From 644982f50aa440413b5939404244f468f75518a6 Mon Sep 17 00:00:00 2001
From: "Alexander A. Klimov" <alexander.klimov@icinga.com>
Date: Wed, 14 Jun 2023 17:00:56 +0200
Subject: [PATCH] Notification#BeginExecuteNotification(): discard likely
 duplicate problem notifications

---
 lib/icinga/notification.cpp  | 16 ++++++++
 test/CMakeLists.txt          |  1 +
 test/icinga-notification.cpp | 71 ++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+)

diff --git a/lib/icinga/notification.cpp b/lib/icinga/notification.cpp
index e545b304dfa..2338f280bfb 100644
--- a/lib/icinga/notification.cpp
+++ b/lib/icinga/notification.cpp
@@ -440,6 +440,22 @@ void Notification::BeginExecuteNotification(NotificationType type, const CheckRe
 			}
 		}
 
+		if (type == NotificationProblem && !reminder && !checkable->GetVolatile()) {
+			auto [host, service] = GetHostService(checkable);
+			uint_fast8_t state = service ? service->GetState() : host->GetState();
+
+			if (state == (uint_fast8_t)GetLastNotifiedStatePerUser()->Get(userName)) {
+				auto stateStr (service ? NotificationServiceStateToString(service->GetState()) : NotificationHostStateToString(host->GetState()));
+
+				Log(LogNotice, "Notification")
+					<< "Notification object '" << notificationName << "': We already notified user '" << userName << "' for a " << stateStr
+					<< " problem. Likely after that another state change notification was filtered out by config. Not sending duplicate '"
+					<< stateStr << "' notification.";
+
+				continue;
+			}
+		}
+
 		Log(LogInformation, "Notification")
 			<< "Sending " << (reminder ? "reminder " : "") << "'" << NotificationTypeToString(type) << "' notification '"
 			<< notificationName << "' for user '" << userName << "'";
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 8919de304dc..d947d3ba05c 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -138,6 +138,7 @@ add_boost_test(base
     icinga_notification/strings
     icinga_notification/state_filter
     icinga_notification/type_filter
+    icinga_notification/duplicate_dueto_filter
     icinga_macros/simple
     icinga_legacytimeperiod/simple
     icinga_legacytimeperiod/advanced
diff --git a/test/icinga-notification.cpp b/test/icinga-notification.cpp
index 5cf3f49e821..72e16062520 100644
--- a/test/icinga-notification.cpp
+++ b/test/icinga-notification.cpp
@@ -1,11 +1,58 @@
 /* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
 
+#include "icinga/host.hpp"
 #include "icinga/notification.hpp"
+#include "icinga/notificationcommand.hpp"
+#include "icinga/service.hpp"
+#include "icinga/user.hpp"
 #include <BoostTestTargetConfig.h>
 #include <iostream>
 
 using namespace icinga;
 
+struct DuplicateDueToFilterHelper
+{
+	Host::Ptr h = new Host();
+	Service::Ptr s = new Service();
+	User::Ptr u = new User();
+	NotificationCommand::Ptr nc = new NotificationCommand();
+	Notification::Ptr n = new Notification();
+	unsigned int called = 0;
+
+	DuplicateDueToFilterHelper()
+	{
+		h->SetName("example.com", true);
+		h->Register();
+
+		s->SetShortName("disk", true);
+		h->AddService(s);
+
+		u->SetName("jdoe", true);
+		u->SetTypeFilter(~0);
+		u->SetStateFilter(~0);
+		u->Register();
+
+		nc->SetName("mail", true);
+		nc->SetExecute(new Function("", [this]() { ++called; }), true);
+		nc->Register();
+
+		n->SetFieldByName("host_name", "example.com", false, DebugInfo());
+		n->SetFieldByName("service_name", "disk", false, DebugInfo());
+		n->SetFieldByName("command", "mail", false, DebugInfo());
+		n->SetUsersRaw(new Array({"jdoe"}), true);
+		n->SetTypeFilter(~NotificationRecovery);
+		n->SetStateFilter(~StateFilterWarning);
+		((ConfigObject*)n.get())->OnAllConfigLoaded(); // link Service
+	}
+
+	~DuplicateDueToFilterHelper()
+	{
+		h->Unregister();
+		u->Unregister();
+		nc->Unregister();
+	}
+};
+
 BOOST_AUTO_TEST_SUITE(icinga_notification)
 
 BOOST_AUTO_TEST_CASE(strings)
@@ -102,4 +149,28 @@ BOOST_AUTO_TEST_CASE(type_filter)
 	std::cout << "#4 Notification type: " << ftype << " against " << notification->GetTypeFilter() << " must fail." << std::endl;
 	BOOST_CHECK(!(notification->GetTypeFilter() & ftype));
 }
+
+BOOST_AUTO_TEST_CASE(duplicate_dueto_filter)
+{
+	DuplicateDueToFilterHelper helper;
+
+	helper.s->SetState(ServiceCritical, true);
+	Application::GetTP().Start();
+	helper.n->BeginExecuteNotification(NotificationProblem, nullptr, false, false, "", "");
+	Application::GetTP().Stop();
+	BOOST_CHECK(helper.called == 1u);
+
+	helper.s->SetState(ServiceWarning, true);
+	Application::GetTP().Start();
+	helper.n->BeginExecuteNotification(NotificationProblem, nullptr, false, false, "", "");
+	Application::GetTP().Stop();
+	BOOST_CHECK(helper.called == 1u);
+
+	helper.s->SetState(ServiceCritical, true);
+	Application::GetTP().Start();
+	helper.n->BeginExecuteNotification(NotificationProblem, nullptr, false, false, "", "");
+	Application::GetTP().Stop();
+	BOOST_CHECK(helper.called == 1u);
+}
+
 BOOST_AUTO_TEST_SUITE_END()