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Add DNS support for PWD instances (play-with-docker#94)
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* Add DNS support for PWD instances

* Store IP address of PWD in all session networks and restore it with the
same IP address

* Remove unnecesary print

* Change url format to pwd<ip>-port for better DNS filtering

* Make PWD listen on 80 and 443 for DNS resolve to work
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@xetorthio
xetorthio authored Feb 17, 2017
1 parent 9c4df83 commit f816be6
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Showing 9 changed files with 102 additions and 31 deletions.
5 changes: 3 additions & 2 deletions Dockerfile.dind
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Expand Up @@ -2,8 +2,9 @@ FROM docker:1.13.1-dind

RUN apk add --no-cache git tmux py2-pip apache2-utils vim build-base gettext-dev curl bash

ENV COMPOSE_VERSION=1.11.1
# Install Compose and Machine
RUN pip install docker-compose==1.10.0-rc1
RUN pip install docker-compose==${COMPOSE_VERSION}
RUN curl -L https://github.com/docker/machine/releases/download/v0.9.0-rc1/docker-machine-Linux-x86_64 \
-o /usr/bin/docker-machine && chmod +x /usr/bin/docker-machine

Expand Down Expand Up @@ -34,6 +35,6 @@ WORKDIR /root
CMD cat /etc/hosts >/etc/hosts.bak && \
sed 's/^::1.*//' /etc/hosts.bak > /etc/hosts && \
dockerd --experimental -g /graph --host=unix:///var/run/docker.sock --host=tcp://0.0.0.0:2375 \
--storage-driver=$DOCKER_STORAGE_DRIVER &>/docker.log & \
--storage-driver=$DOCKER_STORAGE_DRIVER --dns $PWD_IP_ADDRESS --dns 8.8.8.8 &>/docker.log & \
while true ; do /bin/bash ; done
# ... and then put a shell in the foreground, restarting it if it exits
2 changes: 1 addition & 1 deletion README.md
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Expand Up @@ -52,5 +52,5 @@ Notes:

~~We're planning to setup a reverse proxy that handles redirection automatically, in the meantime you can use [ngrok](https://ngrok.com) within PWD running `docker run --name supergrok -d jpetazzo/supergrok` then `docker logs --follow supergrok` , it will give you a ngrok URL, now you can go to that URL and add the IP+port that you want to connect to… e.g. if your PWD instance is 10.0.42.3, you can go to http://xxxxxx.ngrok.io/10.0.42.3:8000 (where the xxxxxx is given to you in the supergrok logs).~~

If you need to access your services from outside, use the following URL pattern `http://ip<underscore_ip>-<port>.play-with-docker.com` (i.e: http://ip10_2_135_3-80.play-with-docker.com/).
If you need to access your services from outside, use the following URL pattern `http://pwd<underscore_ip>-<port>.play-with-docker.com` (i.e: http://pwd10_2_135_3-80.play-with-docker.com/).

48 changes: 44 additions & 4 deletions api.go
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Expand Up @@ -6,6 +6,7 @@ import (
"log"
"net/http"
"os"
"regexp"
"strings"

"github.com/franela/play-with-docker/config"
Expand All @@ -14,6 +15,7 @@ import (
"github.com/franela/play-with-docker/templates"
gh "github.com/gorilla/handlers"
"github.com/gorilla/mux"
"github.com/miekg/dns"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/urfave/negroni"
"github.com/yhat/wsutil"
Expand All @@ -25,6 +27,16 @@ func main() {

bypassCaptcha := len(os.Getenv("GOOGLE_RECAPTCHA_DISABLED")) > 0

// Start the DNS server
dnsServer := &dns.Server{Addr: ":53", Net: "udp"}
dns.HandleFunc(".", handleDnsRequest)
go func() {
err := dnsServer.ListenAndServe()
if err != nil {
log.Fatal(err)
}
}()

server := services.CreateWSServer()
server.On("connection", handlers.WS)
server.On("error", handlers.WSError)
Expand All @@ -49,8 +61,8 @@ func main() {
}

// Specific routes
r.Host(`{node:ip[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}}-{port:[0-9]*}.{tld:.*}`).HandlerFunc(proxyMultiplexer)
r.Host(`{node:ip[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}}.{tld:.*}`).HandlerFunc(proxyMultiplexer)
r.Host(`{node:pwd[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}}-{port:[0-9]*}.{tld:.*}`).HandlerFunc(proxyMultiplexer)
r.Host(`{node:pwd[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}}.{tld:.*}`).HandlerFunc(proxyMultiplexer)
r.HandleFunc("/ping", handlers.Ping).Methods("GET")
r.HandleFunc("/sessions/{sessionId}", handlers.GetSession).Methods("GET")
r.Handle("/sessions/{sessionId}/instances", http.HandlerFunc(handlers.NewInstance)).Methods("POST")
Expand Down Expand Up @@ -98,7 +110,7 @@ func main() {

ssl := mux.NewRouter()
sslProxyHandler := handlers.NewSSLDaemonHandler()
ssl.Host(`{node:ip[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}}-2375.{tld:.*}`).Handler(sslProxyHandler)
ssl.Host(`{node:pwd[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}}-2375.{tld:.*}`).Handler(sslProxyHandler)
log.Println("Listening TLS on port " + config.SSLPortNumber)

s := &http.Server{Addr: "0.0.0.0:" + config.SSLPortNumber, Handler: ssl}
Expand All @@ -107,7 +119,7 @@ func main() {

chunks := strings.Split(clientHello.ServerName, ".")
chunks = strings.Split(chunks[0], "-")
ip := strings.Replace(strings.TrimPrefix(chunks[0], "ip"), "_", ".", -1)
ip := strings.Replace(strings.TrimPrefix(chunks[0], "pwd"), "_", ".", -1)
i := services.FindInstanceByIP(ip)
if i == nil {
return nil, fmt.Errorf("Instance %s doesn't exist", clientHello.ServerName)
Expand All @@ -119,3 +131,31 @@ func main() {
}
log.Fatal(s.ListenAndServeTLS("", ""))
}

var dnsFilter = regexp.MustCompile(`pwd[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}`)

func handleDnsRequest(w dns.ResponseWriter, r *dns.Msg) {
if len(r.Question) > 0 && dnsFilter.MatchString(r.Question[0].Name) {
// this is something we know about and we should try to handle
question := r.Question[0].Name
domainChunks := strings.Split(question, ".")
tldChunks := strings.Split(strings.TrimPrefix(domainChunks[0], "pwd"), "-")
ip := strings.Replace(tldChunks[0], "_", ".", -1)

m := new(dns.Msg)
m.SetReply(r)
m.Authoritative = true
m.RecursionAvailable = true
a, err := dns.NewRR(fmt.Sprintf("%s 60 IN A %s", question, ip))
if err != nil {
log.Fatal(err)
}
m.Answer = append(m.Answer, a)
w.WriteMsg(m)
return
} else {
// we have no information about this and we are not a recursive dns server, so we just fail so the client can fallback to the next dns server it has configured
dns.HandleFailed(w, r)
return
}
}
4 changes: 2 additions & 2 deletions docker-compose.yml
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Expand Up @@ -9,8 +9,8 @@ services:
command: /bin/sh -c 'cd /go/src/github.com/franela/play-with-docker; go run api.go'
ports:
# app exposes port 3000
- "3000:3000"
- "3001:3001"
- "80:3000"
- "443:3001"
volumes:
# since this app creates networks and launches containers, we need to talk to docker daemon
- /var/run/docker.sock:/var/run/docker.sock
Expand Down
8 changes: 4 additions & 4 deletions handlers/reverseproxy.go
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Expand Up @@ -40,9 +40,9 @@ func NewMultipleHostReverseProxy() *httputil.ReverseProxy {
port = "80"
}

if strings.HasPrefix(node, "ip") {
if strings.HasPrefix(node, "pwd") {
// Node is actually an ip, need to convert underscores by dots.
ip := strings.Replace(strings.TrimPrefix(node, "ip"), "_", ".", -1)
ip := strings.Replace(strings.TrimPrefix(node, "pwd"), "_", ".", -1)

if net.ParseIP(ip) == nil {
// Not a valid IP, so treat this is a hostname.
Expand All @@ -69,9 +69,9 @@ func NewSSLDaemonHandler() *httputil.ReverseProxy {
director := func(req *http.Request) {
v := mux.Vars(req)
node := v["node"]
if strings.HasPrefix(node, "ip") {
if strings.HasPrefix(node, "pwd") {
// Node is actually an ip, need to convert underscores by dots.
ip := strings.Replace(strings.TrimPrefix(node, "ip"), "_", ".", -1)
ip := strings.Replace(strings.TrimPrefix(node, "pwd"), "_", ".", -1)

if net.ParseIP(ip) == nil {
// Not a valid IP, so treat this is a hostname.
Expand Down
4 changes: 2 additions & 2 deletions handlers/websocket_reverseproxy.go
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Original file line number Diff line number Diff line change
Expand Up @@ -29,9 +29,9 @@ func NewMultipleHostWebsocketReverseProxy() *wsutil.ReverseProxy {
port = "80"
}

if strings.HasPrefix(node, "ip") {
if strings.HasPrefix(node, "pwd") {
// Node is actually an ip, need to convert underscores by dots.
ip := strings.Replace(strings.TrimPrefix(node, "ip"), "_", ".", -1)
ip := strings.Replace(strings.TrimPrefix(node, "pwd"), "_", ".", -1)

if net.ParseIP(ip) == nil {
// Not a valid IP, so treat this is a hostname.
Expand Down
34 changes: 29 additions & 5 deletions services/docker.go
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Expand Up @@ -135,17 +135,33 @@ func CreateNetwork(name string) error {

return nil
}
func ConnectNetwork(containerId, networkId string) error {
err := c.NetworkConnect(context.Background(), networkId, containerId, &network.EndpointSettings{})
func ConnectNetwork(containerId, networkId, ip string) (string, error) {
settings := &network.EndpointSettings{}
if ip != "" {
settings.IPAddress = ip
}
err := c.NetworkConnect(context.Background(), networkId, containerId, settings)

if err != nil && !strings.Contains(err.Error(), "already exists") {
log.Printf("Connection container to network err [%s]\n", err)

return err
return "", err
}

return nil
// Obtain the IP of the PWD container in this network
container, err := c.ContainerInspect(context.Background(), containerId)
if err != nil {
return "", err
}

n, found := container.NetworkSettings.Networks[networkId]
if !found {
return "", fmt.Errorf("Container [%s] connected to the network [%s] but couldn't obtain it's IP address", containerId, networkId)
}

return n.IPAddress, nil
}

func DisconnectNetwork(containerId, networkId string) error {
err := c.NetworkDisconnect(context.Background(), networkId, containerId, true)

Expand Down Expand Up @@ -217,7 +233,15 @@ func CreateInstance(session *Session, dindImage string) (*Instance, error) {
break
}
}
conf := &container.Config{Hostname: nodeName, Image: dindImage, Tty: true, OpenStdin: true, AttachStdin: true, AttachStdout: true, AttachStderr: true}
conf := &container.Config{Hostname: nodeName,
Image: dindImage,
Tty: true,
OpenStdin: true,
AttachStdin: true,
AttachStdout: true,
AttachStderr: true,
Env: []string{fmt.Sprintf("PWD_IP_ADDRESS=%s", session.PwdIpAddress)},
}
networkConf := &network.NetworkingConfig{
map[string]*network.EndpointSettings{
session.Id: &network.EndpointSettings{Aliases: []string{nodeName}},
Expand Down
26 changes: 16 additions & 10 deletions services/session.go
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Expand Up @@ -42,14 +42,15 @@ func init() {
var wsServer *socketio.Server

type Session struct {
rw sync.Mutex
Id string `json:"id"`
Instances map[string]*Instance `json:"instances"`
clients []*Client `json:"-"`
CreatedAt time.Time `json:"created_at"`
ExpiresAt time.Time `json:"expires_at"`
scheduled bool `json:"-"`
ticker *time.Ticker `json:"-"`
rw sync.Mutex
Id string `json:"id"`
Instances map[string]*Instance `json:"instances"`
clients []*Client `json:"-"`
CreatedAt time.Time `json:"created_at"`
ExpiresAt time.Time `json:"expires_at"`
scheduled bool `json:"-"`
ticker *time.Ticker `json:"-"`
PwdIpAddress string `json:"pwd_ip_address"`
}

func (s *Session) Lock() {
Expand Down Expand Up @@ -239,10 +240,12 @@ func NewSession(duration time.Duration) (*Session, error) {
log.Printf("Network [%s] created for session [%s]\n", s.Id, s.Id)

// Connect PWD daemon to the new network
if err := ConnectNetwork("pwd", s.Id); err != nil {
ip, err := ConnectNetwork("pwd", s.Id, "")
if err != nil {
log.Println("ERROR NETWORKING")
return nil, err
}
s.PwdIpAddress = ip
log.Printf("Connected pwd to network [%s]\n", s.Id)

// Schedule peridic tasks execution
Expand Down Expand Up @@ -315,7 +318,10 @@ func LoadSessionsFromDisk() error {
}

// Connect PWD daemon to the new network
if err := ConnectNetwork("pwd", s.Id); err != nil {
if s.PwdIpAddress == "" {
log.Fatal("Cannot load stored sessions as they don't have the pwd ip address stored with them")
}
if _, err := ConnectNetwork("pwd", s.Id, s.PwdIpAddress); err != nil {
if strings.Contains(err.Error(), "Could not attach to network") {
log.Printf("Network for session [%s] doesn't exist. Removing all instances and session.", s.Id)
CloseSession(s)
Expand Down
2 changes: 1 addition & 1 deletion www/assets/app.js
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Expand Up @@ -176,7 +176,7 @@
}

$scope.getProxyUrl = function(instance, port) {
var url = window.location.protocol + '//ip' + instance.ip.replace(/\./g, '_') + '-' + port + '.' + window.location.host;
var url = window.location.protocol + '//pwd' + instance.ip.replace(/\./g, '_') + '-' + port + '.' + window.location.host;

return url;
}
Expand Down

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