Method: Natsy::Client.start!

Defined in:
lib/natsy/client.rb

.start! ⇒ Object

Start listening for messages with the Natsy::Client::start! method. This will spin up a non-blocking thread that subscribes to subjects (as specified by invocation(s) of ::reply_to) and waits for messages to come in. When a message is received, the appropriate ::reply_to block will be used to compute a response, and that response will be published.

NOTE: If an error is raised in one of the handlers, Natsy::Client will restart automatically.

NOTE: You can invoke ::reply_to to create additional message subscriptions after Natsy::Client.start!, but be aware that this forces the client to restart. You may see (benign, already-handled) errors in the logs generated when this restart happens. It will force the client to restart and re-subscribe after _each additional ::reply_to invoked after ::start!._ So, if you have a lot of additional ::reply_to invocations, you may want to consider refactoring so that your call to Natsy::Client.start! occurs after those additions.

NOTE: The ::start! method can be safely called multiple times; only the first will be honored, and any subsequent calls to ::start! after the client is already started will do nothing (except write a _“NATS is already running”_ log to the logger at the DEBUG level).

Examples:

Natsy::Client.start!



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# File 'lib/natsy/client.rb', line 95

def start!
  log("Starting NATS", level: :debug)

  if started?
    log("NATS is already running", level: :debug)
    return
  end

  started!

  thread = Thread.new do
    Thread.handle_interrupt(StandardError => :never) do
      Thread.handle_interrupt(StandardError => :immediate) { listen }
    rescue NATS::ConnectError => e
      log("Could not connect to NATS server:", level: :error)
      log(e.full_message, level: :error, indent: 2)
      Thread.current.exit
    rescue NewSubscriptionsError => _e
      log("New subscriptions! Restarting...", level: :info)
      restart!
      Thread.current.exit
      # raise e # TODO: there has to be a better way
    rescue StandardError => e
      log("Encountered an error:", level: :error)
      log(e.full_message, level: :error, indent: 2)
      restart!
      Thread.current.exit
      # raise e
    end
  end

  threads << thread
end