--- title: SSH description: Rust SDK - SSH API reference --- Reach a running sandbox over SSH: open a native in-process SSH client, run exec requests, attach an interactive shell, transfer files over SFTP, or stand up a reusable SSH server endpoint. Requires the `ssh` feature. See [SSH](/sandboxes/ssh) for usage flows. ```toml microsandbox = { version = "0.5.8", features = ["ssh"] } ``` ## Sandbox #### sb.ssh() ```rust fn ssh(&self) -> SandboxSshOps ``` ```rust let client = sb.ssh().connect().await?; ``` Return the SSH namespace for this sandbox. The namespace holds the SSH client and server helpers; nothing connects until you call [`connect`](#ssh-connect) or [`server`](#ssh-server).

Returns

SandboxSshOps
SSH namespace for this sandbox.
## SandboxSshOps

Returned by sb.ssh()

SSH operations for a sandbox. #### ssh.connect() ```rust async fn connect(&self) -> MicrosandboxResult ``` ```rust let client = sb.ssh().connect().await?; let out = client.exec("uname -a").await?; ``` Connect a native in-process SSH client to this sandbox. Generates an ephemeral Ed25519 client and host key pair, stands up an internal server bound to a duplex stream, and authenticates over public key. Uses default client options (user `root`, terminal from `$TERM`, SFTP enabled).

Returns

SshClient
Connected SSH client session.
#### ssh.open_client() ```rust async fn open_client(&self) -> MicrosandboxResult ``` Alias for [`connect`](#ssh-connect).

Returns

SshClient
Connected SSH client session.
#### ssh.connect_with() ```rust async fn connect_with( &self, f: impl FnOnce(SshClientOptionsBuilder) -> SshClientOptionsBuilder, ) -> MicrosandboxResult ``` ```rust let client = sb.ssh().connect_with(|opts| opts .user("app") .term("xterm-256color")).await?; ``` Connect a native in-process SSH client with custom options. The closure configures the login user, terminal name, and whether SFTP is enabled on the internal server.

Parameters

Configure user, terminal, and SFTP support.

Returns

Connected SSH client session.
#### ssh.open_client_with() ```rust async fn open_client_with( &self, f: impl FnOnce(SshClientOptionsBuilder) -> SshClientOptionsBuilder, ) -> MicrosandboxResult ``` Alias for [`connect_with`](#ssh-connect_with).

Parameters

Configure user, terminal, and SFTP support.

Returns

Connected SSH client session.
#### ssh.server() Local-only ```rust async fn server(&self) -> MicrosandboxResult ``` ```rust let server = sb.ssh().server().await?; let (client_io, server_io) = tokio::io::duplex(64 * 1024); server.serve(server_io).await?; ``` Prepare a reusable SSH server endpoint for this sandbox. Loads or creates the host key and resolves authorized keys from the default authorized-keys file. The returned [`SshServer`](#sshserver) is cloneable and can serve many connections.

Returns

Reusable SSH server endpoint.
#### ssh.prepare_server() Local-only ```rust async fn prepare_server(&self) -> MicrosandboxResult ``` Alias for [`server`](#ssh-server).

Returns

Reusable SSH server endpoint.
#### ssh.server_with() Limited on cloud ```rust async fn server_with( &self, f: impl FnOnce(SshServerOptionsBuilder) -> SshServerOptionsBuilder, ) -> MicrosandboxResult ``` ```rust let server = sb.ssh().server_with(|opts| opts .authorized_key("ssh-ed25519 AAAAC3Nza...") .user("app") .sftp(false)).await?; ``` Prepare a server endpoint with custom host-key, authorization, guest-user, or SFTP options. If no authorized keys are configured, the default authorized-keys file is loaded; an empty key set is an error.

Parameters

Configure host key, authorized keys, guest user, and SFTP.

Returns

Reusable SSH server endpoint.
#### ssh.prepare_server_with() Limited on cloud ```rust async fn prepare_server_with( &self, f: impl FnOnce(SshServerOptionsBuilder) -> SshServerOptionsBuilder, ) -> MicrosandboxResult ``` Alias for [`server_with`](#ssh-server_with).

Parameters

Configure host key, authorized keys, guest user, and SFTP.

Returns

Reusable SSH server endpoint.
## SshClient

Returned by ssh.connect(), ssh.connect_with()

Native in-process SSH client session. #### client.exec() ```rust async fn exec(&self, command: impl Into) -> MicrosandboxResult ``` ```rust let out = client.exec("echo hello").await?; println!("exit {}: {}", out.status, String::from_utf8_lossy(&out.stdout)); ``` Run an SSH exec request and collect stdout, stderr, and the exit status. The command is run through the sandbox's configured shell (default `/bin/sh -c`). No PTY is requested.

Parameters

commandimpl Into<String>
Command string sent through SSH.

Returns

Captured output and exit status.
#### client.exec_with() ```rust async fn exec_with( &self, command: impl Into, f: impl FnOnce(SshExecOptionsBuilder) -> SshExecOptionsBuilder, ) -> MicrosandboxResult ``` ```rust let out = client.exec_with("top -bn1", |opts| opts.tty(true)).await?; ``` Run an SSH exec request with options. The closure can request a PTY via [`tty`](#sshexecoptionsbuilder); when a PTY is allocated, stderr is folded into stdout.

Parameters

commandimpl Into<String>
Command string sent through SSH.
Configure exec options.

Returns

Captured output and exit status.
#### client.attach() ```rust async fn attach(&self) -> MicrosandboxResult ``` ```rust let code = client.attach().await?; println!("shell exited with {code}"); ``` Attach the local terminal to an interactive SSH shell. Requests a PTY sized to the current terminal, puts the terminal into raw mode, forwards keystrokes, relays window-resize events, and returns when the shell exits or the default detach key sequence is typed.

Returns

i32
Shell exit code (128 if terminated by signal).
#### client.attach_with() ```rust async fn attach_with( &self, f: impl FnOnce(SshAttachOptionsBuilder) -> SshAttachOptionsBuilder, ) -> MicrosandboxResult ``` ```rust let code = client.attach_with(|opts| opts .term("xterm-256color") .detach_keys("ctrl-p,ctrl-q")).await?; ``` Attach an interactive shell with custom terminal and detach-key options.

Parameters

Configure terminal name and detach keys.

Returns

i32
Shell exit code (128 if terminated by signal).
#### client.sftp() ```rust async fn sftp(&self) -> MicrosandboxResult ``` ```rust let sftp = client.sftp().await?; let mut file = sftp.create("/tmp/hello.txt").await?; ``` Open an SFTP client session over this SSH connection. Requests the `sftp` subsystem and returns a high-level SFTP session for reading, writing, and listing files inside the guest.

Returns

SFTP client session.
#### client.close() ```rust async fn close(self) -> MicrosandboxResult<()> ``` ```rust client.close().await?; ``` Close this native SSH client session. Sends a disconnect and aborts the internal server task. Consumes the client. ## SshServer

Returned by ssh.server(), ssh.server_with()

Reusable SSH server endpoint for a sandbox. #### server.serve() ```rust async fn serve(&self, stream: S) -> MicrosandboxResult<()> where S: AsyncRead + AsyncWrite + Unpin + Send + 'static, ``` ```rust let server = sb.ssh().server().await?; let (client_io, server_io) = tokio::io::duplex(64 * 1024); tokio::spawn(async move { server.serve(server_io).await }); ``` Serve one SSH connection over an ordered duplex stream. Runs the SSH handshake and session loop to completion. Returns when the connection closes.

Parameters

streamS: AsyncRead + AsyncWrite
Ordered duplex SSH transport.
#### server.serve_connection() ```rust async fn serve_connection(&self, stream: S) -> MicrosandboxResult<()> where S: AsyncRead + AsyncWrite + Unpin + Send + 'static, ``` Alias for [`serve`](#server-serve).

Parameters

streamS: AsyncRead + AsyncWrite
Ordered duplex SSH transport.
## SshStdioStream

Used by server.serve()

Ordered duplex stream backed by this process's stdin and stdout. Implements `AsyncRead` and `AsyncWrite`. #### SshStdioStream::new() ```rust fn new() -> Self ``` ```rust use microsandbox::SshStdioStream; let server = sb.ssh().server().await?; server.serve(SshStdioStream::new()).await?; ``` Create a stdio SSH transport stream backed by this process's stdin and stdout. Implements [`AsyncRead`](#sshstdiostream) and `AsyncWrite`, so it can be passed straight to [`serve`](#server-serve) to bridge an SSH connection over the parent process's standard streams. Also available via `Default`.

Returns

Duplex stream over stdin/stdout.
## Constants #### DEFAULT_SSH_HOST ```rust pub const DEFAULT_SSH_HOST: &str = "127.0.0.1"; ``` Default SSH listener host used by the CLI adapter when binding a sandbox SSH endpoint. #### DEFAULT_SSH_PORT ```rust pub const DEFAULT_SSH_PORT: u16 = 2222; ``` Default SSH listener port used by the CLI adapter when binding a sandbox SSH endpoint. ## SshClientOptionsBuilder

Used by ssh.connect_with()

Builder for SSH client options. Defaults: user `root`, terminal from `$TERM` (falling back to `xterm`), SFTP enabled. #### client_options.user() ```rust user() ``` SSH login user. Default `root`. #### client_options.term() ```rust term() ``` Terminal name for interactive sessions. #### client_options.sftp() ```rust sftp() ``` Enable or disable SFTP on the internal server. Default `true`. #### client_options.build() ```rust build() ``` Finalize the options. ## SshExecOptionsBuilder

Used by client.exec_with()

Builder for SSH exec options. #### exec_options.tty() ```rust tty() ``` Request a PTY for the exec channel. Default `false`. #### exec_options.build() ```rust build() ``` Finalize the options. ## SshAttachOptionsBuilder

Used by client.attach_with()

Builder for interactive SSH attach options. Default terminal comes from `$TERM` (falling back to `xterm`); detach keys default to the standard sequence. #### attach_options.term() ```rust term() ``` Terminal name for the shell. #### attach_options.detach_keys() ```rust detach_keys() ``` Detach key sequence. #### attach_options.build() ```rust build() ``` Finalize the options. ## SshServerOptionsBuilder

Used by ssh.server_with()

Builder for SSH server options. SFTP is enabled by default; when no authorized keys are provided, the default authorized-keys file is loaded. #### server_options.host_key_path() ```rust host_key_path() ``` Override the host private key path. #### server_options.host_key() ```rust host_key() ``` Use an in-memory host private key. #### server_options.authorized_keys_path() ```rust authorized_keys_path() ``` Override the authorized-keys path. #### server_options.authorized_key() ```rust authorized_key() ``` Add one in-memory authorized public key. #### server_options.user() ```rust user() ``` Override the guest user used for exec requests. #### server_options.sftp() ```rust sftp() ``` Enable or disable SFTP. Default `true`. #### server_options.build() ```rust build() ``` Finalize the options. ## SftpClient

Returned by client.sftp()

High-level SFTP client session. ```rust pub type SftpClient = russh_sftp::client::SftpSession; ``` ## Types ### SshOutput

Returned by client.exec(), client.exec_with()

Output from an SSH exec request. | Field | Type | Description | |-------|------|-------------| | `status` | `i32` | Exit status code. | | `stdout` | `Bytes` | Captured stdout bytes. | | `stderr` | `Bytes` | Captured stderr bytes (folded into stdout when a PTY is allocated). |