How can I check the connection of Mongoid - mongodb

Question

Does Mongoid has any method like ActiveRecord::Base.connected??
I want to check if the connection that's accessible.

Answer 1

We wanted to implement a health check for our running Mongoid client that tells us whether the established connection is still alive. This is what we came up with:
Mongoid.default_client.database_names.present?
Basically it takes your current client and tries to query the databases on its connected server. If this server is down, you will run into a timeout, which you can catch.

Answer 2

My solution:
def check_mongoid_connection
mongoid_config = File.read("#{Rails.root}/config/mongoid.yml")
config = YAML.load(mongoid_config)[Rails.env].symbolize_keys
host, db_name, user_name, password = config[:host], config[:database], config[:username], config[:password]
port = config[:port] || Mongo::Connection::DEFAULT_PORT
db_connection = Mongo::Connection.new(host, port).db(db_name)
db_connection.authenticate(user_name, password) unless (user_name.nil? || password.nil?)
db_connection.collection_names
return { status: :ok }
rescue Exception => e
return { status: :error, data: { message: e.to_s } }
end

Answer 3

snrlx's answer is great.
I use following in my puma config file, FYI:
before_fork do
begin
# load configuration
Mongoid.load!(File.expand_path('../../mongoid.yml', __dir__), :development)
fail('Default client db check failed, is db connective?') unless Mongoid.default_client.database_names.present?
rescue => exception
# raise runtime error
fail("connect to database failed: #{exception.message}")
end
end
One thing to remind is the default server_selection_timeout is 30 seconds, which is too long for db status check at least in development, you can modify this in your mongoid.yml.