Shell

Description and operation

General

A shell is a sandbox whose main process is a shell program, run on a terminal with its input open. The program sees a real terminal: colours, prompts, full-screen programs and Ctrl-C work.

You create the sandbox with tty and stdin, and a shell program as cmd. Then you attach to it. The attach connects your terminal to the process.

The program starts when you attach, or after 60 seconds without an attach. The attach stays open while the program is idle.

The CLI passes the terminal type of your own terminal (TERM) to the sandbox. The sandbox uses xterm-256color when your terminal has none.

A shell has no time limit of its own. It has the timeout_s of the sandbox. The CLI needs a terminal on its standard input and output.

Tasks

Open a shell in a sandbox

Reason for the task: Work in a sandbox on a terminal, with prompts, vim, top and Ctrl-C, or give a program a terminal.

Job set-up

• Access: you.
• References: POST /v1/sandboxes, GET /v1/sandboxes/{id}/attach.

Procedure

1. Create the sandbox with a shell as the command, a terminal and an open input.

   PythonCopy

   sb = kl.sandboxes.create(cmd=["bash"], tty=True, stdin=True, timeout_s=1800)

   TypeScriptCopy

   const sb = await kl.sandboxes.create({ cmd: ["bash"], tty: true, stdin: true, timeoutS: 1800 });

   GoCopy

   sb, err := kl.Sandboxes.Create(kloudlite.CreateSandbox{Cmd: []string{"bash"}, Tty: true, Stdin: true, Timeout: 1800 * time.Second})if err != nil {    log.Fatal(err)}

   RubyCopy

   sb = kl.sandboxes.create(cmd: ["bash"], tty: true, stdin: true, timeout_s: 1800)

   JavaCopy

   var sb = kl.sandboxes().create(new Kloudlite.CreateSandbox().cmd(List.of("bash")).tty(true).stdin(true).timeout(Duration.ofSeconds(1800)));

   CLICopy

   kloudlite sandboxes create -it --timeout-s 1800 -- bash

2. Connect to the shell. The call waits until the sandbox is running.

   PythonCopy

   sh = sb.attach()

   TypeScriptCopy

   const sh = await sb.attach();

   GoCopy

   sh, err := sb.Attach(80, 24)if err != nil {    log.Fatal(err)}defer sh.Close()

   RubyCopy

   sh = sb.attach

   JavaCopy

   var sh = sb.attach();

   CLICopy

   kloudlite sandboxes attach sbx-3c4d5e6f7a8b9c0d

3. Type a command and read the output. End the input with exit.

   PythonCopy

   sh.write("echo $((6 * 7)); exit\n")while (chunk := sh.read()) is not None:    print(chunk.decode(), end="")

   TypeScriptCopy

   sh.write("echo $((6 * 7)); exit\n");for (let c = await sh.read(); c !== null; c = await sh.read()) process.stdout.write(c);

   GoCopy

   sh.Write([]byte("echo $((6 * 7)); exit\n"))if _, err := io.Copy(os.Stdout, sh); err != nil {    log.Fatal(err)}

   RubyCopy

   sh.write("echo $((6 * 7)); exit\n")while (chunk = sh.read)  print chunkend

   JavaCopy

   sh.write("echo $((6 * 7)); exit\n");for (byte[] c = sh.read(); c != null; c = sh.read()) System.out.write(c, 0, c.length);System.out.flush();

   CLICopy

   echo $((6 * 7)); exit

4. Wait for the shell to exit. The call returns the exit code.

   PythonCopy

   print(sh.wait())sh.close()

   TypeScriptCopy

   console.log(await sh.wait());sh.close();

   GoCopy

   code, err := sh.Wait()if err != nil {    log.Fatal(err)}fmt.Println(code)

   RubyCopy

   puts sh.waitsh.close

   JavaCopy

   System.out.println(sh.waitFor());sh.close();

   CLICopy

   echo $?

Close-out

1. Make sure that the output shows 42 and the exit code is 0.

Call resize with the new columns and rows when your window changes. The CLI does this by itself.

To leave a shell running, close the attach and do not type exit. Attach again with the id of the sandbox. To run a program other than a shell, give it as cmd.

Troubleshooting