Gerrit v2.14 / v2.15 talk at Palo Alto

This week we have published the recording of David Pursehouse (CollabNet) talk about Gerrit v2.14 and v2.15. Even though the releases are not new, there are many improvements were made recently, especially regarding the support for Elasticsearch as an engine to store the Gerrit secondary indexes.

Introduction

Hello, I am David Pursehouse, Gerrit Maintainer and release manager.

So, I’m going to talk about 2.14. Actually, this is the same presentation as I already gave last year. So, some of you may have seen it already. Although, I have made … how do I just … I have made some changes.

Basically, 2.14 isn’t new anymore. it’s already 18 months old, but even last year when I presented this, it was already six months old. And it has been in constant development since then. Even until this month we’ve been adding new stuff or making new releases.

And I’ll also touch a bit on 2.15 because yesterday evening we realized that there isn’t a 2.15 talk in the schedule today or tomorrow. So, I will briefly cover 2.15.

What’s new in v2.14

A number of new features in 2.14. I won’t read them all out because I’ve got separate slides for them, but there are some new features as well, which I’ll talk a bit more about later, which were not in 2.14 last year.

Some notes on important things about upgrading to 2.14, and actually the same things apply if you are upgrading to 2.15, 2.16. We require Java 8, so I assume most of you are already on Java 8 at least, so that shouldn’t be an issue, but these things are things that people run into when they’re doing the upgrades on the mailing list and issue tracker. So, these are the things that people have stumbled on that you should know about.

There’s no more HTTP digest authentication. This was basically because of moving to the accounts to NoteDb and not being able to store them in NoteDb. If you upgrade, it will get migrated. I think there were some issues with this initially, but they’ve been fixed in the bug fix releases. And the main thing for users here is that you can’t see your password in the UI anymore. It doesn’t display it. If you want a new password, you have to reset it, and then it disappears.

Also, there’s a new secondary index for groups, and you need to reindex that before you start the server. Otherwise your groups don’t work, and basically, Gerrit doesn’t work. And there are more details about this in the release notes.

Speaking of which, probably you have already seen this already because we’ve been sending out emails with the links, but we’ve moved the release notes to the new homepage, which is on www.gerritcodereview.com. When I wrote this last year, it was the case that the change would go live immediately after we submit them, but we’ve changed the hosting, and that isn’t the case anymore. Luca was going to fix that, but I don’t think he has. No. That will get fixed soon I hope.

New features in v2.14.

We move onto the actual new features. These are not in any particular order. It’s just a brain dump of the new stuff. Changes can now be assigned to people, and you can search for them with the new operators and make it highlighted. And that’s basically it. There’s no workflow around this. Gerrit doesn’t enforce any workflow for assigned changes. You can use it as you like, although I think there’s been some discussion about changing that to make it a more defined workflow so that people are more aware of what assignable changes are. There’s confusion among people about what does it mean when a change gets assigned to somebody. And right now it means nothing. There’s no enforcement of that in Gerrit.

Changes can now be deleted if they’re open or abandoned. This is kind of similar to previously with draft changes. You could delete a draft change, but now you can delete any change that’s basically not merged. And that can be done by the administrator or the owner of the change, assuming they’ve been given the capability. And this basically deletes the change completely. It deletes the ref. It deletes the metadata. And you can’t delete merged changes for obvious reasons.

The next one is reviewer suggestions. If you click on the box to add a new review, it will suggest based on previous users who have already reviewed your changes. And it can also be filtered. Also, there’s an extension point. Plugins can inject suggestions, although I’m not sure if any plugins actually implement that, but it’s there.

New email templates. Now we’re using a different framework for templating. It supports HTML, and the previous templating engine is going to be removed, actually is removed in 2.16. Still present in 2.14, 2.15, but deprecated.

Inbound email. This is a feature that was implemented by Patrick at Google. If you get a notification of a review from Gerrit, you can reply to that, and it will add the comments on the change. And if you click this link, you get more details about that.

Tagged comments. This is a way that enables you to filter the comments in the UI according to whether they’re by humans or robots, in this case meaning CI. So, for example, on the example here, you can see that all the CI comments are not shown on the right side. I think this only works in the new UI. I’m not … Is that right? I don’t know. Maybe it works in both UIs. I’m not sure.

So, in the new UI in 2.14 there’s been a lot of improvements compared to previously, and it’s basically usable for most of the common things that you want to do like reviewing changes, but there’s still a lot missing. A lot of the admin pages are missing. And you can switch between the two. So, if anything’s missing in PolyGerrit, you go to GWT and do it there. And if you look at this talk that’s linked here, it will give you an overview of the development of PolyGerrit, the idea behind it and so on.

The merge list is a dynamically generated list of commits that are going to be included by a merge commit, and it appears in the UI as a file that you can review, which is really useful if the commit author didn’t use a log option on the merge, so you can see what really is coming in by that merge and you can maybe catch if someone’s done it against the wrong parent or something. This isn’t actually a real file. It doesn’t get included in your commit. It’s just generated on the fly by the server.

Support for Elasticsearch as a secondary index

This is new since the last time I did this talk. And I want to thank Marco and David, who are the guys that really made this work. A lot of work went in by these guys to get Elasticsearch working. This is included since 2.14.8 with minimal support for Version 2 of Elasticsearch. And then there are a few maintenance releases which add support for five and six. If you look at this link here, you’ll see the more detailed list of compatibility between Gerrit and Elasticsearch. There actually was this week a new version of Elasticsearch, which will not be supported in 2.14 as far as planned. I’ve got a change up for review that will support that in 2.15.8, whatever the next one is. And I know Elasticsearch 7 is coming soon, but we haven’t started working on that yet. If we do, it’ll be in 2.15.whatever.

This is another new one since the last presentation. This object size limit is an option in Gerrit that’s been there for a long time. It allows you to prevent people uploading big files, but the problem with that was it was kind of weird to configure it. You couldn’t configure it on a project and have it inherited to the children projects. It was either global or per project. So, now you can configure this and have it inherited, but we made it so it’s disabled by default, so it doesn’t mess up anyone’s existing configurations.

And there was one minor update of LFS in 2.14.1. Actually, we added LFS in 2.13, but then we added support for the file locking. And the support for the Amazon S3 and File-system isn’t new, but previously there were separate plugins, and now we’ve rolled them together into the one single LFS plugin.

Overview of new features in v2.15

And now finally just a brief overview of what’s in 2.15. I’ve taken this from Dave’s talk from last year, but he had a lot of details about NoteDb, which I’m not really qualified to talk about, so I’ll kind of gloss over it a bit. There is a lot more PolyGerrit UI functionality, but it’s still not equal with GWT. You need to wait for 2.16 to get that. The support for NoteDb allows having some things that were not available before. The separation of reviewer and CC in the changes with a history of adding reviewers. Hashtags, actually, were introduced a long time ago, I think in 2.13, but required NoteDb, so it couldn’t really be used. The robot comments, which is basically CI can inject comments into the changes and suggest changes. You can also ignore a change, which means it will just not appear in your dashboard. You can mark it as reviewed, so that it will not be highlighted. There is also a really improved experience in diff between rebased patch sets, and again, in Dave’s presentation from last year, there is a lot more detail about that. So, if you want to know more, you can look at that.

We have a new change workflow. The draft changes are removed and replaced by private and work in progress, and David will talk about that this morning. And there’s a lot of other stuff that I kind of missed, but if you want to see that, you can look at Dave’s talk from last year, which is linked here.

Q&A

Q: We recently migrated to 2.14, and we often see the index and losing the indexing being really slow. How do we diagnose those issues, the indexing issues? I don’t see very good documentation on this.

A: If you have specific problems or issues and you have data to support that, you can submit a bug report or you can submit any questions to the mailing list. I don’t really know if there’s any way you can tweak that to make it perform better, but if you have specific questions, we can take them on the mailing list or in the issue tracker.

Q: Gerrit indexing works very badly when we have close to 2000 open changes. Is there a specific configuration to improve the performance? We are using v2.14.10.

A: I don’t know if there are any improvements from 10 up to the latest patch release. One thing about this 2.14 is we have made a much larger number of maintenance releases than previous releases, mainly because of the Elasticsearch support, but also there have been some pretty serious things fixed in these releases, so you probably should check the release notes and see if anything related to your issue is mentioned after 2.14.10.

Q: You mentioned Java 8. I was wondering if any later Java would also work, or does it specifically have to be Java 8? And generally, what’s the thinking about newer versions of Java support?

A: Yeah. There is work ongoing to support later versions of Java, and David Ostrovsky will tell you about that in his presentation.

David Pursehouse (CollabNet) – Gerrit Maintainer and Release Manager.

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