Multi Database MCP Server

package repository import ( "context" "database/sql" "github.com/FreePeak/db-mcp-server/internal/domain" "github.com/FreePeak/db-mcp-server/pkg/dbtools" ) // TODO: Implement caching layer for database metadata to improve performance // TODO: Add observability with tracing and detailed metrics // TODO: Improve concurrency handling with proper locking or atomic operations // TODO: Consider using an interface-based approach for better testability // TODO: Add comprehensive integration tests for different database types // DatabaseRepository implements domain.DatabaseRepository type DatabaseRepository struct{} // NewDatabaseRepository creates a new database repository func NewDatabaseRepository() *DatabaseRepository { return &DatabaseRepository{} } // GetDatabase retrieves a database by ID func (r *DatabaseRepository) GetDatabase(id string) (domain.Database, error) { db, err := dbtools.GetDatabase(id) if err != nil { return nil, err } return &DatabaseAdapter{db: db}, nil } // ListDatabases returns a list of available database IDs func (r *DatabaseRepository) ListDatabases() []string { return dbtools.ListDatabases() } // GetDatabaseType returns the type of a database by ID func (r *DatabaseRepository) GetDatabaseType(id string) (string, error) { // Read database type from configuration without establishing a connection // The type is already validated when the connection is created, so we can trust it // This is especially important for lazy loading to avoid unnecessary connections during startup return dbtools.GetDatabaseType(id) } // IsLazyLoading returns whether lazy loading mode is enabled func (r *DatabaseRepository) IsLazyLoading() bool { return dbtools.IsLazyLoading() } // DatabaseAdapter adapts the db.Database to the domain.Database interface type DatabaseAdapter struct { db interface { Query(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error) Exec(ctx context.Context, query string, args ...interface{}) (sql.Result, error) BeginTx(ctx context.Context, opts *sql.TxOptions) (*sql.Tx, error) } } // Query executes a query on the database func (a *DatabaseAdapter) Query(ctx context.Context, query string, args ...interface{}) (domain.Rows, error) { rows, err := a.db.Query(ctx, query, args...) if err != nil { return nil, err } return &RowsAdapter{rows: rows}, nil } // Exec executes a statement on the database func (a *DatabaseAdapter) Exec(ctx context.Context, statement string, args ...interface{}) (domain.Result, error) { result, err := a.db.Exec(ctx, statement, args...) if err != nil { return nil, err } return &ResultAdapter{result: result}, nil } // Begin starts a new transaction func (a *DatabaseAdapter) Begin(ctx context.Context, opts *domain.TxOptions) (domain.Tx, error) { txOpts := &sql.TxOptions{} if opts != nil { txOpts.ReadOnly = opts.ReadOnly } tx, err := a.db.BeginTx(ctx, txOpts) if err != nil { return nil, err } return &TxAdapter{tx: tx}, nil } // RowsAdapter adapts sql.Rows to domain.Rows type RowsAdapter struct { rows *sql.Rows } // Close closes the rows func (a *RowsAdapter) Close() error { return a.rows.Close() } // Columns returns the column names func (a *RowsAdapter) Columns() ([]string, error) { return a.rows.Columns() } // Next advances to the next row func (a *RowsAdapter) Next() bool { return a.rows.Next() } // Scan scans the current row func (a *RowsAdapter) Scan(dest ...interface{}) error { return a.rows.Scan(dest...) } // Err returns any error that occurred during iteration func (a *RowsAdapter) Err() error { return a.rows.Err() } // ResultAdapter adapts sql.Result to domain.Result type ResultAdapter struct { result sql.Result } // RowsAffected returns the number of rows affected func (a *ResultAdapter) RowsAffected() (int64, error) { return a.result.RowsAffected() } // LastInsertId returns the last insert ID func (a *ResultAdapter) LastInsertId() (int64, error) { return a.result.LastInsertId() } // TxAdapter adapts sql.Tx to domain.Tx type TxAdapter struct { tx *sql.Tx } // Commit commits the transaction func (a *TxAdapter) Commit() error { return a.tx.Commit() } // Rollback rolls back the transaction func (a *TxAdapter) Rollback() error { return a.tx.Rollback() } // Query executes a query within the transaction func (a *TxAdapter) Query(ctx context.Context, query string, args ...interface{}) (domain.Rows, error) { rows, err := a.tx.QueryContext(ctx, query, args...) if err != nil { return nil, err } return &RowsAdapter{rows: rows}, nil } // Exec executes a statement within the transaction func (a *TxAdapter) Exec(ctx context.Context, statement string, args ...interface{}) (domain.Result, error) { result, err := a.tx.ExecContext(ctx, statement, args...) if err != nil { return nil, err } return &ResultAdapter{result: result}, nil }