/
end_estimator.go
77 lines (65 loc) · 1.92 KB
/
end_estimator.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
// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You 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 natsio
import (
"context"
"errors"
"fmt"
"github.com/nats-io/nats.go/jetstream"
)
type endEstimator struct {
js jetstream.JetStream
stream string
subject string
}
func newEndEstimator(js jetstream.JetStream, stream string, subject string) *endEstimator {
return &endEstimator{
js: js,
stream: stream,
subject: subject,
}
}
func (e *endEstimator) Estimate() int64 {
ctx := context.Background()
end, err := e.getEndSeqNo(ctx)
if err != nil {
panic(err)
}
return end
}
func (e *endEstimator) getEndSeqNo(ctx context.Context) (int64, error) {
str, err := e.js.Stream(ctx, e.stream)
if err != nil {
return -1, fmt.Errorf("error getting stream: %v", err)
}
msg, err := str.GetLastMsgForSubject(ctx, e.subject)
if err != nil {
if isMessageNotFound(err) {
return 1, nil
}
return -1, fmt.Errorf("error getting last message: %v", err)
}
return int64(msg.Sequence) + 1, nil
}
func isMessageNotFound(err error) bool {
var jsErr jetstream.JetStreamError
if errors.As(err, &jsErr) {
apiErr := jsErr.APIError()
if apiErr.ErrorCode == jetstream.JSErrCodeMessageNotFound {
return true
}
}
return false
}