-
Notifications
You must be signed in to change notification settings - Fork 911
/
conn_go18.go
247 lines (218 loc) · 5.63 KB
/
conn_go18.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
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
package pq
import (
"context"
"database/sql"
"database/sql/driver"
"fmt"
"io"
"io/ioutil"
"time"
)
const (
watchCancelDialContextTimeout = time.Second * 10
)
// Implement the "QueryerContext" interface
func (cn *conn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
list := make([]driver.Value, len(args))
for i, nv := range args {
list[i] = nv.Value
}
finish := cn.watchCancel(ctx)
r, err := cn.query(query, list)
if err != nil {
if finish != nil {
finish()
}
return nil, err
}
r.finish = finish
return r, nil
}
// Implement the "ExecerContext" interface
func (cn *conn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
list := make([]driver.Value, len(args))
for i, nv := range args {
list[i] = nv.Value
}
if finish := cn.watchCancel(ctx); finish != nil {
defer finish()
}
return cn.Exec(query, list)
}
// Implement the "ConnPrepareContext" interface
func (cn *conn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
if finish := cn.watchCancel(ctx); finish != nil {
defer finish()
}
return cn.Prepare(query)
}
// Implement the "ConnBeginTx" interface
func (cn *conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
var mode string
switch sql.IsolationLevel(opts.Isolation) {
case sql.LevelDefault:
// Don't touch mode: use the server's default
case sql.LevelReadUncommitted:
mode = " ISOLATION LEVEL READ UNCOMMITTED"
case sql.LevelReadCommitted:
mode = " ISOLATION LEVEL READ COMMITTED"
case sql.LevelRepeatableRead:
mode = " ISOLATION LEVEL REPEATABLE READ"
case sql.LevelSerializable:
mode = " ISOLATION LEVEL SERIALIZABLE"
default:
return nil, fmt.Errorf("pq: isolation level not supported: %d", opts.Isolation)
}
if opts.ReadOnly {
mode += " READ ONLY"
} else {
mode += " READ WRITE"
}
tx, err := cn.begin(mode)
if err != nil {
return nil, err
}
cn.txnFinish = cn.watchCancel(ctx)
return tx, nil
}
func (cn *conn) Ping(ctx context.Context) error {
if finish := cn.watchCancel(ctx); finish != nil {
defer finish()
}
rows, err := cn.simpleQuery(";")
if err != nil {
return driver.ErrBadConn // https://golang.org/pkg/database/sql/driver/#Pinger
}
rows.Close()
return nil
}
func (cn *conn) watchCancel(ctx context.Context) func() {
if done := ctx.Done(); done != nil {
finished := make(chan struct{}, 1)
go func() {
select {
case <-done:
select {
case finished <- struct{}{}:
default:
// We raced with the finish func, let the next query handle this with the
// context.
return
}
// Set the connection state to bad so it does not get reused.
cn.err.set(ctx.Err())
// At this point the function level context is canceled,
// so it must not be used for the additional network
// request to cancel the query.
// Create a new context to pass into the dial.
ctxCancel, cancel := context.WithTimeout(context.Background(), watchCancelDialContextTimeout)
defer cancel()
_ = cn.cancel(ctxCancel)
case <-finished:
}
}()
return func() {
select {
case <-finished:
cn.err.set(ctx.Err())
cn.Close()
case finished <- struct{}{}:
}
}
}
return nil
}
func (cn *conn) cancel(ctx context.Context) error {
// Create a new values map (copy). This makes sure the connection created
// in this method cannot write to the same underlying data, which could
// cause a concurrent map write panic. This is necessary because cancel
// is called from a goroutine in watchCancel.
o := make(values)
for k, v := range cn.opts {
o[k] = v
}
c, err := dial(ctx, cn.dialer, o)
if err != nil {
return err
}
defer c.Close()
{
can := conn{
c: c,
}
err = can.ssl(o)
if err != nil {
return err
}
w := can.writeBuf(0)
w.int32(80877102) // cancel request code
w.int32(cn.processID)
w.int32(cn.secretKey)
if err := can.sendStartupPacket(w); err != nil {
return err
}
}
// Read until EOF to ensure that the server received the cancel.
{
_, err := io.Copy(ioutil.Discard, c)
return err
}
}
// Implement the "StmtQueryContext" interface
func (st *stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
list := make([]driver.Value, len(args))
for i, nv := range args {
list[i] = nv.Value
}
finish := st.watchCancel(ctx)
r, err := st.query(list)
if err != nil {
if finish != nil {
finish()
}
return nil, err
}
r.finish = finish
return r, nil
}
// Implement the "StmtExecContext" interface
func (st *stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
list := make([]driver.Value, len(args))
for i, nv := range args {
list[i] = nv.Value
}
if finish := st.watchCancel(ctx); finish != nil {
defer finish()
}
return st.Exec(list)
}
// watchCancel is implemented on stmt in order to not mark the parent conn as bad
func (st *stmt) watchCancel(ctx context.Context) func() {
if done := ctx.Done(); done != nil {
finished := make(chan struct{})
go func() {
select {
case <-done:
// At this point the function level context is canceled,
// so it must not be used for the additional network
// request to cancel the query.
// Create a new context to pass into the dial.
ctxCancel, cancel := context.WithTimeout(context.Background(), watchCancelDialContextTimeout)
defer cancel()
_ = st.cancel(ctxCancel)
finished <- struct{}{}
case <-finished:
}
}()
return func() {
select {
case <-finished:
case finished <- struct{}{}:
}
}
}
return nil
}
func (st *stmt) cancel(ctx context.Context) error {
return st.cn.cancel(ctx)
}