allow partition keys when producing messages

[xandroxygen]

• partition key defaults to the empty string in ruby-land, and is optional
• also makes some changes to the Message constructor
  • ruby doesn't allow overloaded constructors, so Rice ignores all but the last-defined constructor
  • replaced the Message(Message msg) constructor with a Message.from_message(Message msg) method, since Rice doesn't allow constructors to be associated with class methods
  • this is the reason that there is now only one Message constructor pushed to ruby-land, and it's the one that takes both data and partition key
  • it is possible to define default values in a Rice constructor, but since producer.send is providing the default value for partition_key, I didn't think it was necessary. this is up for discussion :)

TODO:

• make Message.from_message actually work
• if needed, that can be part of a later PR since it's not actually used anywhere in ruby-land

test plan:

• launch Pulsar standalone however you will and note the broker url
• in a new terminal:
  • export PULSAR_BROKER_URI=pulsar://<your pulsar url and port>
  • bin/console
  • producer = Pulsar::Client.from_environment.create_producer("test")
• in a second terminal:
  • the same export command as above, and bin/console
  • consumer = Pulsar::Client.from_environment.subscribe("test", "consumer1")
  • msg = consumer.receive
• in the first terminal:
  • producer.send("test without key")
• in the second terminal:
  • assert msg.data is "test without key"
  • assert msg.partition_key is the empty string
  • again, msg = consumer.receive
• in the first terminal:
  • producer.send("test with key", "the key")
• in the second terminal:
  • assert msg.data is "test with key"
  • assert msg.partition_key is "the key"

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[rwstauner]

can we please change to keyword arguments?
like #7 ? we can easily add support for more message builder attributes from there

[rwstauner]

I just pushed #9 to demonstrate how simply we can support additional properties (like partition_key) with the keyword arguments constructor.

[atezs82]

@xandroxygen what do you think about @rwstauner's question above? (We want to close or merge PRs in this repo before proceeding with further development.) Thanks!

[xandroxygen]

yep keyword args are great, and since #9 just got merged then I think this can be closed!

[atezs82]

Closing PR, see reasoning above.