activerecord-mysql-reconnect
It is the library to reconnect automatically when ActiveRecord is disconnected from MySQL.
Installation
Add this line to your application's Gemfile:
gem 'activerecord-mysql-reconnect'
And then execute:
$ bundle
Or install it yourself as:
$ gem install activerecord-mysql-reconnect
Usage
require 'active_record'
require 'activerecord-mysql-reconnect'
require 'logger'
ActiveRecord::Base.establish_connection(
adapter: 'mysql2',
host: '127.0.0.1',
username: 'root',
database: 'employees',
)
ActiveRecord::Base.logger = Logger.new($stdout)
ActiveRecord::Base.logger.formatter = proc {|_, _, _, message| "#{message}\n" }
ActiveRecord::Base.enable_retry = true
ActiveRecord::Base.execution_tries = 3
class Employee < ActiveRecord::Base; end
p Employee.count
system('sudo /etc/init.d/mysqld restart')
p Employee.countshell> ruby test.rb
(64.1ms) SELECT COUNT(*) FROM `employees`
300024
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]
(0.4ms) SELECT COUNT(*) FROM `employees`
Mysql2::Error: MySQL server has gone away: SELECT COUNT(*) FROM `employees`
MySQL server has gone away. Trying to reconnect in 0.5 seconds. (cause: Mysql2::Error: MySQL server has gone away: SELECT COUNT(*) FROM `employees` [ActiveRecord::StatementInvalid], connection: host=127.0.0.1;database=employees;username=root)
(101.5ms) SELECT COUNT(*) FROM `employees`
300024
without_retry
ActiveRecord::Base.without_retry do
Employee.count
endAdd a retry error message
Activerecord::Mysql::Reconnect.handle_rw_error_messages.update(
zapzapzap: 'ZapZapZap'
)
# or `Activerecord::Mysql::Reconnect.handle_r_error_messages...`Use on rails
Gemfile
gem 'activerecord-mysql-reconnect'environment file
MyApp::Application.configure do
...
config.active_record.enable_retry = true
#config.active_record.retry_databases = :employees
# e.g. [:employees]
# ['employees', 'localhost:test', '192.168.1.1:users']
# ['192.168.%:emp\_all']
# ['emp%']
# retry_databases -> nil: retry all databases (default)
config.active_record.execution_tries = 10 # times
# execution_tries -> 0: retry indefinitely
config.active_record.execution_retry_wait = 1.5 # sec
config.active_record.retry_mode = :rw # default: `:r`, valid values: `:r`, `:rw`, `:force`
...
eneRetry mode
-
:rRetry only SELECT / SHOW / SET -
:rwRetry in all SQL, but does not retry ifLost connectionhas happened in write SQL -
:forceRetry in all SQL
Run tests
It requires the following:
- Docker
- Docker Compose
bundle install
bundle exec appraisal install
bundle exec appraisal activerecord-4.2 rake
bundle exec appraisal activerecord-5.0 rake