Reconnect your mysql2 connection if Mysql2::Error: The MySQL server is running with the --read-only option so it cannot execute this statement occurs because of failover.
When mysql2 cluster failovers, the mysql2 master is depromoted to slave and will be READONLY. Such case we have to reconnect mysql2 connection so that new connection goes to new master which is writable.
Add this line to your application's Gemfile:
gem 'mysql2-reconnect_with_readonly'And then execute:
$ bundle
Or install it yourself as:
$ gem install mysql2-reconnect_with_readonly
require 'mysql2/reconnect_with_readonly'This gem tries to reconnect reconnect_attempts times.
It will wait initial_retry_wait * number of retries seconds on each retry.
The waiting interval can be suppressed up to max_retry_wait seconds.
Mysql2::ReconnectWithReadonly.reconnect_attempts = 10 # default: 3 (times)
Mysql2::ReconnectWithReadonly.initial_retry_wait = 1.0 # default: 0.5 (sec)
Mysql2::ReconnectWithReadonly.max_retry_wait = 5.0 # default: nil which means no max (sec)
Mysql2::ReconnectWithReadonly.logger = Logger.new(STDOUT) # default: nil
This gem monkey patches Mysql2::Client.
To create a read-only mysql server:
$ mysql -uroot
root> GRANT CREATE, ALTER, DELETE, INSERT, UPDATE, SELECT ON *.* TO 'test'@'localhost' identified by 'test'
root> SET GLOBAL read_only = ON;
Connect with test user (root has write privilege even in read_only mode):
$ bin/console
> mysql2 = Mysql2::Client.new(username: 'test', password: 'test')
> mysql2.query(%Q[create database 'test'])
Bug reports and pull requests are welcome on GitHub at https://github.com/sonots/mysql2-reconnect_with_readonly. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
The gem is available as open source under the terms of the MIT License.