feat(ssh-cli): add ssh CLI based wrapper Runner implementation (#9)

error.go

@@ -0,0 +1,5 @@
+package runner
+
+import "errors"
+
+var Err = errors.New("runner")

ssh_cli.go

@@ -0,0 +1,133 @@
+package runner
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"strconv"
+)
+
+var (
+	ErrSSHCLI              = fmt.Errorf("%w: sshcli: ", Err)
+	ErrSSHCLINoDestination = fmt.Errorf(
+		"%w: destination must be set", ErrSSHCLI,
+	)
+)
+
+// SSHCLI is a Runner that wraps another Runner, essentially prefixing given
+// commands and arguments with "ssh", relevant SSH CLI arguments, and the given
+// destination. It then passes this new "ssh" command to the underlying Runner.
+//
+// This is useful for running commands on remote hosts via SSH, without having
+// to use the Go ssh package.
+//
+// Interactive commands are not supported, meaning SSH password prompts will not
+// work, and the remote machine's hostkey should already be known and trusted by
+// the ssh CLI client.
+type SSHCLI struct {
+	// Runner is the underlying Runner to run commands with, after wrapping them
+	// with ssh. If not set, running commands will cause a panic.
+	Runner Runner
+
+	// Destination is the remote SSH destination to connect to, which may be
+	// specified as either "[user@]hostname" or a URI of the form
+	// "ssh://[user@]hostname[:port]".
+	Destination string
+
+	// Port is the remote SSH port (-p) flag to use. When 0, no -p flag will be
+	// used.
+	Port int
+
+	// IdentityFile is the remote SSH identity file (-i) flag to use. When
+	// empty, no -i flag will be used.
+	IdentityFile string
+
+	// Login is the remote SSH login (-l) flag to use. When empty, no -l flag
+	// will be used.
+	Login string
+
+	// Args is a string slice of extra arguments to pass to ssh.
+	Args []string
+
+	env []string
+}
+
+var _ Runner = &SSHCLI{}
+
+// Run executes the command remotely via ssh by calling Run on the underlying
+// Runner.
+//
+// Will panic if Runner field is nil.
+// Will return a error if Destination field is empty.
+func (rsc *SSHCLI) Run(
+	stdin io.Reader,
+	stdout io.Writer,
+	stderr io.Writer,
+	command string,
+	args ...string,
+) error {
+	sshArgs, err := rsc.args(command, args)
+	if err != nil {
+		return err
+	}
+
+	return rsc.Runner.Run(stdin, stdout, stderr, "ssh", sshArgs...)
+}
+
+// RunContext executes the command remotely via ssh by calling RunContext on the
+// underlying Runner.
+//
+// Will panic if Runner field is nil.
+// Will return a error if Destination field is empty.
+func (rsc *SSHCLI) RunContext(
+	ctx context.Context,
+	stdin io.Reader,
+	stdout io.Writer,
+	stderr io.Writer,
+	command string,
+	args ...string,
+) error {
+	sshArgs, err := rsc.args(command, args)
+	if err != nil {
+		return err
+	}
+
+	return rsc.Runner.RunContext(ctx, stdin, stdout, stderr, "ssh", sshArgs...)
+}
+
+func (rsc *SSHCLI) args(command string, args []string) ([]string, error) {
+	if rsc.Destination == "" {
+		return nil, ErrSSHCLINoDestination
+	}
+
+	sshArgs := []string{}
+
+	if rsc.Port != 0 {
+		sshArgs = append(sshArgs, "-p", strconv.Itoa(rsc.Port))
+	}
+	if rsc.IdentityFile != "" {
+		sshArgs = append(sshArgs, "-i", rsc.IdentityFile)
+	}
+	if rsc.Login != "" {
+		sshArgs = append(sshArgs, "-l", rsc.Login)
+	}
+	if len(rsc.Args) > 0 {
+		sshArgs = append(sshArgs, rsc.Args...)
+	}
+	sshArgs = append(sshArgs, rsc.Destination, "--")
+
+	if len(rsc.env) > 0 {
+		sshArgs = append(sshArgs, "env")
+		sshArgs = append(sshArgs, rsc.env...)
+	}
+	sshArgs = append(sshArgs, command)
+	sshArgs = append(sshArgs, args...)
+
+	return sshArgs, nil
+}
+
+// Env sets the environment by calling Env on the underlying Runner. Will panic
+// if Runner field is nil on SSH instance.
+func (rsc *SSHCLI) Env(env ...string) {
+	rsc.env = env
+}