Module: Karafka::Testing::Minitest::Helpers

Defined in:
lib/karafka/testing/minitest/helpers.rb

Overview

Minitest helpers module that needs to be included

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

Adds all the needed extra functionalities to the minitest group

Parameters:

  • base (Class) —

    Minitest example group we want to extend



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# File 'lib/karafka/testing/minitest/helpers.rb', line 28

def included(base)
  eval_flow = lambda do
    Karafka::Testing.ensure_karafka_initialized!

    @karafka = Karafka::Testing::Minitest::Proxy.new(self)
    @_karafka_consumer_messages = []
    @_karafka_consumer_client = Karafka::Testing::SpecConsumerClient.new
    @_karafka_producer_client = Karafka::Testing::SpecProducerClient.new(self)

    @_karafka_consumer_messages.clear
    @_karafka_producer_client.reset

    @_karafka_consumer_mappings = {}

    Karafka.producer.stubs(:client).returns(@_karafka_producer_client)
  end

  if base.to_s == "Minitest::Spec"
    base.class_eval do
      before(&eval_flow)
    end
  elsif base.respond_to?(:setup) && base.method(:setup).arity != 0
    base.class_eval do
      setup(&eval_flow)
    end
  else
    setup_mod = Module.new do
      define_method(:setup) do
        instance_exec(&eval_flow)
        super()
      end
    end

    base.prepend(setup_mod)
  end
end

Instance Method Details

#_karafka_add_message_to_consumer_if_needed(message) ⇒ Object

Adds a new Karafka message instance if needed with given payload and options into an internal consumer buffer that will be used to simulate messages delivery to the consumer

Examples:

Send a json message to consumer

@karafka.produce({ 'hello' => 'world' }.to_json)

Send a json message to consumer and simulate, that it is partition 6

@karafka.produce({ 'hello' => 'world' }.to_json, 'partition' => 6)

Parameters:

  • message (Hash) —

    message that was sent to Kafka



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# File 'lib/karafka/testing/minitest/helpers.rb', line 100

def _karafka_add_message_to_consumer_if_needed(message)
  consumer_obj = if message[:consumer_group]
    _karafka_find_consumer_for_message(message)
  elsif defined?(@consumer)
    @consumer
  else
    _karafka_find_consumer_for_message(message)
  end
  # Consumer needs to be defined in order to pass messages to it
  return unless defined?(consumer_obj)
  # We're interested in adding message to consumer only when it is a Karafka consumer
  # Users may want to test other things (models producing messages for example) and in
  # their case consumer will not be a consumer
  return unless consumer_obj.is_a?(Karafka::BaseConsumer)
  # We target to the consumer only messages that were produced to it, since specs may also
  # produce other messages targeting other topics
  return unless message[:topic] == consumer_obj.topic.name
  # If consumer_group is explicitly specified, verify it matches
  return if message[:consumer_group] &&
    message[:consumer_group].to_s != consumer_obj.topic.consumer_group.name

  # Build message metadata and copy any metadata that would come from the message
  metadata = _karafka_message_metadata_defaults(consumer_obj)

  metadata.keys.each do |key|
    message_key = METADATA_DISPATCH_MAPPINGS.fetch(key, key)

    next unless message.key?(message_key)

    metadata[key] = message.fetch(message_key)
  end

  # Add this message to previously produced messages
  @_karafka_consumer_messages << Karafka::Messages::Message.new(
    message[:payload],
    Karafka::Messages::Metadata.new(metadata)
  )
  # Update batch metadata
  batch_metadata = Karafka::Messages::Builders::BatchMetadata.call(
    @_karafka_consumer_messages,
    consumer_obj.topic,
    0,
    Time.now
  )

  # Update consumer messages batch
  consumer_obj.messages = Karafka::Messages::Messages.new(
    @_karafka_consumer_messages,
    batch_metadata
  )
end

#_karafka_consumer_for(requested_topic, requested_consumer_group = nil) ⇒ Object

Creates a consumer instance for a given topic

Examples:

Creates a consumer instance with settings for ‘my_requested_topic`

consumer = @karafka.consumer_for(:my_requested_topic)

Parameters:

  • requested_topic (String, Symbol) —

    name of the topic for which we want to create a consumer instance

  • requested_consumer_group (String, Symbol, nil) (defaults to: nil) —

    optional name of the consumer group if we have multiple consumer groups listening on the same topic

Returns:

  • (Object) —

    Karafka consumer instance

Raises:



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# File 'lib/karafka/testing/minitest/helpers.rb', line 78

def _karafka_consumer_for(requested_topic, requested_consumer_group = nil)
  selected_topics = Testing::Helpers.karafka_consumer_find_candidate_topics(
    requested_topic.to_s,
    requested_consumer_group.to_s
  )

  raise Errors::TopicInManyConsumerGroupsError, requested_topic if selected_topics.size > 1
  raise Errors::TopicNotFoundError, requested_topic if selected_topics.empty?

  _karafka_build_consumer_for(selected_topics.first)
end

#_karafka_consumer_messages ⇒ Array<Karafka::Messages::Message>

Returns array of messages that will be used to construct the final consumer messages batch.

Returns:

  • (Array<Karafka::Messages::Message>) —

    array of messages that will be used to construct the final consumer messages batch



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# File 'lib/karafka/testing/minitest/helpers.rb', line 187

def _karafka_consumer_messages
  @_karafka_consumer_messages
end

#_karafka_produce(payload, metadata = {}) ⇒ Object

Produces message with a given payload to the consumer matching topic

Parameters:

  • payload (String) —

    payload we want to dispatch

  • metadata (Hash) (defaults to: {}) —

    any metadata we want to dispatch alongside the payload. Supports an ‘offset` key to set a custom offset for the message (otherwise offsets auto-increment from 0).



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# File 'lib/karafka/testing/minitest/helpers.rb', line 157

def _karafka_produce(payload, metadata = {})
  # Extract offset before passing to WaterDrop since it is not a valid
  # WaterDrop message attribute (Kafka assigns offsets, not producers)
  @_karafka_next_offset = metadata.delete(:offset)

  topic = if metadata[:topic]
    metadata[:topic]
  elsif defined?(@consumer)
    @consumer.topic.name
  else
    last_consumer = @_karafka_consumer_mappings&.values&.last
    last_consumer&.topic&.name
  end
  Karafka.producer.produce_sync(
    {
      topic: topic,
      payload: payload
    }.merge(metadata)
  )
ensure
  @_karafka_next_offset = nil
end

#_karafka_produce_to(consumer_instance, payload, metadata = {}) ⇒ Object

Produces message to a specific consumer instance Use when testing multiple consumers for the same topic

Examples:

Produce to specific consumer when multiple exist for same topic

consumer1 = @karafka.consumer_for(:events, :analytics_group)
consumer2 = @karafka.consumer_for(:events, :notifications_group)
@karafka.produce_to(consumer1, { 'event' => 'click' }.to_json)

Parameters:

  • consumer_instance (Object) —

    the consumer to produce to

  • payload (String) —

    message content (usually serialized JSON) to deliver to the consumer

  • metadata (Hash) (defaults to: {}) —

    any metadata to dispatch alongside the payload



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# File 'lib/karafka/testing/minitest/helpers.rb', line 203

def _karafka_produce_to(consumer_instance, payload, metadata = {})
  _karafka_produce(
    payload,
    metadata.merge(
      topic: consumer_instance.topic.name,
      consumer_group: consumer_instance.topic.consumer_group.name
    )
  )
end

#_karafka_produced_messages ⇒ Array<Hash>

Returns messages that were produced.

Returns:

  • (Array<Hash>) —

    messages that were produced



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# File 'lib/karafka/testing/minitest/helpers.rb', line 181

def _karafka_produced_messages
  @_karafka_producer_client.messages
end