BenClaw
3e4bcc80c8
- Add Mozo::Counter::Redis with same get/set/incr/decr interface - Add redis gem (~> 5.0) to Gemfile - Update cable.yml to use Redis adapter in production (shared with counters) - Document DrbCounter → Redis migration in broadcasting-migration.md - Redis installed and running on vmi3300327 - Leave Faye as current broadcaster; both switches are one-line changes DrbCounter problems solved: - In-memory → persistent (RDB + AOF) - Single-process DRb → multi-process safe Redis - Atomic INCR/DECR across Puma workers - One less custom process to manage
150 lines
4.5 KiB
Markdown
150 lines
4.5 KiB
Markdown
# Broadcasting: Faye → ActionCable Migration Guide
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## Current state
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```
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Model (SimplyStored::Couch)
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→ ApplicationController.new.broadcast_user # ⚠️ anti-pattern
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→ Mozo.broadcast_user
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→ Mozo::Broadcaster::Faye.new.broadcast # HTTP POST to Faye
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→ Faye server (Thin, port 9296)
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→ WebSocket → browser clients
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```
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## Target state
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```
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Model (Broadcastable concern)
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→ Mozo.broadcast_user
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→ Mozo::Broadcaster::ActionCable.new.broadcast # in-process async
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→ ActionCable (Rails built-in)
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→ WebSocket → browser clients
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```
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## What this branch adds
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| File | Purpose |
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|------|---------|
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| `lib/mozo/broadcaster/action_cable.rb` | Drop-in ActionCable broadcaster adapter |
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| `config/cable.yml` | ActionCable configuration (async for single-server) |
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| `app/channels/application_cable/connection.rb` | WebSocket auth via auth_token |
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| `app/channels/mozo_channel.rb` | Channel authorization for user/supplier/employee |
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| `app/models/concerns/broadcastable.rb` | Clean module for models (replaces old monkey-patch) |
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| `config/routes.rb` | Mounts `/cable` WebSocket endpoint |
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| `config/initializers/model_broadcast.rb` | Fixed: delegates to Mozo directly (no more `ApplicationController.new`) |
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## How to switch
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### 1. Server (one-line change)
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In `config/initializers/mozo_settings.rb`, change:
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```ruby
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# Mozo.broadcaster = Mozo::Broadcaster::Faye.new # old
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Mozo.broadcaster = Mozo::Broadcaster::ActionCable.new # new
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```
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### 2. Client (mozo-user / mozo-supplier)
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**Old Faye client (conceptual):**
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```js
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var client = new Faye.Client('https://events.mozo.bar/faye');
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client.subscribe('/user/123', function(msg) { ... });
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```
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**New ActionCable client:**
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```js
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// Using @rails/actioncable npm package
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import { createConsumer } from "@rails/actioncable";
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const consumer = createConsumer(
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`wss://mozo.bar/cable?auth_token=${authToken}`
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);
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consumer.subscriptions.create(
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{ channel: "MozoChannel", id: "user_123" },
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{
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received(data) {
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// data = { event: "list_closed", data: { id: 42 } }
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handleEvent(data.event, data.data);
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}
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}
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);
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```
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### 3. Remove Faye
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Once stable:
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- Remove `gem 'faye'` from Gemfile
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- Remove `faye/` directory
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- Remove nginx `events.mozo.bar` vhost
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- Stop the Faye Thin process
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## Benefits
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- **No extra process** — ActionCable runs inside Puma
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- **Async** — `broadcast` is non-blocking
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- **Simpler deploys** — one less service to manage
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- **WebSocket native** — no long-polling fallback complexity
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- **Rails auth** — cookies/sessions work automatically
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---
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# Counter: DrbCounter → Redis Migration
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## Current state
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```
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Supplier::Counters (app/models/supplier/counters.rb)
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→ Mozo::Counter.incr/decr/get/set
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→ Mozo::Counter.connection (Mozo::DrbCounter.object)
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→ DRb → druby://localhost:9022
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→ InMemoryQCounter (separate Ruby process)
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→ on startup: reloads counts from CouchDB
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→ in-memory only (lost on restart)
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```
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## Problems
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1. **In-memory only** — restart the DRb process = lose all counts until CouchDB reload
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2. **Single-process** — DRb runs one Ruby process, single point of failure
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3. **Separate process** — another thing to monitor, deploy, and restart
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4. **Race conditions** — between Puma workers, increment/decrement is not atomic across the DRb boundary
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5. **Custom code** — `InMemoryQCounter` is 100 lines of hand-rolled counter logic
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## Target state
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```
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Supplier::Counters
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→ Mozo::Counter.incr/decr/get/set
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→ Mozo::Counter.connection (Mozo::Counter::Redis.new)
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→ Redis (localhost:6379)
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→ persistent, atomic, multi-process safe
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```
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## How to switch
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In `config/initializers/mozo_settings.rb`, change:
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```ruby
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# Mozo::Counter.connection = Mozo::DrbCounter.object # old
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Mozo::Counter.connection = Mozo::Counter::Redis.new # new
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```
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That's it. All existing `Mozo::Counter.get/set/incr/decr` calls work unchanged.
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## What Redis provides
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- **Atomic INCR/DECR** — no race conditions
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- **Persistence** — RDB snapshots + AOF, survives restarts
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- **Multi-process** — all Puma workers share the same Redis
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- **Already needed** — ActionCable uses Redis for pub/sub in production
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- **Battle-tested** — millions of deployments
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## Migration steps
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1. `apt-get install redis-server` — already done on vmi3300327
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2. `gem 'redis', '~> 5.0'` — added to Gemfile
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3. Switch `Mozo::Counter.connection` — one-line change in mozo_settings.rb
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4. Stop the DRb counter process (`drb_counter/drb_counter.rb`)
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