improvements

- don't panic for unparsable dns questions - compress releases (closes #1) - rename to dockness
bamarni · Mar 22, 2016 · efabfc7 · efabfc7
1 parent 6dd287d
commit efabfc7
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diff --git a/Makefile b/Makefile
@@ -1,8 +1,12 @@
-dev:
-	tmuxinator start go
+clean:
+	rm -rf build
 
-release:
-	mkdir -p build
-	GOOS=darwin GOARCH=amd64 go build -o build/docker-machine-dns-darwin-x64 ./docker-machine-dns.go
-	GOOS=linux GOARCH=amd64 go build -o build/docker-machine-dns-linux-x64 ./docker-machine-dns.go
+build: clean
+	mkdir -p build/darwin build/linux
+	GOOS=darwin GOARCH=amd64 go build -o build/darwin/dockness ./dockness.go
+	GOOS=linux GOARCH=amd64 go build -o build/linux/dockness ./dockness.go
 
+release: build
+	mkdir -p build/releases
+	tar -cvzf build/releases/dockness-darwin-x64.tar.gz -C build/darwin dockness
+	tar -cvzf build/releases/dockness-linux-x64.tar.gz -C build/linux dockness
diff --git a/README.md b/README.md
@@ -1,4 +1,4 @@
-# docker-machine-dns
+# dockness
 
 DNS for Docker machines, allows to access them with the following domain format : `{machine}.docker`.
 
@@ -12,31 +12,34 @@ Behind the scene it will run `docker-machine ip {machine}` in order to resolve t
 
 ### Prebuilt binaries
 
-Prebuilt binaries are available in the [releases](https://github.com/bamarni/docker-machine-dns/releases).
+Prebuilt binaries are available in the [releases](https://github.com/bamarni/dockness/releases).
 
 ### From source (requires Go)
 
-    go get github.com/bamarni/docker-machine-dns
+    go get github.com/bamarni/dockness
 
 ## Usage
 
+    dockness [options...]
+
+    Options:
+      -tld          Top-level domain to use (defaults to "docker")
+      -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")
+
 ### 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 :
 
-    > sudo docker-machine-dns
+    > sudo dockness
     2016/02/18 10:39:52 Creating configuration file at /etc/resolver/docker...
     2016/02/18 10:39:52 Listening on :53...
 
-In another terminal, to make sure it works properly (let's say for a machine called `dev`) :
-
-    > dig @localhost dev.docker +short
-    192.168.99.100
-
-## Linux
+### Linux
 
 Even though Linux users might not need a development VM, it can be useful for remote machines
 (eg. `ssh staging2.docker`, ...).
@@ -49,19 +52,69 @@ which provides a lightweight DNS server.
 
 If you have it installed, you can run :
 
-    > docker-machine-dns -port 10053
+    > dockness -port 10053
     2016/02/18 10:40:43 Listening on :10053...
 
 Then let Dnsmasq know about the resolver by running those commands :
 
     > echo "server=/docker/127.0.0.1#10053" | sudo tee -a /etc/dnsmasq.conf
     > sudo /etc/init.d/dnsmasq restart
 
-### Usage reference
+## Configure dockness as a service
 
-    docker-machine-dns [options...]
+As it's not very convenient to run the program manually in a terminal, you can instead set it as a service.
+Doing so, it will be running in the background automatically when booting your computer.
+
+### 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` :
+
+``` xml
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<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>
+        <key>RunAtLoad</key>
+        <true/>
+</dict>
+</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
+
+### Linux
+
+Here again, it will depend on your Linux distribution.
+We'll take as example [Systemd](https://freedesktop.org/wiki/Software/systemd/),
+which is nowadays the default init system in Ubuntu/Debian.
+
+Create the following file at `/etc/systemd/system/dockness.service`:
+
+    TODO
 
-    Options:
-      -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")
diff --git a/docker-machine-dns.go → dockness.go b/docker-machine-dns.go → dockness.go
@@ -27,22 +27,26 @@ func lookup(w dns.ResponseWriter, r *dns.Msg) {
 		}
 
 		domLevels := strings.Split(q.Name, ".")
+		domLevelsLen := len(domLevels)
+		if domLevelsLen < 3 {
+			log.Printf("Couldn't parse the DNS question '%s'", q.Name)
+			continue
+		}
 		machine := domLevels[len(domLevels)-3]
 
-		var stdoutBytes []byte
+		var output []byte
 		var err error
-
 		if user == "" {
-			stdoutBytes, err = exec.Command("docker-machine", "ip", machine).Output()
+			output, err = exec.Command("docker-machine", "ip", machine).CombinedOutput()
 		} else {
-			stdoutBytes, err = exec.Command("sudo", "-u", user, "docker-machine", "ip", machine).Output()
+			output, err = exec.Command("sudo", "-u", user, "docker-machine", "ip", machine).CombinedOutput()
 		}
 
 		if err != nil {
-			log.Printf("No IP found for machine '%s': %s", machine, err)
+			log.Printf("No IP found for machine '%s' (%s)", machine, output)
 			continue
 		}
-		ip := string(stdoutBytes[:len(stdoutBytes)-1])
+		ip := string(output[:len(output)-1])
 
 		rr = &dns.A{
 			Hdr: dns.RR_Header{
@@ -61,13 +65,14 @@ func lookup(w dns.ResponseWriter, r *dns.Msg) {
 }
 
 func main() {
+	tld := flag.String("tld", "docker", "Top-level domain to use")
 	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")
 	flag.Parse()
 
 	if *serverOnly == false && runtime.GOOS == "darwin" {
-		confPath := "/etc/resolver/docker"
+		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 {
@@ -82,7 +87,7 @@ func main() {
 		Net:  "udp",
 	}
 
-	dns.HandleFunc("docker.", lookup)
+	dns.HandleFunc(*tld+".", lookup)
 
 	log.Printf("Listening on %s...", addr)
 	go log.Fatal(server.ListenAndServe())