Introduce adapter for Trilogy, a MySQL-compatible DB client

The [Trilogy database client][trilogy-client] and corresponding
[Active Record adapter][ar-adapter] were both open sourced by GitHub last year.

Shopify has recently taken the plunge and successfully adopted Trilogy in their Rails monolith.
With two major Rails applications running Trilogy successfully, we'd like to propose upstreaming the adapter
to Rails as a MySQL-compatible alternative to Mysql2Adapter.

[trilogy-client]: https://github.com/github/trilogy
[ar-adapter]: https://github.com/github/activerecord-trilogy-adapter

Co-authored-by: Aaron Patterson <tenderlove@github.com>
Co-authored-by: Adam Roben <adam@roben.org>
Co-authored-by: Ali Ibrahim <aibrahim2k2@gmail.com>
Co-authored-by: Aman Gupta <aman@tmm1.net>
Co-authored-by: Arthur Nogueira Neves <github@arthurnn.com>
Co-authored-by: Arthur Schreiber <arthurschreiber@github.com>
Co-authored-by: Ashe Connor <kivikakk@github.com>
Co-authored-by: Brandon Keepers <brandon@opensoul.org>
Co-authored-by: Brian Lopez <seniorlopez@gmail.com>
Co-authored-by: Brooke Kuhlmann <brooke@testdouble.com>
Co-authored-by: Bryana Knight <bryanaknight@github.com>
Co-authored-by: Carl Brasic <brasic@github.com>
Co-authored-by: Chris Bloom <chrisbloom7@github.com>
Co-authored-by: Cliff Pruitt <cliff.pruitt@cliffpruitt.com>
Co-authored-by: Daniel Colson <composerinteralia@github.com>
Co-authored-by: David Calavera <david.calavera@gmail.com>
Co-authored-by: David Celis <davidcelis@github.com>
Co-authored-by: David Ratajczak <david@mockra.com>
Co-authored-by: Dirkjan Bussink <d.bussink@gmail.com>
Co-authored-by: Eileen Uchitelle <eileencodes@gmail.com>
Co-authored-by: Enrique Gonzalez <enriikke@gmail.com>
Co-authored-by: Garrett Bjerkhoel <garrett@github.com>
Co-authored-by: Georgi Knox <georgicodes@github.com>
Co-authored-by: HParker <HParker@github.com>
Co-authored-by: Hailey Somerville <hailey@hailey.lol>
Co-authored-by: James Dennes <jdennes@gmail.com>
Co-authored-by: Jane Sternbach <janester@github.com>
Co-authored-by: Jess Bees <toomanybees@github.com>
Co-authored-by: Jesse Toth <jesse.toth@github.com>
Co-authored-by: Joel Hawksley <joelhawksley@github.com>
Co-authored-by: John Barnette <jbarnette@github.com>
Co-authored-by: John Crepezzi <john.crepezzi@gmail.com>
Co-authored-by: John Hawthorn <john@hawthorn.email>
Co-authored-by: John Nunemaker <nunemaker@gmail.com>
Co-authored-by: Jonathan Hoyt <hoyt@github.com>
Co-authored-by: Katrina Owen <kytrinyx@github.com>
Co-authored-by: Keeran Raj Hawoldar <keeran@gmail.com>
Co-authored-by: Kevin Solorio <soloriok@gmail.com>
Co-authored-by: Leo Correa <lcorr005@gmail.com>
Co-authored-by: Lizz Hale <lizzhale@github.com>
Co-authored-by: Lorin Thwaits <lorint@gmail.com>
Co-authored-by: Matt Jones <al2o3cr@gmail.com>
Co-authored-by: Matthew Draper <matthewd@github.com>
Co-authored-by: Max Veytsman <mveytsman@github.com>
Co-authored-by: Nathan Witmer <nathan@zerowidth.com>
Co-authored-by: Nick Holden <nick.r.holden@gmail.com>
Co-authored-by: Paarth Madan <paarth.madan@shopify.com>
Co-authored-by: Patrick Reynolds <patrick.reynolds@github.com>
Co-authored-by: Rob Sanheim <rsanheim@gmail.com>
Co-authored-by: Rocio Delgado <rocio@github.com>
Co-authored-by: Sam Lambert <sam.lambert@github.com>
Co-authored-by: Shay Frendt <shay@github.com>
Co-authored-by: Shlomi Noach <shlomi-noach@github.com>
Co-authored-by: Sophie Haskins <sophaskins@github.com>
Co-authored-by: Thomas Maurer <tma@github.com>
Co-authored-by: Tim Pease <tim.pease@gmail.com>
Co-authored-by: Yossef Mendelssohn <ymendel@pobox.com>
Co-authored-by: Zack Koppert <zkoppert@github.com>
Co-authored-by: Zhongying Qiao <cryptoque@users.noreply.github.com>

Gemfile

@@ -149,6 +149,7 @@ platforms :ruby, :windows do
   group :db do
     gem "pg", "~> 1.3"
     gem "mysql2", "~> 0.5"
+    gem "trilogy", "~> 2.4"
   end
 end
 

Gemfile.lock

@@ -507,6 +507,7 @@ GEM
     timeout (0.3.2)
     tomlrb (2.0.3)
     trailblazer-option (0.1.2)
+    trilogy (2.4.0)
     turbo-rails (1.3.2)
       actionpack (>= 6.0.0)
       activejob (>= 6.0.0)
@@ -617,6 +618,7 @@ DEPENDENCIES
   sucker_punch
   tailwindcss-rails
   terser (>= 1.1.4)
+  trilogy (~> 2.4)
   turbo-rails
   tzinfo-data
   w3c_validators (~> 1.3.6)

activerecord/CHANGELOG.md

@@ -1,3 +1,23 @@
+*   Introduce adapter for Trilogy database client
+
+    Trilogy is a MySQL-compatible database client. Rails applications can use Trilogy
+    by configuring their `config/database.yml`:
+
+    ```yaml
+    development:
+    adapter: trilogy
+    database: blog_development
+    pool: 5
+    ```
+
+    Or by using the `DATABASE_URL` environment variable:
+
+    ```ruby
+    ENV['DATABASE_URL'] # => "trilogy://localhost/blog_development?pool=5"
+    ```
+
+    *Adrianna Chang*
+
 *   `after_commit` callbacks defined on models now execute in the correct order.
 
     ```ruby

activerecord/RUNNING_UNIT_TESTS.rdoc

@@ -21,6 +21,7 @@ example:
 Simply executing <tt>bundle exec rake test</tt> is equivalent to the following:
 
   $ bundle exec rake test:mysql2
+  $ bundle exec rake test:trilogy
   $ bundle exec rake test:postgresql
   $ bundle exec rake test:sqlite3
 

activerecord/Rakefile

@@ -18,24 +18,24 @@ def run_without_aborting(*tasks)
   abort "Errors running #{errors.join(', ')}" if errors.any?
 end
 
-desc "Run mysql2, sqlite, and postgresql tests by default"
+desc "Run mysql2, trilogy, sqlite, and postgresql tests by default"
 task default: :test
 
 task :package
 
-desc "Run mysql2, sqlite, and postgresql tests"
+desc "Run mysql2, trilogy, sqlite, and postgresql tests"
 task :test do
   tasks = defined?(JRUBY_VERSION) ?
     %w(test_jdbcmysql test_jdbcsqlite3 test_jdbcpostgresql) :
-    %w(test_mysql2 test_sqlite3 test_postgresql)
+    %w(test_mysql2 test_trilogy test_sqlite3 test_postgresql)
   run_without_aborting(*tasks)
 end
 
 namespace :test do
   task :isolated do
     tasks = defined?(JRUBY_VERSION) ?
       %w(isolated_test_jdbcmysql isolated_test_jdbcsqlite3 isolated_test_jdbcpostgresql) :
-      %w(isolated_test_mysql2 isolated_test_sqlite3 isolated_test_postgresql)
+      %w(isolated_test_mysql2 isolated_test_trilogy isolated_test_sqlite3 isolated_test_postgresql)
     run_without_aborting(*tasks)
   end
 
@@ -56,18 +56,19 @@ namespace :db do
   task drop: ["db:mysql:drop", "db:postgresql:drop"]
 end
 
-%w( mysql2 postgresql sqlite3 sqlite3_mem oracle jdbcmysql jdbcpostgresql jdbcsqlite3 jdbcderby jdbch2 jdbchsqldb ).each do |adapter|
+%w( mysql2 trilogy postgresql sqlite3 sqlite3_mem oracle jdbcmysql jdbcpostgresql jdbcsqlite3 jdbcderby jdbch2 jdbchsqldb ).each do |adapter|
   namespace :test do
     Rake::TestTask.new(adapter => "#{adapter}:env") do |t|
       adapter_short = adapter[/^[a-z0-9]+/]
       t.libs << "test"
       files = (FileList["test/cases/**/*_test.rb"].reject {
         |x| x.include?("/adapters/") || x.include?("/encryption/performance")
       } + FileList["test/cases/adapters/#{adapter_short}/**/*_test.rb"])
-      files = files + FileList["test/cases/adapters/abstract_mysql_adapter/**/*_test.rb"] if adapter == "mysql2"
+      files = files + FileList["test/cases/adapters/abstract_mysql_adapter/**/*_test.rb"] if ["mysql2", "trilogy"].include?(adapter)
 
       t.test_files = files
 
+      t.test_files = files
       t.warning = true
       t.verbose = true
       t.ruby_opts = ["--dev"] if defined?(JRUBY_VERSION)

activerecord/bin/test

@@ -15,7 +15,7 @@ module Minitest
     opts.separator ""
     opts.separator "Active Record options:"
     opts.on("-a", "--adapter [ADAPTER]",
-            "Run tests using a specific adapter (sqlite3, sqlite3_mem, mysql2, postgresql)") do |adapter|
+            "Run tests using a specific adapter (sqlite3, sqlite3_mem, mysql2, trilogy, postgresql)") do |adapter|
       ENV["ARCONN"] = adapter.strip
     end
 

activerecord/lib/active_record/connection_adapters/trilogy/errors.rb

@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module Trilogy
+      module Errors
+        # ServerShutdown will be raised when the database server was shutdown.
+        class ServerShutdown < ActiveRecord::ConnectionFailed
+        end
+
+        # ServerLost will be raised when the database connection was lost.
+        class ServerLost < ActiveRecord::ConnectionFailed
+        end
+
+        # ServerGone will be raised when the database connection is gone.
+        class ServerGone < ActiveRecord::ConnectionFailed
+        end
+
+        # BrokenPipe will be raised when a system process connection fails.
+        class BrokenPipe < ActiveRecord::ConnectionFailed
+        end
+
+        # SocketError will be raised when Ruby encounters a network error.
+        class SocketError < ActiveRecord::ConnectionFailed
+        end
+
+        # ConnectionResetByPeer will be raised when a network connection is closed
+        # outside the sytstem process.
+        class ConnectionResetByPeer < ActiveRecord::ConnectionFailed
+        end
+
+        # ClosedConnection will be raised when the Trilogy encounters a closed
+        # connection.
+        class ClosedConnection < ActiveRecord::ConnectionFailed
+        end
+
+        # InvalidSequenceId will be raised when Trilogy ecounters an invalid sequence
+        # id.
+        class InvalidSequenceId < ActiveRecord::ConnectionFailed
+        end
+
+        # UnexpectedPacket will be raised when Trilogy ecounters an unexpected
+        # response packet.
+        class UnexpectedPacket < ActiveRecord::ConnectionFailed
+        end
+      end
+    end
+  end
+end

activerecord/lib/active_record/connection_adapters/trilogy/lost_connection_exception_translator.rb

@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module Trilogy
+      class LostConnectionExceptionTranslator
+        attr_reader :exception, :message, :error_number
+
+        def initialize(exception, message, error_number)
+          @exception = exception
+          @message = message
+          @error_number = error_number
+        end
+
+        def translate
+          translate_database_exception || translate_ruby_exception || translate_trilogy_exception
+        end
+
+        private
+          ER_SERVER_SHUTDOWN = 1053
+          CR_SERVER_LOST = 2013
+          CR_SERVER_LOST_EXTENDED = 2055
+          CR_SERVER_GONE_ERROR = 2006
+
+          def translate_database_exception
+            case error_number
+            when ER_SERVER_SHUTDOWN
+              Errors::ServerShutdown.new(message)
+            when CR_SERVER_LOST, CR_SERVER_LOST_EXTENDED
+              Errors::ServerLost.new(message)
+            when CR_SERVER_GONE_ERROR
+              Errors::ServerGone.new(message)
+            end
+          end
+
+          def translate_ruby_exception
+            case exception
+            when Errno::EPIPE
+              Errors::BrokenPipe.new(message)
+            when SocketError, IOError
+              Errors::SocketError.new(message)
+            when ::Trilogy::ConnectionError
+              if message.include?("Connection reset by peer")
+                Errors::ConnectionResetByPeer.new(message)
+              end
+            end
+          end
+
+          def translate_trilogy_exception
+            return unless exception.is_a?(::Trilogy::Error)
+
+            case message
+            when /TRILOGY_CLOSED_CONNECTION/
+              Errors::ClosedConnection.new(message)
+            when /TRILOGY_INVALID_SEQUENCE_ID/
+              Errors::InvalidSequenceId.new(message)
+            when /TRILOGY_UNEXPECTED_PACKET/
+              Errors::UnexpectedPacket.new(message)
+            end
+          end
+      end
+    end
+  end
+end