0fd3fb0840
The addSSHTimeout and disablePseudoTerminalAllocation were added in commitsa5ebe2282aandf3c2c26b10, and called inside the Dialer function, which means they're called every time the Dialer is called. Given that the sshFlags slice is not mutated by the Dialer, we can call these functions once. Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
94 lines
3.2 KiB
Go
94 lines
3.2 KiB
Go
// Package connhelper provides helpers for connecting to a remote daemon host with custom logic.
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package connhelper
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import (
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"context"
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"net"
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"net/url"
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"strings"
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"github.com/docker/cli/cli/connhelper/commandconn"
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"github.com/docker/cli/cli/connhelper/ssh"
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"github.com/pkg/errors"
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)
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// ConnectionHelper allows to connect to a remote host with custom stream provider binary.
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type ConnectionHelper struct {
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Dialer func(ctx context.Context, network, addr string) (net.Conn, error)
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Host string // dummy URL used for HTTP requests. e.g. "http://docker"
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}
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// GetConnectionHelper returns Docker-specific connection helper for the given URL.
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// GetConnectionHelper returns nil without error when no helper is registered for the scheme.
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//
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// ssh://<user>@<host> URL requires Docker 18.09 or later on the remote host.
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func GetConnectionHelper(daemonURL string) (*ConnectionHelper, error) {
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return getConnectionHelper(daemonURL, nil)
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}
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// GetConnectionHelperWithSSHOpts returns Docker-specific connection helper for
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// the given URL, and accepts additional options for ssh connections. It returns
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// nil without error when no helper is registered for the scheme.
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//
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// Requires Docker 18.09 or later on the remote host.
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func GetConnectionHelperWithSSHOpts(daemonURL string, sshFlags []string) (*ConnectionHelper, error) {
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return getConnectionHelper(daemonURL, sshFlags)
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}
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func getConnectionHelper(daemonURL string, sshFlags []string) (*ConnectionHelper, error) {
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u, err := url.Parse(daemonURL)
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if err != nil {
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return nil, err
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}
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if u.Scheme == "ssh" {
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sp, err := ssh.ParseURL(daemonURL)
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if err != nil {
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return nil, errors.Wrap(err, "ssh host connection is not valid")
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}
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sshFlags = addSSHTimeout(sshFlags)
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sshFlags = disablePseudoTerminalAllocation(sshFlags)
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return &ConnectionHelper{
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Dialer: func(ctx context.Context, network, addr string) (net.Conn, error) {
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args := []string{"docker"}
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if sp.Path != "" {
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args = append(args, "--host", "unix://"+sp.Path)
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}
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args = append(args, "system", "dial-stdio")
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return commandconn.New(ctx, "ssh", append(sshFlags, sp.Args(args...)...)...)
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},
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Host: "http://docker.example.com",
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}, nil
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}
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// Future version may support plugins via ~/.docker/config.json. e.g. "dind"
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// See docker/cli#889 for the previous discussion.
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return nil, err
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}
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// GetCommandConnectionHelper returns Docker-specific connection helper constructed from an arbitrary command.
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func GetCommandConnectionHelper(cmd string, flags ...string) (*ConnectionHelper, error) {
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return &ConnectionHelper{
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Dialer: func(ctx context.Context, network, addr string) (net.Conn, error) {
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return commandconn.New(ctx, cmd, flags...)
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},
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Host: "http://docker.example.com",
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}, nil
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}
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func addSSHTimeout(sshFlags []string) []string {
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if !strings.Contains(strings.Join(sshFlags, ""), "ConnectTimeout") {
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sshFlags = append(sshFlags, "-o ConnectTimeout=30")
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}
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return sshFlags
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}
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// disablePseudoTerminalAllocation disables pseudo-terminal allocation to
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// prevent SSH from executing as a login shell
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func disablePseudoTerminalAllocation(sshFlags []string) []string {
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for _, flag := range sshFlags {
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if flag == "-T" {
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return sshFlags
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}
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}
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return append(sshFlags, "-T")
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}
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