how to create a powershell remote session from inside a Java program?

Question

I have the following code to connect to a remote machine and execute commands.It is working if I create a new session for each Invoke-Command call to the remote machine. I don't want to create a new session each time I use Invoke-Command as that will not scale for thousands of commands on hundreds of machines concurrently and session creation itself is a big overhead. I need a way so that I can reuse the same session object in the $session powershell variable for multiple Invoke-Command calls to the remote machines.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;

public class PowerShellSession {

private static String subModule = "PowerShellSession";
String targetIpAddress;
String username;
String password;

public static Object connectPShellLock = new Object();

public PowerShellSession() {}


public void exec(String cmd, String credentials)  { 

    String ex = "Invoke-Command -Session $session -ScriptBlock {" + cmd + "} -Computer " + targetIpAddress;

    String[] args = new String[] { "powershell", ex};
    try {
        execRemote(args);
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public void close() {
    String command = "Exit-PSSession";
    String[] args = new String[] { "powershell", command};
    try {
        execRemote(args);
    } catch (IOException e) {
        e.printStackTrace();
    }

}

private String getCredentials(String domain, String userName,
        String password) throws IOException {
    String creds = "$PlainPassword ='" + password
            + "'; $SecurePassword = $PlainPassword | ConvertTo-SecureString -AsPlainText -Force;"
            + "$mycred = new-object -typename System.Management.Automation.PSCredential('" + userName + "', $SecurePassword);";
    creds += "$session = New-PSSession -ComputerName " + domain + " -Credential $mycred;";

    String[] args = new String[] { "powershell", creds};
    execRemote(args);
    return creds;
}

private void execRemote(String[] arguments) throws IOException {
    ProcessBuilder builder = new ProcessBuilder(arguments);
    builder.redirectErrorStream(true);
    Process process = builder.start();
    doProcessIO(process);
}

// Do the IO for a passed process
private void doProcessIO(Process p) throws IOException {
    p.getOutputStream().close();
    String line;
    System.out.println("Output:");
    BufferedReader stdout = new BufferedReader(new InputStreamReader(
            p.getInputStream()));
    while ((line = stdout.readLine()) != null) {
        System.out.println(line);
    }
    stdout.close();
    System.out.println("Error:");
    BufferedReader stderr = new BufferedReader(new InputStreamReader(
            p.getErrorStream()));
    while ((line = stderr.readLine()) != null) {
        System.out.println(line);
    }
    stderr.close();
//      System.out.println("Done");
}

public static void main(String[] args) throws IOException {
    PowerShellSession psSession = new PowerShellSession();
    String credentials = psSession.getCredentials("9.120.241.195", "username", "password");
    psSession.targetIpAddress = "9.120.241.195";
    if(!credentials.equals("")) {
        Scanner input = new Scanner(System.in);
        while(true) {
            System.out.print("PS C:\\Windows\\system32> ");
            String cmd = input.nextLine();
            if(cmd.equals("q") || cmd.equals("e") || cmd.equals("quit") || cmd.equals("exit")) break;
            psSession.username = "username";
            psSession.password = "password";
            psSession.exec(cmd, "");
        }
        System.out.println("Finished PowerShell remote session.");
        input.close();
    }
    psSession.close();
}
}

score 2 · Answer 1 · answered Mar 28 '17 at 06:48

See there are lot of logics involves in this which can help you.

Your session invoking is fine; But you cannot directly run a PS command like that. You have to invoke the powershell.exe first then you have to give the respective remote commands what you want to execute.

Finally you have execute the command you will prepare. Let me share you a sample code:

public String executeScript(String psFileName, Systems system) throws NMAException {

        Runtime runtime = Runtime.getRuntime();
        String filePath = ApplicationProperties.getPropertyValue("powershell.scripts.location");
        String command;

        switch (psFileName) {
            case "TerminalServersSystemInfo.ps1":
                command = POWERSHELL + filePath + psFileName + " " + system.getPassword() + " " + system.getUserName()
                        + " " + system.getSystemName();
                break;
            case "SQLServerInfo.ps1":
                command = POWERSHELL + filePath + psFileName + " " + system.getSystemName() + " "
                        + system.getUserName() + " " + system.getPassword();
                break;
            case "MyPS.ps1":

            {
                command = POWERSHELL + filePath + psFileName + " " + system.getSystemName() + " "
                        + system.getUserName()
                        + " " + system.getPassword() + " " + system.getDatabaseName();
                break;
            }

            default:
                throw new NMAException("not available");
        }

Here is how you should form the command object in Java and then you should execute this:

powershell -ExecutionPolicy Bypass -NoLogo -NoProfile -Command {Invoke-command ......}

For triggering a PS file you can use the -Filepath switch.

Next this will help you in executing that:

proc = runtime.exec(command);
            proc.getOutputStream().close();
            InputStream is = proc.getInputStream();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader reader = new BufferedReader(isr);
            StringBuilder sb = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }
            reader.close();
            proc.getOutputStream().close();
            LOGGER.info("Command: " + command);
            LOGGER.info("Result:" + sb.toString());
            return sb.toString();

Hope it gives you a set off.

my requirement is to create a single session and execute multiple commands/scripts. In the above code in every case credentials are passed, which means we are creating multiple sessions.Is there any way so that I can set the credentials only once and then execute multiple commands/scripts? — Manjur, Mar 30 '17 at 11:50
you can create a session variable where you can pass the credentials and then you can utilize that session variable to run multiple threads — Ranadip Dutta, Mar 30 '17 at 15:10

score 0 · Answer 2 · edited May 30 '19 at 14:44

public class PowerShellSession {
    private static String subModule = "PowerShellSession";
    String targetIpAddress;
    String username;
    String password;

    public static Object connectPShellLock = new Object();

    public PowerShellSession() {}


    public void exec(String cmd, String credentials)  { 

        String ex = credentials +" Invoke-Command -ScriptBlock {" + cmd + "} -ComputerName " + targetIpAddress +" -Credential $mycred";

        String[] args = new String[] { "powershell", ex};
        try {
            execRemote(args);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void close() {
        String command = "Exit-PSSession";
        String[] args = new String[] { "powershell", command};
        try {
            execRemote(args);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    private String getCredentials(String domain, String userName,
            String password) throws IOException {
        String creds = "$Username = '"+userName+"';$PlainPassword ='" + password
                + "'; $SecurePassword = ConvertTo-SecureString -AsPlainText $PlainPassword -Force;"
                + "$mycred = New-Object System.Management.Automation.PSCredential -ArgumentList $Username, $SecurePassword;";
        //creds += "$session = New-PSSession -ComputerName " + domain + " -Credential $mycred;";

        String[] args = new String[] { "powershell", creds};
        execRemote(args);
        return creds;
    }

    private void execRemote(String[] arguments) throws IOException {
        ProcessBuilder builder = new ProcessBuilder(arguments);
        builder.redirectErrorStream(true);
        Process process = builder.start();
        doProcessIO(process);
    }

    // Do the IO for a passed process
    private void doProcessIO(Process p) throws IOException {
        p.getOutputStream().close();
        String line;
        System.out.println("Output:");
        BufferedReader stdout = new BufferedReader(new InputStreamReader(
                p.getInputStream()));
        while ((line = stdout.readLine()) != null) {
            System.out.println(line);
        }
        stdout.close();
        System.out.println("Error:");
        BufferedReader stderr = new BufferedReader(new InputStreamReader(
                p.getErrorStream()));
        while ((line = stderr.readLine()) != null) {
            System.out.println(line);
        }
        stderr.close();
        System.out.println("Done");
    }

    public static void main(String[] args) throws IOException {
        PropertiesFileReader propReader = new PropertiesFileReader(System.getProperty("user.dir")+"/cred.properties");

        String user = propReader.getPropertyData("user");
        String pass = propReader.getPropertyData("pass");
        String ip_add = propReader.getPropertyData("ip");

        PowerShellSession psSession = new PowerShellSession();
        String credentials = psSession.getCredentials(ip_add, user, pass);
        psSession.targetIpAddress = ip_add;//;



        String cmdd = propReader.getPropertyData("command");//"Get-Culture";
        if(!credentials.equals("")) {


            psSession.exec(cmdd, credentials);

            System.out.println("Finished PowerShell remote session.");

        }
        psSession.close();
    }

}

@Manjur: I have modified your code i.e. 1st Code and now its working now. — Ajitabh Ranjan, May 30 '19 at 14:26

how to create a powershell remote session from inside a Java program?

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