workshop: implement TERMINATE_CHILDREN for "translate" and "spawn"

Author: MaxKellermann

debian/changelog

@@ -1,6 +1,7 @@
 cm4all-workshop (7.2) unstable; urgency=low
 
   * workshop: disable plan UID check for "translate" plans
+  * workshop: implement TERMINATE_CHILDREN for "translate" and "spawn"
   * cron: support multiple CHILD_TAGs for TERMINATE_CHILDREN
 
  --   

src/Instance.cxx

@@ -216,9 +216,13 @@ Instance::OnControlPacket(BengControl::Command command,
 		break;
 
 	case Command::TERMINATE_CHILDREN:
-		if (const auto tag = ToStringView(payload); !tag.empty())
+		if (const auto tag = ToStringView(payload); !tag.empty()) {
+			for (auto &i : partitions)
+				i.TerminateChildren(tag);
 			for (auto &i : cron_partitions)
 				i.TerminateChildren(tag);
+		}
+
 		break;
 
 	case Command::DISABLE_QUEUE:

src/workshop/Operator.cxx

@@ -33,6 +33,7 @@
 #include "co/Task.hxx"
 #include "util/DeleteDisposer.hxx"
 #include "util/StringCompare.hxx"
+#include "util/StringList.hxx"
 #include "util/UTF8.hxx"
 #include "AllocatorPtr.hxx"
 #include "CgroupAccounting.hxx"
@@ -87,6 +88,12 @@ WorkshopOperator::~WorkshopOperator() noexcept
 	children.clear_and_dispose(DeleteDisposer{});
 }
 
+bool
+WorkshopOperator::IsChildTag(std::string_view value) const noexcept
+{
+	return StringListContains(child_tag, '\0', value);
+}
+
 inline UniqueFileDescriptor
 WorkshopOperator::InitLog(std::size_t max_log_buffer,
 			  bool enable_journal)
@@ -240,6 +247,11 @@ WorkshopOperator::Start2(std::size_t max_log_buffer,
 				       job.plan_name.c_str(),
 				       "", nullptr,
 				       job.args);
+
+		if (translation.execute_options != nullptr &&
+		    !translation.execute_options->child_options.tag.empty() &&
+		    child_tag.empty())
+			child_tag = translation.execute_options->child_options.tag;
 	}
 
 	auto &spawn_service = workplace.GetSpawnService();
@@ -349,6 +361,17 @@ WorkshopOperator::Start2(std::size_t max_log_buffer,
 	}
 }
 
+void
+WorkshopOperator::Cancel() noexcept
+{
+	logger(2, "cancel");
+
+	job.SetDone(-1, "Canceled");
+
+	/* we do not kill the process because this will be done
+	   implicitly by our destructor */
+}
+
 inline void
 WorkshopOperator::OnTaskCompletion(std::exception_ptr &&error) noexcept
 {
@@ -594,6 +617,11 @@ WorkshopOperator::OnControlSpawn(const char *token, const char *param)
 			       token, param,
 			       {});
 
+	if (response.execute_options != nullptr &&
+	    !response.execute_options->child_options.tag.empty() &&
+	    child_tag.empty())
+		child_tag = response.execute_options->child_options.tag;
+
 	auto &spawn_service = workplace.GetSpawnService();
 
 	co_await CoEnqueueSpawner{spawn_service};

src/workshop/Operator.hxx

@@ -58,6 +58,12 @@ class WorkshopOperator final
 
 	const LazyDomainLogger logger;
 
+	/**
+	 * The CHILD_TAG value from the translation response.  Used to
+	 * implement the control command TERMINATE_CHILDREN.
+	 */
+	std::string child_tag;
+
 	FarTimerEvent timeout_event;
 
 	std::unique_ptr<ProgressReader> progress_reader;
@@ -107,9 +113,23 @@ public:
 		return job.plan_name;
 	}
 
+	[[gnu::pure]]
+	bool IsChildTag(std::string_view value) const noexcept;
+
 	void Start(std::size_t max_log_buffer,
 		   bool enable_journal) noexcept;
 
+	/**
+	 * Kill the process and put the database record in a complete
+	 * and failed state, but do not invoke the #WorkshopWorkplace
+	 * (because that is supposed to be the caller who already
+	 * knows the job completes).
+	 *
+	 * After this method returns, the caller is supposed to delete
+	 * this object.
+	 */
+	void Cancel() noexcept;
+
 private:
 	[[nodiscard]]
 	Co::InvokeTask Start2(std::size_t max_log_buffer,

src/workshop/Partition.hxx

@@ -91,6 +91,10 @@ public:
 		queue.EnableAdmin();
 	}
 
+	void TerminateChildren(std::string_view child_tag) noexcept {
+		workplace.CancelTag(child_tag);
+	}
+
 	void UpdateFilter(bool library_modified=false) noexcept;
 	void UpdateLibraryAndFilter(bool force) noexcept;
 

src/workshop/Workplace.cxx

@@ -112,3 +112,17 @@ WorkshopWorkplace::OnTimeout(WorkshopOperator *o) noexcept
 {
 	OnExit(o);
 }
+
+void
+WorkshopWorkplace::CancelTag(std::string_view tag) noexcept
+{
+	const auto n = operators.remove_and_dispose_if([tag](const auto &o){
+		return o.IsChildTag(tag);
+	}, [](auto *o) {
+		o->Cancel();
+		delete o;
+	});
+
+	if (n > 0)
+		exit_listener.OnChildProcessExit(-1);
+}

src/workshop/Workplace.hxx

@@ -98,4 +98,6 @@ public:
 
 	void OnExit(WorkshopOperator *o) noexcept;
 	void OnTimeout(WorkshopOperator *o) noexcept;
+
+	void CancelTag(std::string_view tag) noexcept;
 };