feat: use AnyCable

Gemfile

@@ -18,6 +18,9 @@ gem 'redis', '~> 4.0'
 # Use ActiveModel has_secure_password
 # gem 'bcrypt', '~> 3.1.7'
 
+# Efficient ActionCable replacement to use web-sockets
+gem 'anycable-rails', '~> 0.6'
+
 # Use ActiveStorage variant
 # gem 'mini_magick', '~> 4.8'
 
@@ -31,6 +34,10 @@ group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
   gem 'pry-rails'
+
+  # AnyCable Web Socket server
+  # Disabled. Gem is very unstable.
+  # gem "anycable-rack-server"
 end
 
 group :development do

Gemfile.lock

@@ -42,6 +42,13 @@ GEM
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
+    anycable (0.6.3)
+      anyway_config (~> 1.4.2)
+      grpc (~> 1.17)
+    anycable-rails (0.6.4)
+      anycable (~> 0.6.0)
+      rails (>= 5)
+    anyway_config (1.4.4)
     arel (9.0.0)
     bindex (0.8.1)
     bootsnap (1.4.4)
@@ -55,6 +62,12 @@ GEM
     ffi (1.11.1)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
+    google-protobuf (3.9.2)
+    googleapis-common-protos-types (1.0.4)
+      google-protobuf (~> 3.0)
+    grpc (1.24.0)
+      google-protobuf (~> 3.8)
+      googleapis-common-protos-types (~> 1.0)
     i18n (1.6.0)
       concurrent-ruby (~> 1.0)
     jbuilder (2.9.1)
@@ -153,6 +166,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  anycable-rails (~> 0.6)
   bootsnap (>= 1.1.0)
   byebug
   jbuilder (~> 2.5)

app/channels/application_cable/connection.rb

@@ -3,8 +3,14 @@ class Connection < ActionCable::Connection::Base
     identified_by :current_user
 
     def connect
-      self.current_user = request.session.fetch("username", nil)
+      self.current_user = session.fetch("username", nil)
       reject_unauthorized_connection unless current_user
     end
+
+    # By default we don't have access to the session object
+    # https://edgeguides.rubyonrails.org/action_cable_overview.html#notes
+    def session
+      cookies.encrypted[Rails.application.config.session_options[:key]]
+    end
   end
 end

app/views/layouts/application.html.erb

@@ -4,6 +4,7 @@
     <title>EvilChat</title>
     <%= csrf_meta_tags %>
     <%= csp_meta_tag %>
+    <%= action_cable_meta_tag %>
 
     <%= stylesheet_pack_tag 'application', media: 'all' %>
   </head>

config/application.rb

@@ -27,6 +27,8 @@ class Application < Rails::Application
     # -- all .rb files in that directory are automatically loaded after loading
     # the framework and any gems in your application.
 
+    config.action_cable.url = ENV.fetch("CABLE_URL") { "ws://localhost:3334/cable" }
+
     config.generators do |g|
       # Don't generate assets for Sprockets
       g.assets = nil

config/cable.yml

@@ -1,10 +1,13 @@
+default: &default
+  adapter: <%= ENV.fetch('CABLE_ADAPTER', 'any_cable') %>
+
 development:
-  adapter: async
+  <<: *default
 
 test:
-  adapter: async
+  <<: *default
+  channel_prefix: evil_chat_test
 
 production:
-  adapter: redis
-  url: <%= ENV.fetch("REDIS_URL") { "redis://localhost:6379/1" } %>
+  <<: *default
   channel_prefix: evil_chat_production

config/environments/development.rb

@@ -51,4 +51,7 @@
   # Use an evented file watcher to asynchronously detect changes in source code,
   # routes, locales, etc. This feature depends on the listen gem.
   config.file_watcher = ActiveSupport::EventedFileUpdateChecker
+
+  # Always run gRPC server from anycable-rack-server alongside the app's server
+  # config.any_cable_rack.run_rpc = true
 end

docker-compose.yml

@@ -50,6 +50,8 @@ services:
       - postgres
       - redis
       - webpacker
+      - anycable-ws
+      - anycable-rpc
 
   webpacker:
     <<: *app
@@ -64,6 +66,24 @@ services:
       RAILS_ENV: ${RAILS_ENV:-development}
       WEBPACKER_DEV_SERVER_HOST: 0.0.0.0
 
+  anycable-ws:
+    image: anycable/anycable-go:v0.6.4
+    ports:
+      - '3334:3334'
+    environment:
+      PORT: 3334
+      REDIS_URL: redis://redis:6379/0
+      ANYCABLE_RPC_HOST: anycable-rpc:50051
+    depends_on:
+      - anycable-rpc
+      - redis
+
+  anycable-rpc:
+    <<: *backend
+    command: bundle exec anycable
+    ports:
+      - '50051'
+
   postgres:
     image: postgres:12
     volumes: