Add Queue.SendAndGetID method (#45)

The id is useful to interact with the message without receiving it
first.

See #42

goqite.go

@@ -88,17 +88,36 @@ func (q *Queue) Send(ctx context.Context, m Message) error {
 
 // SendTx is like Send, but within an existing transaction.
 func (q *Queue) SendTx(ctx context.Context, tx *sql.Tx, m Message) error {
+	_, err := q.SendAndGetIDTx(ctx, tx, m)
+	return err
+}
+
+// SendAndGetID is like Send, but also returns the message ID, which can be used
+// to interact with the message without receiving it first.
+func (q *Queue) SendAndGetID(ctx context.Context, m Message) (ID, error) {
+	var id ID
+	err := internalsql.InTx(q.db, func(tx *sql.Tx) error {
+		var err error
+		id, err = q.SendAndGetIDTx(ctx, tx, m)
+		return err
+	})
+	return id, err
+}
+
+// SendAndGetIDTx is like SendAndGetID, but within an existing transaction.
+func (q *Queue) SendAndGetIDTx(ctx context.Context, tx *sql.Tx, m Message) (ID, error) {
 	if m.Delay < 0 {
 		panic("delay cannot be negative")
 	}
 
 	timeout := time.Now().Add(m.Delay).Format(rfc3339Milli)
 
-	_, err := tx.ExecContext(ctx, `insert into goqite (queue, body, timeout) values (?, ?, ?)`, q.name, m.Body, timeout)
-	if err != nil {
-		return err
+	var id ID
+	query := `insert into goqite (queue, body, timeout) values (?, ?, ?) returning id`
+	if err := tx.QueryRowContext(ctx, query, q.name, m.Body, timeout).Scan(&id); err != nil {
+		return "", err
 	}
-	return nil
+	return id, nil
 }
 
 // Receive a Message from the queue, or nil if there is none.

goqite_test.go

@@ -189,6 +189,23 @@ func TestQueue_Receive(t *testing.T) {
 	})
 }
 
+func TestQueue_SendAndGetID(t *testing.T) {
+	t.Run("returns the message ID", func(t *testing.T) {
+		q := newQ(t, goqite.NewOpts{}, ":memory:")
+
+		m := goqite.Message{
+			Body: []byte("yo"),
+		}
+
+		id, err := q.SendAndGetID(context.Background(), m)
+		is.NotError(t, err)
+		is.Equal(t, 34, len(id))
+
+		err = q.Delete(context.Background(), id)
+		is.NotError(t, err)
+	})
+}
+
 func TestQueue_Extend(t *testing.T) {
 	t.Run("does not receive a message that has had the timeout extended", func(t *testing.T) {
 		q := newQ(t, goqite.NewOpts{Timeout: time.Millisecond}, ":memory:")