Checkable: sync state_before_suppression in cluster

This ensures that in case of a failover in an HA zone, the other can take over
properly and has the required state to send the proper notifications.

doc/19-technical-concepts.md

@@ -1370,6 +1370,43 @@ Message updates will be dropped when:
 * Checkable does not exist.
 * Origin endpoint's zone is not allowed to access this checkable.
 
+#### event::SetStateBeforeSuppression <a id="technical-concepts-json-rpc-messages-event-setstatebeforesuppression"></a>
+
+> Location: `clusterevents.cpp`
+
+##### Message Body
+
+Key       | Value
+----------|---------------------------------
+jsonrpc   | 2.0
+method    | event::SetStateBeforeSuppression
+params    | Dictionary
+
+##### Params
+
+Key                        | Type   | Description
+---------------------------|--------|-----------------------------------------------
+host                       | String | Host name
+service                    | String | Service name
+state\_before\_suppression | Number | Checkable state before the current suppression
+
+##### Functions
+
+Event Sender: `Checkable::OnStateBeforeSuppressionChanged`
+Event Receiver: `StateBeforeSuppressionChangedAPIHandler`
+
+Used to sync the checkable state from before a notification suppression (for example
+because the checkable is in a downtime) started within the same HA zone.
+
+##### Permissions
+
+The receiver will not process messages from not configured endpoints.
+
+Message updates will be dropped when:
+
+* Checkable does not exist.
+* Origin endpoint is not within the local zone.
+
 #### event::SetSuppressedNotifications <a id="technical-concepts-json-rpc-messages-event-setsupressednotifications"></a>
 
 > Location: `clusterevents.cpp`

lib/icinga/clusterevents.cpp

@@ -25,6 +25,7 @@ INITIALIZE_ONCE(&ClusterEvents::StaticInitialize);
 REGISTER_APIFUNCTION(CheckResult, event, &ClusterEvents::CheckResultAPIHandler);
 REGISTER_APIFUNCTION(SetNextCheck, event, &ClusterEvents::NextCheckChangedAPIHandler);
 REGISTER_APIFUNCTION(SetLastCheckStarted, event, &ClusterEvents::LastCheckStartedChangedAPIHandler);
+REGISTER_APIFUNCTION(SetStateBeforeSuppression, event, &ClusterEvents::StateBeforeSuppressionChangedAPIHandler);
 REGISTER_APIFUNCTION(SetSuppressedNotifications, event, &ClusterEvents::SuppressedNotificationsChangedAPIHandler);
 REGISTER_APIFUNCTION(SetSuppressedNotificationTypes, event, &ClusterEvents::SuppressedNotificationTypesChangedAPIHandler);
 REGISTER_APIFUNCTION(SetNextNotification, event, &ClusterEvents::NextNotificationChangedAPIHandler);
@@ -45,6 +46,7 @@ void ClusterEvents::StaticInitialize()
 	Checkable::OnNewCheckResult.connect(&ClusterEvents::CheckResultHandler);
 	Checkable::OnNextCheckChanged.connect(&ClusterEvents::NextCheckChangedHandler);
 	Checkable::OnLastCheckStartedChanged.connect(&ClusterEvents::LastCheckStartedChangedHandler);
+	Checkable::OnStateBeforeSuppressionChanged.connect(&ClusterEvents::StateBeforeSuppressionChangedHandler);
 	Checkable::OnSuppressedNotificationsChanged.connect(&ClusterEvents::SuppressedNotificationsChangedHandler);
 	Notification::OnSuppressedNotificationsChanged.connect(&ClusterEvents::SuppressedNotificationTypesChangedHandler);
 	Notification::OnNextNotificationChanged.connect(&ClusterEvents::NextNotificationChangedHandler);
@@ -306,6 +308,68 @@ Value ClusterEvents::LastCheckStartedChangedAPIHandler(const MessageOrigin::Ptr&
 	return Empty;
 }
 
+void ClusterEvents::StateBeforeSuppressionChangedHandler(const Checkable::Ptr& checkable, const MessageOrigin::Ptr& origin)
+{
+	ApiListener::Ptr listener = ApiListener::GetInstance();
+
+	if (!listener)
+		return;
+
+	Host::Ptr host;
+	Service::Ptr service;
+	tie(host, service) = GetHostService(checkable);
+
+	Dictionary::Ptr params = new Dictionary();
+	params->Set("host", host->GetName());
+	if (service)
+		params->Set("service", service->GetShortName());
+	params->Set("state_before_suppression", checkable->GetStateBeforeSuppression());
+
+	Dictionary::Ptr message = new Dictionary();
+	message->Set("jsonrpc", "2.0");
+	message->Set("method", "event::SetStateBeforeSuppression");
+	message->Set("params", params);
+
+	listener->RelayMessage(origin, nullptr, message, true);
+}
+
+Value ClusterEvents::StateBeforeSuppressionChangedAPIHandler(const MessageOrigin::Ptr& origin, const Dictionary::Ptr& params)
+{
+	Endpoint::Ptr endpoint = origin->FromClient->GetEndpoint();
+
+	if (!endpoint) {
+		Log(LogNotice, "ClusterEvents")
+			<< "Discarding 'state before suppression changed' message from '" << origin->FromClient->GetIdentity() << "': Invalid endpoint origin (client not allowed).";
+		return Empty;
+	}
+
+	Host::Ptr host = Host::GetByName(params->Get("host"));
+
+	if (!host)
+		return Empty;
+
+	Checkable::Ptr checkable;
+
+	if (params->Contains("service"))
+		checkable = host->GetServiceByShortName(params->Get("service"));
+	else
+		checkable = host;
+
+	if (!checkable)
+		return Empty;
+
+	if (origin->FromZone && origin->FromZone != Zone::GetLocalZone()) {
+		Log(LogNotice, "ClusterEvents")
+			<< "Discarding 'state before suppression changed' message for checkable '" << checkable->GetName()
+			<< "' from '" << origin->FromClient->GetIdentity() << "': Unauthorized access.";
+		return Empty;
+	}
+
+	checkable->SetStateBeforeSuppression(ServiceState(int(params->Get("state_before_suppression"))), false, origin);
+
+	return Empty;
+}
+
 void ClusterEvents::SuppressedNotificationsChangedHandler(const Checkable::Ptr& checkable, const MessageOrigin::Ptr& origin)
 {
 	ApiListener::Ptr listener = ApiListener::GetInstance();

lib/icinga/clusterevents.hpp

@@ -29,6 +29,9 @@ public:
 	static void LastCheckStartedChangedHandler(const Checkable::Ptr& checkable, const MessageOrigin::Ptr& origin);
 	static Value LastCheckStartedChangedAPIHandler(const MessageOrigin::Ptr& origin, const Dictionary::Ptr& params);
 
+	static void StateBeforeSuppressionChangedHandler(const Checkable::Ptr& checkable, const MessageOrigin::Ptr& origin);
+	static Value StateBeforeSuppressionChangedAPIHandler(const MessageOrigin::Ptr& origin, const Dictionary::Ptr& params);
+
 	static void SuppressedNotificationsChangedHandler(const Checkable::Ptr& checkable, const MessageOrigin::Ptr& origin);
 	static Value SuppressedNotificationsChangedAPIHandler(const MessageOrigin::Ptr& origin, const Dictionary::Ptr& params);