initial

Author: Sergei Egorov

README.md

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+Simple utility for auto forwarding ports from Docker container in boot2docker VM to the host

main.go

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+package main
+
+import (
+	"log"
+	"strconv"
+	"strings"
+
+	// Fork used because original version is not providing forwarded ports info
+	"github.com/bsideup/go-virtualbox"
+	"github.com/fsouza/go-dockerclient"
+)
+
+const forward2dockerPrefix = "forward2docker-"
+
+func main() {
+	client, err := docker.NewClientFromEnv()
+
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	reload(client)
+
+	listener := make(chan *docker.APIEvents)
+	client.AddEventListener(listener)
+	for {
+		select {
+		case event := <-listener:
+			switch event.Status {
+			case "start", "die":
+				reload(client)
+			}
+		}
+	}
+}
+
+func reload(client *docker.Client) {
+	machine, err := virtualbox.GetMachine("boot2docker-vm")
+
+	if err != nil {
+		log.Fatal(err)
+	}
+	forwards := make(map[int64]bool)
+
+	for _, forwarding := range machine.Forwardings {
+		if !strings.HasPrefix(forwarding.Name, forward2dockerPrefix) {
+			continue
+		}
+
+		forwards[int64(forwarding.GuestPort)] = true
+	}
+
+	log.Printf("Previously mapped: %v\n", forwards)
+
+	opts := docker.ListContainersOptions{}
+	containers, err := client.ListContainers(opts)
+
+	if err != nil {
+		log.Println("Failed to list containers", err)
+		return
+	}
+
+	for _, container := range containers {
+		for _, binding := range container.Ports {
+			_, exists := forwards[binding.PublicPort]
+			if !exists {
+				log.Printf("Adding port mapping for %d\n", binding.PublicPort)
+				if binding.PublicPort < 1024 {
+					log.Printf("Exposed port %d is lower than 1024 and will not work if VirtualBox is started without root privileges\n", binding.PublicPort)
+				}
+				rule := virtualbox.PFRule{
+					Proto:     virtualbox.PFTCP,
+					HostPort:  uint16(binding.PublicPort),
+					GuestPort: uint16(binding.PublicPort),
+				}
+				machine.AddNATPF(1, forward2dockerPrefix+strconv.FormatInt(binding.PublicPort, 10), rule)
+			}
+
+			delete(forwards, binding.PublicPort)
+		}
+	}
+
+	if len(forwards) > 0 {
+		log.Printf("To be deleted: %v\n", forwards)
+		for port := range forwards {
+			machine.DelNATPF(1, forward2dockerPrefix+strconv.FormatInt(port, 10))
+		}
+	}
+
+}