Multi-Endpoint Failover

Configure a client with multiple server endpoints for automatic failover (and quick switch‑over) if one goes down. In v11.1+, endpoints can also be updated at runtime.

Scenario

You have two server instances; the client maintains a single active connection and will fail over when needed.

Code Example

using System;
using System.Collections.Generic;
using SocketMeister;

// Define endpoints
var endpoints = new List<SocketEndPoint>
{
    new SocketEndPoint("server1.example.com", 5000),
    new SocketEndPoint("server2.example.com", 5000)
};

var client = new SocketClient(endpoints, EnableCompression: false, friendlyName: "MultiEPClient");

client.ConnectionStatusChanged += (s, e) =>
{
    Console.WriteLine($"Status: {e.OldStatus} -> {e.NewStatus} (Reason: {e.Reason})");
};

client.CurrentEndPointChanged += (s, e) =>
{
    Console.WriteLine($"Endpoint changed: {e.OldEndPoint?.Description} -> {e.NewEndPoint.Description}");
};

client.Start();

// Send messages as usual (to the current active endpoint)
for (int i = 0; i < 10; i++)
{
    var response = client.SendMessage(new object[] { $"Message {i}" }, TimeoutMilliseconds: 5000);
    Console.WriteLine($"Reply length: {response?.Length ?? 0}");
}

client.Stop();

Notes:

  • SocketClient uses the best available endpoint as CurrentEndPoint and automatically reconnects/fails over when needed.
  • Messages are sent over the currently connected endpoint (no per-message round-robin).

Runtime endpoint updates

You can inspect the configured endpoints and update them at runtime without recreating the client:

// Snapshot (array copy)
var current = client.EndPoints; // SocketEndPoint[]

// Replace entire set
client.SetEndPoints(new[]
{
    new SocketEndPoint("server-a.example.com", 5000),
    new SocketEndPoint("server-b.example.com", 5000)
});

// Add or remove specific endpoints
client.AddEndPoint("server-c.example.com", 5001);
client.RemoveEndPoint("server-a.example.com", 5000);

Behavior:

  • The background worker immediately re-evaluates the new set (backoff is cleared for newly provided endpoints).
  • If the currently connected endpoint is removed, the client disconnects and reconnects to an eligible endpoint.
  • The EndPoints property returns a snapshot (modifying it does not change the client’s configuration).

Tip: Subscribe to both ConnectionStatusChanged and CurrentEndPointChanged to log transitions and help with operational visibility.

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