refactor engine: advise TaskBuilder usage for complex task settings

* Remove some obscure overloads of `engine::Async` and `utils::Async` variants

   * If you were using an `Async*` overload that has been removed, then please use @ref utils::TaskBuilder instead

* Advise usage of @ref utils::TaskBuilder::HideSpan instead of @ref engine::AsyncNoSpan
commit_hash:2578bdc78a802c95481cebba0b179dc7c4209309

Author: Anton3

core/include/userver/engine/async.hpp

@@ -8,43 +8,20 @@
 #include <userver/engine/task/shared_task_with_result.hpp>
 #include <userver/engine/task/task_processor_fwd.hpp>
 #include <userver/engine/task/task_with_result.hpp>
-#include <userver/utils/impl/wrapped_call.hpp>
 
 USERVER_NAMESPACE_BEGIN
 
 namespace engine {
 
-namespace impl {
-
-template <template <typename> typename TaskType, typename Function, typename... Args>
-[[nodiscard]] auto MakeTaskWithResult(
-    TaskProcessor& task_processor,
-    Task::Importance importance,
-    Deadline deadline,
-    Function&& f,
-    Args&&... args
-) {
-    using ResultType = typename utils::impl::WrappedCallImplType<Function, Args...>::ResultType;
-    constexpr auto kWaitMode = TaskType<ResultType>::kWaitMode;
-
-    return TaskType<ResultType>{MakeTask(
-        {&task_processor, importance, kWaitMode, deadline},
-        std::forward<Function>(f),
-        std::forward<Args>(args)...
-    )};
-}
-
-}  // namespace impl
-
 /// @brief Runs an asynchronous function call using the specified task processor.
 ///
 /// @warning If any logs are written in the task function (outside any manual tracing::Span scopes),
 /// then those logs will have no `span_id` (yikes!).
 /// If you create a span there manually, it will be disconnected from the outside trace.
 /// **Prefer utils::Async by default instead.**
 ///
-/// @warning To hide a spammy span from traces, use @ref tracing::Span::CurrentSpan plus
-/// @ref tracing::Span::SetLogLevel instead.
+/// @warning To hide a spammy span from traces, use @ref engine::TaskBuilder
+/// with @ref engine::TaskBuilder::HideSpan instead.
 /// Logs will then be linked to the nearest span that is written out.
 ///
 /// @warning Some clients may call tracing::Span::CurrentSpan unconditionally, so don't be too surprised
@@ -56,49 +33,12 @@ template <template <typename> typename TaskType, typename Function, typename...
 /// * some low-level (e.g. driver or filesystem-IO) code where logs are definitely not written;
 /// * breaking traces e.g. this is (rarely) wanted for some background tasks.
 ///
-/// @see utils::Async for main documentation on `Async` function family.
+/// @see @ref utils::Async for main documentation on `Async` function family.
+/// @see @ref engine::TaskBuilder for more `Async` variants.
 template <typename Function, typename... Args>
 [[nodiscard]] auto AsyncNoSpan(TaskProcessor& task_processor, Function&& f, Args&&... args) {
     return impl::MakeTaskWithResult<TaskWithResult>(
-        task_processor,
-        Task::Importance::kNormal,
-        {},
-        std::forward<Function>(f),
-        std::forward<Args>(args)...
-    );
-}
-
-/// @overload
-template <typename Function, typename... Args>
-[[nodiscard]] auto SharedAsyncNoSpan(TaskProcessor& task_processor, Function&& f, Args&&... args) {
-    return impl::MakeTaskWithResult<SharedTaskWithResult>(
-        task_processor,
-        Task::Importance::kNormal,
-        {},
-        std::forward<Function>(f),
-        std::forward<Args>(args)...
-    );
-}
-
-/// @overload
-template <typename Function, typename... Args>
-[[nodiscard]] auto AsyncNoSpan(TaskProcessor& task_processor, Deadline deadline, Function&& f, Args&&... args) {
-    return impl::MakeTaskWithResult<TaskWithResult>(
-        task_processor,
-        Task::Importance::kNormal,
-        deadline,
-        std::forward<Function>(f),
-        std::forward<Args>(args)...
-    );
-}
-
-/// @overload
-template <typename Function, typename... Args>
-[[nodiscard]] auto SharedAsyncNoSpan(TaskProcessor& task_processor, Deadline deadline, Function&& f, Args&&... args) {
-    return impl::MakeTaskWithResult<SharedTaskWithResult>(
-        task_processor,
-        Task::Importance::kNormal,
-        deadline,
+        impl::TaskConfig{.task_processor = &task_processor},
         std::forward<Function>(f),
         std::forward<Args>(args)...
     );
@@ -107,58 +47,19 @@ template <typename Function, typename... Args>
 /// @overload
 template <typename Function, typename... Args>
 [[nodiscard]] auto AsyncNoSpan(Function&& f, Args&&... args) {
-    return AsyncNoSpan(current_task::GetTaskProcessor(), std::forward<Function>(f), std::forward<Args>(args)...);
-}
-
-/// @overload
-template <typename Function, typename... Args>
-[[nodiscard]] auto SharedAsyncNoSpan(Function&& f, Args&&... args) {
-    return SharedAsyncNoSpan(current_task::GetTaskProcessor(), std::forward<Function>(f), std::forward<Args>(args)...);
-}
-
-/// @overload
-template <typename Function, typename... Args>
-[[nodiscard]] auto AsyncNoSpan(Deadline deadline, Function&& f, Args&&... args) {
-    return AsyncNoSpan(
-        current_task::GetTaskProcessor(),
-        deadline,
-        std::forward<Function>(f),
-        std::forward<Args>(args)...
-    );
-}
-
-/// @overload
-template <typename Function, typename... Args>
-[[nodiscard]] auto SharedAsyncNoSpan(Deadline deadline, Function&& f, Args&&... args) {
-    return SharedAsyncNoSpan(
-        current_task::GetTaskProcessor(),
-        deadline,
-        std::forward<Function>(f),
-        std::forward<Args>(args)...
-    );
+    return impl::MakeTaskWithResult<
+        TaskWithResult>(impl::TaskConfig{}, std::forward<Function>(f), std::forward<Args>(args)...);
 }
 
 /// @overload
 /// @see Task::Importance::Critical
 template <typename Function, typename... Args>
 [[nodiscard]] auto CriticalAsyncNoSpan(TaskProcessor& task_processor, Function&& f, Args&&... args) {
     return impl::MakeTaskWithResult<TaskWithResult>(
-        task_processor,
-        Task::Importance::kCritical,
-        {},
-        std::forward<Function>(f),
-        std::forward<Args>(args)...
-    );
-}
-
-/// @overload
-/// @see Task::Importance::Critical
-template <typename Function, typename... Args>
-[[nodiscard]] auto SharedCriticalAsyncNoSpan(TaskProcessor& task_processor, Function&& f, Args&&... args) {
-    return impl::MakeTaskWithResult<SharedTaskWithResult>(
-        task_processor,
-        Task::Importance::kCritical,
-        {},
+        impl::TaskConfig{
+            .task_processor = &task_processor,
+            .importance = Task::Importance::kCritical,
+        },
         std::forward<Function>(f),
         std::forward<Args>(args)...
     );
@@ -168,32 +69,8 @@ template <typename Function, typename... Args>
 /// @see Task::Importance::Critical
 template <typename Function, typename... Args>
 [[nodiscard]] auto CriticalAsyncNoSpan(Function&& f, Args&&... args) {
-    return CriticalAsyncNoSpan(
-        current_task::GetTaskProcessor(),
-        std::forward<Function>(f),
-        std::forward<Args>(args)...
-    );
-}
-
-/// @overload
-/// @see Task::Importance::Critical
-template <typename Function, typename... Args>
-[[nodiscard]] auto SharedCriticalAsyncNoSpan(Function&& f, Args&&... args) {
-    return SharedCriticalAsyncNoSpan(
-        current_task::GetTaskProcessor(),
-        std::forward<Function>(f),
-        std::forward<Args>(args)...
-    );
-}
-
-/// @overload
-/// @see Task::Importance::Critical
-template <typename Function, typename... Args>
-[[nodiscard]] auto CriticalAsyncNoSpan(Deadline deadline, Function&& f, Args&&... args) {
     return impl::MakeTaskWithResult<TaskWithResult>(
-        current_task::GetTaskProcessor(),
-        Task::Importance::kCritical,
-        deadline,
+        impl::TaskConfig{.importance = Task::Importance::kCritical},
         std::forward<Function>(f),
         std::forward<Args>(args)...
     );

core/include/userver/engine/impl/task_context_factory.hpp

@@ -24,7 +24,7 @@ struct TaskConfig final {
     engine::TaskProcessor* task_processor{nullptr};
     Task::Importance importance{Task::Importance::kNormal};
     Task::WaitMode wait_mode{Task::WaitMode::kSingleAwaiter};
-    engine::Deadline deadline;
+    engine::Deadline deadline{};
 };
 
 [[nodiscard]] TaskContext& PlacementNewTaskContext(
@@ -47,7 +47,7 @@ void DeleteFusedTaskContext(std::byte* storage) noexcept;
 // managed by boost::intrusive_ptr<TaskContext> through intrusive_ptr_add_ref
 // and intrusive_ptr_release hooks.
 template <typename Function, typename... Args>
-TaskContextHolder MakeTask(TaskConfig config, Function&& f, Args&&... args) {
+[[nodiscard]] TaskContextHolder MakeTask(TaskConfig&& config, Function&& f, Args&&... args) {
     using WrappedCallType = utils::impl::WrappedCallImplType<Function, Args...>;
 
     constexpr auto kPayloadSize = sizeof(WrappedCallType);
@@ -76,6 +76,15 @@ TaskContextHolder MakeTask(TaskConfig config, Function&& f, Args&&... args) {
     return TaskContextHolder::Adopt(context);
 }
 
+template <template <typename> typename TaskType, typename Function, typename... Args>
+[[nodiscard]] auto MakeTaskWithResult(TaskConfig&& config, Function&& f, Args&&... args) {
+    using ResultType = typename utils::impl::WrappedCallImplType<Function, Args...>::ResultType;
+    constexpr auto kWaitMode = TaskType<ResultType>::kWaitMode;
+    config.wait_mode = kWaitMode;
+
+    return TaskType<ResultType>{MakeTask(std::move(config), std::forward<Function>(f), std::forward<Args>(args)...)};
+}
+
 }  // namespace engine::impl
 
 USERVER_NAMESPACE_END