Update cf-ddns.sh

Added function to register CNAME to short_host()

cf-ddns.sh

@@ -16,7 +16,7 @@ source "$ENV_FILE"
 : "${CF_PROXIED:=false}"
 : "${CF_TTL:=120}"
 
-# --- Derive zone/record from system hostname ---
+# --- Names from system ---
 CF_RECORD_NAME="$(hostname -f 2>/dev/null || true)"
 CF_SHORT_NAME="$(hostname -s 2>/dev/null || true)"
 CF_ZONE_NAME="$(hostname -d 2>/dev/null || true)"
@@ -24,26 +24,39 @@ CF_ZONE_NAME="$(hostname -d 2>/dev/null || true)"
 [[ -n "$CF_RECORD_NAME" ]] || fail "hostname -s returned empty"
 [[ -n "$CF_ZONE_NAME"  ]] || fail "hostname -d returned empty (set a DNS/search domain)"
 
+# --- short_host(): derive short alias used for the CNAME ---
+short_host() {
+  local short_hostname part1 part2 part3 part4 num_parts second_initial transformed_hostname
+  short_hostname="$(hostname -s)"
+  IFS="-" read -r part1 part2 part3 part4 <<< "$short_hostname"
+  num_parts=$(awk -F'-' '{print NF}' <<< "$short_hostname")
+  if [ "$num_parts" -eq 4 ]; then
+    second_initial=${part2:0:1}  # kept in case you want it later
+    transformed_hostname="${part2}-${part4}"
+  else
+    transformed_hostname="$short_hostname"
+  fi
+  echo "$transformed_hostname"
+}
+
+SHORT_ALIAS="$(short_host)"
+SHORT_ALIAS_FQDN="${SHORT_ALIAS}.${CF_ZONE_NAME}"
+
 # Safe filename for state
 safe_name="$(echo "$CF_RECORD_NAME" | tr '/:' '__')"
 LAST_IP_FILE="${STATE_DIR}/last_ipv4_${safe_name}"
-
 mkdir -p "$STATE_DIR"
 
 # --- Detect local IPv4 on default route interface ---
 detect_ip() {
   local iface ip
-
-  # Prefer ip-route default; fallback to ip route get
   iface="$(ip route show default 2>/dev/null | awk '/default/ {print $5; exit}')"
-  if [[ -z "$iface" ]]; then
+  if [[ -z "${iface}" ]]; then
     iface="$(ip -4 route get 1.1.1.1 2>/dev/null | awk '{for (i=1;i<=NF;i++) if ($i=="dev") {print $(i+1); exit}}')"
   fi
   [[ -n "$iface" ]] || fail "Could not detect default route interface"
-
   ip="$(ip -4 addr show dev "$iface" | awk '/inet / {print $2}' | cut -d/ -f1 | head -n1)"
   [[ -n "$ip" ]] || fail "No IPv4 found on default interface '$iface'"
-
   echo "$ip"
 }
 
@@ -65,13 +78,13 @@ zone_id="$(curl -fsS "${hdr[@]}" "${API}/zones?${zone_q}" \
   | sed -n 's/.*"id":"\([^"]*\)".*"name":"'"$CF_ZONE_NAME"'".*/\1/p' | head -n1)"
 [[ -n "$zone_id" ]] || fail "Could not find Zone ID for ${CF_ZONE_NAME}"
 
-# 2) Lookup existing A record by name
+# 2) Lookup existing A record by FQDN
 rec_q="type=A&name=$(urlenc "$CF_RECORD_NAME")"
 record_json="$(curl -fsS "${hdr[@]}" "${API}/zones/${zone_id}/dns_records?${rec_q}")"
 record_id="$(echo "$record_json" | sed -n 's/.*"id":"\([^"]*\)".*"name":"'"$CF_RECORD_NAME"'".*"type":"A".*/\1/p' | head -n1)"
 
-# 3) Create payload + create/update
-json_payload() {
+# 3) A record payload + create/update
+json_payload_a() {
   cat <<JSON
 {"type":"A","name":"${CF_SHORT_NAME}","content":"${current_ip}","ttl":${CF_TTL},"proxied":${CF_PROXIED}}
 JSON
@@ -80,15 +93,42 @@ JSON
 if [[ -z "$record_id" ]]; then
   log "Creating A ${CF_RECORD_NAME} -> ${current_ip}"
   curl -fsS -X POST "${hdr[@]}" \
-    --data "$(json_payload)" \
+    --data "$(json_payload_a)" \
     "${API}/zones/${zone_id}/dns_records" >/dev/null
-  log "Created."
+  log "A record created."
 else
   log "Updating A ${CF_RECORD_NAME} -> ${current_ip}"
   curl -fsS -X PUT "${hdr[@]}" \
-    --data "$(json_payload)" \
+    --data "$(json_payload_a)" \
     "${API}/zones/${zone_id}/dns_records/${record_id}" >/dev/null
-  log "Updated."
+  log "A record updated."
 fi
 
-echo "$current_ip" > "$LAST_IP_FILE"
+# 4) Create/Update CNAME: SHORT_ALIAS -> CF_RECORD_NAME
+if [[ "$SHORT_ALIAS_FQDN" == "$CF_RECORD_NAME" ]]; then
+  log "SHORT_ALIAS equals CF_RECORD_NAME; skipping CNAME to avoid name conflict."
+else
+  cname_q="type=CNAME&name=$(urlenc "$SHORT_ALIAS_FQDN")"
+  cname_json="$(curl -fsS "${hdr[@]}" "${API}/zones/${zone_id}/dns_records?${cname_q}")"
+  cname_id="$(echo "$cname_json" | sed -n 's/.*"id":"\([^"]*\)".*"name":"'"$SHORT_ALIAS_FQDN"'".*"type":"CNAME".*/\1/p' | head -n1)"
+  json_payload_cname() {
+    cat <<JSON
+{"type":"CNAME","name":"${SHORT_ALIAS}","content":"${CF_RECORD_NAME}","ttl":${CF_TTL},"proxied":${CF_PROXIED}}
+JSON
+  }
+  if [[ -z "$cname_id" ]]; then
+    log "Creating CNAME ${SHORT_ALIAS_FQDN} -> ${CF_RECORD_NAME}"
+    curl -fsS -X POST "${hdr[@]}" \
+      --data "$(json_payload_cname)" \
+      "${API}/zones/${zone_id}/dns_records" >/dev/null
+    log "CNAME created."
+  else
+    log "Updating CNAME ${SHORT_ALIAS_FQDN} -> ${CF_RECORD_NAME}"
+    curl -fsS -X PUT "${hdr[@]}" \
+      --data "$(json_payload_cname)" \
+      "${API}/zones/${zone_id}/dns_records/${cname_id}" >/dev/null
+    log "CNAME updated."
+  fi
+fi
+
+echo "$current_ip" > "$LAST_IP_FILE"