-
Notifications
You must be signed in to change notification settings - Fork 1
/
service.go
94 lines (77 loc) · 1.84 KB
/
service.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
package mdlog
import (
"errors"
"fmt"
"golang.org/x/sync/errgroup"
)
var (
ErrUpToDate = errors.New("local posts is up to date with remote posts")
)
type Service struct {
blog Blog
}
func NewService(blog Blog) *Service {
return &Service{
blog: blog,
}
}
func (s *Service) Plan(localPosts []*Post) (Plan, error) {
remotePosts, err := s.blog.GetPosts()
if err != nil {
return nil, fmt.Errorf("cannot get remote posts: %v", err)
}
remotePostsMap := map[string]*Post{}
for _, remotePost := range remotePosts {
remotePostsMap[remotePost.ID] = remotePost
}
plan := map[*Post]*Post{}
for _, localPost := range localPosts {
remotePost := remotePostsMap[localPost.ID]
if remotePost == nil {
return nil, fmt.Errorf("unregistered local post: %s[%s]", localPost.Title, localPost.ID)
}
if !localPost.Equal(remotePost) {
plan[remotePost] = localPost
}
}
return plan, nil
}
func (s *Service) Sync(localPosts []*Post) (Plan, error) {
plan, err := s.Plan(localPosts)
if err != nil {
return nil, fmt.Errorf("cannot make sync plan: %v", err)
}
if len(plan) == 0 {
return nil, ErrUpToDate
}
g := errgroup.Group{}
for _, localPost := range plan {
localPost := localPost
g.Go(func() error {
return s.blog.Update(localPost)
})
}
err = g.Wait()
if err != nil {
g = errgroup.Group{}
for remotePost, _ := range plan {
remotePost := remotePost
g.Go(func() error {
return s.blog.Update(remotePost)
})
}
rollbackErr := g.Wait()
if rollbackErr != nil {
return nil, fmt.Errorf("error on roll back: %v (original err: %v)", rollbackErr, err)
}
return nil, fmt.Errorf("cannot sync with remote posts: %v", err)
}
return plan, nil
}
func (s *Service) Create() (*Post, error) {
post, err := s.blog.CreatePost()
if err != nil {
return nil, fmt.Errorf("cannot create post: %v", err)
}
return post, nil
}