Class: NatsMessaging::NatsService

Inherits:
Object
  • Object
show all
Defined in:
lib/nats_messaging/nats_service.rb

Constant Summary collapse

DEFAULT_CONNECT_OPTIONS =

Reintentos infinitos: con un solo server en el pool, agotar los intentos deja el proceso sin NATS hasta un reinicio manual. ping_interval más corto detecta conexiones zombie en ~1 min en vez de los ~4 min por defecto.

{
  reconnect: true,
  max_reconnect_attempts: -1,
  reconnect_time_wait: 30,
  ping_interval: 30,
  max_outstanding_pings: 2
}.freeze
DEFAULT_INITIAL_CONNECT_TIMEOUT =

nats-pure usa el mismo max_reconnect_attempts tanto para el connect inicial (establish_connection!) como para la reconexión de una conexión ya establecida (attempt_reconnect): con max_reconnect_attempts: -1, can_reuse_server? siempre devuelve true y el connect inicial reintenta para siempre sin lanzar excepción, colgando el arranque del proceso host. El connect_timeout propio de nats-pure no sirve para acotar esto: solo limita un intento de conexión TCP/handshake individual, no la cantidad de reintentos. No hay forma nativa en nats-pure 2.5 de distinguir "primer connect" de "reconexión posterior", así que se acota el connect inicial desde afuera con Timeout.timeout. Es aceptable usar Timeout pese a su conocida rudeza (mata el hilo sin dar chance de cleanup) porque ocurre solo durante el boot, antes de que exista estado que corromper; si el timeout dispara, la instancia parcialmente construida simplemente se descarta al propagar la excepción.

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Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(nats_url, stream_name: nil, subjects: [], connect_options: {}, initial_connect_timeout: DEFAULT_INITIAL_CONNECT_TIMEOUT) ⇒ NatsService

Returns a new instance of NatsService.



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# File 'lib/nats_messaging/nats_service.rb', line 39

def initialize(nats_url, stream_name: nil, subjects: [], connect_options: {}, initial_connect_timeout: DEFAULT_INITIAL_CONNECT_TIMEOUT)
  @pid = Process.pid
  @subscriptions = {} # Store active subscriptions
  begin
    @nats = Timeout.timeout(initial_connect_timeout) do
      NATS.connect(nats_url, DEFAULT_CONNECT_OPTIONS.merge(connect_options))
    end
  rescue Timeout::Error
    raise NatsMessaging::InitialConnectTimeoutError,
      "Could not connect to NATS at #{nats_url} within #{initial_connect_timeout}s"
  end
  register_lifecycle_callbacks
  if stream_name
    @js = @nats.jetstream
    create_stream(stream_name, subjects)
  end
end

Instance Attribute Details

#pid ⇒ Object (readonly)

Returns the value of attribute pid.



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# File 'lib/nats_messaging/nats_service.rb', line 37

def pid
  @pid
end

Instance Method Details

#create_stream(stream_name, subjects) ⇒ Object

Create a stream



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# File 'lib/nats_messaging/nats_service.rb', line 83

def create_stream(stream_name, subjects)
  begin
    start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
    stream = @js.stream_info(stream_name)
    log_duration(start_time, "Stream %s already exists", stream_name)
  rescue NATS::JetStream::Error::NotFound
    @js.add_stream(name: stream_name, subjects: subjects)
    log_duration(start_time, "Stream %s created", stream_name)
  rescue => e
    log_duration(start_time, "Failed to create stream: %s", e.message)
  end
end

#listen_and_reply(subject, reply_message = nil) ⇒ Object

Listen to a subject and reply with a message using MessagePack



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# File 'lib/nats_messaging/nats_service.rb', line 183

def listen_and_reply(subject, reply_message=nil)
  # Cancel active subscription if it already exists for this subject
  if @subscriptions[subject]
    @subscriptions[subject].unsubscribe
  end
  begin
    # Create a new subscription
    logger.info "NATS: Listening on #{subject} with reply message: #{reply_message}"
    start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC) # En caso de que falle antes del segundo begin
    @subscriptions[subject] = @nats.subscribe(subject) do |msg|
      begin
        start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
        unpacked_data = MessagePack.unpack(msg.data) # Deserializar mensaje recibido
        logger.info "NATS: Received request on #{subject}: #{unpacked_data}"
        indifferent_unpacked_data = make_data_indifferent(unpacked_data)
        yield_return = yield(subject, indifferent_unpacked_data) if block_given?
        reply = reply_message.nil? ? yield_return : reply_message
        packed_reply = reply.to_msgpack # Serializar respuesta
        # Asegurar que msg.reply existe antes de responder
        if msg.reply
          @nats.publish(msg.reply, packed_reply)
          log_duration(start_time, "Replied to %s with message: %s", subject, reply.inspect)
        else
          log_duration(start_time, "No reply subject for %s, cannot respond", subject)
        end
        indifferent_unpacked_data
      rescue => e
        log_duration(start_time, "Error while processing message on %s: %s", subject, e.message)
        logger.error e.backtrace.join("\n")
      end
    end
  rescue => e
    log_duration(start_time, "Error while replying: %s", e.message)
  end
end

#log_duration(start_time, message_format, *args) ⇒ Object 



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# File 'lib/nats_messaging/nats_service.rb', line 61

def log_duration(start_time, message_format, *args)
  duration = Process.clock_gettime(Process::CLOCK_MONOTONIC) - start_time
  full_message = "NATS [%.2fs]: #{message_format}" % [duration, *args]
  logger.info full_message
end

#logger ⇒ Object 



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# File 'lib/nats_messaging/nats_service.rb', line 57

def logger
  @logger ||= (defined?(Rails) && Rails.logger) || Logger.new(STDOUT)
end

#make_data_indifferent(data) ⇒ Object 



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# File 'lib/nats_messaging/nats_service.rb', line 121

def make_data_indifferent(data)
  if data.is_a?(Hash)
    data.with_indifferent_access
  else
    data
  end
end

#process_received_message(msg, subject) ⇒ Object

Process received message



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# File 'lib/nats_messaging/nats_service.rb', line 150

def process_received_message(msg, subject)
  begin
    start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
    unpacked_data = MessagePack.unpack(msg.data)
    log_duration(start_time, "Message received on %s: %s", subject, unpacked_data.inspect)
    unpacked_data
  rescue => e
    log_duration(start_time, "Error while processing message on %s: %s", subject, e.message)
  end
end

#publish_message(subject, message) ⇒ Object

Publish a message to a subject using MessagePack



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# File 'lib/nats_messaging/nats_service.rb', line 97

def publish_message(subject, message)
  packed_message = message.to_msgpack # Serializar a MessagePack
  if @js
    begin
      start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
      ack = @js.publish(subject, packed_message)
      log_duration(start_time, "Message sent to %s: %s, ACK: %s", subject, message, ack.inspect)
    rescue NATS::JetStream::Error::NotFound
      @nats.publish(subject, packed_message)
      log_duration(start_time, "Stream not found, falling back to regular NATS publish for subject %s", subject)
    rescue => e
      log_duration(start_time, "Unexpected error while publishing to %s: %s", subject, e.message)
    end
  else
    begin
      start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
      @nats.publish(subject, packed_message)
      log_duration(start_time, "Message sent to %s: %s", subject, message)
    rescue => e
      log_duration(start_time, "Unexpected error: %s", e.message)
    end
  end
end

#register_lifecycle_callbacks ⇒ Object 



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# File 'lib/nats_messaging/nats_service.rb', line 67

def register_lifecycle_callbacks
  @nats.on_disconnect do |e|
    logger.warn "NATS: disconnected#{e ? " (#{e.message})" : ''}"
  end
  @nats.on_reconnect do
    logger.info "NATS: reconnected to #{@nats.connected_server}"
  end
  @nats.on_error do |e|
    logger.error "NATS: error: #{e.message}"
  end
  @nats.on_close do
    logger.error "NATS: connection CLOSED permanently"
  end
end

#send_request(subject, message, timeout = 5) ⇒ Object

Send a request to a subject and wait for response using MessagePack



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# File 'lib/nats_messaging/nats_service.rb', line 162

def send_request(subject, message, timeout = 5)
  logger.info "NATS: Sending request to #{subject} with message: #{message}"
  start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
  begin
    packed_message = message.to_msgpack # Serializar el mensaje
    response = @nats.request(subject, packed_message, timeout: timeout) # Timeout of 5 seconds or custom
    unpacked_response = MessagePack.unpack(response.data) # Deserializar respuesta
    log_duration(start_time, "Received reply: %s", unpacked_response.inspect)
    indifferent_unpacked_data = make_data_indifferent(unpacked_response)
    yield(subject, indifferent_unpacked_data) if block_given?
    indifferent_unpacked_data
  rescue NATS::IO::Timeout
    log_duration(start_time, "Request timed out for subject: %s", subject)
    nil
  rescue => e
    log_duration(start_time, "Unexpected error for subject %s: %s", subject, e.message)
    nil
  end
end

#subscribe_to_subject(subject, durable_name = "durable_name") ⇒ Object

Subscribe to a subject using MessagePack



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# File 'lib/nats_messaging/nats_service.rb', line 130

def subscribe_to_subject(subject, durable_name = "durable_name")
  logger.info "NATS: Subscribing to #{subject}"
  if @js
    @subscriptions[subject] = @js.subscribe(subject, durable: durable_name) do |msg|
                    unpacked_data = process_received_message(msg, subject)
                    indifferent_unpacked_data = make_data_indifferent(unpacked_data)
                    yield(msg.subject, indifferent_unpacked_data) if block_given?
                    indifferent_unpacked_data
                   end
  else
    @subscriptions[subject] = @nats.subscribe(subject) do |msg|
                    unpacked_data = process_received_message(msg, subject)
                    indifferent_unpacked_data = make_data_indifferent(unpacked_data)
                    yield(msg.subject, indifferent_unpacked_data) if block_given?
                    indifferent_unpacked_data
                   end
  end
end