feat: enhance db-wrapper with improved MSSQL and Postgres implementations; add row result handling and dialect support

internal/app/db-wrapper/main.go

@@ -2,12 +2,17 @@ package dbwrapper
 
 import "fmt"
 
+const (
+	postgresDialect = "postgres"
+	mssqlDialect    = "sqlserver"
+)
+
 func NewWrapper(driverType string) (DbWrapper, error) {
 	switch driverType {
-	case "postgres":
-		return &postgresDbWrapper{}, nil
-	case "sqlserver":
-		return &mssqlDbWrapper{}, nil
+	case postgresDialect:
+		return &postgresDbWrapper{dialect: postgresDialect}, nil
+	case mssqlDialect:
+		return &mssqlDbWrapper{dialect: mssqlDialect}, nil
 	default:
 		return nil, fmt.Errorf("driver not yet supported: %s", driverType)
 	}

internal/app/db-wrapper/mssql.go

@@ -3,18 +3,86 @@ package dbwrapper
 import (
 	"context"
 	"database/sql"
+
+	_ "github.com/microsoft/go-mssqldb"
 )
 
-type mssqlDbWrapper struct {
-	db *sql.DB
+type mssqlRowResult struct {
+	columns []string
+	rows    *sql.Rows
 }
 
-func (wrapper *mssqlDbWrapper) Connect(ctx context.Context, dbUrl string) error { return nil }
+func (mr *mssqlRowResult) Close() error {
+	return mr.rows.Close()
+}
 
-func (wrapper *mssqlDbWrapper) Close() error { return nil }
+func (mr *mssqlRowResult) Columns() ([]string, error) {
+	if mr.columns != nil {
+		return mr.columns, nil
+	}
 
-func (wrapper *mssqlDbWrapper) Exec(ctx context.Context, query string, args ...any) (ExecResult, error) {
-	result, execErr := wrapper.db.ExecContext(ctx, query, args...)
+	return mr.rows.Columns()
+}
+
+func (mr *mssqlRowResult) Err() error {
+	return mr.rows.Err()
+}
+
+func (mr *mssqlRowResult) Next() bool {
+	return mr.rows.Next()
+}
+
+func (mr *mssqlRowResult) Scan(dest ...any) error {
+	return mr.rows.Scan(dest...)
+}
+
+func (mr *mssqlRowResult) 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
 	}
@@ -24,15 +92,22 @@ func (wrapper *mssqlDbWrapper) Exec(ctx context.Context, query string, args ...a
 		return ExecResult{}, err
 	}
 
-	return ExecResult{
-		AffectedRows: affectedRows,
-	}, nil
+	return ExecResult{AffectedRows: affectedRows}, nil
 }
 
-func (wrapper *mssqlDbWrapper) Query(ctx context.Context, query string, args ...any) (RowsResult, error) {
-	return nil, nil
+func (mw *mssqlDbWrapper) GetDialect() string {
+	return mw.dialect
 }
 
-func (wrapper *mssqlDbWrapper) SaveMassive(ctx context.Context, schema string, table string, columnNames []string, rows [][]any) (int64, error) {
-	return 0, nil
+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 &mssqlRowResult{columns: nil, rows: rows}, nil
+}
+
+func (mw *mssqlDbWrapper) SaveMassive(ctx context.Context, schema string, table string, columnNames []string, rows [][]any) (int64, error) {
+	return 0, MethodNotSupported
 }

internal/app/db-wrapper/postgres.go

@@ -2,33 +2,108 @@ package dbwrapper
 
 import (
 	"context"
+	"errors"
 
+	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
 )
 
-type postgresDbWrapper struct {
-	db *pgxpool.Pool
+type postgresRowResult struct {
+	columns []string
+	rows    pgx.Rows
 }
 
-func (wrapper *postgresDbWrapper) Connect(ctx context.Context, dbUrl string) error { return nil }
+func (pr *postgresRowResult) Close() error {
+	pr.rows.Close()
+	return nil
+}
 
-func (wrapper *postgresDbWrapper) Close() error { return nil }
+func (pr *postgresRowResult) Columns() ([]string, error) {
+	if pr.columns != nil {
+		return pr.columns, nil
+	}
 
-func (wrapper *postgresDbWrapper) Exec(ctx context.Context, query string, args ...any) (ExecResult, error) {
-	result, err := wrapper.db.Exec(ctx, query, args...)
+	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 *postgresRowResult) Err() error {
+	return pr.rows.Err()
+}
+
+func (pr *postgresRowResult) Next() bool {
+	return pr.rows.Next()
+}
+
+func (pr *postgresRowResult) Scan(dest ...any) error {
+	return pr.rows.Scan(dest...)
+}
+
+func (pr *postgresRowResult) 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
+	return ExecResult{AffectedRows: result.RowsAffected()}, nil
 }
 
-func (wrapper *postgresDbWrapper) Query(ctx context.Context, query string, args ...any) (RowsResult, error) {
-	return nil, nil
+func (pw *postgresDbWrapper) GetDialect() string {
+	return pw.dialect
 }
 
-func (wrapper *postgresDbWrapper) SaveMassive(ctx context.Context, schema string, table string, columnNames []string, rows [][]any) (int64, error) {
-	return 0, nil
+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 &postgresRowResult{columns: nil, rows: rows}, nil
+}
+
+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

@@ -2,24 +2,29 @@ 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()
+	Close() error
+	Columns() ([]string, error)
 	Err() error
 	Next() bool
+	Scan(dest ...any) error
 	Values() ([]any, error)
-	Columns() ([]string, error)
 }
 
 type DbWrapper interface {
-	Connect(ctx context.Context, dbUrl string) error
 	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)
 	SaveMassive(ctx context.Context, schema string, table string, columnNames []string, rows [][]any) (int64, error)
 }