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
|
// Package state provides cross-process state tracking for hakurei container instances.
package state
import (
"strconv"
"hakurei.app/container/check"
"hakurei.app/hst"
"hakurei.app/message"
)
/* this provides an implementation of Store on top of the improved state tracking to ease in the changes */
type Store interface {
// Do calls f exactly once and ensures store exclusivity until f returns.
// Returns whether f is called and any errors during the locking process.
// Cursor provided to f becomes invalid as soon as f returns.
Do(identity int, f func(c Cursor)) (ok bool, err error)
// List queries the store and returns a list of identities known to the store.
// Note that some or all returned identities might not have any active apps.
List() (identities []int, err error)
}
func (s *stateStore) Do(identity int, f func(c Cursor)) (bool, error) {
if h, err := s.identityHandle(identity); err != nil {
return false, err
} else {
return h.do(f)
}
}
// storeAdapter satisfies [Store] via stateStore.
type storeAdapter struct {
msg message.Msg
*stateStore
}
func (s storeAdapter) List() ([]int, error) {
segments, n, err := s.segments()
if err != nil {
return nil, err
}
identities := make([]int, 0, n)
for si := range segments {
if si.err != nil {
if m, ok := message.GetMessage(err); ok {
s.msg.Verbose(m)
} else {
// unreachable
return nil, err
}
continue
}
identities = append(identities, si.identity)
}
return identities, nil
}
// NewMulti returns an instance of the multi-file store.
func NewMulti(msg message.Msg, prefix *check.Absolute) Store {
return storeAdapter{msg, newStore(prefix.Append("state"))}
}
// Cursor provides access to the store of an identity.
type Cursor interface {
Save(state *hst.State) error
Destroy(id hst.ID) error
Load() (map[hst.ID]*hst.State, error)
Len() (int, error)
}
// do implements stateStore.Do on storeHandle.
func (h *storeHandle) do(f func(c Cursor)) (bool, error) {
if unlock, err := h.fileMu.Lock(); err != nil {
return false, &hst.AppError{Step: "acquire lock on store segment " + strconv.Itoa(h.identity), Err: err}
} else {
defer unlock()
}
f(h)
return true, nil
}
/* these compatibility methods must only be called while fileMu is held */
func (h *storeHandle) Save(state *hst.State) error {
return (&stateEntryHandle{nil, h.path.Append(state.ID.String()), state.ID}).save(state)
}
func (h *storeHandle) Destroy(id hst.ID) error {
return (&stateEntryHandle{nil, h.path.Append(id.String()), id}).destroy()
}
func (h *storeHandle) Load() (map[hst.ID]*hst.State, error) {
entries, n, err := h.entries()
if err != nil {
return nil, err
}
r := make(map[hst.ID]*hst.State, n)
for eh := range entries {
if eh.decodeErr != nil {
err = eh.decodeErr
break
}
var s hst.State
if _, err = eh.load(&s); err != nil {
break
}
r[eh.ID] = &s
}
return r, err
}
func (h *storeHandle) Len() (int, error) {
entries, _, err := h.entries()
if err != nil {
return -1, err
}
var n int
for eh := range entries {
if eh.decodeErr != nil {
err = eh.decodeErr
}
n++
}
return n, err
}
|
