printf '%s\n' "$CFG" | sed -n "s/^ *\"$1\": \"\([^\"]*\)\",\{0,1\}\$/\1/p" | sed -n "${2:-1}p"; }
  WEB_BIND="$(field bind 2)"
  SERVER_ID="$(field server_id)"

  if printf '%s\n' "$CFG" | grep -q '"token_generated": true'; then
    TOKEN="$(field auth_token)"
    echo "[rust-link] ================================================================"
    echo "[rust-link] A new sidecar token was generated. It is shown ONCE, here:"
    echo "[rust-link]   ${TOKEN}"
    echo "[rust-link] It is kept in rust-link/sidecar.toml; read it there if you lose it."
    echo "[rust-link] ================================================================"
  fi

  PORT="${WEB_BIND##*:}"
  HOST="${SERVER_IP-}"
  case "$HOST" in ""|0.0.0.0) HOST="<this node's address>" ;; esac
  echo "[rust-link] Admin -> Rust -> Servers: server id '${SERVER_ID:-main}', sidecar URL http://${HOST}:${PORT} (listening on ${WEB_BIND})"
else
  echo "[rust-link] the sidecar could not read its configuration:"
  printf '%s\n' "$CFG" | sed 's/^/[rust-link]   /'
fi

# A background job's redirection fails in the child, invisibly, so writability is asked first. A
# directory the log cannot be written to is one the store and the token cannot be written to either.
if touch "$RL/sidecar.log" 2>/dev/null; then
  env -u LD_PRELOAD "$SIDECAR" >> "$RL/sidecar.log" 2>&1 &
else
  echo "[rust-link] $RL is not writable - the game starts without the sidecar."
fi

# The game BECOMES this process: the panel console keeps its stdin and stdout, and stop still
# stops the server, which takes the sidecar down with the container.
exec "$@"