Tcl

SSH Tunnel Thread Activity Log

Demonstrates the tunnel-log properties KeepTunnelLog, TunnelLog, and TunnelLogPath, which record the activity of the SSH tunnel and client-manager threads.

Note: The log paths are relative to the application's current working directory. Absolute paths may also be used.

Background: This is the counterpart to the accept log, covering the SSH side rather than the listener: the tunnel and client-manager threads that actually move data. As with the accept log, KeepTunnelLog enables the in-memory TunnelLog while TunnelLogPath writes a separate file. Together the two logs let you localize a problem to either the accepting side or the forwarding side.

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Tcl


load ./chilkat.dll

set success 0

#  Demonstrates the SshTunnel tunnel-log properties KeepTunnelLog, TunnelLog, and TunnelLogPath.
#  
#  These log the activity of the SSH tunnel and client-manager threads.

set tunnel [new_CkSshTunnel]

#  Retain the SSH tunnel-thread activity in memory so it can be read from the TunnelLog property.
CkSshTunnel_put_KeepTunnelLog $tunnel 1

#  Optionally also write the tunnel-thread activity to a file (separate from the in-memory log).
CkSshTunnel_put_TunnelLogPath $tunnel "qa_output/tunnel.log"

CkSshTunnel_put_DestHostname $tunnel "db.internal.example.com"
CkSshTunnel_put_DestPort $tunnel 5432

set sshPort 22
set success [CkSshTunnel_Connect $tunnel "ssh.example.com" $sshPort]
if {$success == 0} then {
    puts [CkSshTunnel_lastErrorText $tunnel]
    delete_CkSshTunnel $tunnel
    exit
}

#  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.
set password "mySshPassword"

set success [CkSshTunnel_AuthenticatePw $tunnel "mySshLogin" $password]
if {$success == 0} then {
    puts [CkSshTunnel_lastErrorText $tunnel]
    delete_CkSshTunnel $tunnel
    exit
}

set listenPort 1080
set success [CkSshTunnel_BeginAccepting $tunnel $listenPort]
if {$success == 0} then {
    puts [CkSshTunnel_lastErrorText $tunnel]
    delete_CkSshTunnel $tunnel
    exit
}

#  ... clients transfer data through the tunnel ...

#  Read the accumulated in-memory tunnel log.
puts [CkSshTunnel_tunnelLog $tunnel]

set waitForThreadExit 1
set success [CkSshTunnel_CloseTunnel $tunnel $waitForThreadExit]
if {$success == 0} then {
    puts [CkSshTunnel_lastErrorText $tunnel]
    delete_CkSshTunnel $tunnel
    exit
}


delete_CkSshTunnel $tunnel