56 lines
1.8 KiB
Go
56 lines
1.8 KiB
Go
// Run with go run ./examples/transactions. Uses a deterministic demonstration
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// driver, no external database and no actual uploaded files.
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package main
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import (
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"context"
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"database/sql"
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"errors"
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"fmt"
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"git.yuntuo.hk/k2safe/go-omni/database"
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)
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func main() {
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failure := errors.New("demonstration failure")
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for _, name := range []string{"success", "beginFailure", "workFailure", "rollbackFailure", "commitRejected", "commitAcknowledgementLost"} {
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driver := &demoConnector{}
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var workErr error
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switch name {
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case "beginFailure":
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driver.beginErr = failure
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case "workFailure":
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workErr = failure
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case "rollbackFailure":
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workErr, driver.rollbackErr = failure, failure
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case "commitRejected":
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driver.commitErr = failure
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case "commitAcknowledgementLost":
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driver.commitErr, driver.persistBeforeError = failure, true
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}
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pool := &database.DB{DB: sql.OpenDB(driver)}
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err := pool.InTx(context.Background(), nil, func(tx *sql.Tx) error {
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if _, err := tx.ExecContext(context.Background(), "INSERT demonstration record"); err != nil {
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return err
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}
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return workErr
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})
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_ = pool.Close()
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if err == nil {
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fmt.Printf("%s: committed, stored=%t\n", name, driver.stored.Load())
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continue
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}
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var txErr *database.TxError
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if !errors.As(err, &txErr) || !errors.Is(err, failure) {
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panic("transaction phase or original cause lost")
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}
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// A project decides whether cleanup is appropriate for its own operation.
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// Unknown outcomes must not be treated as evidence that no record exists.
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cleanup := txErr.Outcome == database.TxOutcomeNotStarted || txErr.Outcome == database.TxOutcomeRolledBack
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if cleanup && driver.stored.Load() {
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panic("unsafe cleanup decision")
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}
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fmt.Printf("%s: stage=%s outcome=%s stored=%t cleanup=%t\n", name, txErr.Stage, txErr.Outcome, driver.stored.Load(), cleanup)
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}
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}
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