Time zone analysis

Where do the developers in my FOSS community live? For large open source communities where personal contact with developers is impossible, answering this simple question may be difficult. Fortunately, a simple technique, time zone analysis, can be used on git and mailing list repositories to at least partially answer this question. Read our blog post “Using Git and mailing lists time zones to find out where developers live” in OpenSource.com to learn more about it.

Screenshot from 2015-11-23 22-55-36

Number of commits per time zone for the OpenStack project.

Understanding the code review process in OpenStack

As a part of our tests with Kibana and Elasticserch as frontends for our MetricsGrimoire databases, we’ve set up a dashboard for understanding the code review process in OpenStack (be sure of visiting it with a large screen and a reasonable CPU, otherwise your experience may be a bit frustrating).

Screenshot from 2015-10-22 00-24-53This dashboard includes information about all review processes (changesets) in OpenStack, using information obtained from their Gerrit instance. For each review, we have information such as the submitter (owner), the time it was first uploaded and accepted or abandoned, the number of patchsets (iterations) needed until it was accepted, and the time until it was merged or abandoned. With all of them we have prepared an active visualization that allows both to understand the big picture and to drill down looking for the details. Follow on reading to learn about some of these details.

[Note: this is our second post about our dashboards based on Kibana. If you’re interested, have a look at the first one, about OpenStack code contributions.]

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Testing Kibana: OpenStack code contributions dashboard

We at Bitergia are busy testing new stacks for analyzing and visualizing the software development data we collect. Some our latest tests involve using Kibana for visualization. In this case, we have prepared a dashboard showing the latest contribution data for OpenStack.

Screenshot from 2015-10-19 01-28-46Screenshot from 2015-10-19 01-29-27One of the nice things that these new dashboards allow is the level of filtering and drill down which is possible. For example, in the above dashboard, it is possible to click on any sector on a pie chart, on any entry of a table, on any bar in a bar chart, and the corresponding filter will act. This allows for obtaining specialized dashboards very easily, such as this one with the contributions by RedHat (produced by clicking on RedHat in the list of of top organizations, or the contributions to Liberty, the latest release cycle of OpenStack, by selecting the corresponding period (last bar) in the “OpenStack ten top organizations by release” chart.

If you’re interested in learning about some tips and tricks about what can be done with these dashboards, follow on reading…

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Efficiency analysis in the OpenStack community Liberty release

Liberty is the new release of OpenStack. This shows an increase in activity and people participating in the development of OpenStack.

  • There are 25,268 commits in total merged into master thanks to the work of 1,873 different developers.
  • In order to have that code into master, it was necessary the effort of 2,239 people that submitted at least one patchset to Gerrit. That means that 83% of them are actual contributors of Liberty release.
  • In terms of community, Launchpad activity shows that 9,919 people helped participating in the bug tracking process, opening, commenting and closing tickets.
  • The mailing lists are a busy channel of communication with 1,742 participants, but IRC seems to be the preferred channel with more than 6,000 detected nicknames.
  • Ask.openstack.org is also an interesting communication channel where there have been 1,386 people participating and around 2,200 different questions.

As a disclaimer, this post will not focus on organizations participating in the OpenStack development, but in the software development process. Organizations information can be easily retrieved in the Activity Board. We believe that process in the OpenStack community is important and even more when we are talking about a team of more than 2,000 different contributors.

Efficiency of the community closing changesets

As mentioned, there have been more than 2,200 people in Liberty release that aimed at contributing with a patchset in the OpenStack community. And only a subset of those pieces of code were eligible to be part of the project and merged into master. However, not all of the people that were part of the that set were even reviewed. Each quarter, the community leaves around a 20% of the changesets population open. This can be observed in the following chart. The y-axis represents the percentage of changesets that were closed (abandoned or merged) per quarter (x-axis).

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Mid Liberty Release Cycle: OpenStack Quarterly Report

Finally we released a new version of the OpenStack Quarterly report. This is intended to provide insights about the software development process of the OpenStack projects. This covers information from several data sources such as Git, Launchpad, Gerrit, Mailing lists, ask.openstack.org and IRC channels. And it aims at providing quantitative and qualitative information about the activity, community and software process.
The executive summary of the document is as follows:
  • Users community keeps growing. With an increase of more than a 300% in the total number of questions posted in ask.openstack.org, this is the unique communnication channels with such measured increase. Other channels such as IRCor mailing lists also grow but slower. Although this is the activity measured for the last year, the last quarter shows a significant activity drop.
  • Active Core Reviewers are increasing. Although mid-release cycle analysis usually show drops of activity in most of the areas, the total number of active core reviewers has reached a new peak. Up to 339 core reviewers participated in the review process. This shows an increase of around 9% if compared to the previous quarter analysis.
  • Process keeps stable. The time to merge patches for the main projects show similar numbers than in previous quarter. However, Nova seems to be the project out of the common time to review with up to 10 days. On the other hand, Glance is more in line with the rest of the projects if compared to previous quarter. In any case, Glance shows the second highest meadian time to review with up to 7 days.
  • IRC activity recovers old activity. Due to unknown issues, the total logs analyzed in the last two previous quarters indicated a huge drop of activity. However, last analysis on this data source shows activity in line with previous quarters. Although this is still an unknown issue, the IRC activity has recovered expected activity.

Project teams are also covered in this quarterly report. This quarterly report follows the Governance file for projects, but ignores specs files. Previous versions of the quarterly report such as 2015-Q1 or 2014-Q4 divided projects into the integrated project, specs, clients and others, with specific sections.

This study can be replicated using the databases available for the OpenStack project and the tag 15.02 of the GrimoireLib library that allows to query those databases.

Kilo: the new OpenStack release

[Updated results based on methodological changes]

Kilo, the new OpenStack release, shows a continuous increase of activity if compared to Juno. From Icehouse to Juno, there was an increase of 6.22% in the number of commits and 17,07% in the number of unique authors. From Juno to Kilo, there’s a higher jump in terms of commits (11,23%) and a lower increase in terms of authors (11,16%). However, with this increase, there is a new peak in the number of unique authors contributing to the OpenStack Foundation projects with close to 1,600 different people participating in its development.

After the continuous increase of activity from release to release that we observed in the past, Kilo, the latest release of OpenStack is showing some stabilization. The differences  between Juno (the previous release) and Kilo are the lowest in the history of the analysis we’ve performed for the OpenStack Foundation. Although this release has reached a new peak in contributors, close to 1,500 different persons, the increase from Juno to Kilo was of around 900 commits and 200 authors while from Icehouse to Juno it was of  700 commits and 70 developers.

The list of organizations participating in the development of OpenStack keeps growing as well: close to 170 different organizations have contributed with at least one commit to the development of Kilo.

As the top ten contributors, we find the following organizations:


Regarding to the community itself, the timezones analysis shows a widespread activity around the world. OpenStack is a truly 24 hours-a-day continuous development community. There are three main groups of activity: America, on the left side of the chart, Europa/Africa in the center and Asia, on the right.

Total commits by timezone as detected in Git repositories

Total commits by timezone as detected in Git repositories

Ignoring the UTC 0 activity, that may be biased by developers using UTC 0 as their timezone with independence of their point of residence, the rest of the activity shows North America East and West coasts as the main contributors in number of commits. Europe/Africa is quite close to this activity (most of it due to Europe), although biased by the UTC peak of activity. India could be represented by the the small peak in UTC+5, and finally the rest of Asia, with China and Japan in first place, which is consistent with the localization of some contributing companies.

Methodological notes:

  • Some of the repositories under the OpenStack project have been removed of the analysis. As an example, specification projects are not counted for this analysis. The full list of repositories is available at the last quarterly report sponsorized by the OpenStack Foundation.
  • Developers are counted as the actual authors of the piece of code merged into upstream.
  • The time of commit takes into account the time when that piece of code is merged into upstream.
  • Each release, new repositories are added to the list of analyzed projects. This partially explains the continuous increasing activity in the OpenStack Foundation projects.

Behind the big numbers on the Wikimedia code review process

Having a dashboard usually opens new paths to understand software development communities. This may be seen as the entry point that helps to understand the basics of a community. And on top of this, there may appear new questions related to those basics or to more advanced issues. This is the case of the new work we are working on with the Wikimedia community metrics analytics team: Core Reviewer and Participants.

  • Core reviewers are defined as those developers that can exercise a +2/-2 review in Gerrit. In addition to this, it is of interest for the community to remove auto merges. Although this is an undesired behaviour, that takes place, and those should be removed.
  • On the other hand, Participants in Gerrit are defined as any member leaving any type of trace in the system. In this set we can find reviews (-2,-1,+1,+2), uploads, comments and others.

It is interesting to notice that depending on the community, requirements are slightly different. In the case of the OpenStack community, there are extra requirements for the Core Reviewer definition. And this is that reviews should be found in master branch. This specific measure can be found in the OpenStack quarterly reports for each of the projects of the Foundation.

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