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SSH Tunnel Per-Client Logging and Client Identifier

Demonstrates the ClientLogDir and ClientIdentifier properties. When ClientLogDir is set, a separate log file is created for each tunnel client; ClientIdentifier is the SSH client-identification string sent during the handshake.

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

Background: When many clients share one tunnel, a single combined log is hard to follow, so ClientLogDir gives each connection its own file — the fastest way to diagnose one misbehaving client. ClientIdentifier sets the version string the server sees; overriding the default is occasionally needed for compatibility with servers that key behavior off the client identification, or simply to label your application in server logs.

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const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    // Demonstrates the SshTunnel per-client logging properties ClientLogDir and ClientIdentifier.

    const tunnel = try chilkat.SshTunnel.init();
    defer tunnel.deinit();

    // When ClientLogDir is set, a separate log file is created for each tunnel client in this
    // directory, which is useful for troubleshooting individual connections.
    tunnel.setClientLogDir("qa_output/client_logs");

    // The SSH client-identification string sent to the SSH server during the handshake.
    tunnel.setClientIdentifier("SSH-2.0-MyTunnelApp_1.0");

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

    const ssh_port = 22;
    tunnel.connect("ssh.example.com", ssh_port) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        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.
    const password = "mySshPassword";

    tunnel.authenticatePw("mySshLogin", password) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    const listen_port = 1080;
    tunnel.beginAccepting(listen_port) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("Tunnel running; each client is logged in {s}\n", .{try tunnel.getClientLogDir(alloc)});

    const wait_for_thread_exit = true;
    tunnel.closeTunnel(wait_for_thread_exit) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };
}