Exemplo para transações no mongodb com GoLang

if session, err = client.StartSession(); err != nil {
    t.Fatal(err)
}
if err = session.StartTransaction(); err != nil {
    t.Fatal(err)
}
if err = mongo.WithSession(ctx, session, func(sc mongo.SessionContext) error {
    if result, err = collection.UpdateOne(sc, bson.M{"_id": id}, update); err != nil {
        t.Fatal(err)
    }
    if result.MatchedCount != 1 || result.ModifiedCount != 1 {
        t.Fatal("replace failed, expected 1 but got", result.MatchedCount)
    }

    if err = session.CommitTransaction(sc); err != nil {
        t.Fatal(err)
    }
    return nil
}); err != nil {
    t.Fatal(err)
}
session.EndSession(ctx)