Program.cs

using System;
using System.Threading.Tasks;
using DocoptNet;
using Seq.Api;
using Seq.Api.Model.Signals;
using System.Collections.Generic;

const string usage = @"signal-copy: copy Seq signals from one server to another.

Usage:
    signal-copy.exe <src> <dst> [--srckey=<sk>] [--dstkey=<dk>]
    signal-copy.exe (-h | --help)

Options:
    -h --help     Show this screen.
    --srckey=<sk> Source server API key.
    --dstkey=<dk> Destination server API key.
";

try
{
    var arguments = new Docopt().Apply(usage, args, version: "Seq Signal Copy 0.1", exit: true)!;

    var src = arguments["<src>"].ToString();
    var dst = arguments["<dst>"].ToString();
    var srcKey = Normalize(arguments["--srckey"]);
    var dstKey = Normalize(arguments["--dstkey"]);

    await Run(src, srcKey, dst, dstKey);
}
catch (Exception ex)
{
    Console.ForegroundColor = ConsoleColor.White;
    Console.BackgroundColor = ConsoleColor.Red;
    Console.WriteLine("signal-copy: {0}", ex);
    Console.ResetColor();
    Environment.Exit(-1);
}

static string? Normalize(ValueObject? v)
{
    if (v == null) return null;
    var s = v.ToString();
    return string.IsNullOrWhiteSpace(s) ? null : s;
}

static async Task Run(string src, string? srcKey, string dst, string? dstKey)
{
    var srcConnection = new SeqConnection(src, srcKey);
    var dstConnection = new SeqConnection(dst, dstKey);

    var dstSignals = new Dictionary<string, SignalEntity>();
    foreach (var dstSignal in await dstConnection.Signals.ListAsync())
    {
        if (dstSignals.ContainsKey(dstSignal.Title))
        {
            Console.WriteLine($"The destination server has more than one signal named '{dstSignal.Title}'; only one copy of the signal will be updated.");
            continue;
        }

        dstSignals.Add(dstSignal.Title, dstSignal);
    }

    var count = 0;

    foreach (var signal in await srcConnection.Signals.ListAsync())
    {
        if (dstSignals.TryGetValue(signal.Title, out var target))
        {
            if (target.IsProtected)
            {
                Console.WriteLine($"Skipping restricted signal '{signal.Title}' ({target.Id})");
                continue;
            }

            Console.WriteLine($"Updating existing signal '{signal.Title}' ({target.Id})");
        }
        else
        {
            Console.WriteLine($"Creating new signal '{signal.Title}'");
            target = await dstConnection.Signals.TemplateAsync();
        }

        target.Title = signal.Title;
        target.Filters = signal.Filters;
        target.Columns = signal.Columns;
        target.Description = signal.Description + " (copy)";

        await (target.Id != null ? dstConnection.Signals.UpdateAsync(target) : dstConnection.Signals.AddAsync(target));
        ++count;
    }

    Console.WriteLine($"Done, {count} signals updated.");
}