feat: add admin console, Redis broker and chaos lab for training demo

scripts/hammer.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+# Hit an endpoint in a loop during a deploy and report any non-2xx responses,
+# plus which version/host answered. Proves zero-downtime rollouts.
+#
+#   scripts/hammer.sh https://guestbook.example.com            # /api/time, 10 req/s
+#   scripts/hammer.sh https://guestbook.example.com 20 /healthz
+set -u
+
+BASE="${1:?usage: hammer.sh <base-url> [req-per-sec] [path]}"
+RATE="${2:-10}"
+PATH_="${3:-/api/time}"
+URL="${BASE%/}${PATH_}"
+SLEEP=$(awk "BEGIN { print 1 / $RATE }")
+
+ok=0 fail=0 total=0
+# A temp file instead of an associative array: macOS still ships bash 3.2.
+seen=$(mktemp)
+
+summary() {
+  echo
+  echo "── $total requests · $ok ok · $fail failed ──"
+  sort "$seen" | uniq -c | sort -rn
+  rm -f "$seen"
+  exit 0
+}
+trap summary INT TERM
+
+echo "hammering $URL at ~${RATE} req/s — Ctrl-C for the summary"
+while true; do
+  resp=$(curl -s -m 5 -w '\n%{http_code}' "$URL" 2>/dev/null)
+  code="${resp##*$'\n'}"
+  body="${resp%$'\n'*}"
+  total=$((total + 1))
+  version=$(printf '%s' "$body" | sed -n 's/.*"version":"\([^"]*\)".*/\1/p')
+  host=$(printf '%s' "$body" | sed -n 's/.*"host":"\([^"]*\)".*/\1/p')
+  key="${code} v${version:-?} ${host:-?}"
+  echo "$key" >> "$seen"
+  if [[ "$code" =~ ^2 ]]; then
+    ok=$((ok + 1))
+    printf '\r%s  ok=%d fail=%d  last: %-40s' "$(date +%T)" "$ok" "$fail" "$key"
+  else
+    fail=$((fail + 1))
+    printf '\n%s  FAIL %s\n' "$(date +%T)" "${code:-000}"
+  fi
+  sleep "$SLEEP"
+done