first commit

.gitignore

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+/.bundle/
+/.yardoc
+/_yardoc/
+/coverage/
+/doc/
+/pkg/
+/spec/reports/
+/tmp/
+
+# rspec failure tracking
+.rspec_status

.rspec

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+--format documentation
+--color
+--require spec_helper

.travis.yml

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+---
+language: ruby
+cache: bundler
+rvm:
+  - 2.7.1
+before_install: gem install bundler -v 2.1.4

CHANGELOG.md

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+# Change Log
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/)
+and this project adheres to [Semantic Versioning](http://semver.org/).
+
+## [Unreleased] - yyyy-mm-dd
+
+Here we write upgrading notes for brands. It's a team effort to make them as
+straightforward as possible.
+
+### Added
+- [PROJECTNAME-XXXX](http://tickets.projectname.com/browse/PROJECTNAME-XXXX)
+  MINOR Ticket title goes here.
+- [PROJECTNAME-YYYY](http://tickets.projectname.com/browse/PROJECTNAME-YYYY)
+  PATCH Ticket title goes here.
+
+### Changed
+
+### Fixed
+
+### Security
+
+## [1.0.0] - 2020-05-05
+
+First release!
+

CODE_OF_CONDUCT.md

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+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, gender identity and expression, level of experience,
+nationality, personal appearance, race, religion, or sexual identity and
+orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+  address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at [email protected]. All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at [https://contributor-covenant.org/version/1/4][version]
+
+[homepage]: https://contributor-covenant.org
+[version]: https://contributor-covenant.org/version/1/4/

Gemfile

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+source "https://rubygems.org"
+
+# Specify your gem's dependencies in pgpool_no_load_balance.gemspec
+gemspec
+
+gem "rake", "~> 12.0"
+gem "rspec", "~> 3.0"

LICENSE.txt

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+The MIT License (MIT)
+
+Copyright (c) 2020 cn-kuroda
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

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+# PgpoolNoLoadBalance
+
+This gem exists for you to use [Pgpool-II's load balancing](https://www.pgpool.net/docs/latest/en/html/runtime-config-load-balancing.html) feature.
+
+If you don't want a query that qualifies for the load balancing to be load balanced by Pgpool-II, you can put arbitrary comment(`/*NO LOAD BALANCE*/` is usually used) before the SELECT statement. This will disable the load balance of the particular query and Pgpool-II will send it to the master node (the primary node in Master Slave mode).
+
+## Installation
+
+Add this line to your application's Gemfile:
+
+```ruby
+gem 'pgpool_no_load_balance'
+```
+
+And then execute:
+
+    $ bundle install
+
+Or install it yourself as:
+
+    $ gem install pgpool_no_load_balance
+
+## Usage
+
+### pgpool_nlb method
+
+Using the `pgpool_nlb` method will add a comment to the SQL.
+```irb
+irb(main):001:0> User.pgpool_nlb.all
+  /*NO LOAD BALANCE*/ SELECT "users".* FROM "users" LIMIT $1  [["LIMIT", 11]]
+```
+
+### unscope
+
+Can remove the scope with the unscope method.
+```irb
+irb(main):001:0> user_relation = User.where(name: 'elengine').pgpool_nlb
+irb(main):002:0> user_relation.count
+  /*NO LOAD BALANCE*/ SELECT COUNT(*) FROM "users" WHERE "users"."name" = $1  [["name", "elengine"]]
+irb(main):003:0> user_relation.unscope(:pgpool_nlb).order(:id).limit(3)
+  SELECT "users".* FROM "users" WHERE "users"."name" = $1 ORDER BY "users"."id" ASC LIMIT $2  [["name", "elengine"], ["LIMIT", 3]]
+```
+
+## Contributing
+
+Bug reports and pull requests are welcome on GitHub at https://github.com/elengine/pgpool_no_load_balance. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [code of conduct](https://github.com/elengine/pgpool_no_load_balance/blob/master/CODE_OF_CONDUCT.md).
+
+
+## License
+
+The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).
+
+## Code of Conduct
+
+Everyone interacting in the PgpoolNoLoadBalance project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://github.com/elengine/pgpool_no_load_balance/blob/master/CODE_OF_CONDUCT.md).

Rakefile

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+require "bundler/gem_tasks"
+require "rspec/core/rake_task"
+
+RSpec::Core::RakeTask.new(:spec)
+
+task :default => :spec

bin/console

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+#!/usr/bin/env ruby
+
+require "bundler/setup"
+require "pgpool_no_load_balance"
+
+# You can add fixtures and/or initialization code here to make experimenting
+# with your gem easier. You can also use a different console, if you like.
+
+# (If you use this, don't forget to add pry to your Gemfile!)
+# require "pry"
+# Pry.start
+
+require "irb"
+IRB.start(__FILE__)

bin/setup

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+#!/usr/bin/env bash
+set -euo pipefail
+IFS=$'\n\t'
+set -vx
+
+bundle install
+
+# Do any other automated setup that you need to do here

lib/pgpool_no_load_balance.rb

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+require "pgpool_no_load_balance/active_record/querying"
+require "pgpool_no_load_balance/active_record/relation"
+require "pgpool_no_load_balance/arel/select_manager"
+require "pgpool_no_load_balance/active_record/connection_adapters/postgresql_adapter"
+require "pgpool_no_load_balance/active_record/explain_subscriber"
+require "pgpool_no_load_balance/railtie" if defined?(::Rails::Railtie)
+require "pgpool_no_load_balance/version"
+
+module PgpoolNoLoadBalance
+  NLB_COMMENT = '/*NO LOAD BALANCE*/'
+
+  def self.setup!
+    ::ActiveRecord::Base.extend PgpoolNoLoadBalance::ActiveRecord::Querying
+    ::ActiveRecord::Relation.prepend PgpoolNoLoadBalance::ActiveRecord::Relation
+    ::ActiveRecord::Relation::VALID_UNSCOPING_VALUES << :pgpool_nlb
+    ::Arel::SelectManager.include PgpoolNoLoadBalance::Arel::SelectManager
+    ::ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.prepend PgpoolNoLoadBalance::ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
+    ::ActiveRecord::ExplainSubscriber.prepend PgpoolNoLoadBalance::ActiveRecord::ExplainSubscriber
+  end
+end

lib/pgpool_no_load_balance/active_record/connection_adapters/postgresql_adapter.rb

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+module PgpoolNoLoadBalance
+  module ActiveRecord
+    module ConnectionAdapters
+      module PostgreSQLAdapter
+
+        private
+
+        def to_sql_and_binds(arel_or_sql_string, binds=[])
+          sql, binds = super
+          if arel_or_sql_string.respond_to?(:pgpool_nlb?) && arel_or_sql_string.pgpool_nlb?
+            sql = "#{NLB_COMMENT} #{sql}"
+          end
+          [sql.freeze, binds]
+        end
+      end
+    end
+  end
+end

lib/pgpool_no_load_balance/active_record/explain_subscriber.rb

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+module PgpoolNoLoadBalance
+  module ActiveRecord
+    module ExplainSubscriber
+      def ignore_payload?(payload)
+        payload_for_check = payload.dup
+        payload_for_check[:sql] = payload_for_check[:sql].sub(NLB_COMMENT, '')
+        super payload_for_check
+      end
+    end
+  end
+end

lib/pgpool_no_load_balance/active_record/querying.rb

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+require "active_support"
+
+module PgpoolNoLoadBalance
+  module ActiveRecord
+    module Querying
+      delegate :pgpool_nlb, to: :all
+    end
+  end
+end

lib/pgpool_no_load_balance/active_record/relation.rb

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+module PgpoolNoLoadBalance
+  module ActiveRecord
+    module Relation
+      def pgpool_nlb(value = true)
+        spawn.pgpool_nlb!(value)
+      end
+
+      def pgpool_nlb!(value = true)
+        self.pgpool_nlb_value = value
+        self
+      end
+
+      def pgpool_nlb_value
+        @values.fetch(:pgpool_nlb, nil)
+      end
+
+      def pgpool_nlb_value=(value)
+        assert_mutability!
+        @values[:pgpool_nlb] = value
+      end
+
+      private
+
+      def build_arel(aliases)
+        arel = super
+        arel.pgpool_nlb(pgpool_nlb_value)
+        arel
+      end
+    end
+  end
+end

lib/pgpool_no_load_balance/arel/select_manager.rb

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+module PgpoolNoLoadBalance
+  module Arel
+    module SelectManager
+      def pgpool_nlb(value = true)
+        @pgpool_nlb_flag = !!value
+        self
+      end
+
+      def pgpool_nlb?
+        @pgpool_nlb_flag
+      end
+    end
+  end
+end

lib/pgpool_no_load_balance/railtie.rb

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+module PgpoolNoLoadBalance
+  class Railtie < ::Rails::Railtie
+
+    initializer 'pgpool_nlb.initialize', after: 'active_record.initialize_database' do |app|
+      ActiveSupport.on_load(:active_record) { PgpoolNoLoadBalance.setup! }
+    end
+
+  end
+end

lib/pgpool_no_load_balance/version.rb

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+module PgpoolNoLoadBalance
+  VERSION = "1.0.0"
+end

pgpool_no_load_balance.gemspec

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+require_relative 'lib/pgpool_no_load_balance/version'
+
+Gem::Specification.new do |spec|
+  spec.name          = "pgpool_no_load_balance"
+  spec.version       = PgpoolNoLoadBalance::VERSION
+  spec.authors       = ["elengine"]
+  spec.email         = ["[email protected]"]
+
+  spec.summary       = "Disable load balancing by Pgpool-II for Rails apps."
+  spec.homepage      = "https://github.com/elengine/pgpool_no_load_balance"
+  spec.license       = "MIT"
+  spec.required_ruby_version = Gem::Requirement.new(">= 2.2.2")
+
+  spec.metadata["allowed_push_host"] = "TODO: Set to 'http://mygemserver.com'"
+
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = spec.homepage
+  spec.metadata["changelog_uri"] = "#{spec.homepage}/CHANGELOG.md"
+
+  # Specify which files should be added to the gem when it is released.
+  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
+    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
+  end
+  spec.bindir        = "exe"
+  spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+
+  spec.add_dependency "activerecord", ">= 5.2.0"
+end