Hi everybody, Jason and I were recently discussing command line argument parsing on KAFKA-8131 (or rather the related pull request) [1].
Command line tools and their arguments are somewhat diverse at the moment. Most of the tools use joptsimple for argument parsing, some newer java tools use argparse4j instead and some tools use nothing at all. I've looked for a reason as to why there are two libraries being used, but couldn't really find anything. Paolo brought up the same question on the mailing list a while back [7], but got no response either. Does anybody know why this is the case? This results in no central place to add universal parameters like help and version, as well as the help output looking different between some of the tools. Also, there are a number of parameters that should be renamed to adhere to defaults. There have been a few discussions and initiatives around this in the past. Just of the top of my head (and a 5 minute jira search) there are: - KIP-14 [2] - KAFKA-2111 [3] - KIP-316 [4] - KAFKA-1292 [5] - KAFKA-3530 [6] - and probably many more Would people generally be in favor of revisiting this topic? What I'd propose to do is: - comb through jira and KIPs, clean up old stuff and creae a new umbrella issue to track this (maybe reuse KIP-4 as well) - agree on one library for parsing command line arguments (don't care which one, but two is one too many I think) - refactor tools to use one library and default way of argument parsing with central help and version parameter - add aliases for options that should be renamed according to KIP-4 (and maybe others) so that both new and old work for a while, deprecate old parameters for a cycle or two and then remove them I'll shut up now and see if people would consider this useful or have any other input :) Best regards, Sönke [1] https://github.com/apache/kafka/pull/6481#discussion_r273773003 <https://issues.apache.org/jira/browse/KAFKA-8131> [2] https://cwiki.apache.org/confluence/display/KAFKA/KIP-14+-+Tools+Standardization [3] https://issues.apache.org/jira/browse/KAFKA-2111 [4] https://cwiki.apache.org/confluence/display/KAFKA/KIP-316%3A+Command-line+overrides+for+ConnectDistributed+worker+properties [5] https://issues.apache.org/jira/browse/KAFKA-1292 [6] https://issues.apache.org/jira/browse/KAFKA-3530 [7] https://sematext.com/opensee/m/Kafka/uyzND10ObP01p77VS?subj=From+Scala+to+Java+based+tools+joptsimple+vs+argparse4j
