# Server Boot Parity Design

> **For Claude:** REQUIRED SUB-SKILL: Use superpowers-extended-cc:executing-plans to implement this plan task-by-task.

**Goal:** Wire up `NatsServer.Start()` to call all subsystem startup methods in the same order as Go's `Server.Start()`, enabling a fully booting server that accepts client connections.

**Architecture:** The .NET port already has every subsystem startup method implemented (`AcceptLoop`, `StartMonitoring`, `EnableJetStream`, `StartRouting`, `StartGateways`, `StartLeafNodeAcceptLoop`, `StartWebsocketServer`, etc.). The only gap is that `Start()` (in `NatsServer.Init.cs:976–1037`) stops after system account setup instead of continuing through the full startup sequence. The fix is wiring — calling existing methods in the correct order — plus 3 trivial no-op stubs for missing minor methods and guarding the MQTT `NotImplementedException`.

**Tech Stack:** .NET 10, C# latest, xUnit, NATS.Client.Core (for validation test)

---

## Problem Statement

The .NET `Start()` method currently:
1. Logs version/name info
2. Sets `_running = 1`
3. Enables leafnode flag
4. Writes PID file
5. Sets up system account
6. Starts OCSP response cache
7. Signals `_startupComplete` and logs "Server is ready"

It is missing ~15 subsystem calls that Go's `Start()` makes between steps 5 and 7.

## Design

### 1. Complete `Start()` Body

Insert the following calls in `NatsServer.Init.cs` between the system account setup and the "Server is ready" log, matching Go `server.go:2263–2575`:

```
CheckAuthForWarnings()                         -- new no-op stub
StartRateLimitLogExpiration()                   -- exists in Lifecycle.cs
StartProfiler() if ProfPort != 0               -- exists (stub) in Listeners.cs
Log config file info                            -- opts.ConfigFile notice
Log trusted operators                           -- opts.TrustedOperators loop
StartMonitoring()                               -- exists in Listeners.cs
AccountResolver.Start() if resolver != null     -- exists
StartGWReplyMapExpiration()                     -- exists in Gateways.ReplyMap.cs
EnableJetStream(cfg) if opts.JetStream          -- exists in JetStreamCore.cs
  else: check accounts for JS limits            -- exists (EnableJetStreamAccounts pattern)
StartDelayedApiResponder()                      -- new no-op stub
StartOCSPMonitoring()                           -- exists in Ocsp.cs
InitOCSPResponseCache()                         -- exists (StartOCSPResponseCache)
StartGateways() if Gateway.Port != 0            -- exists in Gateways.ConfigAndStartup.cs
StartWebsocketServer() if Websocket.Port != 0   -- exists in WebSocket.cs
StartLeafNodeAcceptLoop() if LeafNode.Port != 0 -- exists in LeafNodes.ConfigAndConnect.cs
SolicitLeafNodeRemotes() if remotes.Count > 0   -- exists in LeafNodes.ConfigAndConnect.cs
StartMqtt() if MQTT.Port != 0                   -- guard NotImplementedException
StartRouting() if Cluster.Port != 0             -- exists in Routes.Connections.cs
LogPorts() if PortsFileDir != empty             -- new no-op stub
Signal _startupComplete                         -- move to here (from current position)
AcceptLoop() if !DontListen                     -- exists in Listeners.cs
StartOCSPResponseCache()                        -- exists (move to after AcceptLoop)
Noticef("Server is ready")                      -- move to end
```

### 2. New Method Stubs

**`CheckAuthForWarnings()`** — `NatsServer.Auth.cs`
- No-op. In Go this logs warnings about insecure auth configs. Can be implemented later.

**`StartDelayedApiResponder()`** — `NatsServer.JetStreamCore.cs`
- Starts a background task that will process delayed JetStream API responses.
- Initial implementation: no-op goroutine that exits when `_quitCts` cancels.

**`LogPorts()`** — `NatsServer.Init.cs`
- No-op. Writes ports info to file when `PortsFileDir` configured. Minor utility.

### 3. MQTT Guard

Change `MqttServerExtensions.StartMqtt()` from throwing `NotImplementedException` to logging a warning and returning. This prevents `Start()` from crashing when MQTT port is configured.

### 4. Validation Test

New test file: `dotnet/tests/ZB.MOM.NatsNet.Server.IntegrationTests/ServerBootTests.cs`

Test: `ServerBoot_AcceptsClientConnection_ShouldSucceed`
- Creates server with ephemeral port, JetStream enabled, temp store dir
- Calls `Start()`
- Connects with `NATS.Client.Core.NatsConnection`
- Publishes to `test.subject` and verifies subscribe receives message
- Calls `Shutdown()`

### 5. Files Changed

| File | Change |
|------|--------|
| `NatsServer.Init.cs` | Complete `Start()` body, add `LogPorts()` stub |
| `NatsServer.Auth.cs` | Add `CheckAuthForWarnings()` stub |
| `NatsServer.JetStreamCore.cs` | Add `StartDelayedApiResponder()` stub |
| `Mqtt/MqttHandler.cs` | Guard `StartMqtt()` to not throw |
| `ServerBootTests.cs` | New integration test |

### 6. Success Criteria

- `dotnet build` passes with 0 errors
- Existing unit tests still pass (2659 pass, 53 skip)
- Existing integration tests still pass (113 pass, 854 skip, 0 fail)
- New `ServerBoot_AcceptsClientConnection_ShouldSucceed` test passes
- Server logs show full startup sequence matching Go's output pattern