Checkable#ProcessCheckResult(): discard CR or delay its producers shutdown

lib/icinga/checkable-check.cpp

@@ -14,6 +14,7 @@
 #include "base/convert.hpp"
 #include "base/utility.hpp"
 #include "base/context.hpp"
+#include <shared_mutex>
 
 using namespace icinga;
 
@@ -94,7 +95,7 @@ double Checkable::GetLastCheck() const
 	return schedule_end;
 }
 
-Checkable::ProcessingResult Checkable::ProcessCheckResult(const CheckResult::Ptr& cr, const MessageOrigin::Ptr& origin)
+Checkable::ProcessingResult Checkable::ProcessCheckResult(const CheckResult::Ptr& cr, const CheckResultProducer::Ptr& producer, const MessageOrigin::Ptr& origin)
 {
 	using Result = Checkable::ProcessingResult;
 
@@ -106,6 +107,9 @@ Checkable::ProcessingResult Checkable::ProcessCheckResult(const CheckResult::Ptr
 	if (!cr)
 		return Result::NoCheckResult;
 
+	if (!producer)
+		return Result::NoCheckResult;
+
 	double now = Utility::GetTime();
 
 	if (cr->GetScheduleStart() == 0)
@@ -134,6 +138,14 @@ Checkable::ProcessingResult Checkable::ProcessCheckResult(const CheckResult::Ptr
 			cr->SetCheckSource(command_endpoint->GetName());
 	}
 
+	std::shared_lock producerLock (*producer, std::try_to_lock);
+
+	if (!producerLock) {
+		// Discard the check result to not delay the current reload.
+		// We'll re-run the check immediately after the reload.
+		return Result::CheckableInactive;
+	}
+
 	/* agent checks go through the api */
 	if (command_endpoint && GetExtension("agent_check")) {
 		ApiListener::Ptr listener = ApiListener::GetInstance();

lib/icinga/checkable-script.cpp

@@ -9,18 +9,18 @@
 
 using namespace icinga;
 
-static void CheckableProcessCheckResult(const CheckResult::Ptr& cr)
+static void CheckableProcessCheckResult(const CheckResult::Ptr& cr, const CheckResultProducer::Ptr& producer)
 {
 	ScriptFrame *vframe = ScriptFrame::GetCurrentFrame();
 	Checkable::Ptr self = vframe->Self;
 	REQUIRE_NOT_NULL(self);
-	self->ProcessCheckResult(cr);
+	self->ProcessCheckResult(cr, producer);
 }
 
 Object::Ptr Checkable::GetPrototype()
 {
 	static Dictionary::Ptr prototype = new Dictionary({
-		{ "process_check_result", new Function("Checkable#process_check_result", CheckableProcessCheckResult, { "cr" }, false) }
+		{ "process_check_result", new Function("Checkable#process_check_result", CheckableProcessCheckResult, { "cr", "producer" }, false) }
 	});
 
 	return prototype;

lib/icinga/checkable.hpp

@@ -12,6 +12,7 @@
 #include "icinga/notification.hpp"
 #include "icinga/comment.hpp"
 #include "icinga/downtime.hpp"
+#include "remote/crproducer.hpp"
 #include "remote/endpoint.hpp"
 #include "remote/messageorigin.hpp"
 #include <condition_variable>
@@ -119,7 +120,8 @@ public:
 		CheckableInactive,
 		NewerCheckResultPresent,
 	};
-	ProcessingResult ProcessCheckResult(const CheckResult::Ptr& cr, const MessageOrigin::Ptr& origin = nullptr);
+
+	ProcessingResult ProcessCheckResult(const CheckResult::Ptr& cr, const CheckResultProducer::Ptr& producer, const MessageOrigin::Ptr& origin = nullptr);
 
 	Endpoint::Ptr GetCommandEndpoint() const;
 

lib/remote/CMakeLists.txt

@@ -13,6 +13,7 @@ set(remote_SOURCES
   apilistener.cpp apilistener.hpp apilistener-ti.hpp apilistener-configsync.cpp apilistener-filesync.cpp
   apilistener-authority.cpp
   apiuser.cpp apiuser.hpp apiuser-ti.hpp
+  crproducer.hpp
   configfileshandler.cpp configfileshandler.hpp
   configobjectslock.cpp configobjectslock.hpp
   configobjectutility.cpp configobjectutility.hpp

lib/remote/crproducer.hpp

@@ -0,0 +1,34 @@
+/* Icinga 2 | (c) 2025 Icinga GmbH | GPLv2+ */
+
+#pragma once
+
+#include "base/object.hpp"
+
+namespace icinga
+{
+
+/**
+ * A component that produces check results and hence is responsible for them, e.g. CheckerComponent.
+ * I.e. on its shutdown it has to clean up and/or wait for its own ongoing checks if any.
+ *
+ * @ingroup icinga
+ */
+class CheckResultProducer : virtual public Object
+{
+public:
+	DECLARE_PTR_TYPEDEFS(CheckResultProducer);
+
+	/**
+	 * Requests to delay the producer shutdown (if any) for a CheckResult to be processed.
+	 *
+	 * @return Whether request was accepted.
+	 */
+	virtual bool try_lock_shared() noexcept = 0;
+
+	/**
+	 * Releases one semaphore slot acquired for CheckResult processing.
+	 */
+	virtual void unlock_shared() noexcept = 0;
+};
+
+}