Esempio n. 1
0
func ExampleTransaction() {
	ctx := Example_auth()
	const retries = 3

	// Increment a counter.
	// See https://cloud.google.com/appengine/articles/sharding_counters for
	// a more scalable solution.
	type Counter struct {
		Count int
	}

	key := datastore.NewKey(ctx, "counter", "CounterA", 0, nil)

	for i := 0; i < retries; i++ {
		tx, err := datastore.NewTransaction(ctx)
		if err != nil {
			break
		}

		var c Counter
		if err := tx.Get(key, &c); err != nil && err != datastore.ErrNoSuchEntity {
			break
		}
		c.Count++
		if _, err := tx.Put(key, &c); err != nil {
			break
		}

		// Attempt to commit the transaction. If there's a conflict, try again.
		if _, err := tx.Commit(); err != datastore.ErrConcurrentTransaction {
			break
		}
	}

}
Esempio n. 2
0
// LogRunComplete logs the end of a completed (failed of finished) run of
// a coduno testrun
func LogRunComplete(pKey *datastore.Key, build *BuildData, in,
	out, extra string, exit error, prepLog string, stats syscall.Rusage) {
	tx, err := datastore.NewTransaction(ctx)
	if err != nil {
		fmt.Fprintf(os.Stderr, "LogRunComplete: Could not get transaction!")
	}
	build.EndTime = time.Now()
	if exit != nil {
		build.Status = "failed"
	} else {
		build.Status = "good"
	}
	_, err = tx.Put(pKey, build)
	if err != nil {
		fmt.Fprintf(os.Stderr, "LogRunComplete: Putting build failed!")
		tx.Rollback()
		return
	}
	data := &LogData{in, out, extra, prepLog, stats}
	k := datastore.NewIncompleteKey(ctx, buildKind, pKey)
	_, err = tx.Put(k, data)
	if err != nil {
		fmt.Fprintf(os.Stderr, "LogRunComplete: Putting data failed!")
		tx.Rollback()
		return
	}
	tx.Commit()
}