Module: GSKCache

Defined in:
lib/gsk_cache.rb

Constant Summary collapse

SIGNING_KEY_URL =

Keys used for signing in production

'https://payments.developers.google.com/paymentmethodtoken/keys.json'.freeze
TEST_SIGNING_KEY_URL =

Keys used for signing in a testing environment

'https://payments.developers.google.com/paymentmethodtoken/test/keys.json'.freeze
MAX_CACHE_TIMEOUT =

One month

31 * 24 * 3600
MIN_CACHE_TIMEOUT =

10 minutes

600
BOOT_WAIT_TIME_MAX = 
8
HEADER_KEY = 
'Cache-Control'.freeze
READ_TIMEOUT = 
10
CONNECT_TIMEOUT = 
10
UPDATER_BLOCK = 
proc do
  loop do
    begin
      timeout = 0

      conn = Excon.new(@@source, connect_timeout: @@connect_timeout, read_timeout: @@read_timeout)
      resp = conn.get

      raise 'Unable to update keys: ' + resp.data[:status_line] unless resp.status == 200

      if resp.headers.key?(HEADER_KEY) && resp.headers[HEADER_KEY].is_a?(String)
        cache_control = resp.headers[HEADER_KEY].split(/,\s*/)
        h = cache_control.map { |x| /\Amax-age=(?<timeout>\d+)\z/ =~ x; timeout }.compact
        timeout = h.first.to_i if h.length == 1
      else
        log(:warning, "Missing/malformed #{HEADER_KEY} header")
      end

      if timeout.nil? || !timeout.positive?
        log(:warning, 'Cache timeout was not parsed, falling back to 1 day')
        timeout = 86400
      end

      # Fallback to longer cache if less than 10 minutes
      if timeout < MIN_CACHE_TIMEOUT
        log(:warning, "Cache timeout less than 10 minutes (#{timeout}s), defaulting to #{MIN_CACHE_TIMEOUT / 60} minutes")
        timeout = MIN_CACHE_TIMEOUT
      end

      # Fallback to shorter cache if longer than 30 days
      if timeout > MAX_CACHE_TIMEOUT
        log(:warning, "Cache timeout more than a month (#{timeout}s), defaulting to #{MAX_CACHE_TIMEOUT / (24 * 3600)} days")
        timeout = MAX_CACHE_TIMEOUT
      end

      Thread.current.thread_variable_set('keys', resp.body)

      # Supposedly recommended by Tink library
      sleep_time = timeout / 2

      log(:info, "Updated Google signing keys. Sleeping for #{seconds_to_time(sleep_time)}")

      sleep sleep_time
    rescue Interrupt => e
      # When interrupted
      log(:fatal, 'Quitting: ' + e.message)
      return
    rescue => e
      log(:error, "Exception updating Google signing keys: '#{e.message}' at #{e.backtrace}")

      # Don't retry excessively.
      sleep 1
    end
  end
end
@@key_updater_semaphore = 
Mutex.new
@@key_updater_thread = 
nil

Class Method Summary collapse

Class Method Details

.set_timeout(read_timeout: nil, connect_timeout: nil) ⇒ Object 



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# File 'lib/gsk_cache.rb', line 115

def self.set_timeout(read_timeout: nil, connect_timeout: nil)
  @@read_timeout    = read_timeout    if read_timeout
  @@connect_timeout = connect_timeout if connect_timeout
end

.signing_keys ⇒ Object 



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# File 'lib/gsk_cache.rb', line 120

def self.signing_keys
  start if @@key_updater_thread.nil?

  @@key_updater_thread.thread_variable_get('keys')
end

.start(logger: nil, source: nil, waittime: BOOT_WAIT_TIME_MAX) ⇒ Object

Start a thread that keeps the Google signing keys updated.



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# File 'lib/gsk_cache.rb', line 84

def self.start(logger: nil, source: nil, waittime: BOOT_WAIT_TIME_MAX)
  @@key_updater_semaphore.synchronize do
    # Another thread might have been waiting for on the mutex
    break unless @@key_updater_thread.nil?

    @@logger = logger
    @@source = if source
                 source
               elsif ENV['ENVIRONMENT'] == 'production'
                 SIGNING_KEY_URL
               else
                 TEST_SIGNING_KEY_URL
               end
    @@read_timeout    = READ_TIMEOUT
    @@connect_timeout = CONNECT_TIMEOUT

    new_thread = Thread.new(&UPDATER_BLOCK)

    start_time = Time.now.to_i

    while new_thread.thread_variable_get('keys').nil? && Time.now.to_i - start_time < waittime
      sleep 0.2
    end
    # Body has now been set.
    # Let other clients through.
    @@key_updater_thread = new_thread

    nil
  end
end

.terminate ⇒ Object

Required for specs



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# File 'lib/gsk_cache.rb', line 127

def self.terminate
  @@key_updater_thread&.terminate
  @@key_updater_thread = nil
end