initial design

weed/admin/task/failure_handler.go

@@ -0,0 +1,123 @@
+package task
+
+import (
+	"time"
+
+	"github.com/seaweedfs/seaweedfs/weed/glog"
+)
+
+// FailureHandler handles various failure scenarios in the task system
+type FailureHandler struct {
+	config *AdminConfig
+}
+
+// NewFailureHandler creates a new failure handler
+func NewFailureHandler(config *AdminConfig) *FailureHandler {
+	return &FailureHandler{
+		config: config,
+	}
+}
+
+// HandleWorkerTimeout handles worker timeout scenarios
+func (fh *FailureHandler) HandleWorkerTimeout(workerID string, affectedTasks []*InProgressTask) {
+	glog.Warningf("Handling worker timeout for worker %s with %d affected tasks", workerID, len(affectedTasks))
+
+	for _, task := range affectedTasks {
+		fh.handleTaskFailure(task, "worker_timeout", "Worker became unresponsive")
+	}
+}
+
+// HandleTaskStuck handles stuck task scenarios
+func (fh *FailureHandler) HandleTaskStuck(task *InProgressTask) {
+	glog.Warningf("Handling stuck task %s (no progress for %v)", task.Task.ID, time.Since(task.LastUpdate))
+
+	fh.handleTaskFailure(task, "task_stuck", "Task made no progress within timeout period")
+}
+
+// HandleTaskFailure handles general task failure scenarios
+func (fh *FailureHandler) HandleTaskFailure(task *InProgressTask, reason string, details string) {
+	glog.Errorf("Handling task failure for task %s: %s - %s", task.Task.ID, reason, details)
+
+	fh.handleTaskFailure(task, reason, details)
+}
+
+// handleTaskFailure is the internal handler for task failures
+func (fh *FailureHandler) handleTaskFailure(task *InProgressTask, reason string, details string) {
+	// Record failure reason
+	task.Task.Error = details
+
+	// Determine if task should be retried
+	if task.Task.RetryCount < fh.config.MaxRetries {
+		fh.scheduleRetry(task, reason)
+	} else {
+		fh.markTaskFailed(task, reason)
+	}
+}
+
+// scheduleRetry schedules a task for retry
+func (fh *FailureHandler) scheduleRetry(task *InProgressTask, reason string) {
+	task.Task.RetryCount++
+
+	// Calculate retry delay with exponential backoff
+	retryDelay := time.Duration(task.Task.RetryCount) * 5 * time.Minute
+	task.Task.ScheduledAt = time.Now().Add(retryDelay)
+
+	glog.Infof("Scheduling retry %d/%d for task %s (reason: %s, delay: %v)",
+		task.Task.RetryCount, fh.config.MaxRetries, task.Task.ID, reason, retryDelay)
+}
+
+// markTaskFailed permanently marks a task as failed
+func (fh *FailureHandler) markTaskFailed(task *InProgressTask, reason string) {
+	glog.Errorf("Task %s permanently failed after %d retries (reason: %s)",
+		task.Task.ID, task.Task.RetryCount, reason)
+
+	// Could trigger alerts or notifications here
+	fh.sendFailureAlert(task, reason)
+}
+
+// sendFailureAlert sends alerts for permanently failed tasks
+func (fh *FailureHandler) sendFailureAlert(task *InProgressTask, reason string) {
+	// In a real implementation, this would:
+	// 1. Send notifications to administrators
+	// 2. Update monitoring dashboards
+	// 3. Log to audit trails
+	// 4. Possibly trigger automatic remediation
+
+	glog.Errorf("ALERT: Task permanently failed - ID: %s, Type: %s, Volume: %d, Reason: %s",
+		task.Task.ID, task.Task.Type, task.Task.VolumeID, reason)
+}
+
+// HandleDuplicateTask handles duplicate task detection
+func (fh *FailureHandler) HandleDuplicateTask(existingTaskID string, duplicateTaskID string, volumeID uint32) {
+	glog.Warningf("Detected duplicate task for volume %d: existing=%s, duplicate=%s",
+		volumeID, existingTaskID, duplicateTaskID)
+
+	// Cancel the duplicate task
+	// In a real implementation, this would send a cancellation signal
+}
+
+// HandleResourceExhaustion handles resource exhaustion scenarios
+func (fh *FailureHandler) HandleResourceExhaustion(workerID string, taskType string) {
+	glog.Warningf("Worker %s reported resource exhaustion for task type %s", workerID, taskType)
+
+	// Could implement:
+	// 1. Temporary worker blacklisting
+	// 2. Task redistribution
+	// 3. Resource monitoring alerts
+}
+
+// GetFailureStats returns failure statistics
+func (fh *FailureHandler) GetFailureStats() map[string]interface{} {
+	// In a real implementation, this would track:
+	// - Failure rates by type
+	// - Worker reliability scores
+	// - Task retry statistics
+	// - System health metrics
+
+	return map[string]interface{}{
+		"enabled":        true,
+		"max_retries":    fh.config.MaxRetries,
+		"task_timeout":   fh.config.TaskTimeout.String(),
+		"worker_timeout": fh.config.WorkerTimeout.String(),
+	}
+}