function RateLimitingHandler:access()

in kong/kong/plugins/rate-limiting/handler.lua [120:205]

• 69 lines of code
• 12 McCabe index (conditional complexity)

function RateLimitingHandler:access(conf)
  local current_timestamp = time() * 1000

  
  local identifier = get_identifier(conf)
  local fault_tolerant = conf.fault_tolerant

  
  local limits = {
    second = conf.second,
    minute = conf.minute,
    hour = conf.hour,
    day = conf.day,
    month = conf.month,
    year = conf.year,
  }

  local usage, stop, err = get_usage(conf, identifier, current_timestamp, limits)
  if err then
    if not fault_tolerant then
      return error(err)
    end

    kong.log.err("failed to get usage: ", tostring(err))
  end

  if usage then
    
    local reset
    local headers
    if not conf.hide_client_headers then
      headers = {}
      local timestamps
      local limit
      local window
      local remaining
      for k, v in pairs(usage) do
        local current_limit = v.limit
        local current_window = EXPIRATION[k]
        local current_remaining = v.remaining
        if stop == nil or stop == k then
          current_remaining = current_remaining - 1
        end
        current_remaining = max(0, current_remaining)

        if not limit or (current_remaining < remaining)
                     or (current_remaining == remaining and
                         current_window > window)
        then
          limit = current_limit
          window = current_window
          remaining = current_remaining

          if not timestamps then
            timestamps = timestamp.get_timestamps(current_timestamp)
          end

          reset = max(1, window - floor((current_timestamp - timestamps[k]) / 1000))
        end

        headers[X_RATELIMIT_LIMIT[k]] = current_limit
        headers[X_RATELIMIT_REMAINING[k]] = current_remaining
      end

      headers[RATELIMIT_LIMIT] = limit
      headers[RATELIMIT_REMAINING] = remaining
      headers[RATELIMIT_RESET] = reset
    end

    
    if stop then
      headers = headers or {}
      headers[RETRY_AFTER] = reset
      return kong.response.error(429, "API rate limit exceeded", headers)
    end

    if headers then
      kong.response.set_headers(headers)
    end
  end

  local ok, err = timer_at(0, increment, conf, limits, identifier, current_timestamp, 1)
  if not ok then
    kong.log.err("failed to create timer: ", err)
  end
end