managing-apps/REDIS_SIGNALR_DEPLOYMENT.md

Redis + SignalR Multi-Instance Deployment Guide

Summary

The Managing API now supports multiple instances with SignalR (for LlmHub, BotHub, BacktestHub) using a Redis backplane.

This solves the "No Connection with that ID" error that occurs when:

• /llmhub/negotiate hits instance A
• WebSocket connection hits instance B (which doesn't know about the connection ID)

What Was Added

1. Infrastructure Layer - Generic Redis Service

Files Created:

• src/Managing.Application.Abstractions/Services/IRedisConnectionService.cs - Interface
• src/Managing.Infrastructure.Storage/RedisConnectionService.cs - Implementation
• src/Managing.Infrastructure.Storage/README-REDIS.md - Documentation

Purpose: Generic Redis connectivity that can be used for SignalR, caching, or any Redis needs.

2. SignalR Redis Backplane

Files Modified:

• src/Managing.Api/Program.cs - Auto-configures SignalR with Redis when available
• src/Managing.Bootstrap/ApiBootstrap.cs - Registers Redis service

How It Works:

• Checks if Redis is configured
• If yes: Adds Redis backplane to SignalR
• If no: Runs in single-instance mode (graceful degradation)

3. Configuration

Files Modified:

• src/Managing.Api/appsettings.json - Default config (empty, for local dev)
• src/Managing.Api/appsettings.Sandbox.json - srv-captain--redis:6379
• src/Managing.Api/appsettings.Production.json - srv-captain--redis:6379

4. NuGet Packages Added

• Microsoft.AspNetCore.SignalR.StackExchangeRedis (8.0.10) - SignalR backplane
• Microsoft.Extensions.Caching.StackExchangeRedis (8.0.10) - Redis caching
• StackExchange.Redis (2.8.16) - Redis client

Deployment Steps for CapRover

Step 1: Create Redis Service

1. In CapRover, go to Apps
2. Click One-Click Apps/Databases
3. Search for "Redis"
4. Deploy Redis (or use existing one)
5. Note the service name: srv-captain--redis (or your custom name)

Step 2: Configure CapRover App

For dev-managing-api (Sandbox):

1. Enable WebSocket Support

   • Go to HTTP Settings
   • Toggle "WebSocket Support" to ON
   • Save

2. Enable Sticky Sessions

   • In HTTP Settings
   • Toggle "Enable Sticky Sessions" to ON
   • Save

3. Verify Redis Connection String

   • The connection string is already in appsettings.Sandbox.json
   • Default: srv-captain--redis:6379
   • If you used a different Redis service name, update via environment variable:

     ConnectionStrings__Redis=srv-captain--your-redis-name:6379
     

   • Or use the fallback:

     REDIS_URL=srv-captain--your-redis-name:6379
     

Step 3: Deploy

1. Build and deploy the API:

   cd src/Managing.Api
   # Your normal deployment process
   

2. Watch the logs during startup. You should see:

   ✅ Configuring SignalR with Redis backplane: srv-captain--redis:6379
   ✅ Redis connection established successfully
   

Step 4: Scale to Multiple Instances

1. In CapRover, go to your dev-managing-api app
2. App Configs tab
3. Set "Number of app instances" to 2 or 3
4. Click Save & Update

Step 5: Test

1. Open the frontend (Kaigen Web UI)
2. Open the AI Chat
3. Send a message
4. Should work without "No Connection with that ID" errors

Verification Checklist

After deployment, verify:

• Redis service is running in CapRover
• WebSocket support is enabled
• Sticky sessions are enabled
• API logs show Redis connection success
• Multiple instances are running
• AI Chat works without connection errors
• Browser Network tab shows WebSocket upgrade successful

Troubleshooting

Issue: "No Connection with that ID" Still Appears

Check:

1. Redis service is running: redis-cli -h srv-captain--redis ping
2. API logs show Redis connected (not "Redis not configured")
3. Sticky sessions are ON
4. WebSocket support is ON

Quick Test:

• Temporarily set instances to 1
• If it works with 1 instance, the issue is multi-instance setup
• If it fails with 1 instance, check WebSocket/proxy configuration

Issue: Redis Connection Failed

Check Logs For:

⚠️  Failed to configure SignalR Redis backplane: <error>
SignalR will work in single-instance mode only

Solutions:

1. Verify Redis service name matches configuration
2. Ensure Redis is not password-protected (or add password to config)
3. Check Redis service health in CapRover

Issue: WebSocket Upgrade Failed

Not related to Redis. Check:

1. CapRover WebSocket support is ON
2. Nginx configuration allows upgrades
3. Browser console for detailed error

Configuration Reference

Connection String Formats

Simple (no password):

srv-captain--redis:6379

With Password:

srv-captain--redis:6379,password=your-password

Multiple Options:

srv-captain--redis:6379,password=pwd,ssl=true,abortConnect=false

Configuration Priority

The app checks these in order:

1. ConnectionStrings:Redis (appsettings.json or ConnectionStrings__Redis environment variable)
2. REDIS_URL (fallback environment variable)

Recommended: Use ConnectionStrings__Redis environment variable to override appsettings without rebuilding.

Architecture Benefits

Before (Single Instance)

Frontend → Nginx → API Instance
                    - In-memory SignalR
                    - Connection IDs stored locally
                    ❌ Scale limited to 1 instance

After (Multi-Instance with Redis)

Frontend → Nginx (sticky) → API Instance 1 ┐
                         → API Instance 2 ├─→ Redis ← SignalR Backplane
                         → API Instance 3 ┘
                         
- Connection IDs in Redis
- Messages distributed via pub/sub
- Any instance can handle any connection
✅ Scale to N instances

Next Steps

After successful deployment:

1. Monitor Performance

   • Watch Redis memory usage
   • Check API response times
   • Monitor WebSocket connection stability

2. Consider Redis Clustering

   • For high availability
   • If scaling beyond 3-4 API instances

3. Extend Redis Usage

   • Distributed caching
   • Rate limiting
   • Session storage

Rollback Plan

If issues occur:

1. Immediate: Set instances to 1
2. Environment Variable: Set REDIS_URL= (empty) to disable Redis
3. Code Rollback: Previous version still works (graceful degradation)

The implementation is backward-compatible and doesn't require Redis to function.

Support

For issues:

1. Check logs: src/Managing.Infrastructure.Storage/README-REDIS.md
2. Review this guide
3. Check CapRover app logs for Redis/SignalR messages
4. Test with 1 instance first, then scale up