/
common.go
97 lines (85 loc) · 2.91 KB
/
common.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
// Copyright 2016 The Cockroach 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 crdb
import (
"context"
)
// Tx abstracts the operations needed by ExecuteInTx so that different
// frameworks (e.g. go's sql package, pgx, gorm) can be used with ExecuteInTx.
type Tx interface {
Exec(context.Context, string, ...interface{}) error
Commit(context.Context) error
Rollback(context.Context) error
}
// ExecuteInTx runs fn inside tx. This method is primarily intended for internal
// use. See other packages for higher-level, framework-specific ExecuteTx()
// functions.
//
// *WARNING*: It is assumed that no statements have been executed on the
// supplied Tx. ExecuteInTx will only retry statements that are performed within
// the supplied closure (fn). Any statements performed on the tx before
// ExecuteInTx is invoked will *not* be re-run if the transaction needs to be
// retried.
//
// fn is subject to the same restrictions as the fn passed to ExecuteTx.
func ExecuteInTx(ctx context.Context, tx Tx, fn func() error) (err error) {
defer func() {
r := recover()
if r == nil && err == nil {
// Ignore commit errors. The tx has already been committed by RELEASE.
_ = tx.Commit(ctx)
return
}
// We always need to execute a Rollback() so sql.DB releases the
// connection.
_ = tx.Rollback(ctx)
if r != nil {
panic(r)
}
}()
// Specify that we intend to retry this txn in case of CockroachDB retryable
// errors.
if err = tx.Exec(ctx, "SAVEPOINT cockroach_restart"); err != nil {
return err
}
// TODO(rafi): make the maxRetryCount configurable. Maybe pass it in the context?)
const maxRetries = 50
retryCount := 0
for {
releaseFailed := false
err = fn()
if err == nil {
// RELEASE acts like COMMIT in CockroachDB. We use it since it gives us an
// opportunity to react to retryable errors, whereas tx.Commit() doesn't.
if err = tx.Exec(ctx, "RELEASE SAVEPOINT cockroach_restart"); err == nil {
return nil
}
releaseFailed = true
}
// We got an error; let's see if it's a retryable one and, if so, restart.
if !errIsRetryable(err) {
if releaseFailed {
err = newAmbiguousCommitError(err)
}
return err
}
if rollbackErr := tx.Exec(ctx, "ROLLBACK TO SAVEPOINT cockroach_restart"); rollbackErr != nil {
return newTxnRestartError(rollbackErr, err)
}
retryCount++
if retryCount > maxRetries {
return newMaxRetriesExceededError(err, maxRetries)
}
}
}