feat: add source and target database type fields

Add source_db_type and target_db_type to the migration config so the same binary can drive any supported direction.

internal/app/db-wrapper/main.go

@@ -0,0 +1,19 @@
+package dbwrapper
+
+import "fmt"
+
+type Factory func() DbWrapper
+
+var drivers = make(map[string]Factory)
+
+func Register(name string, factory Factory) {
+	drivers[name] = factory
+}
+
+func New(driverType string) (DbWrapper, error) {
+	factory, ok := drivers[driverType]
+	if !ok {
+		return nil, fmt.Errorf("driver not yet supported: %s", driverType)
+	}
+	return factory(), nil
+}

internal/app/db-wrapper/mssql.go

@@ -0,0 +1,176 @@
+package dbwrapper
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+
+	mssql "github.com/microsoft/go-mssqldb"
+)
+
+func init() {
+	Register("sqlserver", func() DbWrapper {
+		return &mssqlDbWrapper{dialect: "sqlserver"}
+	})
+}
+
+type mssqlRowResult struct {
+	row *sql.Row
+}
+
+func (mr *mssqlRowResult) Scan(dest ...any) error {
+	return mr.row.Scan(dest...)
+}
+
+type mssqlRowsResult struct {
+	columns []string
+	rows    *sql.Rows
+}
+
+func (mr *mssqlRowsResult) Close() error {
+	return mr.rows.Close()
+}
+
+func (mr *mssqlRowsResult) Columns() ([]string, error) {
+	if mr.columns != nil {
+		return mr.columns, nil
+	}
+
+	return mr.rows.Columns()
+}
+
+func (mr *mssqlRowsResult) Err() error {
+	return mr.rows.Err()
+}
+
+func (mr *mssqlRowsResult) Next() bool {
+	return mr.rows.Next()
+}
+
+func (mr *mssqlRowsResult) Scan(dest ...any) error {
+	return mr.rows.Scan(dest...)
+}
+
+func (mr *mssqlRowsResult) Values() ([]any, error) {
+	columns, err := mr.Columns()
+	if err != nil {
+		return nil, err
+	}
+
+	rowValues := make([]any, len(columns))
+	scanArgs := make([]any, len(columns))
+	for i := range rowValues {
+		scanArgs[i] = &rowValues[i]
+	}
+
+	if err := mr.rows.Scan(scanArgs...); err != nil {
+		return nil, err
+	}
+
+	return rowValues, nil
+}
+
+type mssqlDbWrapper struct {
+	db      *sql.DB
+	dialect string
+}
+
+func (mw *mssqlDbWrapper) Connect(ctx context.Context, dbUrl string) error {
+	db, err := sql.Open("sqlserver", dbUrl)
+	if err != nil {
+		return err
+	}
+
+	if err := db.PingContext(ctx); err != nil {
+		if err := db.Close(); err != nil {
+			return err
+		}
+		return err
+	}
+
+	mw.db = db
+	return nil
+}
+
+func (mw *mssqlDbWrapper) Close() error {
+	return mw.db.Close()
+}
+
+func (mw *mssqlDbWrapper) Exec(ctx context.Context, query string, args ...any) (ExecResult, error) {
+	result, execErr := mw.db.ExecContext(ctx, query, args...)
+	if execErr != nil {
+		return ExecResult{}, execErr
+	}
+
+	affectedRows, err := result.RowsAffected()
+	if err != nil {
+		return ExecResult{}, err
+	}
+
+	return ExecResult{AffectedRows: affectedRows}, nil
+}
+
+func (mw *mssqlDbWrapper) GetDialect() string {
+	return mw.dialect
+}
+
+func (mw *mssqlDbWrapper) Query(ctx context.Context, query string, args ...any) (RowsResult, error) {
+	rows, err := mw.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, err
+	}
+
+	return &mssqlRowsResult{columns: nil, rows: rows}, nil
+}
+
+func (mw *mssqlDbWrapper) QueryRow(ctx context.Context, query string, args ...any) RowResult {
+	row := mw.db.QueryRowContext(ctx, query, args...)
+	return &mssqlRowResult{row: row}
+}
+
+func (mw *mssqlDbWrapper) SaveMassive(ctx context.Context, schema string, table string, columnNames []string, rows [][]any) (int64, error) {
+	tx, err := mw.db.BeginTx(ctx, nil)
+	if err != nil {
+		return 0, err
+	}
+
+	fullTableName := fmt.Sprintf("[%s].[%s]", schema, table)
+
+	stmt, err := tx.PrepareContext(ctx, mssql.CopyIn(fullTableName, mssql.BulkOptions{}, columnNames...))
+	if err != nil {
+		tx.Rollback()
+		return 0, err
+	}
+
+	for _, row := range rows {
+		_, err = stmt.ExecContext(ctx, row...)
+		if err != nil {
+			stmt.Close()
+			tx.Rollback()
+			return 0, err
+		}
+	}
+
+	result, err := stmt.ExecContext(ctx)
+	if err != nil {
+		stmt.Close()
+		tx.Rollback()
+		return 0, err
+	}
+
+	if err := stmt.Close(); err != nil {
+		tx.Rollback()
+		return 0, err
+	}
+
+	if err := tx.Commit(); err != nil {
+		return 0, err
+	}
+
+	rowsAffected, raErr := result.RowsAffected()
+	if raErr != nil {
+		return 0, nil
+	}
+
+	return rowsAffected, nil
+}

internal/app/db-wrapper/postgres.go

@@ -0,0 +1,128 @@
+package dbwrapper
+
+import (
+	"context"
+	"errors"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+func init() {
+	Register("postgres", func() DbWrapper {
+		return &postgresDbWrapper{dialect: "postgres"}
+	})
+}
+
+type postgresRowResult struct {
+	row pgx.Row
+}
+
+func (pr *postgresRowResult) Scan(dest ...any) error {
+	return pr.row.Scan(dest...)
+}
+
+type postgresRowsResult struct {
+	columns []string
+	rows    pgx.Rows
+}
+
+func (pr *postgresRowsResult) Close() error {
+	pr.rows.Close()
+	return nil
+}
+
+func (pr *postgresRowsResult) Columns() ([]string, error) {
+	if pr.columns != nil {
+		return pr.columns, nil
+	}
+
+	rawColumns := pr.rows.FieldDescriptions()
+	if rawColumns == nil {
+		return nil, errors.New("error retrieving columns")
+	}
+
+	columns := make([]string, 0, len(rawColumns))
+	for _, rc := range rawColumns {
+		columns = append(columns, rc.Name)
+	}
+
+	return columns, nil
+}
+
+func (pr *postgresRowsResult) Err() error {
+	return pr.rows.Err()
+}
+
+func (pr *postgresRowsResult) Next() bool {
+	return pr.rows.Next()
+}
+
+func (pr *postgresRowsResult) Scan(dest ...any) error {
+	return pr.rows.Scan(dest...)
+}
+
+func (pr *postgresRowsResult) Values() ([]any, error) {
+	return pr.rows.Values()
+}
+
+type postgresDbWrapper struct {
+	db      *pgxpool.Pool
+	dialect string
+}
+
+func (pw *postgresDbWrapper) Connect(ctx context.Context, dbUrl string) error {
+	pool, err := pgxpool.New(ctx, dbUrl)
+	if err != nil {
+		return err
+	}
+
+	if err := pool.Ping(ctx); err != nil {
+		pool.Close()
+		return err
+	}
+
+	pw.db = pool
+	return nil
+}
+
+func (pw *postgresDbWrapper) Close() error {
+	pw.db.Close()
+	return nil
+}
+
+func (pw *postgresDbWrapper) Exec(ctx context.Context, query string, args ...any) (ExecResult, error) {
+	result, err := pw.db.Exec(ctx, query, args...)
+	if err != nil {
+		return ExecResult{}, err
+	}
+
+	return ExecResult{AffectedRows: result.RowsAffected()}, nil
+}
+
+func (pw *postgresDbWrapper) GetDialect() string {
+	return pw.dialect
+}
+
+func (pw *postgresDbWrapper) Query(ctx context.Context, query string, args ...any) (RowsResult, error) {
+	rows, err := pw.db.Query(ctx, query, args...)
+	if err != nil {
+		return nil, err
+	}
+
+	return &postgresRowsResult{columns: nil, rows: rows}, nil
+}
+
+func (pw *postgresDbWrapper) QueryRow(ctx context.Context, query string, args ...any) RowResult {
+	row := pw.db.QueryRow(ctx, query, args...)
+	return &postgresRowResult{row: row}
+}
+
+func (pw *postgresDbWrapper) SaveMassive(ctx context.Context, schema string, table string, columnNames []string, rows [][]any) (int64, error) {
+	affectedRows, err := pw.db.CopyFrom(ctx, pgx.Identifier{schema, table}, columnNames, pgx.CopyFromRows(rows))
+	if err != nil {
+		return 0, err
+	}
+
+	return affectedRows, nil
+}

internal/app/db-wrapper/types.go

@@ -0,0 +1,35 @@
+package dbwrapper
+
+import (
+	"context"
+	"errors"
+)
+
+var MethodNotSupported error = errors.New("Method not supported by driver... yet :P")
+
+type ExecResult struct {
+	AffectedRows int64
+}
+
+type RowsResult interface {
+	Close() error
+	Columns() ([]string, error)
+	Err() error
+	Next() bool
+	Scan(dest ...any) error
+	Values() ([]any, error)
+}
+
+type RowResult interface {
+	Scan(dest ...any) error
+}
+
+type DbWrapper interface {
+	Close() error
+	Connect(ctx context.Context, dbUrl string) error
+	Exec(ctx context.Context, query string, args ...any) (ExecResult, error)
+	GetDialect() string
+	Query(ctx context.Context, query string, args ...any) (RowsResult, error)
+	QueryRow(ctx context.Context, query string, args ...any) RowResult
+	SaveMassive(ctx context.Context, schema string, table string, columnNames []string, rows [][]any) (int64, error)
+}