README_TX.md

Transactions

dbw supports transactions via RW.DoTx(...) which uses any backoff strategy that implements the Backoff interface. There are two backoffs provided by the package: ConstBackOff and ExpBackoff.

// Example with ExpBackoff
retryErrFn := func(_ error) bool { return true }
_, err = rw.DoTx(
    context.Background(),
    func(_ error) bool { return true }, // retry all errors
    3,                                  // three retries
    ExpBackoff{},                       // exponential backoff
    func(w Writer) error {
        // the TxHandler updates the user's name
        _, err := w.Update(context.Background(), 
            user, 
            []string{"Name"}, 
            nil,
            dbw.WithVersion(&user.Version),
        )
        if err != nil {
            return err
        }
    },
)
if err != nil {
    // handle errors from the transaction...
}

You can also control the transaction yourself using:

• RW.Begin(...),
• RW.Rollback(...)
• RW.Commit(...)

// begin a transaction
tx, err := rw.Begin(ctx)

// do some database operations like creating a resource
if err := tx.Create(...); err != nil {

    // rollback the transaction if you 
    if err := tx.Rollback(ctx); err != nil {
        // you'll need to handle rollback errors... perhaps via retry.
    }
}

// commit the transaction if there are not errors
if err := tx.Commit(ctx); err != nil {
    // handle commit errors
}