initial codes

files/healthcheck.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Simple TCP healthcheck against the first server in NATS_SERVERS
+# Accepts schemes nats:// or tls://
+first_server=$(awk '{print $1}' <<< "${NATS_SERVERS:-}")
+if [[ -z "${first_server}" ]]; then
+  echo "NATS_SERVERS not set" >&2
+  exit 1
+fi
+
+# Extract host and port
+scheme="${first_server%%://*}"
+rest="${first_server#*://}"
+
+host="${rest%:*}"
+port="${rest##*:}"
+
+# If rest still contains '/', strip path
+host="${host%%/*}"
+port="${port%%/*}"
+
+: "${port:=4222}"
+
+# Try TCP connect (bash /dev/tcp)
+timeout 3 bash -c "cat < /dev/null > /dev/tcp/${host}/${port}" 2>/dev/null || {
+  echo "Cannot connect to ${host}:${port}" >&2
+  exit 1
+}
+
+# Optionally add more checks later (e.g., NATS /varz on 8222)
+exit 0