-
Notifications
You must be signed in to change notification settings - Fork 0
/
main.go
250 lines (213 loc) · 5.75 KB
/
main.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
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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
package main
import (
"encoding/json"
"log"
"math/rand"
"net"
"net/http"
"net/http/httputil"
"net/url"
"os"
"strings"
"sync"
"time"
"github.com/jmoiron/sqlx"
_ "github.com/mattn/go-sqlite3"
)
var (
nodeHealthCheckCycleTime = 60 * time.Second
timeout = time.Second * 2
BuildNumber = "4"
db *sqlx.DB
servers map[string][]Server
current int
configMutex = &sync.Mutex{}
initLogsTable = `CREATE TABLE IF NOT EXISTS logs ( request_id TEXT, request_ip TEXT, user_agent TEXT, server_addr TEXT, domain TEXT, timestamp DATETIME DEFAULT CURRENT_TIMESTAMP, http_response INTEGER);`
insertLogEntry = `INSERT INTO logs (request_id, request_ip, user_agent, server_addr, domain, http_response) VALUES (?, ?, ?, ?, ?, ?)`
enumerateDomainStats = `SELECT domain, COUNT(*) AS total_requests, MAX(timestamp) AS most_recent_time
FROM logs GROUP BY domain`
)
type Server struct {
Addr string
Domain string
Active bool
}
type DomainReport struct {
Domain string `json:"domain"`
TotalRequests int `json:"total_requests"`
MostRecentTime time.Time `json:"most_recent_time"`
}
type DomainConfig struct {
Domain string `json:"domain"`
Servers []string `json:"servers"`
}
func main() {
var err error
nodeHealthCheckCycle()
initSqlite(err)
loadConfig()
routeHandlers()
log.Fatal(http.ListenAndServe(":8080", nil))
}
func routeHandlers() {
http.HandleFunc("/", proxyHandler)
http.HandleFunc("/health", healthHandler)
http.HandleFunc("/report", reportHandler)
http.HandleFunc("/reload", reloadHandler)
}
func initSqlite(err error) {
db, err = sqlx.Connect("sqlite3", "./loadbalancer.db")
if err != nil {
log.Fatalln(err)
}
_, err = db.Exec(initLogsTable)
if err != nil {
log.Fatalln(err)
}
}
func loadConfig() map[string][]Server {
data, err := os.ReadFile("./config/domains.json")
if err != nil {
log.Println("Error reading domains.json:", err)
return nil
}
var config []DomainConfig
err = json.Unmarshal(data, &config)
if err != nil {
log.Println("Error parsing domains.json:", err)
return nil
}
newServers := make(map[string][]Server)
for _, domainConfig := range config {
for _, serverAddr := range domainConfig.Servers {
if checkServerHealth(serverAddr) {
newServers[domainConfig.Domain] = append(newServers[domainConfig.Domain], Server{
Addr: serverAddr,
Domain: domainConfig.Domain,
Active: true,
})
}
}
}
return newServers
}
func proxyHandler(w http.ResponseWriter, r *http.Request) {
configMutex.Lock()
defer configMutex.Unlock()
domainServers, ok := servers[r.Host]
if !ok || len(domainServers) == 0 {
http.Error(w, "No servers available for domain", http.StatusInternalServerError)
return
}
var server Server
for i := 0; i < len(domainServers); i++ {
server = domainServers[current]
current = (current + 1) % len(domainServers)
if server.Active {
break
}
}
if !server.Active {
http.Error(w, "No active servers available for domain", http.StatusInternalServerError)
return
}
target, err := url.Parse(server.Addr)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
proxy := httputil.NewSingleHostReverseProxy(target)
proxy.ModifyResponse = logResponse
proxy.ServeHTTP(w, r)
}
func nodeHealthCheckCycle() {
go func() {
for range time.Tick(nodeHealthCheckCycleTime) {
checkAllServerHealth()
}
}()
}
func logResponse(r *http.Response) error {
requestID := generateHash(32)
requestIP := strings.Split(r.Request.RemoteAddr, ":")[0]
userAgent := r.Request.UserAgent()
serverAddr := r.Request.URL.Host
domain := r.Request.Host
_, err := db.Exec(insertLogEntry,
requestID, requestIP, userAgent, serverAddr, domain, r.StatusCode)
if err != nil {
return err
}
r.Header.Set("X-Request-ID", requestID)
return nil
}
func reportHandler(w http.ResponseWriter, r *http.Request) {
rows, err := db.Queryx(enumerateDomainStats)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
defer rows.Close()
var reports []DomainReport
for rows.Next() {
var report DomainReport
err = rows.StructScan(&report)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
reports = append(reports, report)
}
jsonData, err := json.Marshal(reports)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "application/json")
w.Write(jsonData)
}
func healthHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
w.Write([]byte("ok"))
}
func generateHash(length int) string {
chars := "76cf1d83b5e42a09"
result := make([]byte, length)
for i := range result {
result[i] = chars[rand.Intn(len(chars))]
}
return string(result)
}
func checkServerHealth(serverAddr string) bool {
conn, err := net.DialTimeout("tcp", serverAddr+"/v0/health", timeout)
if err != nil {
log.Println("Server health check failed:", err)
return false
}
conn.Close()
return true
}
func checkAllServerHealth() {
configMutex.Lock()
defer configMutex.Unlock()
for domain, domainServers := range servers {
for i, server := range domainServers {
if !checkServerHealth(server.Addr) {
servers[domain] = append(domainServers[:i], domainServers[i+1:]...)
log.Println("Server removed:", server.Addr)
}
}
}
}
func reloadHandler(w http.ResponseWriter, r *http.Request) {
newServers := loadConfig()
if newServers == nil {
http.Error(w, "Invalid configuration", http.StatusInternalServerError)
return
}
configMutex.Lock()
servers = newServers
configMutex.Unlock()
w.Header().Set("Content-Type", "application/json")
w.Write([]byte("Configuration reloaded"))
}