| // Copyright 2018 The LUCI Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package model |
| |
| import ( |
| "context" |
| |
| "go.chromium.org/luci/common/errors" |
| "go.chromium.org/luci/common/logging" |
| "go.chromium.org/luci/common/retry/transient" |
| "go.chromium.org/luci/gae/service/datastore" |
| ) |
| |
| // Txn runs the callback in a datastore transaction, marking commit errors with |
| // transient tag. |
| // |
| // The given name will be used for logging and error messages. |
| func Txn(c context.Context, name string, cb func(context.Context) error) error { |
| c = logging.SetField(c, "txn", name) |
| |
| var attempt int |
| var innerErr error |
| |
| err := datastore.RunInTransaction(c, func(c context.Context) error { |
| attempt++ |
| if attempt != 1 { |
| logging.Warningf(c, "Retrying the transaction: failed to commit") |
| } |
| innerErr = cb(c) |
| return innerErr |
| }, nil) |
| |
| if err != innerErr { |
| return errors.Annotate(err, "failed to land %s transaction", name).Tag(transient.Tag).Err() |
| } |
| return innerErr |
| } |