PgFailover

Handle potential failover events in PostgreSQL database connections by reconnecting if the database is in a recovery mode. This check occurs when a connection is checked out of the connection pool.

Installation

Add this line to your application's Gemfile:

gem 'pg_failover'

And then execute:

$ bundle

Or install it yourself as:

$ gem install pg_failover

Usage

This library can be configured via a code block or environment variables.

The configuration aspects are as follows:

• Enabled - Hooks a callback to the pg adapter.
• Max retries - How many times an attempt to reconnect should be made.
• Throttle interval - The period between checks on database connections.

In an initializer:

PgFailover.configure do |config|
  config.enabled = true
  config.max_retries = 3
  config.throttle_interval = 3.3
end

You can also configure the logging device to be used:

PgFailover.configure do |config|
  config.logger = Rails.logger
end

Using environment variables:

POSTGRES_FAILOVER_ENABLED=true
POSTGRES_FAILOVER_MAX_RETRIES=3
POSTGRES_FAILOVER_THROTTLE_INTERVAL=3.3

The above settings demonstrate enabling the failover checks and will only attempt to re-establish a database connection 3 times with a pause of 3.3 seconds between each attempt.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in pg_failover.gemspec, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/FundingCircle/pg_failover.

License

Copyright © 2019 Funding Circle.

Distributed under the BSD 3-Clause License.