SSH Parallel Remote Commands on Multiple Servers

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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.

#import <CkoSsh.h>
#import <NSString.h>

BOOL success = NO;

//  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.

CkoSsh *ssh1 = [[CkoSsh alloc] init];
CkoSsh *ssh2 = [[CkoSsh alloc] init];
CkoSsh *ssh3 = [[CkoSsh alloc] init];

int 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.
NSString *password = @"mySshPassword";

success = [ssh1 Connect: @"ssh-server1.example.com" port: [NSNumber numberWithInt: port]];
if (success == NO) {
    NSLog(@"%@",ssh1.LastErrorText);
    return;
}

success = [ssh1 AuthenticatePw: @"mySshLogin" password: password];
if (success == NO) {
    NSLog(@"%@",ssh1.LastErrorText);
    return;
}

success = [ssh2 Connect: @"ssh-server2.example.com" port: [NSNumber numberWithInt: port]];
if (success == NO) {
    NSLog(@"%@",ssh2.LastErrorText);
    return;
}

success = [ssh2 AuthenticatePw: @"mySshLogin" password: password];
if (success == NO) {
    NSLog(@"%@",ssh2.LastErrorText);
    return;
}

success = [ssh3 Connect: @"ssh-server3.example.com" port: [NSNumber numberWithInt: port]];
if (success == NO) {
    NSLog(@"%@",ssh3.LastErrorText);
    return;
}

success = [ssh3 AuthenticatePw: @"mySshLogin" password: password];
if (success == NO) {
    NSLog(@"%@",ssh3.LastErrorText);
    return;
}

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

//  Start the command on each server.  QuickCmdSend returns immediately.
int channel1 = [[ssh1 QuickCmdSend: cmd] intValue];
if (channel1 < 0) {
    NSLog(@"%@",ssh1.LastErrorText);
    return;
}

int channel2 = [[ssh2 QuickCmdSend: cmd] intValue];
if (channel2 < 0) {
    NSLog(@"%@",ssh2.LastErrorText);
    return;
}

int channel3 = [[ssh3 QuickCmdSend: cmd] intValue];
if (channel3 < 0) {
    NSLog(@"%@",ssh3.LastErrorText);
    return;
}

//  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.)
int pollTimeoutMs = 50;
int numFinished = 0;
BOOL finished1 = NO;
BOOL finished2 = NO;
BOOL finished3 = NO;

while (numFinished < 3) {
    if (!finished1) {
        int ch1 = [[ssh1 QuickCmdCheck: [NSNumber numberWithInt: pollTimeoutMs]] intValue];
        if (ch1 == -2) {
            NSLog(@"%@",ssh1.LastErrorText);
            return;
        }

        if (ch1 >= 0) {
            NSLog(@"%@%d%@",@"---- ssh1 channel ",ch1,@" finished ----");
            NSString *out1 = [ssh1 GetReceivedText: [NSNumber numberWithInt: ch1] charset: @"utf-8"];
            if (ssh1.LastMethodSuccess == NO) {
                NSLog(@"%@",ssh1.LastErrorText);
                return;
            }

            NSLog(@"%@",out1);
            finished1 = YES;
            numFinished = numFinished + 1;
        }

    }

    if (!finished2) {
        int ch2 = [[ssh2 QuickCmdCheck: [NSNumber numberWithInt: pollTimeoutMs]] intValue];
        if (ch2 == -2) {
            NSLog(@"%@",ssh2.LastErrorText);
            return;
        }

        if (ch2 >= 0) {
            NSLog(@"%@%d%@",@"---- ssh2 channel ",ch2,@" finished ----");
            NSString *out2 = [ssh2 GetReceivedText: [NSNumber numberWithInt: ch2] charset: @"utf-8"];
            if (ssh2.LastMethodSuccess == NO) {
                NSLog(@"%@",ssh2.LastErrorText);
                return;
            }

            NSLog(@"%@",out2);
            finished2 = YES;
            numFinished = numFinished + 1;
        }

    }

    if (!finished3) {
        int ch3 = [[ssh3 QuickCmdCheck: [NSNumber numberWithInt: pollTimeoutMs]] intValue];
        if (ch3 == -2) {
            NSLog(@"%@",ssh3.LastErrorText);
            return;
        }

        if (ch3 >= 0) {
            NSLog(@"%@%d%@",@"---- ssh3 channel ",ch3,@" finished ----");
            NSString *out3 = [ssh3 GetReceivedText: [NSNumber numberWithInt: ch3] charset: @"utf-8"];
            if (ssh3.LastMethodSuccess == NO) {
                NSLog(@"%@",ssh3.LastErrorText);
                return;
            }

            NSLog(@"%@",out3);
            finished3 = YES;
            numFinished = numFinished + 1;
        }

    }

}

[ssh1 Disconnect];
[ssh2 Disconnect];
[ssh3 Disconnect];