How can I check the connection of Mongoid

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.

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

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}")  endend

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.