(Tcl) 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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load ./chilkat.dll

# 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..
set ssh1 [new_CkSsh]

set ssh2 [new_CkSsh]

set ssh3 [new_CkSsh]

set port 22
set success [CkSsh_Connect $ssh1 "ssh-server1.com" $port]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh1]
    delete_CkSsh $ssh1
    delete_CkSsh $ssh2
    delete_CkSsh $ssh3
    exit
}

# Authenticate using login/password:
set success [CkSsh_AuthenticatePw $ssh1 "sshLogin1" "sshPassword1"]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh1]
    delete_CkSsh $ssh1
    delete_CkSsh $ssh2
    delete_CkSsh $ssh3
    exit
}

# Connect and authenticate with 2 more servers.
# For brevity, the success/failure won't be checked...
set success [CkSsh_Connect $ssh2 "ssh-server2.com" $port]
set success [CkSsh_AuthenticatePw $ssh2 "sshLogin2" "sshPassword2"]
set success [CkSsh_Connect $ssh3 "ssh-server3.com" $port]
set success [CkSsh_AuthenticatePw $ssh3 "sshLogin3" "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.
set cmd "sleep 5; date"

# Start each command
set ssh1Channel [CkSsh_QuickCmdSend $ssh1 $cmd]
if {$ssh1Channel < 0} then {
    puts [CkSsh_lastErrorText $ssh1]
    delete_CkSsh $ssh1
    delete_CkSsh $ssh2
    delete_CkSsh $ssh3
    exit
}

# For brevity, we're not checking the return values here:
set ssh2Channel [CkSsh_QuickCmdSend $ssh2 $cmd]
set ssh3Channel [CkSsh_QuickCmdSend $ssh3 $cmd]

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

# Now collect the results of each command.
set pollTimeoutMs 50
set numFinished 0

# Note: You would rewrite this code to use arrays.
set ssh1Finished 0
set ssh2Finished 0
set ssh3Finished 0
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 != 1} then {
        set channel [CkSsh_QuickCmdCheck $ssh1 $pollTimeoutMs]
        if {$channel == -2} then {
            puts [CkSsh_lastErrorText $ssh1]
            delete_CkSsh $ssh1
            delete_CkSsh $ssh2
            delete_CkSsh $ssh3
            exit
        }

        if {$channel == $ssh1Channel} then {
            puts "---- ssh1 channel $channel finished ----"
            puts [CkSsh_getReceivedText $ssh1 $channel ansi]
            set numFinished [expr $numFinished + 1]
            set ssh1Finished 1
        }

    }

    if {$ssh2Finished != 1} then {
        set channel [CkSsh_QuickCmdCheck $ssh2 $pollTimeoutMs]
        if {$channel == -2} then {
            puts [CkSsh_lastErrorText $ssh2]
            delete_CkSsh $ssh1
            delete_CkSsh $ssh2
            delete_CkSsh $ssh3
            exit
        }

        if {$channel == $ssh2Channel} then {
            puts "---- ssh2 channel $channel finished ----"
            puts [CkSsh_getReceivedText $ssh2 $channel ansi]
            set numFinished [expr $numFinished + 1]
            set ssh2Finished 1
        }

    }

    if {$ssh3Finished != 1} then {
        set channel [CkSsh_QuickCmdCheck $ssh3 $pollTimeoutMs]
        if {$channel == -2} then {
            puts [CkSsh_lastErrorText $ssh3]
            delete_CkSsh $ssh1
            delete_CkSsh $ssh2
            delete_CkSsh $ssh3
            exit
        }

        if {$channel == $ssh3Channel} then {
            puts "---- ssh3 channel $channel finished ----"
            puts [CkSsh_getReceivedText $ssh3 $channel ansi]
            set numFinished [expr $numFinished + 1]
            set ssh3Finished 1
        }

    }

}

# --------------
# 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

delete_CkSsh $ssh1
delete_CkSsh $ssh2
delete_CkSsh $ssh3