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Krystie 86cc21c7a4 [glm-grade=B+] ops: self-healing watchdog for DNS2 (container, port 3001, Caddyfile, caddy)
30s systemd timer heals four real failure classes: container down (docker
start -> start.sh fallback), rogue host process on :3001, Caddyfile wiped
by foreign generators (known-good snapshot + size/site-block/marker
gates), caddy down/not serving. Telegram alerts with 15-min per-class
cooldown; stamp only burned on successful send. Adversarial review B-
(both blockers fixed: snapshot poisoning via multi-gate integrity +
refresh lockout, deployment). Live kill-tested twice: full recovery in
one cycle, alerts delivered, cooldown verified.
2026-08-14 23:59:50 -07:00

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#!/bin/bash
# /usr/local/bin/dashcaddy-watchdog — self-healing guard for DashCaddy on DNS2.
#
# Heals four failure classes that have actually knocked DashCaddy down:
# 1. Container down/unhealthy/removed -> docker start / bash start.sh
# 2. Rogue host node process stealing :3001 -> kill it, restart container
# 3. Caddyfile wiped by a foreign generator -> restore known-good, restart caddy
# 4. Caddy down or not serving -> restart caddy
#
# Runs from dashcaddy-watchdog.service (systemd timer, every 30s) or manually.
# Alerts go to Telegram (Sami) on every corrective action; rate-limited per
# action class (default 15 min) to avoid spam during flapping. All state in
# /var/lib/dashcaddy-watchdog/ so restarts of the watchdog never flap.
#
# Exit codes: 0 = healthy or healed cleanly. Healing never exits non-zero —
# a permanently-failed unit would pollute systemctl --failed monitoring.
set -u
CONTAINER="dashcaddy-api"
START_SH="/opt/dashcaddy/start.sh"
CADDYFILE="/etc/caddy/Caddyfile"
KNOWN_GOOD="/var/lib/dashcaddy-watchdog/known-good-Caddyfile"
STATE_DIR="/var/lib/dashcaddy-watchdog"
LOG="/var/log/dashcaddy-watchdog.log"
ALERT_COOLDOWN=$((15 * 60)) # seconds between alerts of the same class
LOG_MAX=1048576 # 1 MiB
# Caddyfile integrity gates (adversarial review: markers alone can be
# satisfied by a damaged file). Size floor excludes the 4952-byte foreign-
# generator file from the 2026-08-13 incident; service-block floor excludes
# marker-duplication damage.
CADDYFILE_MIN_BYTES=10000
CADDYFILE_MIN_SITES=10
mkdir -p "$STATE_DIR"
touch "$LOG"
log() { echo "$(date -u +%Y-%m-%dT%H:%M:%SZ) $*" >> "$LOG"; }
# --- Telegram alerting (best-effort; a notify failure never blocks healing) ---
notify() { # notify <class> <message>
local class="$1" msg="$2"
local now last elapsed
now=$(date +%s)
local stamp="$STATE_DIR/alert-$class"
if [ -f "$stamp" ]; then
last=$(cat "$stamp" 2>/dev/null | tr -cd '0-9')
last="${last:-0}"
elapsed=$(( now - last ))
if [ "$elapsed" -lt "$ALERT_COOLDOWN" ]; then
log "ALERT-SUPPRESSED class=$class (${elapsed}s < ${ALERT_COOLDOWN}s)"
return 0
fi
fi
local token chat sent
token=$(grep -E '^HERMES_ENV_TELEGRAM_BOT_TOKEN=' /root/.hermes/.env | head -1 | cut -d= -f2-)
chat="637130179"
if [ -z "$token" ]; then
log "ALERT-NO-TOKEN class=$class msg=$msg"
return 0
fi
sent=$(curl -s -m 10 -X POST "https://api.telegram.org/bot${token}/sendMessage" \
-d chat_id="$chat" -d text="🛡️ DashCaddy watchdog (DNS2): $msg" \
2>/dev/null | grep -c '"ok":true')
if [ "${sent:-0}" -ge 1 ]; then
date +%s > "$stamp"
log "ALERT-SENT class=$class msg=$msg"
else
log "ALERT-SEND-FAILED class=$class (cooldown NOT burned)"
fi
}
log_rotate() {
[ -f "$LOG" ] || return 0
local size
size=$(stat -c%s "$LOG" 2>/dev/null || echo 0)
if [ "$size" -gt "$LOG_MAX" ]; then
tail -c $((LOG_MAX / 2)) "$LOG" > "${LOG}.tmp" && mv "${LOG}.tmp" "$LOG"
fi
}
# --- Health probes -----------------------------------------------------------
container_running() {
docker ps --filter "name=^${CONTAINER}$" --format '{{.Names}}' 2>/dev/null | grep -q "^${CONTAINER}$"
}
container_healthy() {
local st started age
st=$(docker inspect -f '{{.State.Health.Status}}' "$CONTAINER" 2>/dev/null) || return 1
if [ "$st" = "healthy" ]; then return 0; fi
if [ "$st" = "starting" ]; then
# Max-starting-age guard (adversarial review): never park forever on a
# container stuck in 'starting'. StartPeriod is 10s; allow 90s slack.
started=$(docker inspect -f '{{.State.StartedAt}}' "$CONTAINER" 2>/dev/null)
age=$(( $(date +%s) - $(date -d "${started:-1970-01-01}" +%s 2>/dev/null || echo 0) ))
[ "$age" -le 90 ]
return
fi
return 1
}
rogue_on_port() {
# any listener on 127.0.0.1:3001 that is NOT docker-proxy
ss -H -tlnp 'sport = :3001' 2>/dev/null | grep -v docker-proxy | grep -q .
}
caddy_up() {
systemctl is-active --quiet caddy
}
caddy_serving() {
# status.sami via loopback; internal CA cert -> -k
curl -sk -m 8 -o /dev/null -w '%{http_code}' --resolve status.sami:443:127.0.0.1 https://status.sami/ 2>/dev/null | grep -qE '^[23]'
}
caddyfile_intact() {
# Integrity gates (adversarial review hardened): markers + size floor +
# service-block floor + caddy syntax validation.
[ -f "$CADDYFILE" ] || return 1
local refs ca bytes sites
refs=$(grep -c 'dashcaddy_auth' "$CADDYFILE" 2>/dev/null || echo 0)
ca=$(grep -c 'sami-ca' "$CADDYFILE" 2>/dev/null || echo 0)
bytes=$(stat -c%s "$CADDYFILE" 2>/dev/null || echo 0)
sites=$(grep -cE '^[a-z0-9.-]+\.(sami|net|com|me|org)[^a-z0-9-]*\{$' "$CADDYFILE" 2>/dev/null || echo 0)
[ "$refs" -ge 8 ] && [ "$ca" -ge 1 ] && [ "$bytes" -ge "$CADDYFILE_MIN_BYTES" ] && [ "$sites" -ge "$CADDYFILE_MIN_SITES" ]
}
refresh_known_good() {
# Refuse to refresh within 10 minutes of a caddyfile heal (prevents the
# partial-write / post-heal window from poisoning the snapshot).
local heal_stamp="$STATE_DIR/last-caddyfile-heal"
if [ -f "$heal_stamp" ]; then
local since=$(( $(date +%s) - $(cat "$heal_stamp" | tr -cd '0-9' || echo 0) ))
if [ "$since" -lt 600 ]; then
return 0
fi
fi
if caddyfile_intact; then
if [ -f "$KNOWN_GOOD" ] && cmp -s "$CADDYFILE" "$KNOWN_GOOD"; then
return 0 # unchanged — keep existing snapshot (preserves mtime)
fi
cp -a "$CADDYFILE" "$KNOWN_GOOD"
log "KNOWN-GOOD refreshed ($(stat -c%s "$KNOWN_GOOD" 2>/dev/null || echo '?') bytes)"
fi
}
# --- Remediation --------------------------------------------------------------
heal_container_start() {
log "HEAL container-start"
docker start "$CONTAINER" >/dev/null 2>&1
if ! container_running; then
log "HEAL container-start failed; falling back to start.sh"
bash "$START_SH" >> "$LOG" 2>&1
fi
notify container "container was down — restarted it"
}
heal_container_recreate() {
log "HEAL container-recreate (start.sh)"
bash "$START_SH" >> "$LOG" 2>&1
notify container "container unhealthy — recreated via start.sh"
}
heal_rogue_port() {
local pids
pids=$(ss -H -tlnp 'sport = :3001' 2>/dev/null | grep -v docker-proxy | grep -oP 'pid=\K[0-9]+' | sort -u)
log "HEAL rogue-port pids=$pids"
for pid in $pids; do
[ "$pid" = "$$" ] && continue
local cmdline
cmdline=$(cat /proc/$pid/cmdline 2>/dev/null | tr '\0' ' ')
case "$cmdline" in
*docker-proxy*|*dashcaddy-watchdog*) continue ;;
esac
# PID recycling guard: the process must still be listening on :3001
if ! ss -H -tlnp 'sport = :3001' 2>/dev/null | grep -q "pid=$pid"; then
continue
fi
log "KILL pid=$pid cmd=$cmdline"
kill "$pid" 2>/dev/null || true
done
sleep 3
ss -H -tlnp 'sport = :3001' | grep -q docker-proxy || docker restart "$CONTAINER" >/dev/null 2>&1
notify rogue-port "rogue host process was holding port 3001 — killed it, container restarted"
}
heal_caddyfile() {
log "HEAL caddyfile-restore"
if [ -f "$KNOWN_GOOD" ]; then
cp -a "$KNOWN_GOOD" "$CADDYFILE"
chown caddy:caddy "$CADDYFILE" 2>/dev/null || true
systemctl restart caddy
notify caddyfile "Caddyfile was wiped/overwritten by a foreign generator — restored known-good and restarted Caddy"
else
notify caddyfile "Caddyfile damaged and no known-good snapshot exists — MANUAL ACTION NEEDED"
fi
# Post-heal grace stamp: caddy_serving() skipped for 60s after this point.
date +%s > "$STATE_DIR/last-caddyfile-heal"
}
heal_caddy_down() {
log "HEAL caddy-restart"
systemctl restart caddy
notify caddy "caddy was down — restarted it"
}
heal_caddy_5xx() {
log "HEAL caddy-5xx"
systemctl restart caddy
notify caddy "caddy was not serving status.sami (non-2xx/3xx) — restarted it"
}
# --- Main ----------------------------------------------------------------------
log_rotate
ACTION_TAKEN=0
# 0. Maintain known-good Caddyfile snapshot whenever current file is intact.
refresh_known_good
# 3. Caddyfile integrity (before caddy health so restore happens first).
if ! caddyfile_intact && [ -f "$KNOWN_GOOD" ]; then
heal_caddyfile
ACTION_TAKEN=1
fi
# 4. Caddy up + serving
if ! caddy_up; then
heal_caddy_down
ACTION_TAKEN=1
fi
if ! caddy_serving; then
# Skip if we JUST restarted caddy this cycle (post-heal grace).
if [ -f "$STATE_DIR/last-caddyfile-heal" ]; then
local_grace=$(( $(date +%s) - $(cat "$STATE_DIR/last-caddyfile-heal" | tr -cd '0-9' || echo 0) ))
if [ "$local_grace" -lt 60 ]; then
log "caddy_serving skipped (post-caddyfile-heal grace ${local_grace}s)"
else
heal_caddy_5xx
ACTION_TAKEN=1
fi
else
heal_caddy_5xx
ACTION_TAKEN=1
fi
fi
# 2. Rogue host process on :3001
if rogue_on_port; then
heal_rogue_port
ACTION_TAKEN=1
fi
# 1. Container down/unhealthy (last: start.sh recreates and re-binds 3001)
if ! container_running; then
heal_container_start
ACTION_TAKEN=1
elif ! container_healthy; then
heal_container_recreate
ACTION_TAKEN=1
fi
if [ "$ACTION_TAKEN" = "1" ]; then
log "cycle complete: corrective action taken"
else
log "cycle complete: healthy"
fi
exit 0