From: "byroot (Jean Boussier)" <noreply@...>
Date: 2022-07-28T07:31:23+00:00
Subject: [ruby-core:109348] [Ruby master Feature#18944] Add SizedQueue#push(timeout:)

Issue #18944 has been reported by byroot (Jean Boussier).

----------------------------------------
Feature #18944: Add SizedQueue#push(timeout:)
https://bugs.ruby-lang.org/issues/18944

* Author: byroot (Jean Boussier)
* Status: Open
* Priority: Normal
----------------------------------------
While implementing [Feature #18774] It appeared to me that adding this timeout was quite obvious.

And @matz explicitly asked for a separate ticket to be opened for that feature if someone wanted it: https://github.com/ruby/dev-meeting-log/blob/master/DevMeeting-2022-05-19.md#feature-18774-add-queuepoptimeout-eregon


`SizedQueue#push` already has a `non_block` argument like `pop`, so mirroring the change makes sense, and the implementations share a lot of code so it's really isn't that much maintainance.


As for the use case, I'd like to use a `SizedQueue` [in our `StatsD` library](https://github.com/Shopify/statsd-instrument/blob/da8a74c7fbe8fdd421aa1df7eda2a996bc7c3f11/lib/statsd/instrument/batched_udp_sink.rb), the code would look a bit like this (simplified code):

```ruby
@event_queue = SizedQueue.new(MAX_BUFFER_SIZE)
@dispatcher_thread = Thread.new do
  while event = event_queue.pop
    send_event(event)
  end
end

def emit_event(event)
  unless @event_queue.push(event, timeout: 0.1)
    if dispatcher_thread.alive?
      StatsD.logger.warn("Dropped event")
    else
      StatsD.logger.warn("Dispatcher thread died, restarting it")   
      # ...
    end
  end
end
```

But more generally, any action that may block forever (or for very long) should offer a timeout even if it's only used to be able to log that something is not supposed to happen an then retry. 



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