Tcl

SSH Tunnel Listener Activity Log

Demonstrates the listener-log properties KeepAcceptLog, AcceptLog, and AcceptLogPath, which record the activity of the background listener thread started by BeginAccepting.

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

Background: Because the listener runs on a background thread, an activity log is often the only practical way to see what it is doing — which connections it accepted and when. KeepAcceptLog must be enabled for the in-memory AcceptLog to be populated; AcceptLogPath is an independent file-based log that persists across the run. This log covers the listener specifically, as distinct from the TunnelLog that records the SSH tunnel threads.

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Tcl


load ./chilkat.dll

set success 0

#  Demonstrates the SshTunnel listener-log properties KeepAcceptLog, AcceptLog, and AcceptLogPath.
#  
#  These log the activity of the background listener thread started by BeginAccepting.

set tunnel [new_CkSshTunnel]

#  Retain the listener activity log in memory so it can be read from the AcceptLog property.
CkSshTunnel_put_KeepAcceptLog $tunnel 1

#  Optionally also write the listener activity to a file (separate from the in-memory log).
CkSshTunnel_put_AcceptLogPath $tunnel "qa_output/accept.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
}

#  ... the listener accepts connections for a while ...

#  Read the accumulated in-memory listener log.
puts [CkSshTunnel_acceptLog $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