loggingdriver

Overview ¶

Package loggingdriver wraps a database/sql/driver.Driver to log SQL execution and optionally interpolate placeholders for readable logs.

Adaptor implementations (for example mysql) call Wrap around the native driver before sql.OpenDB, so every Query / Exec / transaction is timed and recorded through logx with driver name, interpolated query text, and cost.

Wrap ¶

dc := loggingdriver.Wrap(mysql.MySQLDriver{}, "mysql",
	loggingdriver.WithDsnParser(ParseDSN),
	loggingdriver.WithErrorLeveler(ErrorLevel),
	loggingdriver.WithInterpolator(loggingdriver.DefaultInterpolate),
)
conn, err := dc.OpenConnector(dsn)

Wrap returns a driver.DriverContext. OpenConnector may rewrite the DSN via WithDsnParser, and marks read-only pools when the DSN query has `_ro=true` (driver name becomes `name::ro` for logs).

Logging behavior ¶

• QueryContext / ExecContext: optional interpolate, then log cost_ms and query; failures use Error or Warn based on WithErrorLeveler (level > 0 → Error, else Warn); success → Debug
• BeginTx / Commit / Rollback: transaction boundary Debug lines
• Prepare is deliberately unimplemented (panics) so dialects stay on context Exec/Query paths

Interpolation ¶

• DefaultInterpolate: substitute `?` with literal SQL values (for logs or when the native driver does not interpolate); returns empty remaining args
• OrderedInterpolator: rewrite `?` to `$1`, `$2`, ... (PostgreSQL-style)
• Interpolate / NewPrinter: core substitution helpers used by logging

Migrator dry-run output also uses DefaultInterpolate to print a full SQL script from collected fragments.