csharpfritz/discord-minecraft/discord-net-worker-service

Context

When building a Discord bot as part of a larger .NET service architecture (Aspire, microservices), the bot needs to integrate with the generic host lifecycle rather than running standalone.

Patterns

• Register DiscordSocketConfig and DiscordSocketClient as singletons in DI
• Create a BackgroundService that receives the client via constructor injection
• In ExecuteAsync: wire events → LoginAsync → StartAsync → Task.Delay(Infinite, token) → StopAsync
• Bridge Discord.NET's LogSeverity to Microsoft.Extensions.Logging.LogLevel via the client.Log event
• Register slash commands in the client.Ready event (gateway is fully connected at that point)
• Handle slash commands via client.SlashCommandExecuted event
• Bot token from IConfiguration["Discord:BotToken"] — works with user secrets and env vars
• Wire channel events via client.ChannelCreated, client.ChannelDestroyed, client.ChannelUpdated — detect category vs text channel with is ICategoryChannel
• Inject IConnectionMultiplexer (from Aspire's AddRedisClient) to get ISubscriber for Redis pub/sub
• Use RedisChannel.Literal(channelName) for publish — avoid pattern-matching overhead
• Filter ChannelUpdated events to only publish when meaningful properties change (name, position) — Discord fires this event for many property changes

Examples

// Program.cs
builder.Services.AddSingleton(new DiscordSocketConfig
{
    GatewayIntents = GatewayIntents.Guilds,
    LogLevel = LogSeverity.Info
});
builder.Services.AddSingleton<DiscordSocketClient>();
builder.Services.AddHostedService<DiscordBotWorker>();

// Graceful shutdown in ExecuteAsync
try { await Task.Delay(Timeout.Infinite, stoppingToken); }
catch (OperationCanceledException) { }
await client.StopAsync();

Anti-Patterns

• Do NOT create DiscordSocketClient per-request or as transient — it manages a persistent WebSocket
• Do NOT register slash commands outside the Ready event — the client isn't connected yet
• Do NOT use while (!token.IsCancellationRequested) { await Task.Delay(...) } — Task.Delay(Infinite) is cleaner and avoids unnecessary wake-ups
• Do NOT use guild-specific commands for dev convenience without documenting the tradeoff (instant registration vs. global's 1-hour propagation)