VoteNow/walkthrough.md.resolved at main · Akmalwizdom/VoteNow · GitHub

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
# VoteNow - Implementasi 3 Mode Konsistensi

## Ringkasan Perubahan

VoteNow mendukung **Strong, Weak, dan Eventual Consistency** dalam satu aplikasi. Mode dipilih via query parameter `?consistency=strong|weak|eventual`.

## File yang Dimodifikasi

### Backend

| File | Perubahan |
|------|-----------|
| [consistencyService.js](file:///c:/Akmal/Tugas_Kuliah/VoteNow/backend/services/consistencyService.js) | **[NEW]** Service untuk simulasi 3 node + replication logic |
| [Poll.js](file:///c:/Akmal/Tugas_Kuliah/VoteNow/backend/models/Poll.js) | Tambah field `lastModified` dan `version` |
| [pollController.js](file:///c:/Akmal/Tugas_Kuliah/VoteNow/backend/controllers/pollController.js) | [voteOnPoll](file:///c:/Akmal/Tugas_Kuliah/VoteNow/backend/controllers/pollController.js#160-255) dengan consistency param |
| [server.js](file:///c:/Akmal/Tugas_Kuliah/VoteNow/backend/server.js) | Endpoint `/api/nodes/*` |

---

## API Endpoints Baru

### Vote dengan Consistency Mode
```
POST /api/polls/:id/vote?consistency=strong|weak|eventual
```

### Cek Status Node
```
GET /api/nodes/status?pollId={optional}
```

### Trigger Manual Sync
```
POST /api/nodes/sync
```

---

## Cara Testing

### 1. Start Server
```bash
cd backend
npm run dev
```

### 2. Test Strong Consistency
```powershell
# Vote
Invoke-WebRequest -Uri "http://localhost:5000/api/polls/{pollId}/vote?consistency=strong" `
  -Method POST -ContentType "application/json" `
  -Body '{"optionIndex": 0, "voterId": "test1"}'

# Cek node status - semua harus sama
Invoke-WebRequest -Uri "http://localhost:5000/api/nodes/status?pollId={pollId}"
```

### 3. Test Weak Consistency
```powershell
# Vote - langsung return, sync async di background
Invoke-WebRequest -Uri "http://localhost:5000/api/polls/{pollId}/vote?consistency=weak" `
  -Method POST -ContentType "application/json" `
  -Body '{"optionIndex": 0, "voterId": "test2"}'
```

### 4. Test Eventual Consistency
```powershell
# Vote
Invoke-WebRequest -Uri "http://localhost:5000/api/polls/{pollId}/vote?consistency=eventual" `
  -Method POST -ContentType "application/json" `
  -Body '{"optionIndex": 0, "voterId": "test3"}'

# Tunggu 5 detik, semua node akan sync
Start-Sleep -Seconds 5
Invoke-WebRequest -Uri "http://localhost:5000/api/nodes/status?pollId={pollId}"
```

---

## Perilaku Mode

| Mode | Respons | Node States |
|------|---------|-------------|
| **Strong** | Tunggu semua node sync | Selalu konsisten |
| **Weak** | Langsung return | Mungkin berbeda sementara |
| **Eventual** | Langsung return | Konsisten setelah 5 detik |

---

## Contoh Response

### Vote Response (dengan replicationStatus)
```json
{
  "message": "Vote recorded successfully",
  "poll": { ... },
  "consistency": "strong",
  "replicationStatus": {
    "mode": "strong",
    "allNodesSynced": true,
    "nodesUpdated": ["NodeA", "NodeB", "NodeC"]
  }
}
```

### Node Status Response
```json
{
  "timestamp": 1734054600000,
  "backgroundSyncActive": true,
  "syncInterval": "5 seconds",
  "nodes": {
    "NodeA": { "lastSync": 1734054600000, "pollsTracked": 1, "pollState": {...} },
    "NodeB": { "lastSync": 1734054600000, "pollsTracked": 1, "pollState": {...} },
    "NodeC": { "lastSync": 1734054600000, "pollsTracked": 1, "pollState": {...} }
  },
  "pollConsistency": { "pollId": "xxx", "isConsistent": true }
}
```