e2e: Add a simple ssh client.

The client has the same interface as the one in pluton framework,
makes it easier for us to migrate tests.

Author: Yifan Gu

e2e/smoke_test.go

@@ -19,7 +19,7 @@ func TestSmoke(t *testing.T) {
 	}
 	d, ok := di.(*v1beta1.Deployment)
 	if !ok {
-		t.Fatalf("expected manifest to decode into *api.Service, got %T", di)
+		t.Fatalf("expected manifest to decode into *api.deployment, got %T", di)
 	}
 	_, err = client.ExtensionsV1beta1().Deployments(namespace).Create(d)
 	if err != nil {

e2e/ssh_client.go

@@ -0,0 +1,81 @@
+package e2e
+
+import (
+	"bytes"
+	"io/ioutil"
+	"log"
+	"net"
+	"os"
+
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
+)
+
+type SSHClient struct {
+	*ssh.ClientConfig
+}
+
+// NewSSHClientOrDie tries to create an ssh client.
+// If $SSH_AUTH_SOCK is set, the use the ssh agent to create the client,
+// otherwise read the private key directly.
+func NewSSHClientOrDie(keypath string) *SSHClient {
+	var authMethod ssh.AuthMethod
+
+	sock := os.Getenv("SSH_AUTH_SOCK")
+	if sock != "" {
+		log.Println("Creating ssh client with ssh agent")
+		sshAgent, err := net.Dial("unix", sock)
+		if err != nil {
+			panic(err)
+		}
+
+		authMethod = ssh.PublicKeysCallback(agent.NewClient(sshAgent).Signers)
+	} else {
+		log.Println("Creating ssh client with private key")
+		key, err := ioutil.ReadFile(keypath)
+		if err != nil {
+			panic(err)
+		}
+
+		signer, err := ssh.ParsePrivateKey(key)
+		if err != nil {
+			panic(err)
+		}
+
+		authMethod = ssh.PublicKeys(signer)
+	}
+
+	sshConfig := &ssh.ClientConfig{
+		User:            "core", // TODO(yifan): Assume all nodes are container linux nodes for now.
+		Auth:            []ssh.AuthMethod{authMethod},
+		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
+	}
+
+	return &SSHClient{sshConfig}
+}
+
+func (c *SSHClient) SSH(host, cmd string) (stdout, stderr []byte, err error) {
+	client, err := ssh.Dial("tcp", host+":22", c.ClientConfig) // TODO(yifan): Assume all nodes are listening on :22 for ssh requests for now.
+	if err != nil {
+		return nil, nil, err
+	}
+	defer client.Conn.Close()
+
+	session, err := client.NewSession()
+	if err != nil {
+		return nil, nil, err
+	}
+	defer session.Close()
+
+	outBuf := bytes.NewBuffer(nil)
+	errBuf := bytes.NewBuffer(nil)
+	session.Stdout = outBuf
+	session.Stderr = errBuf
+
+	err = session.Run(cmd)
+
+	stdout = bytes.TrimSpace(outBuf.Bytes())
+	stderr = bytes.TrimSpace(errBuf.Bytes())
+
+	return stdout, stderr, err
+}