Class: WaterDrop::Producer

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
Karafka::Core::Helpers::Time, Async, Buffer, Sync
Defined in:
lib/waterdrop/producer.rb,
lib/waterdrop/producer/sync.rb,
lib/waterdrop/producer/async.rb,
lib/waterdrop/producer/buffer.rb,
lib/waterdrop/producer/status.rb,
lib/waterdrop/producer/builder.rb

Overview

Main WaterDrop messages producer

Defined Under Namespace

Modules: Async, Buffer, Sync Classes: Builder, Status

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Buffer

#buffer, #buffer_many, #flush_async, #flush_sync

Methods included from Async

#produce_async, #produce_many_async

Methods included from Sync

#produce_many_sync, #produce_sync

Constructor Details

#initialize(&block) ⇒ Producer

Creates a not-yet-configured instance of the producer

Parameters:

  • block (Proc) —

    configuration block



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# File 'lib/waterdrop/producer.rb', line 36

def initialize(&block)
  @operations_in_progress = Concurrent::AtomicFixnum.new(0)
  @buffer_mutex = Mutex.new
  @connecting_mutex = Mutex.new
  @operating_mutex = Mutex.new

  @status = Status.new
  @messages = Concurrent::Array.new

  return unless block

  setup(&block)
end

Instance Attribute Details

#config ⇒ Object (readonly)

Returns dry-configurable config object.

Returns:

  • (Object) —

    dry-configurable config object



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# File 'lib/waterdrop/producer.rb', line 31

def config
  @config
end

#id ⇒ String (readonly)

Returns uuid of the current producer.

Returns:

  • (String) —

    uuid of the current producer



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# File 'lib/waterdrop/producer.rb', line 23

def id
  @id
end

#messages ⇒ Concurrent::Array (readonly)

Returns internal messages buffer.

Returns:

  • (Concurrent::Array) —

    internal messages buffer



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# File 'lib/waterdrop/producer.rb', line 27

def messages
  @messages
end

#monitor ⇒ Object (readonly)

Returns monitor we want to use.

Returns:

  • (Object) —

    monitor we want to use



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# File 'lib/waterdrop/producer.rb', line 29

def monitor
  @monitor
end

#status ⇒ Status (readonly)

Returns producer status object.

Returns:

  • (Status) —

    producer status object



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# File 'lib/waterdrop/producer.rb', line 25

def status
  @status
end

Instance Method Details

#client ⇒ Rdkafka::Producer

Note:

Client is lazy initialized, keeping in mind also the fact of a potential fork that can happen any time.

Note:

It is not recommended to fork a producer that is already in use so in case of bootstrapping a cluster, it’s much better to fork configured but not used producers

Returns raw rdkafka producer.

Returns:

  • (Rdkafka::Producer) —

    raw rdkafka producer

Raises:



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# File 'lib/waterdrop/producer.rb', line 71

def client
  return @client if @client && @pid == Process.pid

  # Don't allow to obtain a client reference for a producer that was not configured
  raise Errors::ProducerNotConfiguredError, id if @status.initial?

  @connecting_mutex.synchronize do
    return @client if @client && @pid == Process.pid

    # We undefine all the finalizers, in case it was a fork, so the finalizers from the parent
    # process don't leak
    ObjectSpace.undefine_finalizer(id)

    # We should raise an error when trying to use a producer with client from a fork. Always.
    if @client
      # We need to reset the client, otherwise there might be attempt to close the parent
      # client
      @client = nil
      raise Errors::ProducerUsedInParentProcess, Process.pid
    end

    # Finalizer tracking is needed for handling shutdowns gracefully.
    # I don't expect everyone to remember about closing all the producers all the time, thus
    # this approach is better. Although it is still worth keeping in mind, that this will
    # block GC from removing a no longer used producer unless closed properly but at least
    # won't crash the VM upon closing the process
    ObjectSpace.define_finalizer(id, proc { close })

    @pid = Process.pid
    @client = Builder.new.call(self, @config)

    # Register statistics runner for this particular type of callbacks
    ::Karafka::Core::Instrumentation.statistics_callbacks.add(
      @id,
      Instrumentation::Callbacks::Statistics.new(@id, @client.name, @config.monitor)
    )

    # Register error tracking callback
    ::Karafka::Core::Instrumentation.error_callbacks.add(
      @id,
      Instrumentation::Callbacks::Error.new(@id, @client.name, @config.monitor)
    )

    @status.connected!
  end

  @client
end

#close ⇒ Object

Flushes the buffers in a sync way and closes the producer



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# File 'lib/waterdrop/producer.rb', line 121

def close
  @operating_mutex.synchronize do
    return unless @status.active?

    @monitor.instrument(
      'producer.closed',
      producer_id: id
    ) do
      @status.closing!

      # No need for auto-gc if everything got closed by us
      # This should be used only in case a producer was not closed properly and forgotten
      ObjectSpace.undefine_finalizer(id)

      # We save this thread id because we need to bypass the activity verification on the
      # producer for final flush of buffers.
      @closing_thread_id = Thread.current.object_id

      # Wait until all the outgoing operations are done. Only when no one is using the
      # underlying client running operations we can close
      sleep(0.001) until @operations_in_progress.value.zero?

      # Flush has its own buffer mutex but even if it is blocked, flushing can still happen
      # as we close the client after the flushing (even if blocked by the mutex)
      flush(true)

      # We should not close the client in several threads the same time
      # It is safe to run it several times but not exactly the same moment
      # We also mark it as closed only if it was connected, if not, it would trigger a new
      # connection that anyhow would be immediately closed
      if @client
        client.close
        @client = nil
      end

      # Remove callbacks runners that were registered
      ::Karafka::Core::Instrumentation.statistics_callbacks.delete(@id)
      ::Karafka::Core::Instrumentation.error_callbacks.delete(@id)

      @status.closed!
    end
  end
end

#setup(&block) ⇒ Object

Sets up the whole configuration and initializes all that is needed

Parameters:

  • block (Block) —

    configuration block

Raises:



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# File 'lib/waterdrop/producer.rb', line 52

def setup(&block)
  raise Errors::ProducerAlreadyConfiguredError, id unless @status.initial?

  @config = Config
            .new
            .setup(&block)
            .config

  @id = @config.id
  @monitor = @config.monitor
  @contract = Contracts::Message.new(max_payload_size: @config.max_payload_size)
  @status.configured!
end