# Setup any specified hard limit on the virtual size of the process
if APP_CONFIG.include?('hard_memory_limit') and Process.const_defined?(:RLIMIT_AS)
  Process.setrlimit Process::RLIMIT_AS, APP_CONFIG['hard_memory_limit']*1024*1024, Process::RLIM_INFINITY
end

# If we're running under passenger and a soft memory limit is
# configured then setup some rack middleware to police the limit
if APP_CONFIG.include?('soft_memory_limit') and defined?(PhusionPassenger)
  # Define some rack middleware to police the soft memory limit
  module OSM
    class MemoryLimit
      def initialize(app)
        @app = app
      end

      def call(env)
        # Process this requst
        status, headers, body = @app.call(env)

        # Restart if we've hit our memory limit
        if resident_size > APP_CONFIG['soft_memory_limit']
          Process.kill("USR1", 0)
        end

        # Return the result of this request
        [status, headers, body]
      end
      private
      def resident_size
        # Read statm to get process sizes. Format is
        #   Size RSS Shared Text Lib Data
        fields = File.open("/proc/self/statm") do |file|
          fields = file.gets.split(" ")
        end

        # Return resident size in megabytes
        return fields[1].to_i / 256
      end
    end
  end

  # Install the memory limit checker
  Rails.configuration.middleware.use OSM::MemoryLimit
end