Merge pull request #7 from bigeagle/upstream

Redis option and only cache successful lookups

godns.conf

@@ -37,6 +37,7 @@ maxcount = 0 #If set zero. The Sum of cache itmes will be unlimit.
 #If set false, will not query hosts file and redis hosts record
 enable = false
 host-file = "/etc/hosts"
+redis-enable = true
 redis-key = "godns:hosts"
 ttl = 600
 

handler.go

@@ -147,7 +147,7 @@ func (h *GODNSHandler) do(Net string, w dns.ResponseWriter, req *dns.Msg) {
 
 	w.WriteMsg(mesg)
 
-	if IPQuery > 0 {
+	if IPQuery > 0 && len(mesg.Answer) > 0 {
 		err = h.cache.Set(key, mesg)
 
 		if err != nil {

hosts.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bufio"
+	"errors"
 	"net"
 	"os"
 	"regexp"
@@ -17,8 +18,14 @@ type Hosts struct {
 
 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}
+
+	var rc *redis.Client
+	if hs.RedisEnable {
+		rc = &redis.Client{Addr: rs.Addr(), Db: rs.DB, Password: rs.Password}
+	} else {
+		rc = nil
+	}
+	redisHosts := &RedisHosts{rc, hs.RedisKey}
 
 	hosts := Hosts{fileHosts.GetAll(), redisHosts}
 	return hosts
@@ -69,17 +76,26 @@ type RedisHosts struct {
 }
 
 func (r *RedisHosts) GetAll() map[string]string {
+	if r.redis == nil {
+		return 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) {
+	if r.redis == nil {
+		return "", false
+	}
 	b, err := r.redis.Hget(r.key, domain)
 	return string(b), err == nil
 }
 
 func (r *RedisHosts) Set(domain, ip string) (bool, error) {
+	if r.redis == nil {
+		return false, errors.New("Redis not enabled")
+	}
 	return r.redis.Hset(r.key, domain, []byte(ip))
 }
 

settings.go

@@ -57,6 +57,7 @@ type CacheSettings struct {
 type HostsSettings struct {
 	Enable      bool
 	HostsFile   string `toml:"host-file"`
+	RedisEnable bool   `toml:"redis-enable"`
 	RedisKey    string `toml:"redis-key"`
 	TTL         uint32 `toml:"ttl"`
 }