Merge pull request #21 from mageddo/feature/MG-337

Feature/mg 337

README.md

@@ -73,7 +73,8 @@ You can also configure the options at the configuration file
 
 ```javascript
 {
-  "remoteDnsServers": [], // not used at the current version
+  "remoteDnsServers": [ [8,8,8,8], [4,4,4,4] ], // Remote DNS servers to be asked when can not solve from docker or local storage 
+                                                // If no one server was specified then the 8.8.8.8 will be used
   "envs": [ // all existent environments 
     {
       "name": "", // empty string is the default

src/dns.go

@@ -43,7 +43,7 @@ func handleQuestion(respWriter dns.ResponseWriter, reqMsg *dns.Msg) {
 		questionsQtd, firstQuestion.Name, utils.DnsQTypeCodeToName(firstQuestion.Qtype))
 
 	// loading the solvers and try to solve the hostname in that order
-	solvers := []proxy.DnsSolver{proxy.LocalDnsSolver{}, proxy.DockerDnsSolver{}, proxy.RemoteDnsSolver{}}
+	solvers := []proxy.DnsSolver{proxy.DockerDnsSolver{}, proxy.LocalDnsSolver{}, proxy.RemoteDnsSolver{}}
 	for _, solver := range solvers {
 
 		solverID := reflect.TypeOf(solver).Name()

src/github.com/mageddo/dns-proxy-server/events/local/LocalEvents.go

@@ -104,6 +104,11 @@ func GetConfiguration(ctx context.Context) *LocalConfiguration {
 
 
 type LocalConfiguration struct {
+	/**
+	 * The remote servers to ask when, DPS can not solve from docker or local file,
+	 * it will try one by one in order, if no one is specified then 8.8.8.8 is used by default
+	 * DO NOT call this variable directly, use GetRemoteDnsServers instead
+	 */
 	RemoteDnsServers [][4]byte `json:"remoteDnsServers"`
 	Envs []EnvVo `json:"envs"`
 	ActiveEnv string `json:"activeEnv"`
@@ -345,4 +350,13 @@ func (lc *LocalConfiguration) SetActiveEnv(ctx context.Context, env EnvVo) error
 
 func NewEmptyEnv() []EnvVo {
 	return []EnvVo{{Hostnames:[]HostnameVo{}, Name:""}}
+}
+
+func (lc *LocalConfiguration) GetRemoteServers(ctx context.Context) [][4]byte {
+	if len(lc.RemoteDnsServers) == 0 {
+		lc.RemoteDnsServers = append(lc.RemoteDnsServers, [4]byte{8, 8, 8, 8})
+		logger := log.GetLogger(ctx)
+		logger.Infof("status=put-default-server")
+	}
+	return lc.RemoteDnsServers
 }

src/github.com/mageddo/dns-proxy-server/proxy/RemoteDnsSolver.go

@@ -6,6 +6,8 @@ import (
 	"errors"
 	"fmt"
 	"golang.org/x/net/context"
+	"github.com/mageddo/dns-proxy-server/events/local"
+	"github.com/mageddo/log"
 )
 
 type RemoteDnsSolver struct {
@@ -15,26 +17,40 @@ type RemoteDnsSolver struct {
 // reference https://miek.nl/2014/August/16/go-dns-package/
 func (RemoteDnsSolver) Solve(ctx context.Context, question dns.Question) (*dns.Msg, error) {
 
-		//config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
-		c := new(dns.Client)
+	logger := log.GetLogger(ctx)
+	c := new(dns.Client)
+	m := new(dns.Msg)
+	m.SetQuestion(dns.Fqdn(question.Name), question.Qtype) // CAN BE A, AAA, MX, etc.
+	m.RecursionDesired = true
 
-		m := new(dns.Msg)
-		m.SetQuestion(dns.Fqdn(question.Name), question.Qtype) // CAN BE A, AAA, MX, etc.
-		m.RecursionDesired = true
+	var err error
+	config := local.GetConfiguration(ctx)
 
-		//r, _, err := c.Exchange(m, net.JoinHostPort(config.Servers[0], config.Port)) // server and port to ask
-		r, _, err := c.Exchange(m, net.JoinHostPort("8.8.8.8", "53")) // server and port to ask
+	for _, server := range config.GetRemoteServers(ctx) {
 
-		// if the answer not be returned
-		if r == nil {
-			return nil, errors.New(fmt.Sprintf("status=answer-can-not-be-bull, err=%v", err))
+		if len(server) != 4 {
+			logger.Warning("status=wrong-server, server=%+v", server)
+			continue
 		}
 
-		// what the code of the return message ?
-		if r.Rcode != dns.RcodeSuccess {
-			return nil, errors.New(fmt.Sprintf("status=invalid-answer-name, name=%s, rcode=%d", question.Name, r.Rcode))
+		// server and port to ask
+		formatServer := fmt.Sprintf("%d.%d.%d.%d", server[0], server[1], server[2], server[3])
+		logger.Debugf("status=format-server, server=%s", formatServer)
+
+		var r *dns.Msg
+		r, _, err = c.Exchange(m, net.JoinHostPort(formatServer, "53"))
+
+			// if the answer not be returned
+			if r == nil {
+				err = errors.New(fmt.Sprintf("status=answer-can-not-be-null, err=%v", err))
+				logger.Infof("status=no-answer, err=%s", err)
+				continue
+			} else if r.Rcode != dns.RcodeSuccess { // what the code of the return message ?
+				err = errors.New(fmt.Sprintf("status=invalid-answer-name, name=%s, rcode=%d", question.Name, r.Rcode))
+				logger.Infof("status=bad-code, name=%s, rcode=%d, err=%s", question.Name, r.Rcode, err)
+				continue
+			}
+			return r, nil
 		}
-
-		return r, nil
-
+		return nil, err
 	}