Extra space in `[Producer ]` prefix of async producer logs

[junegunn]

If this is a bug report, please fill out the following:

• Version of Ruby: 3.1.0
• Version of Kafka: 1.1.1
• Version of ruby-kafka: 1.4.0

Please verify that the problem you're seeing hasn't been fixed by the current master of ruby-kafka.

Steps to reproduce

require 'logger'
require 'kafka'

kafka = Kafka.new('broker', logger: Logger.new($stdout))
producer = kafka.async_producer
producer.produce('{}', topic: 'foo')
  # I, [2022-03-28T09:58:47.029059 #16575]  INFO -- : [Producer ] Starting async producer in the background...
producer.deliver_messages
  # I, [2022-03-28T09:59:05.392330 #16575]  INFO -- : [Producer ] New topics added to target list: foo
  # I, [2022-03-28T09:59:05.393114 #16575]  INFO -- : [Producer ] Fetching cluster metadata from kafka://broker:9092

Expected outcome

I would expect to see [Producer] (without the space after r), or [Producer foo] once I see New topics added to target list: foo message.

Actual outcome

[Producer ]

I looked at the code and it seems that the trailing space was not intended.

https://github.com/zendesk/ruby-kafka/blob/d5def61ad82ca6ed2645939c202ec967208d7787/lib/kafka/async_producer.rb#L212

https://github.com/zendesk/ruby-kafka/blob/d5def61ad82ca6ed2645939c202ec967208d7787/lib/kafka/producer.rb#L160-L162

(@target_topics is empty when push_tags is called.)

Suggestion

• Add chomp or strip to Producer#to_s
• Or if it's possible, update the prefix when @target_topics of sync producer is updated. (proc tag?)