Shadow daemon notification target during demotion

ocf/loxthelion/managed-container.d/applications/postgresql/notify.sh

@@ -1,5 +1,69 @@
 # Sourced by managed-container; uses the shared OCF and parameter environment.
 
+mc_pg_notify_target_daemon_shadow()
+{
+    local expected_node="$1"
+    local expected_successor="$2"
+    local socket_path resource response rc
+
+    socket_path="${MC_PROXY_SOCKET:-/run/user/1000/managed-containerd/managed-containerd.sock}"
+    resource="${OCF_RESOURCE_INSTANCE:-}"
+    resource="${resource%%:*}"
+
+    [ -n "${resource}" ] || return 0
+
+    response="$(
+        timeout --kill-after=1s 3s \
+            python3 \
+            "${MC_PROXY_CLIENT:-/usr/lib/ocf/resource.d/loxthelion/managed-container.d/proxy_client.py}" \
+            "${socket_path}" \
+            "${resource}" \
+            "notify.target" \
+            10 \
+            11
+    )"
+    rc=$?
+
+    if [ "${rc}" -ne 0 ]; then
+        ocf_log warn \
+            "managed-containerd notify.target shadow unavailable rc=${rc}"
+        return 0
+    fi
+
+    if MC_DAEMON_RESPONSE="${response}" \
+       MC_EXPECTED_NODE="${expected_node}" \
+       MC_EXPECTED_SUCCESSOR="${expected_successor}" \
+       python3 -c '
+import json
+import os
+import sys
+
+try:
+    response = json.loads(os.environ["MC_DAEMON_RESPONSE"])
+except (KeyError, TypeError, json.JSONDecodeError):
+    raise SystemExit(1)
+
+if (
+    response.get("ocf_rc") != 0
+    or response.get("target") is not True
+    or response.get("target_node", "").lower()
+        != os.environ["MC_EXPECTED_NODE"].lower()
+    or response.get("successor_node", "").lower()
+        != os.environ["MC_EXPECTED_SUCCESSOR"].lower()
+):
+    raise SystemExit(1)
+'; then
+        ocf_log info \
+            "managed-containerd notify.target shadow: comparison=MATCH target=${expected_node} successor=${expected_successor}"
+    else
+        ocf_log err \
+            "managed-containerd notify.target shadow MISMATCH: expected_target=${expected_node} expected_successor=${expected_successor} response=${response}"
+    fi
+
+    return 0
+}
+
+
 mc_pg_demote_notification_target()
 {
     local allow_self="${1:-false}"
@@ -43,6 +107,8 @@ mc_pg_demote_notification_target()
         return 1
     fi
 
+    mc_pg_notify_target_daemon_shadow         "${local_node}"         "${promote_uname}"
+
     printf '%s\n' "${promote_uname}"
 }