Module: Push::Daemon::DatabaseReconnectable

Included in:
Push::Daemon, App, Feedback::FeedbackFeeder, Feeder, Feedback, Message
Defined in:
lib/push/daemon/database_reconnectable.rb

Instance Method Summary collapse

Instance Method Details

#adaptor_errors ⇒ Object 



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# File 'lib/push/daemon/database_reconnectable.rb', line 4

def adaptor_errors
  errors = [ActiveRecord::StatementInvalid, ActiveRecord::ConnectionNotEstablished]
  if defined?(::PG::Error)
    errors << ::PG::Error
  elsif defined?(::PGError)
    errors << ::PGError
  end
  errors << ::Mysql2::Error if defined?(::Mysql2)
  errors
end

#check_database_is_connected ⇒ Object 



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# File 'lib/push/daemon/database_reconnectable.rb', line 52

def check_database_is_connected
  # Simply asking the adapter for the connection state is not sufficient.
  Push::Message.count
end

#database_connection_lost(name) ⇒ Object 



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# File 'lib/push/daemon/database_reconnectable.rb', line 25

def database_connection_lost(name)
  Push::Daemon.logger.warn("[#{name}] Lost connection to database, reconnecting...")
  attempts = 0
  loop do
    begin
      Push::Daemon.logger.warn("[#{name}] Attempt #{attempts += 1}")
      reconnect_database
      check_database_is_connected
      break
    rescue *adaptor_errors => e
      Push::Daemon.logger.error(e, :error_notification => false)
      sleep_to_avoid_thrashing
    end
  end
  Push::Daemon.logger.warn("[#{name}] Database reconnected")
end

#reconnect_database ⇒ Object 



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# File 'lib/push/daemon/database_reconnectable.rb', line 42

def reconnect_database
  begin
    ActiveRecord::Base.clear_all_connections!
  rescue
    Push::Daemon.logger.error("ActiveRecord::Base.clear_all_connections! failed")
  ensure
    ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations[ENV['RAILS_ENV']])
  end
end

#sleep_to_avoid_thrashing ⇒ Object 



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# File 'lib/push/daemon/database_reconnectable.rb', line 57

def sleep_to_avoid_thrashing
  sleep 2
end

#with_database_reconnect_and_retry(name) ⇒ Object 



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# File 'lib/push/daemon/database_reconnectable.rb', line 15

def with_database_reconnect_and_retry(name)
  begin
    yield
  rescue *adaptor_errors => e
    Push::Daemon.logger.error(e)
    database_connection_lost(name)
    retry
  end
end