In high level I see this work as needed cleanup indeed and very much needed
On Tue, 11 Jun 2024 at 20:29 Lari Hotari <lhot...@apache.org> wrote: > Hi all, > > We have the next LTS release, Pulsar 4.0, scheduled for October. The > current master branch will most likely become the 4.0 release branch in > September. > > Since 4.0 will be the next LTS release, we aim to complete larger > changes in the codebase before the release. I'm particularly interested > in cleaning up the Managed Ledger interface. > > The cleanup of the Managed Ledger interface involves changing the Pulsar > core to depend on the interface, not on the implementation details. > Currently, this is not the case. A lot of Pulsar core code specifically > depends on implementation classes such as ManagedLedgerImpl, > ManagedCursorImpl and PositionImpl. > > In addition to decoupling the core of Pulsar from the implementation > details of Managed Ledger, I'm also planning to rename the base package > of the Pulsar Managed Ledger module from org.apache.bookkeeper.mledger > to org.apache.pulsar.mledger. There are historical reasons why the > package prefix is org.apache.bookkeeper. I suppose there was a plan a > long time ago to move the module as part of the Bookkeeper project. That > goal no longer exists. The consequence of the > org.apache.bookkeeper.mledger package is that Managed Ledger log > messages contain the org.apache.bookkeeper.mledger prefix, which often > confuses Pulsar users and developers about the component's origin. This > will finally be addressed during this work. > > I plan to make changes gradually in the master branch without breaking > external Pulsar end-user interfaces. Therefore, these changes can be > considered as internal cleanup and refactoring, which don't necessarily > require a PIP decision before proceeding. > > I do plan to create a PIP document later to collect some of the design > decisions once they are made. However, at this moment, there are no > significant up-front design decisions that need to be made by the > community. In Apache projects, decisions are made on the mailing list > and this thread is one form of making decisions. Unless there are > objections to what is presented here, I will proceed with the work > as planned. Individual work items will be reviewed in PRs as usual. > > One detail to solve and document is how Pulsar code maintenance will be > handled once the master branch has diverged significantly from the > maintenance branches. It seems that Pulsar 4.0 will be the first branch > where there will be significant differences between the previous > maintenance branches. This challenge will be addressed in the PIP > document when it becomes timely. It will also require documenting > changes to contribution guidelines so that contributors know how to > contribute to the maintenance branches. Currently we primarily target > the master branch in PRs. > > Decoupling Pulsar core from Managed Ledger implementations will open up > ways to add new Managed Ledger implementations in the future and make it > pluggable. This will help Apache Pulsar stay relevant in the future. I > believe other Pulsar contributors share and support this goal too. > > Please review the first PR for cleaning up Managed Ledger interfaces: > "Replace dependencies on PositionImpl with Position interface" > https://github.com/apache/pulsar/pull/22891 > > Since this is a prerequisite for the next work items in Managed Ledger > interface cleanup, I hope that we can complete the review of this PR asap. > We don't have much time to waste before the 4.0 release freeze in > September. > > Looking forward to your feedback and contributions in this area, > > -Lari >
