Второе занятие

Gemfile

@@ -5,6 +5,7 @@ gem 'puma', '>= 6.5.0'
 
 # Базы данных
 gem 'pg'
+gem 'redis-actionpack' # hiredes
 
 # Многопоточное выполнение
 gem 'parallel'

Gemfile.lock

@@ -316,6 +316,19 @@ GEM
     rdoc (6.7.0)
       psych (>= 4.0.0)
     redcarpet (3.6.0)
+    redis (5.4.0)
+      redis-client (>= 0.22.0)
+    redis-actionpack (5.5.0)
+      actionpack (>= 5)
+      redis-rack (>= 2.1.0, < 4)
+      redis-store (>= 1.1.0, < 2)
+    redis-client (0.23.2)
+      connection_pool
+    redis-rack (3.0.0)
+      rack-session (>= 0.2.0)
+      redis-store (>= 1.2, < 2)
+    redis-store (1.11.0)
+      redis (>= 4, < 6)
     regexp_parser (2.9.2)
     reline (0.5.9)
       io-console (~> 0.5)
@@ -466,6 +479,7 @@ DEPENDENCIES
   pry-rails
   puma (>= 6.5.0)
   rails (>= 8.0.1)
+  redis-actionpack
   rspec-rails (>= 7.1)
   rubocop-performance
   rubocop-rails

app/admin/book.rb

@@ -19,19 +19,23 @@
          as: :select,
          label: I18n.t('active_admin.filters.genre'),
          collection: proc {
+          #ActiveRecord::Base.connected_to(role: :reading, prevent_writes: true) do
            # TODO query + декоратор
            Genre.order(:name)
                 .pluck(:name, :id)
                 .map { |g| [ truncate(g.first, length: 25), g.last ] }
+          #end
          }
   filter :keywords_id_eq,
          as: :select,
          label: I18n.t('active_admin.filters.keyword'),
          collection: proc {
+          #ActiveRecord::Base.connected_to(role: :reading, prevent_writes: true) do
            # TODO query + декоратор
            Keyword.order(:name)
                   .pluck(:name, :id)
                   .map { |k| [ truncate(k.first, length: 25), k.last ] }
+          #end
          }
 
   controller do

app/models/application_record.rb

@@ -1,4 +1,5 @@
 class ApplicationRecord < ActiveRecord::Base
   primary_abstract_class
   self.implicit_order_column = 'created_at'
+  # connects_to database: { writing: :primary, reading: :primary_replica }
 end

config/application.rb

@@ -32,6 +32,12 @@ class Application < Rails::Application
     # Common ones are `templates`, `generators`, or `middleware`, for example.
     config.autoload_lib(ignore: %w[assets tasks])
     # config.eager_load_paths << Rails.root.join('extras')
+    config.cache_store = :redis_cache_store, { url: ENV['REDIS_CACHE_URL'] }
+    config.session_store :redis_store,
+      servers: [ENV['REDIS_SESSION_URL']],
+      expire_after: 90.minutes,
+      key: '_library_session',
+      threadsafe: false
 
     config.generators do |g|
       g.org             :active_record

config/database.yml

@@ -17,9 +17,18 @@ development:
 
 test:
   <<: *default
+  <<: *postgre
   database: library_test
 
 production:
-  <<: *default
-  <<: *postgre
-  database: library_production
+  primary:
+    <<: *default
+    <<: *postgre
+    host: <%= ENV.fetch('POSTGRES_HOST_MASTER', 'localhost') %>
+    database: library_production
+  primary_replica:
+    <<: *default
+    <<: *postgre
+    host: <%= ENV.fetch('POSTGRES_HOST_SLAVE', 'localhost') %>
+    database: library_production
+    replica: true

config/environments/development.rb

@@ -26,7 +26,7 @@
   end
 
   # Change to :null_store to avoid any caching.
-  config.cache_store = :memory_store
+  # config.cache_store = :memory_store
 
   # Print deprecation notices to the Rails logger.
   config.active_support.deprecation = :log

config/environments/production.rb

@@ -35,7 +35,8 @@
   config.logger   = ActiveSupport::TaggedLogging.logger(STDOUT)
 
   # Change to "debug" to log everything (including potentially personally-identifiable information!)
-  config.log_level = ENV.fetch('RAILS_LOG_LEVEL') { 'info' }
+  config.log_level = ENV.fetch('RAILS_LOG_LEVEL') { 'debug' }
+  config.active_record.verbose_query_logs = true
 
   # Prevent health checks from clogging up the logs.
   config.silence_healthcheck_path = '/up'

db/master/init.sql

@@ -0,0 +1 @@
+CREATE USER repluser REPLICATION PASSWORD 'repluser';

db/master/pg_hba.conf

@@ -0,0 +1,15 @@
+# TYPE  DATABASE        USER            ADDRESS                 METHOD
+
+# "local" is for Unix domain socket connections only
+local   all             all                                     trust
+host    all             all             127.0.0.1/32            trust
+host    all             all             ::1/128                 trust
+# Allow replication connections from localhost, by a user with the
+# replication privilege.
+local   replication     all                                     trust
+host    replication     all             127.0.0.1/32            trust
+host    replication     all             ::1/128                 trust
+
+host    replication     all             172.18.0.0/16           md5
+
+host all all all scram-sha-256

db/slave/.pgpass

@@ -0,0 +1,2 @@
+*:*:*:postgres:postgres
+*:*:*:repluser:repluser

db/slave/init-slave.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+set -e
+
+rm -rf /var/lib/postgresql/data/*
+pg_basebackup --host=master --username=repluser --pgdata=/var/lib/postgresql/data --wal-method=stream --write-recovery-conf

docker-compose.yml

@@ -1,11 +1,39 @@
 services:
-  db:
+  # db:
+  #   image: postgres:17
+  #   environment:
+  #     POSTGRES_USER: 'postgres'
+  #     POSTGRES_PASSWORD: 'postgres'
+  #   volumes:
+  #     - db:/var/lib/postgresql/data
+  postgresql_master:
     image: postgres:17
-    environment:
-      POSTGRES_USER: 'postgres'
-      POSTGRES_PASSWORD: 'postgres'
+    container_name: master
+    restart: always
+    networks:
+      - db-repl
     volumes:
-      - db:/var/lib/postgresql/data
+      - ./db/data/master:/var/lib/postgresql/data
+      - ./db/master/pg_hba.conf:/var/lib/postgresql/pg_hba.conf
+      - ./db/master/init.sql:/docker-entrypoint-initdb.d/init.sql
+    env_file:
+      - ./.env.postgresql
+
+  postgresql_slave:
+    image: postgres:17
+    container_name: slave
+    restart: always
+    networks:
+      - db-repl
+    volumes:
+      - ./db/slave/.pgpass:/var/lib/postgresql/.pgpass
+      - ./db/slave/.pgpass:/root/.pgpass
+      - ./db/data/slave/:/var/lib/postgresql/data
+      - ./db/master/pg_hba.conf:/var/lib/postgresql/pg_hba.conf
+      - ./db/slave/init-slave.sh:/var/lib/postgresql/init-slave.sh
+    env_file:
+      - ./.env.postgresql
+
   web:
     tty: true
     stdin_open: true
@@ -22,16 +50,28 @@ services:
       - .:/rails
       - "$DOCKER_COMPOSE_ARCHIVE_FOLDER:/rails/db/data"
     networks:
-      - default
+      - db-repl
     ports:
       - "8080:3000"
     depends_on:
-      - db
+      - postgresql_master
     environment:
       RAILS_LOG_TO_STDOUT: 'yes'
       PAGER: 'more'
-      POSTGRES_HOST: 'db'
+      POSTGRES_HOST_MASTER: 'postgresql_master'
+      POSTGRES_HOST_SLAVE: 'postgresql_slave'
       POSTGRES_USER: 'postgres'
       POSTGRES_PASSWORD: 'postgres'
-volumes:
-  db:
+
+networks:
+  db-repl:
+    driver: bridge
+    name: db-repl
+    ipam:
+      driver: default
+      config:
+        - subnet: 172.18.0.0/16
+          gateway: 172.18.0.1
+
+# volumes:
+#   db: