Java

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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import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.SshTunnel;

public class ChilkatExample {

    public static void main(String[] args) {
        // Demonstrates the SshTunnel tunnel-log properties KeepTunnelLog, TunnelLog, and TunnelLogPath.
        //
        // These log the activity of the SSH tunnel and client-manager threads.

        SshTunnel tunnel = new SshTunnel();

        // Retain the SSH tunnel-thread activity in memory so it can be read from the TunnelLog property.
        tunnel.setKeepTunnelLog(true);

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

        tunnel.setDestHostname("db.internal.example.com");
        tunnel.setDestPort(5432);

        int sshPort = 22;
        try {
            tunnel.connect("ssh.example.com", sshPort);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // 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.
        String password = "mySshPassword";

        try {
            tunnel.authenticatePw("mySshLogin", password);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        int listenPort = 1080;
        try {
            tunnel.beginAccepting(listenPort);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // ... clients transfer data through the tunnel ...

        // Read the accumulated in-memory tunnel log.
        System.out.println(tunnel.getTunnelLog());

        boolean waitForThreadExit = true;
        try {
            tunnel.closeTunnel(waitForThreadExit);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }
    }
}