[Question] Handle user input to interactive commands

[Catalin Dinuta]

Hi team,

I have the following piece of code which seems to work on Windows, but not on Linux.

private static void sendStdInputToProcess(ProcessState processState, String stdInput) throws IOException {
        OutputStream stdin = processState.getStartedProcess().getProcess().getOutputStream();
        InputStream stdout = processState.getStartedProcess().getProcess().getInputStream();

        BufferedWriter writer = null;

        try {
            writer = new BufferedWriter(new OutputStreamWriter(stdin));
            //reader = new BufferedReader(new InputStreamReader(stdout));

            writer.write(stdInput);
            writer.flush();

            Scanner scanner = new Scanner(stdout); //<- reader
            while (scanner.hasNextLine()) {
                System.out.println(scanner.nextLine());
            }
        } finally {
            writer.close();
        }
    }

Inputs & Outputs:
Win: cmd.exe /c "set /P id=Enter id: " stdInput= "something\n". Result: PASS
Linux: "/bin/sh -c ssh-keygen" or any command that needs interactive input. stdInput= "some\some\n". Result: FAIL because it hangs forever

Do you see anything what I miss here ?

[Neeme Praks]

Are you adding a line break to the end of your input?
Maybe add writer.newLine() after writer.write(stdInput)?

[Catalin Dinuta]

Thank you, one more question please.

I use the following when starting the process

 StartedProcess startedProcess = new ProcessExecutor()
                .command(command)
                .environment(environment.getEnvAndVirtualEnv())
                .destroyOnExit()
                .readOutput(true)
                .redirectError(outputStream)
                .redirectInput(System.in)
                .start();

I wonder if .redirectInput(System.in) is fine from your point of view, because for any interactive and non-interactive command I obtain an Interrupted exception:

11:13:57.034 [ForkJoinPool.commonPool-worker-3] DEBUG org.zeroturnaround.exec.ProcessExecutor - Executing [/bin/sh, -c, read A] with environment {SWAPPED_ENV}.
11:13:57.042 [ForkJoinPool.commonPool-worker-3] DEBUG org.zeroturnaround.exec.ProcessExecutor - Started Process[pid=4378, exitValue="not exited"]
11:13:57.869 [main] INFO com.axway.b2bi.automation.signitrack.agent.utils.ProcessStateUtils - Sent stdIn user string 'y'
11:13:57.869 [main] INFO com.axway.b2bi.automation.signitrack.agent.utils.ProcessStateUtils - Sent enter KEY
11:13:57.869 [main] INFO com.axway.b2bi.automation.signitrack.agent.utils.ProcessStateUtils - Sent enter KEY
11:13:57.870 [WaitForProcess-Process[pid=4378, exitValue="not exited"]] DEBUG org.zeroturnaround.exec.WaitForProcess - Process[pid=4378, exitValue=0] stopped with exit code 0
11:13:57.880 [Thread-0] ERROR org.zeroturnaround.exec.stream.InputStreamPumper - Got exception while reading/writing the stream
java.lang.InterruptedException: sleep interrupted
	at java.base/java.lang.Thread.sleep(Native Method)
	at org.zeroturnaround.exec.stream.InputStreamPumper.run(InputStreamPumper.java:89)
	at java.base/java.lang.Thread.run(Thread.java:829)