Class: Idempotency

Inherits:
Object
  • Object
show all
Extended by:
Dry::Configurable
Defined in:
lib/idempotency.rb,
lib/idempotency/cache.rb,
lib/idempotency/rails.rb,
lib/idempotency/hanami.rb,
lib/idempotency/version.rb,
lib/idempotency/constants.rb,
lib/idempotency/testing/helpers.rb,
lib/idempotency/instrumentation/statsd_listener.rb

Overview

rubocop:disable Metrics/ClassLength

Defined Under Namespace

Modules: Events, Hanami, Instrumentation, Rails, Testing Classes: Cache, Constants

Constant Summary collapse

VERSION = 
'0.3.0'

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(config: Idempotency.config, cache: Cache.new(config:)) ⇒ Idempotency

Returns a new instance of Idempotency.



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# File 'lib/idempotency.rb', line 58

def initialize(config: Idempotency.config, cache: Cache.new(config:))
  @config = config
  @cache = cache
end

Class Method Details

.configure ⇒ Object 



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# File 'lib/idempotency.rb', line 45

def self.configure
  super

  if config.metrics.statsd_client
    config.instrumentation_listeners << Idempotency::Instrumentation::StatsdListener.new(
      config.metrics.statsd_client,
      config.metrics.namespace
    )
  end

  config.instrumentation_listeners.each(&:setup_subscriptions)
end

.notifier ⇒ Object 



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# File 'lib/idempotency.rb', line 15

def self.notifier
  @monitor.synchronize do
    @notifier ||= Dry::Monitor::Notifications.new(:idempotency_gem).tap do |n|
      Events::ALL_EVENTS.each { |event| n.register_event(event) }
    end
  end
end

.use_cache(request, request_identifiers, lock_duration: nil, action: nil, &blk) ⇒ Object 



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# File 'lib/idempotency.rb', line 63

def self.use_cache(request, request_identifiers, lock_duration: nil, action: nil, &blk)
  new.use_cache(request, request_identifiers, lock_duration:, action:, &blk)
end

Instance Method Details

#use_cache(request, request_identifiers, lock_duration: nil, action: nil) ⇒ Object

rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity



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# File 'lib/idempotency.rb', line 68

def use_cache(request, request_identifiers, lock_duration: nil, action: nil)
  duration_start = Process.clock_gettime(::Process::CLOCK_MONOTONIC)
  action_name = action || "#{request.request_method}:#{request.path}"

  with_apm_instrumentation('idempotency.use_cache', action_name) do
    return yield unless cache_request?(request)

    request_headers = request.env
    idempotency_key = unquote(request_headers[Constants::RACK_HEADER_KEY] || SecureRandom.hex)

    fingerprint = calculate_fingerprint(request, idempotency_key, request_identifiers)

    cached_response = cache.get(fingerprint)

    if (cached_status, cached_headers, cached_body = cached_response)
      cached_headers.merge!(Constants::HEADER_KEY => idempotency_key)
      instrument(Events::CACHE_HIT, request:, action:, duration: calculate_duration(duration_start))

      return [cached_status, cached_headers, cached_body]
    end

    lock_duration ||= config.default_lock_expiry
    response_status, response_headers, response_body = cache.with_lock(fingerprint, lock_duration) do
      yield
    end

    if cache_response?(response_status)
      cache.set(fingerprint, response_status, response_headers, response_body)
      response_headers.merge!({ Constants::HEADER_KEY => idempotency_key })
    end

    instrument(Events::CACHE_MISS, request:, action:, duration: calculate_duration(duration_start))
    [response_status, response_headers, response_body]
  end
rescue Idempotency::Cache::LockConflict
  instrument(Events::LOCK_CONFLICT, request:, action:, duration: calculate_duration(duration_start))
  [409, {}, config.response_body.concurrent_error]
end