/
filecheckpointer.go
104 lines (84 loc) · 2.81 KB
/
filecheckpointer.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
/*
Copyright 2022 IBM All Rights Reserved.
SPDX-License-Identifier: Apache-2.0
*/
package client
import (
"encoding/json"
"os"
)
// FileCheckpointer is a Checkpoint implementation backed by persistent file storage. It can be used to checkpoint
// progress after successfully processing events, allowing eventing to be resumed from this point.
//
// Instances should be created using the NewFileCheckpointer() constructor function. Close() should be called when the
// checkpointer is no longer needed to free resources.
type FileCheckpointer struct {
file *os.File
state *checkpointState
}
type checkpointState struct {
BlockNumber uint64 `json:"blockNumber"`
TransactionID string `json:"transactionId"`
}
// NewFileCheckpointer creates a properly initialized FileCheckpointer.
func NewFileCheckpointer(name string) (*FileCheckpointer, error) {
file, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE, 0600) //#nosec G304 -- Caller responsible for safe file name
if err != nil {
return nil, err
}
checkpointer := &FileCheckpointer{
file: file,
state: &checkpointState{},
}
if fileInfo, err := file.Stat(); err == nil && fileInfo.Size() > 0 {
decoder := json.NewDecoder(file)
if err := decoder.Decode(checkpointer.state); err != nil {
return nil, err
}
}
if err := checkpointer.save(); err != nil {
return nil, err
}
return checkpointer, nil
}
// CheckpointBlock records a successfully processed block.
func (c *FileCheckpointer) CheckpointBlock(blockNumber uint64) error {
return c.CheckpointTransaction(blockNumber+1, "")
}
// CheckpointTransaction records a successfully processed transaction within a given block.
func (c *FileCheckpointer) CheckpointTransaction(blockNumber uint64, transactionID string) error {
c.state.BlockNumber = blockNumber
c.state.TransactionID = transactionID
return c.save()
}
// CheckpointChaincodeEvent records a successfully processed chaincode event.
func (c *FileCheckpointer) CheckpointChaincodeEvent(event *ChaincodeEvent) error {
return c.CheckpointTransaction(event.BlockNumber, event.TransactionID)
}
// BlockNumber in which the next event is expected.
func (c *FileCheckpointer) BlockNumber() uint64 {
return c.state.BlockNumber
}
// TransactionID of the last successfully processed event within the current block.
func (c *FileCheckpointer) TransactionID() string {
return c.state.TransactionID
}
// Close the checkpointer when it is no longer needed to free resources.
func (c *FileCheckpointer) Close() error {
return c.file.Close()
}
// Sync commits the current state to stable storage.
func (c *FileCheckpointer) Sync() error {
return c.file.Sync()
}
func (c *FileCheckpointer) save() error {
data, err := json.Marshal(c.state)
if err != nil {
return err
}
size, err := c.file.WriteAt(data, 0)
if err != nil {
return err
}
return c.file.Truncate(int64(size))
}