feat: add dinamic query building

cmd/go_migrate/main.go

@@ -4,12 +4,13 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"strings"
 	"time"
 
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/db"
 	"github.com/jackc/pgx/v5"
-	"github.com/jackc/pgx/v5/pgconn"
+	"github.com/jackc/pgx/v5/pgxpool"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -21,10 +22,35 @@ func main() {
 	log.SetLevel(log.DebugLevel)
 
 	log.Info("Starting migration...")
-	rowValues, colNames, err := extractData()
+
+	ctxSource, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+	defer cancel()
+
+	sourcePool, err := db.Connect(ctxSource, config.App.FromDb.Url)
+	defer db.Close(sourcePool)
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Info("Successfully connected to from_db")
+
+	ctxTarget, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+	defer cancel()
+
+	targetPool, err := db.Connect(ctxTarget, config.App.ToDb.Url)
+	defer db.Close(targetPool)
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Info("Successfully connected to to_db")
+
+	schema := "test"
+	table := "migration_test"
+	colNames := []string{"id", "nombre_producto", "descripcion", "stock", "precio", "es_activo", "fecha_creacion", "ultima_actualizacion", "configuracion_json", "etiquetas", "binario_test", "ip_servidor", "rango_prueba"}
+
+	rowValues, err := extractData(ctxSource, sourcePool, schema, table, colNames, 2)
 
 	if err != nil {
-		log.Fatal("Unexpected error when extracting data")
+		log.Fatal("Unexpected error when extracting data", err)
 	}
 
 	for index, row := range rowValues {
@@ -34,50 +60,48 @@ func main() {
 		}
 	}
 
+	insertedRows, err := insertData(ctxTarget, targetPool, schema, table, colNames, rowValues)
+	if err != nil {
+		log.Fatal("Unexpected error when inserting rows: ", err)
+	}
+
+	log.Infof("Inserted rows: %d", insertedRows)
+
 	log.Info("Migration completed successfully!")
 }
 
-func extractData() ([][]any, []string, error) {
-	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
-	defer cancel()
+func buildExtractSqlSentence(schema, table string, colNames []string) string {
+	var sbColumns strings.Builder
 
-	pool, err := db.Connect(ctx, config.App.FromDb.Url)
-	defer db.Close(pool)
-	if err != nil {
-		log.Fatal(err)
+	for i, col := range colNames {
+		sbColumns.WriteString(`"`)
+		sbColumns.WriteString(col)
+		sbColumns.WriteString(`"`)
+		if i < len(colNames)-1 {
+			sbColumns.WriteString(", ")
+		}
 	}
 
-	log.Info("Successfully connected to from_db")
-	limit := 2
+	return fmt.Sprintf(`SELECT %s FROM "%s"."%s" LIMIT $1`, sbColumns.String(), schema, table)
+}
 
-	/* This query will become dinamyc later */
-	sql := `
-SELECT
-	id,
-	nombre_producto,
-	descripcion,
-	stock,
-	precio,
-	es_activo,
-	fecha_creacion,
-	ultima_actualizacion,
-	configuracion_json,
-	etiquetas,
-	binario_test,
-	ip_servidor,
-	rango_prueba
-FROM test.migration_test
-LIMIT $1;
-`
+func extractData(ctx context.Context, sourcePool *pgxpool.Pool, schema string, table string, colNames []string, limit int) ([][]any, error) {
+	if len(colNames) == 0 {
+		return nil, errors.New("Empty column names received")
+	}
 
-	rows, err := pool.Query(ctx, sql, limit)
+	sql := buildExtractSqlSentence(schema, table, colNames)
+
+	log.Debug("Executing query: ", sql)
+
+	rows, err := sourcePool.Query(ctx, sql, limit)
 	if err != nil {
 		if !errors.Is(err, pgx.ErrNoRows) {
-			return nil, nil, fmt.Errorf("Unexpected error: %w", err)
+			return nil, fmt.Errorf("Unexpected error: %w", err)
 		}
 
 		log.Warn("Unexpected error", err)
-		return [][]any{}, []string{}, nil
+		return [][]any{}, nil
 	}
 	defer rows.Close()
 
@@ -101,9 +125,24 @@ LIMIT $1;
 		rowValues = append(rowValues, values)
 	}
 
-	return rowValues, Map(cols, func(col pgconn.FieldDescription) string {
-		return col.Name
-	}), nil
+	return rowValues, nil
+}
+
+func insertData(ctx context.Context, targetPool *pgxpool.Pool, schema string, table string, colNames []string, rowValues [][]any) (int64, error) {
+	identifier := pgx.Identifier{schema, table}
+
+	count, err := targetPool.CopyFrom(
+		ctx,
+		identifier,
+		colNames,
+		pgx.CopyFromRows(rowValues),
+	)
+
+	if err != nil {
+		return 0, fmt.Errorf("error en CopyFrom: %w", err)
+	}
+
+	return count, nil
 }
 
 func Map[T any, V any](input []T, mapper func(T) V) []V {