PIP-242: Topic name restrictions

[mattisonchao]

Motivation

Currently, the Apache Pulsar has no restrictions on the topic name. For example, we allowed users to create topic with -partition- keyword, which is confusing for our developers to identify whether this is a partition of a partitioned topic. Plus, we need to add more logic to be compatible with this special topic name. for example:

• [fix][broker] Support deleting partitioned topics with the keyword -partition- (#19230) #19240
• [fix][broker] Support deleting partitioned topics with the keyword -partition- #19230
• [fix][broker] Allow user lookup topic name with -partition- but no metadata #19171
• [fix][broker] Reject create non-existent persistent partitions #19086
• ...

Goal

This proposal aimed to add more restrictions for a topic name. that includes three parts as follows:

1. Using NamedEntity to validate the topic name characters.
2. Make the -partition- string the keyword. That allows the user to use it when it's a partitioned topic.

Create a topic:
no corresponding partitioned topic

• persistent://public/default/local-name (passed)
• persistent://public/default/local-name-partition-z (rejected by keyword)
• persistent://public/default/local-name-partition-0 (rejected by keyword)

Has corresponding partitioned topic, partitions=2 and topic partition name is persistent://public/default/local-name

• persistent://public/default/local-name-partition-0 (passed, Because it is the partition topic's sub-partition)
• persistent://public/default/local-name-partition-z (rejected by keyword)
• persistent://public/default/local-name-partition-4 (rejected, Because it exceeds the number of maximum partitions)

Create a partitioned topic(topic metadata)

• persistent://public/default/local-name (passed)
• persistent://public/default/local-name-partition-z (rejected by keyword)
• persistent://public/default/local-name-partition-0 (rejected by keyword)

Compatibility

We will introduce the new configuration strictTopicNameEnabled to support compatibility. Users can easily disable it to get rid of the restrictions.

API Changes

Add a new configuration, strictTopicNameEnabled=false.

Implementation

1. Add configuration strictTopicNameEnabled=false and make it dynamic.
2. Add topic name validation by NamedEntity
3. Add partitioned topic rejection logic.
4. Add warning logs to inform users that we do not recommend creating topics that name with the restrictions name when users disable enableStrictTopicName.
5. Make strictTopicNameEnabled=true in the next major release. and mark that this config will be removed in the future.

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