refactor: implement extractor retry logic and streamline extractor interface

internal/app/etl/extractors/extract-with-retries.go

@@ -0,0 +1,70 @@
+package extractors
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/custom_errors"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
+	"github.com/google/uuid"
+)
+
+func extractWithRetries(
+	ctx context.Context,
+	extractor etl.Extractor,
+	tableInfo config.SourceTableInfo,
+	columns []models.ColumnType,
+	batchSize int,
+	partition models.Partition,
+	indexPrimaryKey int,
+	chBatchesOut chan<- models.Batch,
+) (int64, error) {
+	var totalRowsRead int64
+	delay := time.Duration(time.Second * 1)
+	currentParitition := partition
+
+	for {
+		rowsRead, err := extractor.Exec(
+			ctx,
+			tableInfo,
+			columns,
+			batchSize,
+			currentParitition,
+			indexPrimaryKey,
+			chBatchesOut,
+		)
+		totalRowsRead += rowsRead
+
+		if err == nil {
+			return totalRowsRead, nil
+		}
+
+		var exError *custom_errors.ExtractorError
+		if errors.As(err, &exError) {
+			currentParitition.RetryCounter++
+
+			if currentParitition.RetryCounter > 3 {
+				return totalRowsRead, &custom_errors.JobError{
+					Msg:  fmt.Sprintf("Partition %v reached max retries", exError.Partition.Id),
+					Prev: err,
+				}
+			}
+
+			if exError.HasLastId {
+				currentParitition.ParentId = exError.Partition.Id
+				currentParitition.Id = uuid.New()
+				currentParitition.Range.Min = exError.LastId
+				currentParitition.Range.IsMinInclusive = false
+			}
+
+			time.Sleep(delay)
+			continue
+		}
+
+		return totalRowsRead, err
+	}
+}