SSH Parallel Remote Commands on Multiple Servers

See more SSH Examples

Demonstrates running the same command on several servers simultaneously. It is simply a matter of using one Ssh object per server, starting the command on each with QuickCmdSend, and then polling each connection with QuickCmdCheck until all have finished.

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Ssh;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  ssh1: TSsh;
  ssh2: TSsh;
  ssh3: TSsh;
  port: Integer;
  password: string;
  cmd: string;
  channel1: Integer;
  channel2: Integer;
  channel3: Integer;
  pollTimeoutMs: Integer;
  numFinished: Integer;
  finished1: Boolean;
  finished2: Boolean;
  finished3: Boolean;
  ch1: Integer;
  out1: string;
  ch2: Integer;
  out2: string;
  ch3: Integer;
  out3: string;

begin
  success := False;

  //  This example requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  //  Demonstrates running the same command on several servers simultaneously.  It is simply a
  //  matter of using one Ssh object per server.

  ssh1 := TSsh.Create;
  ssh2 := TSsh.Create;
  ssh3 := TSsh.Create;

  port := 22;

  //  Normally you would not hard-code the password in source.  You should instead obtain it
  //  from an interactive prompt, environment variable, or a secrets vault.
  password := 'mySshPassword';

  success := ssh1.Connect('ssh-server1.example.com',port);
  if (success = False) then
    begin
      WriteLn(ssh1.LastErrorText);
      Exit;
    end;
  success := ssh1.AuthenticatePw('mySshLogin',password);
  if (success = False) then
    begin
      WriteLn(ssh1.LastErrorText);
      Exit;
    end;

  success := ssh2.Connect('ssh-server2.example.com',port);
  if (success = False) then
    begin
      WriteLn(ssh2.LastErrorText);
      Exit;
    end;
  success := ssh2.AuthenticatePw('mySshLogin',password);
  if (success = False) then
    begin
      WriteLn(ssh2.LastErrorText);
      Exit;
    end;

  success := ssh3.Connect('ssh-server3.example.com',port);
  if (success = False) then
    begin
      WriteLn(ssh3.LastErrorText);
      Exit;
    end;
  success := ssh3.AuthenticatePw('mySshLogin',password);
  if (success = False) then
    begin
      WriteLn(ssh3.LastErrorText);
      Exit;
    end;

  //  This command sleeps for 5 seconds and then prints the system date/time, making the parallel
  //  execution easy to observe.
  cmd := 'sleep 5; date';

  //  Start the command on each server.  QuickCmdSend returns immediately.
  channel1 := ssh1.QuickCmdSend(cmd);
  if (channel1 < 0) then
    begin
      WriteLn(ssh1.LastErrorText);
      Exit;
    end;

  channel2 := ssh2.QuickCmdSend(cmd);
  if (channel2 < 0) then
    begin
      WriteLn(ssh2.LastErrorText);
      Exit;
    end;

  channel3 := ssh3.QuickCmdSend(cmd);
  if (channel3 < 0) then
    begin
      WriteLn(ssh3.LastErrorText);
      Exit;
    end;

  //  The command is now running on all three servers at once.  Poll each connection until every
  //  command has finished.  (Production code would keep the objects in arrays rather than
  //  repeating the logic.)
  pollTimeoutMs := 50;
  numFinished := 0;
  finished1 := False;
  finished2 := False;
  finished3 := False;

  while numFinished < 3 do
    begin
      if (not finished1) then
        begin
          ch1 := ssh1.QuickCmdCheck(pollTimeoutMs);
          if (ch1 = -2) then
            begin
              WriteLn(ssh1.LastErrorText);
              Exit;
            end;
          if (ch1 >= 0) then
            begin
              WriteLn('---- ssh1 channel ' + ch1 + ' finished ----');
              out1 := ssh1.GetReceivedText(ch1,'utf-8');
              if (ssh1.LastMethodSuccess = False) then
                begin
                  WriteLn(ssh1.LastErrorText);
                  Exit;
                end;
              WriteLn(out1);
              finished1 := True;
              numFinished := numFinished + 1;
            end;
        end;

      if (not finished2) then
        begin
          ch2 := ssh2.QuickCmdCheck(pollTimeoutMs);
          if (ch2 = -2) then
            begin
              WriteLn(ssh2.LastErrorText);
              Exit;
            end;
          if (ch2 >= 0) then
            begin
              WriteLn('---- ssh2 channel ' + ch2 + ' finished ----');
              out2 := ssh2.GetReceivedText(ch2,'utf-8');
              if (ssh2.LastMethodSuccess = False) then
                begin
                  WriteLn(ssh2.LastErrorText);
                  Exit;
                end;
              WriteLn(out2);
              finished2 := True;
              numFinished := numFinished + 1;
            end;
        end;

      if (not finished3) then
        begin
          ch3 := ssh3.QuickCmdCheck(pollTimeoutMs);
          if (ch3 = -2) then
            begin
              WriteLn(ssh3.LastErrorText);
              Exit;
            end;
          if (ch3 >= 0) then
            begin
              WriteLn('---- ssh3 channel ' + ch3 + ' finished ----');
              out3 := ssh3.GetReceivedText(ch3,'utf-8');
              if (ssh3.LastMethodSuccess = False) then
                begin
                  WriteLn(ssh3.LastErrorText);
                  Exit;
                end;
              WriteLn(out3);
              finished3 := True;
              numFinished := numFinished + 1;
            end;
        end;
    end;

  ssh1.Disconnect();
  ssh2.Disconnect();
  ssh3.Disconnect();


  ssh1.Free;
  ssh2.Free;
  ssh3.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.