add core lib

worker/poller.go

@@ -0,0 +1,70 @@
+package worker
+
+import (
+	"context"
+	"log/slog"
+	"time"
+)
+
+const defaultTaskName = "batch worker"
+
+// BatchRunner executes one batch and returns the number of processed records.
+// Returning 0 stops the current drain cycle.
+type BatchRunner func(ctx context.Context, limit int) (int, error)
+
+func Run(ctx context.Context, runner BatchRunner, interval time.Duration, batchSize int, logger *slog.Logger, taskName string) {
+	if runner == nil || interval <= 0 || batchSize <= 0 {
+		return
+	}
+	if logger == nil {
+		logger = slog.Default()
+	}
+	if taskName == "" {
+		taskName = defaultTaskName
+	}
+
+	RunOnce(ctx, runner, batchSize, logger, taskName)
+
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			RunOnce(ctx, runner, batchSize, logger, taskName)
+		}
+	}
+}
+
+func RunOnce(ctx context.Context, runner BatchRunner, batchSize int, logger *slog.Logger, taskName string) {
+	if runner == nil || batchSize <= 0 {
+		return
+	}
+	if logger == nil {
+		logger = slog.Default()
+	}
+	if taskName == "" {
+		taskName = defaultTaskName
+	}
+
+	totalProcessed := 0
+	for {
+		processed, err := runner(ctx, batchSize)
+		if err != nil {
+			if ctx.Err() == nil {
+				logger.Warn(taskName+" run failed", "error", err)
+			}
+			return
+		}
+		if processed <= 0 {
+			break
+		}
+		totalProcessed += processed
+	}
+
+	if totalProcessed > 0 {
+		logger.Info(taskName+" completed", "processed", totalProcessed)
+	}
+}