V2 podman system connection

* Implement command
* Refactor podman-remote to pull from containers.conf by default
* podman-remote defaults to --remote being true
* Write podman-system-connection.1.md

Signed-off-by: Jhon Honce <jhonce@redhat.com>

1 files changed, 188 insertions, 33 deletions

diff --git a/cmd/podman/system/connection.go b/cmd/podman/system/connection.go
index 3af905fad..d8c709d6e 100644
--- a/cmd/podman/system/connection.go
+++ b/cmd/podman/system/connection.go
@@ -1,54 +1,209 @@
-// +build !remote
-
 package system
 
 import (
+	"bytes"
+	"fmt"
+	"net"
+	"net/url"
+	"os"
+	"os/user"
+	"regexp"
+
+	"github.com/containers/common/pkg/config"
 	"github.com/containers/libpod/cmd/podman/registry"
+	"github.com/containers/libpod/libpod/define"
 	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/containers/libpod/pkg/terminal"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
 )
 
+const schemaPattern = "^[A-Za-z][A-Za-z0-9+.-]*:"
+
 var (
-	connectionDescription = `TBD
-`
-	connectionCommand = &cobra.Command{
-		Use: "connection",
-		//Args:    validate.NoArgs,
-		Long:  connectionDescription,
-		Short: "Add remote ssh connection",
-		RunE:  connection,
-		Example: `podman system connection server.foobar.com
-podman system connection --identity ~/.ssh/dev_rsa --default root@server.foobar.com:222`,
+	// Skip creating engines since this command will obtain connection information to engine
+	noOp = func(cmd *cobra.Command, args []string) error {
+		return nil
+	}
+	connectionCmd = &cobra.Command{
+		Use:  "connection [flags] destination",
+		Args: cobra.ExactArgs(1),
+		Long: `Store ssh destination information in podman configuration.
+  "destination" is of the form [user@]hostname or
+  an URI of the form ssh://[user@]hostname[:port]
+`,
+		Short:              "Record remote ssh destination",
+		PersistentPreRunE:  noOp,
+		PersistentPostRunE: noOp,
+		TraverseChildren:   false,
+		RunE:               connection,
+		Example: `podman system connection server.fubar.com
+  podman system connection --identity ~/.ssh/dev_rsa ssh://root@server.fubar.com:2222
+  podman system connection --identity ~/.ssh/dev_rsa -port 22 root@server.fubar.com`,
 	}
-)
 
-var connectionOptions = struct {
-	Alias      string
-	Default    bool
-	Identity   string
-	SocketPath string
-	User       string
-}{}
+	cOpts = struct {
+		Identity string
+		Port     int
+		UDSPath  string
+	}{}
+)
 
 func init() {
 	registry.Commands = append(registry.Commands, registry.CliCommand{
-		Mode:    []entities.EngineMode{entities.ABIMode},
-		Command: connectionCommand,
+		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
+		Command: connectionCmd,
 		Parent:  systemCmd,
 	})
-	flags := connectionCommand.Flags()
-	flags.StringVar(&connectionOptions.Alias, "alias", "", "alias name for connection")
-	flags.BoolVar(&connectionOptions.Default, "default", false, "set as the default connection")
-	flags.StringVar(&connectionOptions.Identity, "identity", "", "path to ssh identity file")
-	//flags.StringVar(&connectionOptions.User, "user", "", "remote username")
-	flags.StringVar(&connectionOptions.SocketPath, "socket-path", "", "path to podman socket on remote host")
+
+	flags := connectionCmd.Flags()
+	flags.StringVar(&cOpts.Identity, "identity", "", "path to ssh identity file")
+	flags.IntVarP(&cOpts.Port, "port", "p", 22, "port number for destination")
+	flags.StringVar(&cOpts.UDSPath, "socket-path", "", "path to podman socket on remote host. (default '/run/podman/podman.sock' or '/run/user/{uid}/podman/podman.sock)")
 }
 
 func connection(cmd *cobra.Command, args []string) error {
-	// if no user is provided, assume local user name
-	// if no socket is provided, then do an ssh to look for it
-	// default connection, if exists, is then assumed with podman remote
-	// if no identity exists, should we be prompting for password?
+	// Default to ssh: schema if none given
+	dest := []byte(args[0])
+	if match, err := regexp.Match(schemaPattern, dest); err != nil {
+		return errors.Wrapf(err, "internal regex error %q", schemaPattern)
+	} else if !match {
+		dest = append([]byte("ssh://"), dest...)
+	}
+
+	uri, err := url.Parse(string(dest))
+	if err != nil {
+		return errors.Wrapf(err, "failed to parse %q", string(dest))
+	}
+
+	if uri.User.Username() == "" {
+		if uri.User, err = getUserInfo(uri); err != nil {
+			return err
+		}
+	}
+
+	if cmd.Flag("socket-path").Changed {
+		uri.Path = cmd.Flag("socket-path").Value.String()
+	}
+
+	if cmd.Flag("port").Changed {
+		uri.Host = net.JoinHostPort(uri.Hostname(), cmd.Flag("port").Value.String())
+	}
+
+	if uri.Port() == "" {
+		uri.Host = net.JoinHostPort(uri.Hostname(), cmd.Flag("port").DefValue)
+	}
+
+	if uri.Path == "" {
+		if uri.Path, err = getUDS(cmd, uri); err != nil {
+			return errors.Wrapf(err, "failed to connect to  %q", uri.String())
+		}
+	}
+
+	custom, err := config.ReadCustomConfig()
+	if err != nil {
+		return err
+	}
+
+	if cmd.Flag("identity").Changed {
+		custom.Engine.RemoteIdentity = cOpts.Identity
+	}
+
+	custom.Engine.RemoteURI = uri.String()
+	return custom.Write()
+}
+
+func getUserInfo(uri *url.URL) (*url.Userinfo, error) {
+	var (
+		usr *user.User
+		err error
+	)
+	if u, found := os.LookupEnv("_CONTAINERS_ROOTLESS_UID"); found {
+		usr, err = user.LookupId(u)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to find user %q", u)
+		}
+	} else {
+		usr, err = user.Current()
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to obtain current user")
+		}
+	}
+
+	pw, set := uri.User.Password()
+	if set {
+		return url.UserPassword(usr.Username, pw), nil
+	}
+	return url.User(usr.Username), nil
+}
+
+func getUDS(cmd *cobra.Command, uri *url.URL) (string, error) {
+	var authMethods []ssh.AuthMethod
+	passwd, set := uri.User.Password()
+	if set {
+		authMethods = append(authMethods, ssh.Password(passwd))
+	}
+
+	ident := cmd.Flag("identity")
+	if ident.Changed {
+		auth, err := terminal.PublicKey(ident.Value.String(), []byte(passwd))
+		if err != nil {
+			return "", errors.Wrapf(err, "Failed to read identity %q", ident.Value.String())
+		}
+		authMethods = append(authMethods, auth)
+	}
+
+	if sock, found := os.LookupEnv("SSH_AUTH_SOCK"); found {
+		logrus.Debugf("Found SSH_AUTH_SOCK %q, ssh-agent signer enabled", sock)
+
+		c, err := net.Dial("unix", sock)
+		if err != nil {
+			return "", err
+		}
+		a := agent.NewClient(c)
+		authMethods = append(authMethods, ssh.PublicKeysCallback(a.Signers))
+	}
 
-	return nil
+	config := &ssh.ClientConfig{
+		User:            uri.User.Username(),
+		Auth:            authMethods,
+		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
+	}
+	dial, err := ssh.Dial("tcp", uri.Host, config)
+	if err != nil {
+		return "", errors.Wrapf(err, "failed to connect to %q", uri.Host)
+	}
+	defer dial.Close()
+
+	session, err := dial.NewSession()
+	if err != nil {
+		return "", errors.Wrapf(err, "failed to create new ssh session on %q", uri.Host)
+	}
+	defer session.Close()
+
+	// Override podman binary for testing etc
+	podman := "podman"
+	if v, found := os.LookupEnv("PODMAN_BINARY"); found {
+		podman = v
+	}
+	run := podman + " info --format=json"
+
+	var buffer bytes.Buffer
+	session.Stdout = &buffer
+	if err := session.Run(run); err != nil {
+		return "", errors.Wrapf(err, "failed to run %q", run)
+	}
+
+	var info define.Info
+	if err := json.Unmarshal(buffer.Bytes(), &info); err != nil {
+		return "", errors.Wrapf(err, "failed to parse 'podman info' results")
+	}
+
+	if info.Host.RemoteSocket == nil || !info.Host.RemoteSocket.Exists {
+		return "", fmt.Errorf("remote podman %q failed to report its UDS socket", uri.Host)
+	}
+	return info.Host.RemoteSocket.Path, nil
 }