class Aws::EndpointProvider

def expand(pattern, region, service)
  'https://' + pattern.sub('{region}', region).sub('{service}', service)
end

def keys(region, service)
  ["#{region}/#{service}", "#{region}/*", "*/#{service}", "*/*"]
end

def resolve(region, service)
  keys(region, service).each do |key|
    if match = RULES[key]
      return expand(match['endpoint'], region.to_s, service.to_s)
    end
  end
end