use libmachine directly

README.md

@@ -11,7 +11,7 @@ DNS for Docker machines, allows to access them with the following domain format
 
 It spins up a simplistic DNS server, only listening for questions about A records.
 
-Behind the scene it will run `docker-machine ip {machine}` in order to resolve the IP address of a given machine.
+Behind the scene it will use [libmachine](https://github.com/docker/machine) in order to resolve IP addresses.
 
 ## Installation
 
@@ -21,33 +21,31 @@ Prebuilt binaries are available in the [releases](https://github.com/bamarni/doc
 
 ### From source (requires Go)
 
-    go get github.com/miekg/dns
-    go get github.com/bamarni/dockness
+    go get github.com/miekg/dns github.com/docker/machine github.com/bamarni/dockness
 
 ## Usage
 
     dockness [options...]
 
     Options:
-      -tld          Top-level domain to use (defaults to "docker")
-      -ttl          Time to Live for DNS records (defaults to 0)
-      -port         Port to listen on (defaults to "53")
-      -server-only  Server only, doesn't try to create a resolver configuration file
-      -user         Execute the "docker-machine ip" command as a different user (defaults to "SUDO_USER")
+      -tld    Top-level domain to use (defaults to "docker")
+      -ttl    Time to Live for DNS records (defaults to 0)
+      -port   Port to listen on (defaults to "53")
+      -debug  Enable debugging (defaults to false)
 
 ### Mac OSX
 
 To develop on Mac you probably have a local VM, using VirtualBox for example.
 However this machine gets assigned a dynamic IP address.
 
-The program can be up and running in one command :
+You can be up and running in a few commands, first :
 
-    > sudo dockness
-    2016/02/18 10:39:52 Creating configuration file at /etc/resolver/docker...
-    2016/02/18 10:39:52 Listening on :53...
+    > echo "nameserver 127.0.0.1\nport 10053" | sudo tee /etc/resolver/docker
 
-*If you don't want to run the program as root, you can create the resolver file yourself and use a high port.
-Cf. example in the [Configure as a service](#configure-dockness-as-a-service) section.*
+It tells your Mac that the resolver for `.docker` TLD listens locally on port 10053. You can now run the resolver on this port :
+
+    > dockness -port 10053
+    2016/02/18 10:39:52 Listening on :10053...
 
 ### Linux
 
@@ -77,11 +75,7 @@ Doing so, it will be running in the background automatically when booting your c
 
 ### Mac OSX
 
-Run this command : `echo "nameserver 127.0.0.1\nport 10053" | sudo tee /etc/resolver/docker`
-
-It tells your Mac that the resolver for `.docker` TLD listens locally on port 10053.
-
-You can now create the appropriate service configuration file at `~/Library/LaunchAgents/local.dockness.plist` :
+You can create the appropriate service configuration file at `~/Library/LaunchAgents/local.dockness.plist` :
 
 ``` xml
 <?xml version="1.0" encoding="UTF-8"?>
@@ -90,17 +84,11 @@ You can now create the appropriate service configuration file at `~/Library/Laun
 <dict>
         <key>Disabled</key>
         <false/>
-        <key>EnvironmentVariables</key>
-        <dict>
-                <key>PATH</key>
-                <string>/usr/local/bin</string>
-        </dict>
         <key>Label</key>
         <string>local.dockness</string>
         <key>ProgramArguments</key>
         <array>
                 <string>/path/to/dockness</string>
-                <string>-server-only</string>
                 <string>-port</string>
                 <string>10053</string>
         </array>
@@ -110,10 +98,6 @@ You can now create the appropriate service configuration file at `~/Library/Laun
 </plist>
 ```
 
-You'll have to adapt 2 parameters :
-- `/path/to/dockness`
-- `/usr/local/bin`, which is the directory containing your `docker-machine` executable
-
 Finally, the service can be enabled :
 
     launchctl load ~/Library/LaunchAgents/local.dockness.plist

dockness.go

@@ -2,17 +2,18 @@ package main
 
 import (
 	"flag"
+	"github.com/docker/machine/commands/mcndirs"
+	"github.com/docker/machine/libmachine"
+	mcnlog "github.com/docker/machine/libmachine/log"
 	"github.com/miekg/dns"
-	"io/ioutil"
 	"log"
 	"net"
 	"os"
-	"os/exec"
 	"os/signal"
-	"runtime"
 	"strings"
 )
 
+var api *libmachine.Client
 var ttl uint
 var user string
 
@@ -33,21 +34,19 @@ func lookup(w dns.ResponseWriter, r *dns.Msg) {
 			log.Printf("Couldn't parse the DNS question '%s'", q.Name)
 			continue
 		}
-		machine := domLevels[len(domLevels)-3]
-
-		var output []byte
-		var err error
-		if user == "" {
-			output, err = exec.Command("docker-machine", "ip", machine).CombinedOutput()
-		} else {
-			output, err = exec.Command("sudo", "-u", user, "docker-machine", "ip", machine).CombinedOutput()
+		machineName := domLevels[len(domLevels)-3]
+
+		machine, err := api.Load(machineName)
+		if err != nil {
+			log.Printf("Couldn't load machine '%s' : %s", machineName, err)
+			continue
 		}
 
+		ip, err := machine.Driver.GetIP()
 		if err != nil {
-			log.Printf("No IP found for machine '%s' (%s)", machine, output)
+			log.Printf("Couldn't find IP for machine '%s' : %s", machineName, err)
 			continue
 		}
-		ip := string(output[:len(output)-1])
 
 		rr = &dns.A{
 			Hdr: dns.RR_Header{
@@ -69,19 +68,12 @@ func main() {
 	tld := flag.String("tld", "docker", "Top-level domain to use")
 	flag.UintVar(&ttl, "ttl", 0, "Time to Live for DNS records")
 	port := flag.String("port", "53", "Port to listen on")
-	serverOnly := flag.Bool("server-only", false, "Server only, doesn't try to create a resolver configuration")
-	flag.StringVar(&user, "user", os.Getenv("SUDO_USER"), "Execute the 'docker-machine ip' command as this user")
+	debug := flag.Bool("debug", false, "Enable debugging")
 	flag.Parse()
 
-	if *serverOnly == false && runtime.GOOS == "darwin" {
-		confPath := "/etc/resolver/" + *tld
-		log.Printf("Creating configuration file at %s...", confPath)
-		conf := []byte("nameserver 127.0.0.1\nport " + *port + "\n")
-		if err := ioutil.WriteFile(confPath, conf, 0644); err != nil {
-			log.Fatalf("Could not create configuration file: %s", err)
-		}
-		defer os.Remove(confPath)
-	}
+	mcnlog.SetDebug(*debug)
+	api = libmachine.NewClient(mcndirs.GetBaseDir(), mcndirs.GetMachineCertDir())
+	defer api.Close()
 
 	addr := ":" + *port
 	server := &dns.Server{