Class: NatsAsync::Client

Inherits:
Object
  • Object
show all
Defined in:
lib/nats_async/client.rb

Defined Under Namespace

Classes: RequestPromise

Constant Summary collapse

AckError = 
NatsAsync::AckError
ConnectionError = 
NatsAsync::ConnectionError
MsgAlreadyAcked = 
NatsAsync::MsgAlreadyAcked
NotAckable = 
NatsAsync::NotAckable
RequestError = 
NatsAsync::RequestError
ProtocolError = 
NatsAsync::ProtocolError
Message = 
NatsAsync::Message

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(url: "nats://127.0.0.1:4222", verbose: true, js_api_prefix: "$JS.API", ping_interval: 30, ping_timeout: 5, tls: nil, tls_verify: true, tls_ca_file: nil, tls_ca_path: nil, tls_hostname: nil, tls_handshake_first: false, user: nil, password: nil, nkey_seed: nil, nkey_seed_file: nil, nkey_public_key: nil, reconnect: false, reconnect_interval: 1, max_reconnect_attempts: nil, flush_delay: 0.01, flush_max_buffer: 5000) ⇒ Client

Returns a new instance of Client.



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# File 'lib/nats_async/client.rb', line 94

def initialize(
  url: "nats://127.0.0.1:4222",
  verbose: true,
  js_api_prefix: "$JS.API",
  ping_interval: 30,
  ping_timeout: 5,
  tls: nil,
  tls_verify: true,
  tls_ca_file: nil,
  tls_ca_path: nil,
  tls_hostname: nil,
  tls_handshake_first: false,
  user: nil,
  password: nil,
  nkey_seed: nil,
  nkey_seed_file: nil,
  nkey_public_key: nil,
  reconnect: false,
  reconnect_interval: 1,
  max_reconnect_attempts: nil,
  flush_delay: 0.01,
  flush_max_buffer: 5000
)
  @js_api_prefix = normalize_subject_prefix(js_api_prefix)
  @ping_interval = ping_interval
  @ping_timeout = ping_timeout
  @reconnect = reconnect
  @reconnect_interval = reconnect_interval
  @max_reconnect_attempts = max_reconnect_attempts
  @logger = Console.logger.with(level: (verbose ? :debug : :error), verbose: false)
  @connection_options = {
    url: url,
    logger: @logger,
    tls: tls,
    tls_verify: tls_verify,
    tls_ca_file: tls_ca_file,
    tls_ca_path: tls_ca_path,
    tls_hostname: tls_hostname,
    tls_handshake_first: tls_handshake_first,
    user: user,
    password: password,
    nkey_seed: nkey_seed,
    nkey_seed_file: nkey_seed_file,
    nkey_public_key: nkey_public_key,
    flush_delay: flush_delay,
    flush_max_buffer: flush_max_buffer
  }
  @connection = build_connection

  @ping_task = nil
  @reconnect_task = nil
  @request_timeout_task = nil
  @request_callback_task = nil
  @request_callback_queue = nil
  @read_error = nil
  @started = false
  @closed = true
  @status = :closed
  @sid_seq = 0
  @request_seq = 0
  @subscriptions = {}
  @pending_requests = {}
  @pending_request_condition = Async::Condition.new

  # Response multiplexing state
  @resp_mux_prefix = nil
  @resp_mux_subsid = nil
  @resp_mux_lock = Async::Semaphore.new(1)
  @resp_map = {}
  @resp_map_lock = Async::Semaphore.new(1)
end

Instance Attribute Details

#js_api_prefix ⇒ Object (readonly)

Returns the value of attribute js_api_prefix.



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# File 'lib/nats_async/client.rb', line 166

def js_api_prefix
  @js_api_prefix
end

#status ⇒ Object (readonly)

Returns the value of attribute status.



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# File 'lib/nats_async/client.rb', line 166

def status
  @status
end

Instance Method Details

#cleanup_resp_mux ⇒ Object

Clean up the response multiplexing subscription



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# File 'lib/nats_async/client.rb', line 248

def cleanup_resp_mux
  return unless @resp_mux_subsid

  @resp_mux_lock.acquire do
    @subscriptions.delete(@resp_mux_subsid)
    safe_unsubscribe(@resp_mux_subsid)
    @resp_mux_subsid = nil
    @resp_mux_prefix = nil
    @resp_map.clear
  end
end

#close ⇒ Object 



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# File 'lib/nats_async/client.rb', line 190

def close
  return true if closed?

  @closed = true
  stop
  @started = false
  @status = :closed
  true
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/nats_async/client.rb', line 269

def closed?
  @closed
end

#connected? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/nats_async/client.rb', line 265

def connected?
  @status == :connected && @started && !@closed && @connection.connected?
end

#drain(timeout: 5) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 221

def drain(timeout: 5)
  @ping_task&.stop
  @ping_task = nil
  flush(timeout: timeout) if connected?
  true
ensure
  close
end

#ensure_resp_mux_sub!(task:) ⇒ Object

Ensure the response multiplexing subscription is set up Creates a single wildcard subscription to handle all request responses



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# File 'lib/nats_async/client.rb', line 299

def ensure_resp_mux_sub!(task:)
  return if @resp_mux_prefix

  @resp_mux_lock.acquire do
    return if @resp_mux_prefix

    # Generate unique prefix for this connection
    @resp_mux_prefix = "_INBOX.#{SecureRandom.hex(8)}"

    # Create wildcard subscription to handle all responses
    # Messages for request replies come with subject = the reply inbox
    @resp_mux_subsid = subscribe("#{@resp_mux_prefix}.*") do |msg|
      # Extract token from subject (format: _INBOX.<prefix>.<token>)
      token = msg.subject.split(".").last
      process_mux_response(token, msg)
    end
  end

  # Flush immediately to ensure subscription is registered before any requests
  @connection.flush_pending
  # The flush is async, so we just wait a tiny bit to ensure it's sent
  sleep(0.001)
end

#flush(timeout: 2) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 260

def flush(timeout: 2)
  ping!(timeout: timeout)
  true
end

#generate_resp_token ⇒ Object

Generate a unique token for request tracking



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# File 'lib/nats_async/client.rb', line 340

def generate_resp_token
  SecureRandom.hex(8)
end

#jetstream ⇒ Object 



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# File 'lib/nats_async/client.rb', line 414

def jetstream
  @jetstream ||= JetStream.new(self)
end

#js_api_subject(*tokens) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 410

def js_api_subject(*tokens)
  [js_api_prefix, *tokens.flatten].compact.map(&:to_s).reject(&:empty?).join(".")
end

#last_error ⇒ Object 



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# File 'lib/nats_async/client.rb', line 273

def last_error
  @read_error || @connection.last_error
end

#ping!(timeout: 2) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 277

def ping!(timeout: 2)
  @connection.ping!(timeout: timeout)
end

#process_mux_response(token, message) ⇒ Object

Process a response message from the multiplexed subscription



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# File 'lib/nats_async/client.rb', line 324

def process_mux_response(token, message)
  @resp_map_lock.acquire do
    pending = @resp_map.delete(token)
    return unless pending

    if pending[:callback]
      enqueue_request_callback(pending, message)
    else
      pending[:promise].fulfill(message)
    end
  rescue StandardError
    @logger.error("mux response handler error")
  end
end

#publish(subject, payload = "", reply: nil, headers: nil) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 281

def publish(subject, payload = "", reply: nil, headers: nil)
  ensure_connected!
  @connection.publish(subject, payload, reply: reply, headers: headers)
end

#received_pings ⇒ Object 



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# File 'lib/nats_async/client.rb', line 350

def received_pings = @connection.received_pings

#received_pongs ⇒ Object 



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# File 'lib/nats_async/client.rb', line 352

def received_pongs = @connection.received_pongs

#request(subject, payload = "", timeout: 0.5, headers: nil, &block) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 358

def request(subject, payload = "", timeout: 0.5, headers: nil, &block)
  ensure_connected!

  # If block is provided, use old-style per-request subscription
  if block
    return request_old_style(subject, payload, timeout: timeout, headers: headers, &block)
  end

  # Use multiplexed subscription for promise-based requests
  ensure_resp_mux_sub!(task: @reactor_task)
  token = generate_resp_token
  inbox = "#{@resp_mux_prefix}.#{token}"

  promise = RequestPromise.new(id: token)

  begin
    # Track request with token-based lookup in mux response handler
    @resp_map_lock.acquire do
      @resp_map[token] = {
        promise: promise,
        deadline: monotonic_now + timeout,
        timeout: timeout,
        callback: nil
      }
    end
    @pending_request_condition.signal

    publish(subject, request_payload(payload), reply: inbox, headers: headers)
    promise
  rescue StandardError
    @resp_map_lock.acquire do
      @resp_map.delete(token)
    end
    raise
  end
end

#request_old_style(subject, payload = "", timeout: 0.5, headers: nil, &block) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 395

def request_old_style(subject, payload = "", timeout: 0.5, headers: nil, &block)
  # Old-style request with per-request subscription (for callback support)
  request_id = next_request_id
  promise = RequestPromise.new(id: request_id)
  inbox = request_inbox(request_id)
  sid = nil

  sid = subscribe(inbox, handler: lambda { |message| complete_request(request_id, message) })
  track_request(request_id, subject: subject, sid: sid, promise: promise, timeout: timeout, callback: block)
  publish(subject, request_payload(payload), reply: inbox, headers: headers)
  promise
rescue StandardError => e
  reject_request_setup(request_id: request_id, promise: promise, sid: sid, error: e)
end

#resolve_backend(mode: :auto, stream: nil) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 200

def resolve_backend(mode: :auto, stream: nil)
  mode = mode.to_sym
  return :core if mode == :core

  raise ArgumentError, "stream is required for #{mode} backend" if stream.to_s.empty?

  case mode
  when :jetstream
    jetstream.stream_info(stream)
    :jetstream
  when :auto
    jetstream.stream_exists?(stream) ? :jetstream : :core
  else
    raise ArgumentError, "unsupported backend mode: #{mode.inspect}"
  end
rescue JetStream::Error
  raise if mode == :jetstream

  :core
end

#sent_pings ⇒ Object 



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# File 'lib/nats_async/client.rb', line 354

def sent_pings = @connection.sent_pings

#server_info ⇒ Object 



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# File 'lib/nats_async/client.rb', line 356

def server_info = @connection.server_info

#start(task:) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 168

def start(task:)
  return self if connected?

  @reactor_task = task
  @status = :connecting
  @connection.start(task: task)
  @started = true
  @closed = false
  ping!(timeout: @ping_timeout)
  @status = :connected
  start_ping_loop(task)
  start_request_timeout_loop(task)
  start_request_callback_loop(task)
  self
rescue StandardError
  stop
  @started = false
  @closed = true
  @status = :closed
  raise
end

#stop ⇒ Object 



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# File 'lib/nats_async/client.rb', line 230

def stop
  @request_timeout_task&.stop
  close_error = IOError.new("client closed")
  reject_pending_requests(close_error)
  reject_queued_request_callbacks(close_error)
  @request_callback_task&.stop
  @ping_task&.stop
  @reconnect_task&.stop
  cleanup_resp_mux
  @connection.close
  @request_timeout_task = nil
  @request_callback_task = nil
  @request_callback_queue = nil
  @ping_task = nil
  @reconnect_task = nil
end

#subscribe(subject, queue: nil, handler: nil, &block) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/nats_async/client.rb', line 286

def subscribe(subject, queue: nil, handler: nil, &block)
  ensure_open!
  callback = handler || block
  raise ArgumentError, "handler or block required for subscribe" unless callback

  sid = next_sid
  @subscriptions[sid] = {subject: subject, queue: queue, callback: callback}
  @connection.subscribe(subject, sid: sid, queue: queue) if connected?
  sid
end

#unsubscribe(sid) ⇒ Object 



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# File 'lib/nats_async/client.rb', line 344

def unsubscribe(sid)
  @subscriptions.delete(sid)
  @connection.unsubscribe(sid)
  true
end