package main import ( "bufio" "github.com/hoisie/redis" "os" "regexp" "strings" ) type Hosts struct { FileHosts map[string]string RedisHosts *RedisHosts } func NewHosts(hs HostsSettings, rs RedisSettings) Hosts { fileHosts := &FileHosts{hs.HostsFile} redis := &redis.Client{Addr: rs.Addr(), Db: rs.DB, Password: rs.Password} redisHosts := &RedisHosts{redis, hs.RedisKey} hosts := Hosts{fileHosts.GetAll(), redisHosts} return hosts } /* 1. Resolve hosts file only one times 2. Request redis on every get called, may lead to performance lose serious 3. Match local /etc/hosts file first, remote redis records second */ func (h *Hosts) Get(domain string) (ip string, ok bool) { if ip, ok = h.FileHosts[domain]; ok { return } if ip, ok = h.RedisHosts.Get(domain); ok { return } return "", false } func (h *Hosts) GetAll() map[string]string { m := make(map[string]string) for domain, ip := range h.RedisHosts.GetAll() { m[domain] = ip } for domain, ip := range h.FileHosts { m[domain] = ip } return m } type RedisHosts struct { redis *redis.Client key string } func (r *RedisHosts) GetAll() map[string]string { var hosts = make(map[string]string) r.redis.Hgetall(r.key, hosts) return hosts } func (r *RedisHosts) Get(domain string) (ip string, ok bool) { b, err := r.redis.Hget(r.key, domain) return string(b), err == nil } func (r *RedisHosts) Set(domain, ip string) (bool, error) { return r.redis.Hset(r.key, domain, []byte(ip)) } type FileHosts struct { file string } func (f *FileHosts) GetAll() map[string]string { var hosts = make(map[string]string) buf, err := os.Open(f.file) if err != nil { panic("Can't open " + f.file) } scanner := bufio.NewScanner(buf) for scanner.Scan() { line := scanner.Text() line = strings.TrimSpace(line) if strings.HasPrefix(line, "#") || line == "" { continue } sli := strings.Split(line, " ") if len(sli) == 1 { sli = strings.Split(line, "\t") } if len(sli) < 2 { continue } domain := sli[len(sli)-1] ip := sli[0] if !f.isDomain(domain) || !f.isIP(ip) { continue } hosts[domain] = ip } return hosts } func (f *FileHosts) isDomain(domain string) bool { match, _ := regexp.MatchString("^[a-z]", domain) return match } func (f *FileHosts) isIP(ip string) bool { match, _ := regexp.MatchString("^[1-9]", ip) return match }