(Objective-C) SSH Parallel Remote Commands on Multiple Servers

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Shows how to execute a command in parallel on multiple servers.

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

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

// Executing a command on multiple servers simultaneously is straightforward.
// It's just 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;
BOOL success = [ssh1 Connect: @"ssh-server1.com" port: [NSNumber numberWithInt: port]];
if (success != YES) {
    NSLog(@"%@",ssh1.LastErrorText);
    return;
}

// Authenticate using login/password:
success = [ssh1 AuthenticatePw: @"sshLogin1" password: @"sshPassword1"];
if (success != YES) {
    NSLog(@"%@",ssh1.LastErrorText);
    return;
}

// Connect and authenticate with 2 more servers.
// For brevity, the success/failure won't be checked...
success = [ssh2 Connect: @"ssh-server2.com" port: [NSNumber numberWithInt: port]];
success = [ssh2 AuthenticatePw: @"sshLogin2" password: @"sshPassword2"];
success = [ssh3 Connect: @"ssh-server3.com" port: [NSNumber numberWithInt: port]];
success = [ssh3 AuthenticatePw: @"sshLogin3" password: @"sshPassword3"];

// Note: If we wanted, we could've used ConnectAsync and AuthenticatePwAsync
// to do the connecting and authenticating in parallel...

// The command to be run on each SSH server will sleep for 5 seconds,
// and then show the current system date/time.
NSString *cmd = @"sleep 5; date";

// Start each command
int ssh1Channel = [[ssh1 QuickCmdSend: cmd] intValue];
if (ssh1Channel < 0) {
    NSLog(@"%@",ssh1.LastErrorText);
    return;
}

// For brevity, we're not checking the return values here:
int ssh2Channel = [[ssh2 QuickCmdSend: cmd] intValue];
int ssh3Channel = [[ssh3 QuickCmdSend: cmd] intValue];

// OK, at this point the command is running simultaneously on each server.

// Now collect the results of each command.
int pollTimeoutMs = 50;
int numFinished = 0;
int channel;
// Note: You would rewrite this code to use arrays.
BOOL ssh1Finished = NO;
BOOL ssh2Finished = NO;
BOOL ssh3Finished = NO;
while (numFinished < 3) {
    // Check to see if anything has finished.
    // QuickCmdCheck returns -1 if there are no errors and nothing else finished
    // QuickCmdCheck returns -2 if there was an error (such as a lost connection)
    // QuickCmdCheck returns a channel number if a channel finished.
    if (ssh1Finished != YES) {
        channel = [[ssh1 QuickCmdCheck: [NSNumber numberWithInt: pollTimeoutMs]] intValue];
        if (channel == -2) {
            NSLog(@"%@",ssh1.LastErrorText);
            return;
        }

        if (channel == ssh1Channel) {
            NSLog(@"%@%d%@",@"---- ssh1 channel ",channel,@" finished ----");
            NSLog(@"%@",[ssh1 GetReceivedText: [NSNumber numberWithInt: channel] charset: @"ansi"]);
            numFinished = numFinished + 1;
            ssh1Finished = YES;
        }

    }

    if (ssh2Finished != YES) {
        channel = [[ssh2 QuickCmdCheck: [NSNumber numberWithInt: pollTimeoutMs]] intValue];
        if (channel == -2) {
            NSLog(@"%@",ssh2.LastErrorText);
            return;
        }

        if (channel == ssh2Channel) {
            NSLog(@"%@%d%@",@"---- ssh2 channel ",channel,@" finished ----");
            NSLog(@"%@",[ssh2 GetReceivedText: [NSNumber numberWithInt: channel] charset: @"ansi"]);
            numFinished = numFinished + 1;
            ssh2Finished = YES;
        }

    }

    if (ssh3Finished != YES) {
        channel = [[ssh3 QuickCmdCheck: [NSNumber numberWithInt: pollTimeoutMs]] intValue];
        if (channel == -2) {
            NSLog(@"%@",ssh3.LastErrorText);
            return;
        }

        if (channel == ssh3Channel) {
            NSLog(@"%@%d%@",@"---- ssh3 channel ",channel,@" finished ----");
            NSLog(@"%@",[ssh3 GetReceivedText: [NSNumber numberWithInt: channel] charset: @"ansi"]);
            numFinished = numFinished + 1;
            ssh3Finished = YES;
        }

    }

}

// --------------
// Sample output:

// 	---- ssh2 channel 101 finished ----
// 	Fri Dec 23 00:25:48 UTC 2016
// 
// 	---- ssh3 channel 102 finished ----
// 	Thu Dec 22 18:25:12 CST 2016
// 
// 	---- ssh1 channel 100 finished ----
// 	Thu Dec 22 18:25:48 CST 2016