Merge pull request #55 from dmcgowan/rexec_example

dmcgowan · dmcgowan · commit 8acda1e7bc9b · 2014-08-14T09:38:34.000-07:00
Remote execution example
diff --git a/examples/rexec/README.md b/examples/rexec/README.md
@@ -0,0 +1,36 @@
+# rexec
+
+rexec is a sample application demonstrating libchan nested channels and
+bytestreams through remote executation calls.  This is a minimal
+implementation to demonstrate the usage of libchan.
+
+### Usage
+
+Server
+~~~~
+$ cd rexec_server
+$ go build .
+$ ./rexec_server
+~~~~
+
+Client
+~~~~
+$ go build .
+$ ./rexec /bin/echo "hello"
+hello
+$ ./rexec /bin/sh -c "exit 4"
+$ echo $?
+4
+~~~~
+
+### Usage with TLS
+Server
+~~~~
+$ TLS_CERT=./cert.pem TLS_KEY=./key.pem ./rexec_server
+~~~~
+
+Client
+~~~~
+$ USE_TLS=true ./rexec /bin/echo "hello"
+hello
+~~~~
diff --git a/examples/rexec/client.go b/examples/rexec/client.go
@@ -0,0 +1,75 @@
+package main
+
+import (
+	"crypto/tls"
+	"io"
+	"log"
+	"net"
+	"os"
+
+	"github.com/docker/libchan"
+	"github.com/docker/libchan/spdy"
+)
+
+type RemoteCommand struct {
+	Cmd        string
+	Args       []string
+	Stdin      io.Writer
+	Stdout     io.Reader
+	Stderr     io.Reader
+	StatusChan libchan.Sender
+}
+
+type CommandResponse struct {
+	Status int
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		log.Fatal("usage: <command> [<arg> ]")
+	}
+
+	var client net.Conn
+	var err error
+	if os.Getenv("USE_TLS") != "" {
+		client, err = tls.Dial("tcp", "127.0.0.1:9323", &tls.Config{InsecureSkipVerify: true})
+	} else {
+		client, err = net.Dial("tcp", "127.0.0.1:9323")
+	}
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	transport, err := spdy.NewClientTransport(client)
+	if err != nil {
+		log.Fatal(err)
+	}
+	sender, err := transport.NewSendChannel()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	receiver, remoteSender := libchan.Pipe()
+
+	command := &RemoteCommand{
+		Cmd:        os.Args[1],
+		Args:       os.Args[2:],
+		Stdin:      os.Stdin,
+		Stdout:     os.Stdout,
+		Stderr:     os.Stderr,
+		StatusChan: remoteSender,
+	}
+
+	err = sender.Send(command)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	response := &CommandResponse{}
+	err = receiver.Receive(response)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	os.Exit(response.Status)
+}
diff --git a/examples/rexec/rexec_server/cert.pem b/examples/rexec/rexec_server/cert.pem
@@ -0,0 +1,18 @@
+-----BEGIN CERTIFICATE-----
+MIIC1zCCAcGgAwIBAgIBADALBgkqhkiG9w0BAQUwEDEOMAwGA1UEChMFcmV4ZWMw
+HhcNMTMxMjMxMjM1OTU5WhcNNDkxMjMxMjM1OTU5WjAQMQ4wDAYDVQQKEwVyZXhl
+YzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMZs3mSUB352e5yCh0ho
+nbr/dvvHaHsS2KERyILQBynqbD2DvLpdL2n1IYb+uHFt6XPnZKnkCznGviVLPGcf
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+YLTya68Tf6vCre4=
+-----END CERTIFICATE-----
diff --git a/examples/rexec/rexec_server/key.pem b/examples/rexec/rexec_server/key.pem
@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIEpAIBAAKCAQEAxmzeZJQHfnZ7nIKHSGiduv92+8doexLYoRHIgtAHKepsPYO8
+ul0vafUhhv64cW3pc+dkqeQLOca+JUs8Zx9ZqHMbTi6l299j+5eHWbtbP4n8MOV2
+SoYTk87f24LWsqRtMYqeHbVTktV5F/ODOc1WkSFrQhYERkh1Gb+ukH07KdQf/LOa
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+fsSNCw1iLLKB3pcbJ6lgnTjO1lJCrHwn1lleIa+rAOeQ3OnMZK6u095BLKI9Sv/U
+p1wxxnE9Il4a5IFfhh8zezECgYAoC05dtDPWhRyXxfkiRaW6CQieqfUGikm8EM9f
+oxzIAZaqzFnLmO8dgkqTWN49/SQqpud1Z+Gtoz63reShiKvwJ3mWuMY7dW1CeWy4
+gZD6PPQ1Mj8PLeMv6JmL4t6LeB7kUcKdn9sHrfkRg3fSO7y8BMbg/TtzMXhFUNa2
+koxphQKBgQDC2b9vzR2I8UgK63RjcFJQjsyNbBcF3FJ7+eaakRkTflOaBkeuXTs4
+ZxO9c0ShMVZ6lcBrll2ZrHx1yLrUFgQYYvzJQvMjG1Y7Up4l2gurMvckfG2lGI/B
+NHuXlarw598fJP9PX75TyD3+ayDtm/pazBH9kSMupNJ7RNVuKy5v8w==
+-----END RSA PRIVATE KEY-----
diff --git a/examples/rexec/rexec_server/server.go b/examples/rexec/rexec_server/server.go
@@ -0,0 +1,122 @@
+package main
+
+import (
+	"crypto/tls"
+	"io"
+	"log"
+	"net"
+	"os"
+	"os/exec"
+	"syscall"
+
+	"github.com/docker/libchan"
+	"github.com/docker/libchan/spdy"
+)
+
+type RemoteCommand struct {
+	Cmd        string
+	Args       []string
+	Stdin      io.Reader
+	Stdout     io.WriteCloser
+	Stderr     io.WriteCloser
+	StatusChan libchan.Sender
+}
+
+type CommandResponse struct {
+	Status int
+}
+
+func main() {
+	cert := os.Getenv("TLS_CERT")
+	key := os.Getenv("TLS_KEY")
+
+	var listener net.Listener
+	if cert != "" && key != "" {
+		tlsCert, err := tls.LoadX509KeyPair(cert, key)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		tlsConfig := &tls.Config{
+			InsecureSkipVerify: true,
+			Certificates:       []tls.Certificate{tlsCert},
+		}
+
+		listener, err = tls.Listen("tcp", "localhost:9323", tlsConfig)
+		if err != nil {
+			log.Fatal(err)
+		}
+	} else {
+		var err error
+		listener, err = net.Listen("tcp", "localhost:9323")
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	tl, err := spdy.NewTransportListener(listener, spdy.NoAuthenticator)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for {
+		t, err := tl.AcceptTransport()
+		if err != nil {
+			log.Print(err)
+			break
+		}
+
+		go func() {
+			for {
+				receiver, err := t.WaitReceiveChannel()
+				if err != nil {
+					log.Print(err)
+					break
+				}
+
+				go func() {
+					for {
+						command := &RemoteCommand{}
+						err := receiver.Receive(command)
+						if err != nil {
+							log.Print(err)
+							break
+						}
+
+						cmd := exec.Command(command.Cmd, command.Args...)
+						cmd.Stdout = command.Stdout
+						cmd.Stderr = command.Stderr
+
+						stdin, err := cmd.StdinPipe()
+						if err != nil {
+							log.Print(err)
+							break
+						}
+						go func() {
+							io.Copy(stdin, command.Stdin)
+							stdin.Close()
+						}()
+
+						res := cmd.Run()
+						command.Stdout.Close()
+						command.Stderr.Close()
+						returnResult := &CommandResponse{}
+						if res != nil {
+							if exiterr, ok := res.(*exec.ExitError); ok {
+								returnResult.Status = exiterr.Sys().(syscall.WaitStatus).ExitStatus()
+							} else {
+								log.Print(res)
+								returnResult.Status = 10
+							}
+						}
+
+						err = command.StatusChan.Send(returnResult)
+						if err != nil {
+							log.Print(err)
+						}
+					}
+				}()
+			}
+		}()
+	}
+}
