Gerrit Code Review is unstoppable: despite the recent COVID-19 pandemic and the cancellation of the Spring Hackathon 2020, the community has made an extraordinary effort to deliver remotely and on-time the Gerrit v3.2 release on the 1st of June.
The migration process performs the cleanup of the zombie draft comments in the All-Users.git repository that has been left behind since the introduction of NoteDb back in v2.16.
Every user commenting on any change was creating a series of commits on the All-Users.git repository, where the draft comments are stored. Once the comments were finalised and applied to the change, they were not fully removed from the All-Users.git. That created a backlog of zombie comments on All-Users.git that are now being completely removed during the Gerrit v3.2 migration process.
Since Gerrit v2.16.16, there is a standalone utility to remove the zombie draft comments. You may want to do that operation upfront to make sure that the migration to v3.2 does not have a lot of processing during the init step. Also, make sure that the All-Users.git resides on a fast access local filesystem for minimizing the migration time.
If you do nothing, the cleanup utility will be automatically executed when migrating to Gerrit v3.2, bearing in mind that it may take quite a long time to complete. In our tests, it took around 10 minutes for 10k zombie comments.
WARNING: the execution time is not linear and it may take up to 48h of processing time for a staggering number of 1M zombie comments.
Migrate with zero-downtime
If you have on Gerrit v3.1.x in a high-availability configuration, you can upgrade seamlessly to Gerrit v3.2, without having to suspend or degrading the service in any way. GerritForge has a record number of installations done in high-availability and multi-site: if you are running a single Gerrit master today, you should get in touch with the GerritForge Team to help moving to high-availability.
For the very first time, the whole Gerrit Community can benefit from the ability to perform a rolling upgrade without any downtime.
The zero-downtime upgrade consists of the following steps:
Have Gerrit masters upgraded to v3.1.6 (or later) in a high-availability configuration, healthy and able to handle the incoming traffic properly.
Set gerrit.experimentalRollingUpgrade to true in gerrit.config on both Gerrit masters.
Set the first Gerrit master unhealthy.
Shutdown the first Gerrit master and then upgrade to v3.2.
Startup the first Gerrit master and wait for the on-line reindex to complete.
Please verify that the first Gerrit master is working correctly and then make it healthy again.
Wait for the first Gerrit master to start serving traffic regularly.
Repeat steps 3. to 7. for the second Gerrit master.
Remove gerrit.experimentalRollingUpgrade from gerrit.config on both Gerrit masters.
GerritHub.io has been successfully upgraded on the 1st of June without any interruption of any kind using the above procedure.
Java 11 official support
Gerrit is now officially supported on Java 11, in addition to Java 8. Running on Java 11 was already possible from v2.16.13, v3.0.4 and v3.1.0, but not officially supported because of the lack of a CI validation on Java 11 for stable-2.16, stable-3.0 and stable-3.1 branches.
Gerrit v3.2 has been validated with Java 11, with the following known issues:
Issue 12639: WARNING: An illegal reflective access operation has occurred, when starting Gerrit.
After 24h of adoption of Gerrit v3.2 on GerritHub.io, we have seen two major benefits from the migration to Java 11: overall reduction of the “old generation” build up in the JVM heap and massive reduction of GC cycles times and full-GCs.
Before the 29th of May, all GerritHub.io nodes were on Gerrit v3.1 / Java8. The old-generation JVM heap keeps on building up constantly until it reaches the 60GB and triggers a full GC cycle. After the upgrade to Gerrit v3.2 / Java11, memory consumption is very much under control. There are still possibilities of peaks with associated full GCs (see the one on the 30th of May around 12:00 BST) but there isn’t build up of old-generation objects anymore.
Java11 brings a lot of benefits also in reducing the latency of the individual GC cycles, showing much better performance with large heaps.
After the migration on the 29th of May, the GC graph is pretty much flat. The only full GC peak that is noticeable on the 30th of May lasted for just 5 msecs while the normal GC cycles are well below 1 msec, barely noticeable.
Performance is a feature
Shawn Pearce, the Gerrit Code Review project founder, used to say “performance is a feature”, which is very true. Any software nowadays can provide some basic out of the box features, thanks to the plethora of open-source components available out of the box. However, designing architecture and making it scale and perform to the levels that an Enterprise Code Review system needs, it is not easy.
Gerrit v3.2 is yet another significant milestone in the continued effort of the Gerrit maintainers and contributors in making Gerrit Code Review faster, more stable and available than ever before.
New accounts cache
From the data collected on googlesource.com Patrick Hiesel (Google) has identified the accounts loading from NoteDb as a significant cause of the delay of backend calls. That is true for all Gerrit installations, but especially for distributed setups or setups that restart often.
Gerrit v3.2 introduces a brand-new AccountCache decomposed into smaller chunks that can be cached individually:
External IDs + user name (cached in ExternalIdCache)
CachedAccountDetails (newly cached)
Gerrit’s default settings CachedAccountDetails – a new class representing all information stored under the user’s ref (refs/users/<sharded-id>).
The new structure is cleverly designed to require a lot less I/O when an entry needs to be reloaded and lowering the ratio of cache-miss in case of user’s details updates.
The new structure has the following advantages:
CachedAccountDetails contains only details from refs/users/<sharded-id>. By that, we can use the SHA1 of that ref as cache key and start serializing the cache to eliminate cold start penalty as well as router assignment change penalty (for distributed setups). It also means that we don’t have to do invalidation ourselves anymore.
When the server’s default preferences change, we don’t have to invalidate all accounts anymore.
The projected speed improvements that come from persisting the cache makes it so that we can remove the logic to load accounts in parallel.
Migration to Polymer 3
PolyGerrit UX roadmap continues with yet another important milestone: the migration to Polymer 3. The result is visible with an improved polishing of the GUI and significant speedup of rendering and reduction of page loading times.
There are a significant amount of small refinements to the GUI as well, coming from a meticulous work of fixes included in this release.
Not by surprise, the number of issues fixed in v3.2 on the PolyGerrit UX outnumbers by far the overall changes in the release notes.
PolyGerrit is giving special attention to the classification of the feedback coming from robots rather than humans.
Most of the efforts made in the past 12 months target the improvement the support for robot-comments and giving some extra dedicated space for them.
In Gerrit v3.2 there is a special place for them in a brand-new “Findings” tab. It is currently empty on GerritHub.io as people did not start using them much. However, I do see a lot of space of adoption of this new feature, giving the ability for more integration of linters and automatic validation feedback in this tab.
A flooding of fixes and small improvements
The list of fixes and improvements in Gerrit v3.2 is really huge. Please check the release notes on the Gerrit Code Review release page for all the details.
There are a lot of reasons to migrate to Gerrit v3.2, the fastest, more stable and scalable release of Gerrit Code Review ever.
Thanks a lot to the whole Gerrit Code Review Community of maintainers and contributors for making this release happen. Thanks to Patrick Hiesel for the technical description of the account cache improvements and the replication clustering.
The second presentation this week from the Gerrit User Summit 2017 is about PolyGerrit, the new Polymer-based UX for Gerrit Code Review, officially feature complete for Code Review in Gerrit Ver. 2.15.
I am going to talk about the development of PolyGerrit, why we are making PolyGerrit and what we’ve done over the past two years.
Arnab is going to present a new visual design we are going to start rolling out to googlesource.com, and to the next release of Gerrit.
Dustin is going to give some findings from the user research on the survey I believe that many of the people in this room may have received the questionnaire on Gerrit and have responded.
Established November 2015
Author: Andrew Bonventre <email@example.com>
Date: Wed Nov 4 11:14:54 2015 -0500
Add the skeleton of a new UI based on Polymer, PolyGerrit
This is the beginnings of an experimental new non-GWT web UI developed
using a modern JS web framework, http://www.polymer-project.org/. It
will coexist alongside the GWT UI until it is feature-complete.
That is the very first commit we did on the PolyGerrit project, it was founded by Andrew Bonventre from the Chromium project and the commit message summaries up pretty well.
Based on the Polymer Project
Polymer is pretty essential to PolyGerrit, and that’s why is part of the name. The Polymer project is not a framework but rather a collection of libraries and tools and components that have been developed by Chrome at Google. The idea is the build beautiful web applications on top of the standard web platform. Some critical aspects of the web platform that we use are web components which are built on top of templates that you can import into your HTML file and shadow DOM which is a way of encapsulating your stylesheets into your templates so that you can build reusable components.
Another significant aspect of the Polymer project is the collection of custom elements. They are organized into groups and given chemistry names. We use iron elements pretty heavily; they are the basic building blocks for HTML.
We are starting to use elements from the paper collection which are higher level UI elements that introduce material design. They look nice, they are high level and reusable elements. They let us focus on building code-review without having to rebuild everything from scratch.
Q: Can you explain a bit more on what material design means?
A. (Arnab) Material design is a new design language that Google came out of it in 2015. It’s a library of all the modern components with great look and feel.
Material design elements come with a lot of features like animations and smooth transitions which makes your UI more dynamic, it’s hard to show in slides all that dynamism.
Current status of PolyGerrit
We have been working on PolyGerrit for two years now, and in that time we got a lot of contributions from outside the project, we have a few dozens of contributors, checked in thousands of commits, and we closed almost a thousand issues from our issue tracker.
As far as I know, there is no other significant deployment of PolyGerrit outside of Google and GerritHub.io, but we have been having used in Google for a while, and we see 10k code-reviews a day involving PolyGerrit, at least on a workday. We have got a few major OpenSource projects using it, Chromium has recently transitioned to PolyGerrit, and brings up almost 2000 developers.
I’ve put some other recognizable OpenSource projects like GoLang and also the Gerrit project itself, where we configured gerrit-review.googlesource.com to use PolyGerrit by default. That helps us get early feedback on the functionality and the design of PolyGerrit.
Chromium migration to PolyGerrit
What about Chromium? It is a significant milestone for our Team, and I also think for the Gerrit project. The Chromium project has a very complex system for checking their code and for builds. They have built the system themselves and they used it to run their code-review system them as well based on Rietveld. Unfortunately, that is a sort of unmaintained instance of Rietveld running on AppEngine they did not want to use anymore and also it wasn’t scaling very well for them. There were even commits that they couldn’t review on that system because they were too large.
So a lot we’ve been working at that time, it was allowing Gerrit to come to a state so that Chromium could use it. Part of that was building a nice UI, and part of that was taking features they have been enjoying in Rietveld and bringing them over to Gerrit. Some of them are small things like user account statuses, so that you can tell people that you are not in the office and you can’t do code reviews this week, or having descriptions to your patch-sets so that you can explain what this revision means.
And also they’ve built a lot of new customizations, and they got us flush out a plugins API, and I’ll show one example here. So Chromium has a pretty heavyweight CI system because they have to build Chromium for a lot of different platforms and different architectures and they have a lot of incoming commits. So they need to find a way to verify that a commit that is coming into the code, actually works and in which order to check in those changes, so that is not breaking the build.
One thing that they’ve built for PolyGerrit is a plugin to add these elements to the screen for visibility to what’s going on in their system. The builds that are running for their commits, their status, often the flaky, so that by clicking on these you can see the output of the build. You can also use this UI to start a particular build and chose which architecture you want to run on or re-run things that failed. I think we should be building better integration to Gerrit for these sort of things because those are what big and small projects need, but it is cool that we can do these things with plugins as they are now.
What’s new in Gerrit 2.15 for PolyGerrit
We made a lot of performance improvements in the application. For example, sometimes we have commits that have thousands of files, and we have to have a way to display them intelligently, we cannot just throw them on the screen. We needed a sort of new navigation for these kinds of things, and we have adapted PolyGerrit to work with any variety of commits of different shapes and sizes.
Some specific things we added that are kind of cute. PolyGerrit offers a reply dialog to manage your reviews, reply to comments, vote on labels, and submit that all as a single batch operation. We added some nice features to this reply dialog since Ver. 2.14, one is being able to preview how your reply will be formatted. Not just to show you how your answer is going to look like but now it renders in the same it would end up in the e-mail because we have HTML e-mails.
We have also reorganized how voting buttons are arranged, there is this beautiful vertical alignment, and you can see the labels that give you the meaning what +1 means for that label. We have a slightly updated patchset selector. That is important because one of the things people struggle with it is navigating a code-review. If there are more patches, understanding where the comments are can be challenging, because of comments land on different patchsets.
We also introduced the feature of resolvable comments, so that you can mark a comment as fixed or done and we can track that for you. You can see that on some patchsets there are some comments you haven’t reply to yet or has a review, and you can verify that everything has been addressed.
The PolyGerrit Admin UI
Another major area that we have been working at is one of the significant features that PolyGerrit has compared to the old version: the admin UI.
A lot of our users had to switch back and forth to do the admin work. We’ve been building up this part of the application. We have rearranged that a little bit, we changed the title by clicking on the browse link on the top menu. Our idea is that you can get to this like the project home page for a repository, where you have to check out instructions and is also the entry point for administering the project.
We have almost all the primary forms for managing groups and projects completed. We have also released a read-only version of the sophisticated project access rules editor. It is read-only mode because we don’t want anybody to risk losing their project.config because of a bug in this: project.config tends to be a very security sensitive thing.
What’s next for PolyGerrit.
We are still working on replacing the GWT UI; we’re getting close. One of the significant features remaining is in-line edit. We’ll be working on that over the next few months, as long as the long tail of the specific missing pieces of the UI. And then we are going to roll out a new visual design which Arnad will be talking about shortly.
We also want to do in the longer term more significant changes to the UI of Gerrit, to show how accessible is to the users, because when people learn how to use Gerrit they love it, but the initial learning curve is a bit difficult at the moment.
PolyGerrit UX New Look (Arnab Banerjee, Google)
We are working on a new look; I’ll just be giving you a quick glimpse of what it looks like. We know that Gerrit and PolyGerrit work very well for the users, but we want to improve its usability as well as the status of the tool.
For improving usability we think there is a long process. We don’t want to break what’s already working for you, and that’s why it will be more an evolutionary process based on user-research and feedback.
However, we started by looking at the aesthetics of PolyGerrit and giving it a new look. A few critical goal that we had is that design should represent what PolyGerrit is and stands for, having a more contained group of information in a way that you know exactly where to find a particular group of information. Also more consistent UI behavior across the board: as soon as you look at the component you see what you can expect what the element is supposed to do. Also, we want to introduce a more up-to-date style of components and fonts, which means: material design.
What should drive the experience we want to create is what we really want to achieve with PolyGerrit.
Confidence: we want you to be confident with the code you are submitting and is going out there.
Scalability: we want PolyGerrit to manage the small as the significant and more complicated change.
Efficiency: we want to increase the efficiency of your team as making the code review process more efficient.
Intelligence: PolyGerrit should be smart enough to do all the repetitive task that you otherwise would have had to do manually. Wisdom: PolyGerrit should be mean to share the knowledge on the team.
PolyGerrit is Blue
One color that captures all of that very very well is blue. So we picked blue and made the primary color of PolyGerrit.
That is going to be the default primary color but you can change it for your team.
That is the new and refreshed look of PolyGerrit.
There are three distinct layouts for PolyGerrit:
The change screen
PolyGerrit new Change Screen
The change screen is the most used screen in PolyGerrit, so we thought why not start by giving this a new look.
For this presentation, I will just talk about how the new PolyGerrit style works on it. Let’s talk about the visual elements on this page and look at it with a little bit of detail.
One of the things we have added in PolyGerrit is the breadcrumb where you can quickly jump back to wherever you came from. The next is the status, and now we have a clear status indication of the change so that just looking at this state you can understand if the change is it is closed or opened, and the color line adds to this the indication of the change.
Let’s talk about the meta-data of this page, we have now a much more visual structure of spaces, fonts and colors and actions that are now material flat buttons, and they are different from links, which will be all caps and different fonts altogether. So visually you see the difference in what will take you to another space and what will take action. When you click on add assignee, you get this in-line box which let you add assignee, and this is just a more elegant way of putting inline data, it just makes the action so much more clear.
When you click save, you can see the assignee name populated and assigned to the assignee label.
Once you start typing will just suggest the names while you are typing and topics also work in the same way.
Now coming arguably to the most used section of this page which is the files table, and you may notice these two header rows, the file heading and we just combined the information of these two rows into one row.
Let’s look at the elements of this particular section. The first part is the patchset selector. If have both the selected patchset as well as the original patchset, you can see them together side-by-side, so that you don’t have to look all the way to the right to select the referenced patchset.
Once you click on the patchset dropdown, you have a different layout for this different drop-down menu. On the left side you can see the patchset as well as the patchset description, and on the right side, you can look at the comments and the unresolved comments. That makes scanning through this list so much more comfortable, especially if this list is long.
Then adding patchset description also works in the very same way. It just shows the inline edit box, and you just enter the patchset description and say “save.”
Now we have a separate interaction for marking the file as reviewed when you hover on this rows. The mark reviewed shows up on the right-hand side, when you click it you can see a column on the right-hand side of the mark as reviewed and when you click review this text shows up a toggle button.
On the top-right, we have now the table actions, and we just have two actions by default. The first action is “expand all” and the other is “download.” If you click on expand all you see this diff view expanded and you see some icons that appear on the top. So the “expand all” button changes into “collapse all” and you can change from side-by-side to unified diff-view or even change your diff-view preferences.
That is just a tiny step towards what we can do and is just the tip of the iceberg, and I think we’ll reach out to you for more feedback and do more user research for really making PolyGerrit a tool that you’d love as code-review tool.
PolyGerrit User Research (Dustin Smith, Google)
I am a user researcher at Google, and my job is to communicate with our users and take what you tell me and distill what we can do and what changes we need to do to our product.
Being an advocate for all of you in the meetings because I am not a developer I am not a designer and my role is mainly to communicate what you need to our developers and feedback them to our designers. I collect feedback and distill your needs. Arnab will come up with new designs, and we will come back to you and say “how did we do based on your feedback?” Then we will repeat that process to infinity, and that’s how research gets integrated into the design.
So if you are not a member of the Gerrit Google Group (repo-discuss) , I highly recommend you to join. You can yell at us there; you can say “I really don’t like what’s going on in the product, ” or you can praise us, whatever you like. At some point, you can send us surveys through there and hopefully not a very long survey that helps us aggregate all your needs.
User Survey results on Gerrit Code Review
An example of that we sent out a survey in June and 600 of you responded. We received a lot of nice praise, and that’s great, but we’re also looking at ways to improve Gerrit, and we asked you to rank of what would be your priority.
What you see on the top here is that all the people that answered the survey is interested in improving the navigation of Gerrit, whether it is a patchset navigation, commenting, or other UI navigation. There is also another related to better integration with other tools. We are curing that feedback. Something to keep in mind is that even though there are things at the bottom that are ranked at zero, that doesn’t mean that you don’t want those things but they are relatively listed.
Q (Han-Wen Nienhuys, Google). I am wondering, who is in this group of users you asked because one of the things entirely at the bottom says “improve the reliability of the backend” and then very much at the bottom is “better performance” which is kind of what our Team is continuously worried about. Even yesterday we had a Hackathon and the friends from the Android Team on Sunday morning, and we were all in panic, but I see that “nobody cares about it,” how comes?
A. That’s a fair question, who did we sample? These users were external users of Gerrit, and only 13 of them were PolyGerrit users, so what you’re looking at here, 95% of them are external users. Having said that, why ranking better performance and reliability the lowest, I am not sure how to answer that question.
A. (Gerrit admin from the audience). For us obviously reliability of the backend is important, but the question was “does reliability need improving?” and for us, Gerrit works quite well and we are very happy with it.
A. (Luca Milanesio, GerritForge) I believe that my is very similar to that. First of all, the people you are aking to. You’re not asking Gerrit administrator, but just people that are using as a UI. The people that are using the GUI are saying “reliability is currently 99.99%, do you need to make it 99.99999%? Not really”. What needs improving is what you guys are focused on: usability, discoverability, and leveraging all the power that is out there.
A. That’s a great point and keep in mind that all the items on the bottom of this list don’t mean that people don’t like them just that other aspects that need improvements are ranked above it.
People did not say “I dislike the idea of better performance, ” but more often than not, people selected the options above it before the better performance.
Other highlights from people, maybe people that is one of you, navigation is important “Getting an overview of the change I’m reviewing is hard. When a change is composed of several files, the file navigation feels like a pain”.
We are taking these feedback and then moving forward, and also some complaints about the search itself. The search could be better, for example, “I want to search a commit that includes a particular file.”
And then, integration. I would like more Jenkins integration for passing code coverage reports into Gerrit. If these quotes that I pulled out are jelly with you wonderful, if you like there are things that are missing and you are not being heard, I am the person to talk to. I need to make sure that you are heard. There are also some other options I am going to show you. How many of you are aware of userresearch.google.com?
PolyGerrit Research: call to action
If you’d like to, you can sign up here. What we will do is substantially having a look at the new designs, you can spend an hour with me, maybe 30′ depending on how busy you are, and I’ll show you some new designs, and you’ll get a gift for your time. I am not the only user searcher at Google, and this is not the only product that is supported by this, but I am interested in hearing your feedback about Gerrit and runs studies on here, and you’re welcome to join me.
Today and tomorrow we have a booth that you may have seen already with this banner, and we have a new dashboard design, a new patch navigation system and a new navigation for related changes that we’d loved to have you have a look at. We are not showing them on these slides on purpose because we want you to see the designs and come with a bunch of feedback on your first impression to the UI.
Please come to the booth and talk to any of us, there is Jason Buberel with us (our Product Manager), you’re welcome to come and speak with him as well, and almost all the Googlers here are willing to show some of the new designs.
Q. How exactly you come out with a new design, the layout, how to make it better. How do you know that the user experience is better compared to the previous old one?
A. I take what your pinpoints, what you love, and I tell Arnab, and then he comes with a new concept. How do you know if that is better? Typically you generate tasks of what you would usually do with our UI, and we then do a tasks assessment where you see the goal that you go through those tasks and see if they failed. You talk aloud thinking while you go through those tasks and you may say “I really don’t like this new UI” and from that, you do mainly a mini A/B test. You can go through this process for just a few people and you don’t have to build up the entire product that everyone sees.
Q. I remember when a couple of years ago there was the announcement that we are going to have the new PolyGerrit project. We all asked “when the new GUI is going to be available?” and the answer was “six, maybe twelve months.” Now after two years we have something that works that is PolyGerrit, we started using it, and we like it. There are still gaps that are not really on the change screen, which is way better than the old one. I can use it on my Tube in the morning on the mobile phone while the old GUI did not even render or it was so tiny that you could not even see it. The gaps are more on the other parts of the UI. 50% of the users are using Gerrit as a very reliable Git server, have you put on your radar all the other use-cases not directly related to code-review that currently PolyGerrit is not covering?. The on-line editing, the code-browsing, the user-journeys from the code to the review and the way back, integrated search across code and the associated reviews?
A. Something is clearly in the scope of Gerrit, and something is not, but that does not mean we are not interested in it. Source browsing is one example of it, and I don’t think it will be in PolyGerrit but that does not mean that we are not interested in a way to browse source code. We are working on the in-line edit, maybe is not something we looked at the usability of it yet, it is a bit lower on the list of priorities, but are starting with the implementation and Arnad has been helping us with the basic design elements of that. It will be a basic feature at first, but it will look nice and be usable to some extent, and then we iterate.
Q. What about the completely new redesign? Are your efforts directed in completing what is there or are on reinventing everything from the ground up and we have to wait for another two years?
A. We are focused on the immediate terms of completing PolyGerrit because for many technical reasons we want to replace the GWT UI and we want to have more users using PolyGerrit so that we can get feedback to keep going. As we get more and more feedback and more and more iterations on PolyGerrit in the wild, we will come up with a lot more work for us to do. In the near term, we are going to implement what Arnad has presented and while we are doing that Arnad will help us by collecting some more feedback around what you will see at the booth, around the new dashboards and we are going to keep working on that. PolyGerrit is not going to stay static as it is today, it is going to be more iterative process based on Gerrit @Google and the Gerrit master branch. At every release cycle of the Gerrit OpenSource project, we will include some significant improvements on the user experience.
Q. I am just wondering how the new users get represented in your user research. Maybe people coming from GitHub or GitLab but even other people coming from different source control systems such as Perforce or SVN. How do you capture their experience? A lot of us have used Gerrit for a while and understand to a degree, Gerrit. However for other people, at times is a kind of a ping-pong, even though you are a new user for a very short time until you learn Gerrit.
A. On-boarding is definitely on our radar, we take users that have not used Gerrit before, and we ask to perform certain tasks. That is the kind of the recipe: take people that never used the product and working with Arnad on their feedback to make that process smoother.
Q. How many research you have made on the other code-review tools, advantages and disadvantages over Gerrit?
A (Dustin). It is an approach I am willing to take, doing a kind of competitive analysis. I have not started yet, but it is definitely on the roadmap for research.
A. (Jason). If there are other code-review tools that you’ve used and something that worked well, something that Gerrit or PolyGerrit could benefit from their knowledge or usage, please let us know. Nothing is off the table here concerning what we will improve or consider improving. If you used other code review tools, e.g. “hey reviewable.io got this very pretty good thing, you should do something really similar to that”, by all means, please let us know because we are opened to improvements in all areas.
Q. Following-up on this question, there will be talk tomorrow on this, our friends from CollabNet that are contributing to Gerrit Code Review have clients that are using not only Gerrit but even other tools like GitHub and many of them are hearing concerns of people getting lost without their pull requests. Because they are coming from other tools like Atlassian BitBucket, they have the concept that “without a pull request there is no review.” They have as well the misunderstanding that Gerrit forces you to amend the latest commit all the times, which is wrong. Gerrit allows you doing whatever you want. If you want to amend, you can do it; if you want to use feature branches you can do it as well. I remember Martin last year saying that they are using feature branches at Qualcomm and there is nothing wrong with it. CollabNet has developed a very basic UI that allows people that are coming from the pull request workflow to keep on using that paradigm. This UI is a sort of lightweight code review that helps to digest Gerrit gradually. That could be even the key to solve the dilemma raised on a recent discussion in the GoLang project where people asked to stop using Gerrit and instead using GitHub to review contributions. Following the discussion thread, it emerged that Gerrit is “too good” and does exactly what they need while GitHub doesn’t. However, there are concerns about other potential contributors coming from a GitHub experience having to invest 15′, maybe 30′ or even one day of learning of the Gerrit Code Review workflow and a new UI paradigm. They may decide to give up and avoid contributing at all. If the project would move to GitHub pull requests, this problem would just disappear. Are you guys taking into consideration how to make this transition from GitHub smoother and Gerrit easier to understand for those guys?
A. That’s a great question, and as the formal product manager for the GoLang project, I heard from some members of the community of the project that they were relatively unwilling to contribute. We saw this type of disparity from the casual contributors. Those are the people that find a typo in the docs and just want to fix it quickly. With the GitHub UI is nice because they see the problem, they click Fork, edit the code on a single line or merely a single file, and they create the pull-request with a straightforward review process and gets merged and done. You never had to clone the repository, did not have to figure out the authentication bits, and that is simple. You know, whether we want or not to take Gerrit down a path where we want to make these casual contributions super-simple it is something we are open to if that is what the Gerrit community thinks is a significant capability. At the same time, we do not want to displace GitHub with Gerrit, there is a vast community there for a reason, but there are specific workflows like the casual contributors’ workflow that are certainly easier on GitHub and much more difficult for users that are new to Gerrit. It is an area where if we think there is a need for, we should think about it and consider how we may support such a thing. We are open to hearing more feedback on things like that.
A. I just came from the OpenStack developers’ summit in Colorado a couple of weeks ago, and we were having the same conversation regarding onboarding contributors to OpenStack. Most of the people coming from GitHub are having the same hurdle. One of the things that were discussed out there was having some documentation, some quick-start, cheat-sheet, crash course, for people that are familiar with GitHub. It is not just about enhancing Gerrit code to make it more friendly and port the workflow they are used to use but provide content that helps people, coming over.
A. Dave is one of the tech writers at Google who works explicitly with Code Review. If you have a specific part of the documentation set that you think it needs improving or a brand new part of the documentation set that could be useful to new users, come to him and talk today or during the next days. He will be happy to help.
A. I have started already building a spreadsheet, a kind of rosetta-stone of mapping concepts and commands for mapping one to the other and I’ll show you that. That is just one approach, yes, but there are some pros as well.
See below an overview of the topics that will be presented and discussed during the User Summit.
What’s new in Gerrit 2.14.x.
Gerrit v2.14 was released during the last Hackathon in April and has gone through three patch releases. David Pursehouse from CollabNet will give an overview of the new features introduced which would be highly beneficial for all of those who haven’t migrated yet.
Gerrit at Google: Multi-master, Mutli-tenant.
Google is the founder, main contributor and possibly the most advanced user of the Gerrit Code Review: learning from their experience is a unique opportunity to learn and being able to leverage and use the tool at its best.
Patrick Hiesel from Google will go through the insights of their Gerrit Code Review architecture and will provide some of their metrics of scale. In addition to that, he will present some findings from the recent switch of their load-balancing infrastructure and the associated pitfalls encountered.
Google is possibly the only one in the world using Gerrit in a multi-tenant setup, having a unique multi-master installation that serves a constellation of domains and projects, including huge and familiar ones like Android and Chromium.
Standing “on the shoulders of giants” like Google helps a lot in preventing scalability issues as the audience and adoption of Gerrit Code Review grows in large companies: being part of the audience in the talk is a unique opportunity to learn and ask questions directly to the maintainers of their infrastructure.
PolyGerrit: a new UX experience for Gerrit Code Review
Google has invested a lot in reinventing and reengineering the user interface of Gerrit Code Review, which remained mostly unchanged for almost a decade. A new team has been put together in their San Francisco offices with experienced UX developers that leveraged the new Polymer framework of web components.
The result is PolyGerrit, a modern web UX which provides an unprecedented browsing speed and flexible rendering across different devices, including mobile and tablets.
The PolyGerrit Team will be presenting the findings of their user-experience research and show some of the features and insights of the new UX.
Gerrit CI and keeping logs forever.
Gerrit Code Review itself is a large project, involving over 300 developers across the globe and using the most advanced DevOps practices. The CI/CD pipeline has been provided and managed by GerritForge on the https://gerrit-ci.gerritforge.com and Luca Milanesio from GerritForge will present the latest improvements in the pipeline plus an interesting way of collecting and reusing the logs.
Leveraging the logs for identifying the bottlenecks of the CI/CD pipeline is the way to drive improvement. GerritForge leveraged the expertise of his engineers to harvest and organize data and will give it back to the community as powerful dashboards.
Gerrit is great. However, it is also quite an important part of a bigger ALM process. Jacek Centkowski from CollabNet will describe how multiple tools can be unified under a single TeamForge umbrella and what are the immediate benefits of it.
What’s coming in Gerrit 2.15
After only four months, we are already close to the v2.15 of Gerrit Code Review, which would be possibly the last one before the step to the v3.0.
Dave Borowitz from Google, principal maintainer of the Gerrit Code Review project, will go through the new features of v2.15 and possibly give a glimpse in what to expect from v3.0.
Mining Gerrit Data to Study Contentious Reviews and Community Evolution
Gerrit Code Review is much more than a tool, it is a way for people working together in companies that are large and mostly distributed across the globe.
Shane McIntosh from McGill University has been running a research lab on this topic. The Software REBELs—a research lab at McGill University—mine code review data to study topics like the impact that code review practices have on software release and design quality. Our more recent work mines code review data to study the reviewing process itself. In this talk, I will describe the results of two empirical studies of data that we collected from the Gerrit instances of the OpenStack project. The first study aims to understand the reviews where reviewers disagree about a patch. The second study follows how the concerns that reviewers raise evolve as the OpenStack community ages and individual reviews accrue experience.
Gerrit Analytics: dashboards, networks, KPI
Gerrit has always been lacking major code analytics features compared to other Git Server tools like GitBlit or GitLab. GerritForge Ltd is filling the gap and adds one important asset to the Gerrit Code Review platform: code review analytics.
We need to harvest and unify the logs and events coming from the different components of the CI/CD pipeline by putting at the center of it the people and teams that are building and discussing the code on Gerrit. The resulting data-lake of information can be later analyzed and correlated to calculate the cycle time of the entire pipeline.
Luca Milanesio from GerritForge will show the new analytics dashboards that are going to be published and provided back to the Team that is developing the Gerrit Code Review project as a precious contribution to the community.
How to extend Gerrit using Scripting Plugins
Gerrit Code Review has a robust set of API that can be used to extend its functionalities and provide a more integrated development workflow for the Teams.
Luca Milanesio from GerritForge will present how to use different scripting tools to extend the capabilities of Gerrit without the need of developing and building a plugin, using Jython, Groovy and Scala.
A new simpler but powerful Gerrit Jenkins plugin
Gerrit Code Review is an essential part of a larger CI/CD pipeline. Most of the times it is used in conjunction with Jenkins, the most popular OpenSource Continuous Integration and Delivery tool.
The integration between Gerrit and Jenkins (Gerrit Trigger Plugin) was developed back in 2010 at Sony and since then has been extended and adopted in thousands of Jenkins installations. However, Jenkins has evolved too and has now a brand new concept and definition of multi-branch pipeline which struggles to be seamlessly integrated with the current Gerrit Trigger Plugin.
Luca Milanesio from GerritForge will present a brand new plugin based on the new Jenkins branch discovery API which works seamlessly with Jenkins multi-branch pipelines and provides a simpler interface with Gerrit by leveraging the new WebHooks.
Diffy with enterprise grade
Since 2012 CollabNet has been working on improving Gerrit integration with TeamForge. Many features have been created to satisfy the needs of enterprise customers. Eryk Szymanski from CollabNet will present features like RBAC, history protection, Git style notifications, quality gates, pull request and code browser which have been implemented on top of vanilla Gerrit.
Q&A with the maintainers
Have you ever wondered why something is working in a certain way? Have you ever wanted to explain any complaint about some parts of Gerrit? Would you give your congratulation to the people that made this project? Would you like to make a feature request or propose new ideas?
This is the moment where you can speak directly face-to-face to the people that are building this project every single day, the Gerrit maintainers.
Alternatively you can click on the “PolyGerrit” link at the bottom of the GerritHub.io footer.
What is Polymer and why it matters?
Why is Gerrit moving away from GWT? Well, there are many reasons for steering direction:
With Web Components, the core building blocks of the UX are transferred once and then cached by the browser, giving a much faster and fluid user experience.
Multi-sized screen support.
Web Components are “instructed” to be rendered differently on different devices, giving the best user experience and accessibility of the device’s form factor and native interactions.
By using native HTML and CSS rendering, it becomes much easier to control and customize the look and feel of Gerrit.
Web Components development allow focusing on basic building blocks that are straightforward and testable. It becomes much easier to develop much more stable and robust components.
Typically, web developers find themselves more comfortable in using a front-end language and have much more control of what gets generated, understood and rendered by the web browser.
GerritHub.io on mobile
One interesting feature of PolyGerrit is the mobile view of Gerrit UX.
Gerrit’s GWT interface has always been quite a challenge on small-screen devices, mainly because of the inability of being sensitive to the reorganization fo the page real estate based on the device’s form factor.
Additionally, the buttons did not have enough real estate needed for “big thumbs”.
The ability to use Polymer has opened up a wide range of possibilities of interactions and, for the first time, a real fully featured review experience “on the road”.
Big thumbs up for the new Gerrit Mobile UX !
What and when?
What is currently implemented in the new Gerrit Polymer-UX? Not much in terms of screens, but a lot of the core functionality of the Code Review: the changes list and the review panels. What is missing? All the other Gerrit screens more dedicated to the management of the platform and the account, the projects and groups listing, and all the support for the UX plugins.
The PolyGerrit project announced at the Gerrit User Summit 2016 last year that they are making good progress and expect to have the first “production-ready” release by Feb/Mar 2017. In the meantime, all the code is stable and the current screens are good enough to be used on a daily basis.
Do I still need the GWT UX?
Yes, at least for the functionality that isn’t available yet in PolyGerrit. To switch back to GWT, simply add “?polygerrit=0” to the target URL.
Many thanks to the Google’s PolyGerrit Team, lead by Andrew Bonventre, which started the Polymer support for Gerrit UX. A special thank to David Ostrovsky, who implemented the Gerrit switcher support to enable to use both GWT-UI and PolyGerrit-UI at the same time.