feat: Tolerate collector failures (#1769)

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

internal/headers/schedule_service/schedule_service.go

@@ -0,0 +1,88 @@
+// Copyright 2024 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schedule_service
+
+import (
+	"errors"
+	"fmt"
+	"runtime"
+
+	"github.com/go-ole/go-ole"
+	"github.com/go-ole/go-ole/oleutil"
+)
+
+type ScheduleService struct {
+	taskSchedulerObj *ole.IUnknown
+	taskServiceObj   *ole.IDispatch
+	taskService      *ole.VARIANT
+}
+
+func New() *ScheduleService {
+	return &ScheduleService{}
+}
+
+func (s *ScheduleService) Connect() error {
+	// The only way to run WMI queries in parallel while being thread-safe is to
+	// ensure the CoInitialize[Ex]() call is bound to its current OS thread.
+	// Otherwise, attempting to initialize and run parallel queries across
+	// goroutines will result in protected memory errors.
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if err := ole.CoInitializeEx(0, ole.COINIT_MULTITHREADED|ole.COINIT_DISABLE_OLE1DDE); err != nil {
+		var oleCode *ole.OleError
+		if errors.As(err, &oleCode) && oleCode.Code() != ole.S_OK && oleCode.Code() != 0x00000001 {
+			return err
+		}
+	}
+
+	scheduleClassID, err := ole.ClassIDFrom("Schedule.Service")
+	if err != nil {
+		return err
+	}
+
+	s.taskSchedulerObj, err = ole.CreateInstance(scheduleClassID, nil)
+	if err != nil || s.taskSchedulerObj == nil {
+		return err
+	}
+
+	s.taskServiceObj = s.taskSchedulerObj.MustQueryInterface(ole.IID_IDispatch)
+
+	s.taskService, err = oleutil.CallMethod(s.taskServiceObj, "Connect")
+	if err != nil {
+		return fmt.Errorf("failed to connect to task service: %w", err)
+	}
+
+	return nil
+}
+
+func (s *ScheduleService) GetOLETaskServiceObj() *ole.IDispatch {
+	return s.taskServiceObj
+}
+
+func (s *ScheduleService) Close() {
+	if s.taskService != nil {
+		_ = s.taskService.Clear()
+	}
+
+	if s.taskServiceObj != nil {
+		s.taskServiceObj.Release()
+	}
+
+	if s.taskSchedulerObj != nil {
+		s.taskSchedulerObj.Release()
+	}
+
+	ole.CoUninitialize()
+}