Lua

Get an SSH Tunnel's Current State (Diagnostics)

Demonstrates the Chilkat SshTunnel.GetCurrentState method, which returns an XML snapshot describing the tunnel manager, SSH channels, and current tunnel clients. It takes no arguments and is intended for diagnostics and monitoring.

Background: Because the tunnel forwards traffic on a background thread, there is no natural place in your code to observe what it is doing at a given moment. GetCurrentState provides that visibility — byte counts, active channels, and connected clients — as structured XML suited to logging or a monitoring dashboard. It is a read-only snapshot and does not affect the tunnel.

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Lua

local chilkat = require("chilkat")

-- Demonstrates the SshTunnel.GetCurrentState method, which returns an XML snapshot describing the
-- tunnel manager, SSH channels, and current tunnel clients.  It takes no arguments and is
-- intended for diagnostics and monitoring.

local tunnel = chilkat.SshTunnel.new()

-- The tunnel forwards accepted local connections to this destination through the SSH server.
tunnel.dest_hostname = "db.internal.example.com"
tunnel.dest_port = 5432

-- Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
-- does not authenticate yet.
local sshPort = 22
local success = tunnel:connect("ssh.example.com", sshPort)
if not success then
    print(tunnel.last_error_text)
    return
end

-- 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.
local password = "mySshPassword"

success = tunnel:authenticate_pw("mySshLogin", password)
if not success then
    print(tunnel.last_error_text)
    return
end

-- Begin accepting so there is live tunnel state to inspect.
local listenPort = 1080
success = tunnel:begin_accepting(listenPort)
if not success then
    print(tunnel.last_error_text)
    return
end

-- Get a diagnostic snapshot of the tunnel's current state as XML.
local stateXml = tunnel:get_current_state()
if not tunnel.last_method_success then
    print(tunnel.last_error_text)
    return
end

print(stateXml)

local waitForThreadExit = true
success = tunnel:close_tunnel(waitForThreadExit)
if not success then
    print(tunnel.last_error_text)
    return
end