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main.go
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package main
import (
"crypto/tls"
"errors"
"fmt"
"io/fs"
"net/http"
"os"
"sync"
"time"
"github.com/charmbracelet/log"
"github.com/go-playground/validator/v10"
"github.com/pelageech/BDUTS/auth"
"github.com/pelageech/BDUTS/backend"
"github.com/pelageech/BDUTS/cache"
"github.com/pelageech/BDUTS/config"
"github.com/pelageech/BDUTS/db"
"github.com/pelageech/BDUTS/email"
"github.com/pelageech/BDUTS/lb"
"github.com/pelageech/BDUTS/metrics"
"github.com/pelageech/BDUTS/timer"
)
const (
dbFillFactor = 0.9
lbConfigPath = "./resources/config.json"
serversConfigPath = "./resources/servers.json"
loggerPrefixMain = "BDUTS"
loggerPrefixCache = "BDUTS_CACHE"
loggerPrefixLB = "BDUTS_LB"
loggerPrefixTimer = "BDUTS_TIMER"
loggerPrefixPool = "BDUTS_POOL"
readWriteExecuteOwnerGroupOthers = 0o777
readWriteExecuteOwner = 0o700
goroutinesToWait = 2
usersDB = "./db/users.db"
usersDBPermissions = 0o600
certFile = "resources/fullchain.pem"
keyFile = "resources/privkey.pem"
)
var logger *log.Logger
func loadBalancerConfigure() *config.LoadBalancerConfig {
loadBalancerReader, err := config.NewLoadBalancerReader(lbConfigPath)
if err != nil {
logger.Fatal("Failed to create LoadBalancerReader", "err", err)
}
defer func(loadBalancerReader *config.LoadBalancerReader) {
err := loadBalancerReader.Close()
if err != nil {
logger.Fatal("Failed to close LoadBalancerReader", "err", err)
}
}(loadBalancerReader)
lbConfig, err := loadBalancerReader.ReadLoadBalancerConfig()
if err != nil {
logger.Fatal("Failed to read LoadBalancerConfig", "err", err)
}
return lbConfig
}
func serversConfigure() []config.ServerConfig {
serversReader, err := config.NewServersReader(serversConfigPath)
if err != nil {
logger.Fatal("Failed to create ServersReader", "err", err)
}
defer func(serversReader *config.ServersReader) {
err := serversReader.Close()
if err != nil {
logger.Fatal("Failed to close ServersReader", "err", err)
}
}(serversReader)
serversConfig, err := serversReader.ReadServersConfig()
if err != nil {
logger.Fatal("Failed to read ServersConfig", "err", err)
}
return serversConfig
}
func cacheCleanerConfigure(dbControllerTicker *time.Ticker, maxCacheSize int64) *cache.CacheCleaner {
err := os.Mkdir(cache.DbDirectory, readWriteExecuteOwnerGroupOthers)
if err != nil && !os.IsExist(err) {
logger.Fatal("Cache files directory creation error", "err", err)
}
// create directory for cache files
err = os.Mkdir(cache.PagesPath, readWriteExecuteOwnerGroupOthers)
if err != nil && !os.IsExist(err) {
logger.Fatal("DB files directory creation error", "err", err)
}
// open directory with cache files
dbDir, err := os.Open(cache.PagesPath)
if err != nil {
logger.Fatal("DB files opening error", "err", err)
}
return cache.NewCacheCleaner(dbDir, maxCacheSize, dbFillFactor, dbControllerTicker)
}
func isFileExist(file string) bool {
if _, err := os.Stat(file); errors.Is(err, fs.ErrNotExist) {
return false
}
return true
}
func main() {
logger = log.NewWithOptions(os.Stderr, log.Options{
ReportCaller: true,
ReportTimestamp: true,
})
logger.SetPrefix(loggerPrefixMain)
cache.LoggerConfig(loggerPrefixCache)
backend.LoggerConfig(loggerPrefixPool)
timer.LoggerConfig(loggerPrefixTimer)
lb.LoggerConfig(loggerPrefixLB)
lbConfJSON := loadBalancerConfigure()
lbConfig := lb.NewLoadBalancerConfig(
lbConfJSON.Port,
time.Duration(lbConfJSON.HealthCheckPeriod)*time.Millisecond,
lbConfJSON.MaxCacheSize,
time.Duration(lbConfJSON.ObserveFrequency)*time.Millisecond,
)
// database
logger.Info("Opening cache database")
if err := os.Mkdir(cache.DbDirectory, readWriteExecuteOwner); err != nil && !os.IsExist(err) {
logger.Fatal("Couldn't create a directory "+cache.DbDirectory, "err", err)
}
boltdb, err := cache.OpenDatabase(cache.DbDirectory + "/" + cache.DbName)
if err != nil {
logger.Fatal("Failed to open boltdb", "err", err)
}
defer cache.CloseDatabase(boltdb)
// thread that clears the cache
dbControllerTicker := time.NewTicker(lbConfig.ObserveFrequency())
controller := cacheCleanerConfigure(dbControllerTicker, lbConfig.MaxCacheSize())
defer dbControllerTicker.Stop()
cacheProps := cache.NewCachingProperties(boltdb, controller)
cacheProps.CalculateSize()
// health checker configuration
healthCheckFunc := func(server *backend.Backend) {
alive := server.CheckIfAlive()
server.SetAlive(alive)
if alive {
logger.Infof("[%s] is alive.\n", server.URL().Host)
} else {
logger.Warnf("[%s] is down.\n", server.URL().Host)
}
}
// creating new load balancer
loadBalancer := lb.NewLoadBalancerWithPool(
lbConfig,
cacheProps,
healthCheckFunc,
serversConfigure(),
)
// Firstly, identify the working servers
logger.Info("Configured! Now setting up the first health check...")
wg := sync.WaitGroup{}
wg.Add(len(loadBalancer.Pool().Servers()))
for _, server := range loadBalancer.Pool().Servers() {
server := server
go func() {
loadBalancer.HealthCheckFunc()(server)
wg.Done()
}()
}
wg.Wait()
logger.Info("Ready!")
// set up health check
go loadBalancer.HealthChecker()
go loadBalancer.CacheProps().Observe()
dbService := db.Service{}
dbService.SetLogger(logger)
// if users database doesn't exist, create it and add admin user
// with login "admin" and password "admin"
addDefaultUser := false
if !isFileExist(usersDB) {
addDefaultUser = true
}
err = dbService.Connect(usersDB, usersDBPermissions, nil)
if err != nil {
logger.Fatal("Unable to connect to users bolt database", "err", err)
}
logger.Info("Connected to users bolt database")
defer func(dbService *db.Service) {
err = dbService.Close()
if err != nil {
logger.Warn("Unable to close users bolt database", "err", err)
return
}
logger.Info("Users bolt database is closed")
}(&dbService)
// set up email
smtpUser := os.Getenv("SMTP_USER")
smtpPassword := os.Getenv("SMTP_PASSWORD")
smtpHost := os.Getenv("SMTP_HOST")
smtpPort := os.Getenv("SMTP_PORT")
sender, err := email.New(smtpUser, smtpPassword, smtpHost, smtpPort, logger)
if err != nil {
logger.Fatal("Unable to set up email sender", "err", err)
}
// set up auth
validate := validator.New()
signKey, found := os.LookupEnv("JWT_SIGNING_KEY")
if !found {
logger.Fatal("JWT signing key is not found")
}
authSvc := auth.New(&dbService, sender, validate, []byte(signKey), logger)
if addDefaultUser {
err = authSvc.SignUpDefaultUser()
if err != nil {
logger.Fatal("Unable to add default user", "err", err)
}
}
// Create a CORS middleware handler function
cors := func(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// Add CORS headers to the response
w.Header().Set("Access-Control-Allow-Origin", "*")
w.Header().Set("Access-Control-Allow-Methods", "*")
w.Header().Set("Access-Control-Allow-Headers", "*")
w.Header().Set("Access-Control-Expose-Headers", "Authorization")
// If the request method is OPTIONS, return a successful response with no body
if r.Method == "OPTIONS" {
w.WriteHeader(http.StatusOK)
return
}
// Call the next handler function in the chain
h.ServeHTTP(w, r)
})
}
// Serving
http.HandleFunc("/", loadBalancer.LoadBalancerHandler)
http.Handle("/serverPool/add", cors(authSvc.AuthenticationMiddleware(http.HandlerFunc(loadBalancer.AddServerHandler))))
http.Handle("/serverPool/remove", cors(authSvc.AuthenticationMiddleware(http.HandlerFunc(loadBalancer.RemoveServerHandler))))
http.Handle("/serverPool", cors(authSvc.AuthenticationMiddleware(http.HandlerFunc(loadBalancer.GetServersHandler))))
http.Handle("/admin/signup", cors(authSvc.AuthenticationMiddleware(http.HandlerFunc(authSvc.SignUp))))
http.Handle("/admin/password", cors(authSvc.AuthenticationMiddleware(http.HandlerFunc(authSvc.ChangePassword))))
http.Handle("/admin/signin", cors(http.HandlerFunc(authSvc.SignIn)))
http.Handle("/admin", cors(authSvc.AuthenticationMiddleware(http.HandlerFunc(authSvc.DeleteUser))))
http.Handle("/admin/clear", cors(authSvc.AuthenticationMiddleware(http.HandlerFunc(loadBalancer.ClearCacheHandler))))
// Config TLS: setting a pair crt-key
Crt, err := tls.LoadX509KeyPair(certFile, keyFile)
if err != nil {
logger.Fatal("Failed to load crt and key", "err", err)
}
tlsConfig := &tls.Config{Certificates: []tls.Certificate{Crt}}
ln, err := tls.Listen("tcp", fmt.Sprintf(":%d", loadBalancer.Config().Port()), tlsConfig)
if err != nil {
logger.Fatal("Failed to start tcp listener", "err", err)
}
wg.Add(goroutinesToWait)
logger.Infof("Load Balancer started at :%d\n", loadBalancer.Config().Port())
go func() {
if err := http.Serve(ln, nil); err != nil {
logger.Fatal("Failed to serve tcp listener", "err", err)
}
wg.Done()
}()
// prometheus part
metrics.Init(loadBalancer.CacheProps().Size, loadBalancer.CacheProps().PagesCount)
server := http.Server{
Addr: ":8081",
Handler: metrics.Handler(),
}
go func() {
if err := server.ListenAndServe(); err != nil {
logger.Fatal("Failed to start prometheus server", "err", err)
}
wg.Done()
}()
wg.Wait()
}