/
sink_ack_ordering.go
96 lines (80 loc) · 1.95 KB
/
sink_ack_ordering.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
package helper
import (
"context"
"github.com/uw-labs/substrate"
"golang.org/x/sync/errgroup"
)
var _ substrate.AsyncMessageSink = (*AckOrderingSink)(nil)
func NewAckOrderingSink(sink substrate.AsyncMessageSink) *AckOrderingSink {
return &AckOrderingSink{sink}
}
type AckOrderingSink struct {
innerSink substrate.AsyncMessageSink
}
func (s *AckOrderingSink) PublishMessages(ctx context.Context, acks chan<- substrate.Message, messages <-chan substrate.Message) error {
eg, ctx := errgroup.WithContext(ctx)
fromInner := make(chan substrate.Message, 1024)
toInner := make(chan substrate.Message, 1024)
needAcks := make(chan substrate.Message, 1024)
eg.Go(func() error {
return s.innerSink.PublishMessages(ctx, fromInner, toInner)
})
eg.Go(func() error {
for {
select {
case m := <-messages:
select {
case needAcks <- m:
case <-ctx.Done():
return ctx.Err()
}
select {
case toInner <- m:
case <-ctx.Done():
return ctx.Err()
}
case <-ctx.Done():
return ctx.Err()
}
}
})
eg.Go(func() error {
needed := make([]substrate.Message, 0, 1024)
gotAcks := make(map[substrate.Message]struct{}, 1024)
for {
select {
case m := <-needAcks:
needed = append(needed, m)
case a, ok := <-fromInner:
if !ok {
panic("?")
}
gotAcks[a] = struct{}{}
case <-ctx.Done():
return ctx.Err()
}
for len(gotAcks) > 0 && len(needed) != 0 && contains(gotAcks, needed[0]) {
select {
case m := <-needAcks:
needed = append(needed, m)
case acks <- needed[0]:
delete(gotAcks, needed[0])
needed = needed[1:]
case <-ctx.Done():
return ctx.Err()
}
}
}
})
return eg.Wait()
}
func contains(msgs map[substrate.Message]struct{}, msg substrate.Message) bool {
_, ok := msgs[msg]
return ok
}
func (s *AckOrderingSink) Close() error {
return s.innerSink.Close()
}
func (s *AckOrderingSink) Status() (*substrate.Status, error) {
return s.innerSink.Status()
}