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[WIP] Refactor podman system connection
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* Add support to manage multiple connections
  * Add connection
  * Remove connection
  * Rename connection
  * Set connection as default
  * Add markdown/man pages
* Fix recursion in hack/xref-helpmsgs-manpages

Signed-off-by: Jhon Honce <[email protected]>

<MH: Fixed build after rebase>

Signed-off-by: Matt Heon <[email protected]>
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jwhonce authored and mheon committed Aug 20, 2020
1 parent 7c13b8c commit ee956b0
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Showing 17 changed files with 836 additions and 234 deletions.
1 change: 1 addition & 0 deletions cmd/podman/main.go
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@ import (
_ "github.com/containers/libpod/v2/cmd/podman/pods"
"github.com/containers/libpod/v2/cmd/podman/registry"
_ "github.com/containers/libpod/v2/cmd/podman/system"
_ "github.com/containers/libpod/v2/cmd/podman/system/connection"
_ "github.com/containers/libpod/v2/cmd/podman/volumes"
"github.com/containers/libpod/v2/pkg/rootless"
"github.com/containers/libpod/v2/pkg/terminal"
Expand Down
31 changes: 24 additions & 7 deletions cmd/podman/root.go
Original file line number Diff line number Diff line change
Expand Up @@ -221,16 +221,12 @@ func loggingHook() {

func rootFlags(cmd *cobra.Command, opts *entities.PodmanConfig) {
cfg := opts.Config
uri, ident := resolveDestination()

lFlags := cmd.Flags()
custom, _ := config.ReadCustomConfig()
defaultURI := custom.Engine.RemoteURI
if defaultURI == "" {
defaultURI = registry.DefaultAPIAddress()
}
lFlags.BoolVarP(&opts.Remote, "remote", "r", false, "Access remote Podman service (default false)")
lFlags.StringVar(&opts.URI, "url", defaultURI, "URL to access Podman service (CONTAINER_HOST)")
lFlags.StringVar(&opts.Identity, "identity", custom.Engine.RemoteIdentity, "path to SSH identity file, (CONTAINER_SSHKEY)")
lFlags.StringVar(&opts.URI, "url", uri, "URL to access Podman service (CONTAINER_HOST)")
lFlags.StringVar(&opts.Identity, "identity", ident, "path to SSH identity file, (CONTAINER_SSHKEY)")

pFlags := cmd.PersistentFlags()
pFlags.StringVar(&cfg.Engine.CgroupManager, "cgroup-manager", cfg.Engine.CgroupManager, "Cgroup manager to use (\"cgroupfs\"|\"systemd\")")
Expand Down Expand Up @@ -277,3 +273,24 @@ func rootFlags(cmd *cobra.Command, opts *entities.PodmanConfig) {
pFlags.BoolVar(&useSyslog, "syslog", false, "Output logging information to syslog as well as the console (default false)")
}
}

func resolveDestination() (string, string) {
if uri, found := os.LookupEnv("CONTAINER_HOST"); found {
var ident string
if v, found := os.LookupEnv("CONTAINER_SSHKEY"); found {
ident = v
}
return uri, ident
}

cfg, err := config.ReadCustomConfig()
if err != nil {
return registry.DefaultAPIAddress(), ""
}

uri, ident, err := cfg.ActiveDestination()
if err != nil {
return registry.DefaultAPIAddress(), ""
}
return uri, ident
}
201 changes: 13 additions & 188 deletions cmd/podman/system/connection.go
Original file line number Diff line number Diff line change
@@ -1,209 +1,34 @@
package system

import (
"bytes"
"fmt"
"net"
"net/url"
"os"
"os/user"
"regexp"

"github.com/containers/common/pkg/config"
"github.com/containers/libpod/v2/cmd/podman/registry"
"github.com/containers/libpod/v2/libpod/define"
"github.com/containers/libpod/v2/cmd/podman/validate"
"github.com/containers/libpod/v2/pkg/domain/entities"
"github.com/containers/libpod/v2/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 (
// Skip creating engines since this command will obtain connection information to engine
// Skip creating engines since this command will obtain connection information to said engines
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://[email protected]:2222
podman system connection --identity ~/.ssh/dev_rsa --port 22 [email protected]`,
}

cOpts = struct {
Identity string
Port int
UDSPath string
}{}
ConnectionCmd = &cobra.Command{
Use: "connection",
Short: "Manage remote ssh destinations",
Long: `Manage ssh destination information in podman configuration`,
DisableFlagsInUseLine: true,
PersistentPreRunE: noOp,
RunE: validate.SubCommandExists,
PersistentPostRunE: noOp,
TraverseChildren: false,
}
)

func init() {
registry.Commands = append(registry.Commands, registry.CliCommand{
Mode: []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
Command: connectionCmd,
Command: ConnectionCmd,
Parent: systemCmd,
})

flags := connectionCmd.Flags()
flags.IntVarP(&cOpts.Port, "port", "p", 22, "SSH port number for destination")
flags.StringVar(&cOpts.Identity, "identity", "", "path to SSH identity file")
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 {
// 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))
}

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 || len(info.Host.RemoteSocket.Path) == 0 {
return "", fmt.Errorf("remote podman %q failed to report its UDS socket", uri.Host)
}
return info.Host.RemoteSocket.Path, nil
}
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