500 Commits of Summer: My story of FOSS and GSoC

This story of summer started in a dull grey winter at home. Bored, I started lingering around IRC channels and much like the Alice of Wonderland, stumbled into the wonderful world of FOSS. Little did I know, it was gonna be one of the best things that happened to me. Below is a story of bugs, PRs , repos, commits, and some more commits. But it is also a story of curiosity, learning, frustrations (a lot of it), resilience (more than you think) and some amazing amazing people of the community. If I have to sum it up for you, I couldn’t think of a way better than this. So here it goes…

Disclaimer: It was a long journey, hence the long blog. Continue reading

GSoC 2017: Rating System in CritiqueBrainz


I am Pinank Solanki, an undergrad at Indian Institute of Technology (IIT) Mandi, India. I worked with the MetaBrainz Foundation on one of its projects, as part of the Google Summer of Code 2017 over the last summer. It was one of the best and exciting summers I ever had.

Let me begin from the beginning. I first came to know about MusicBrainz in January and first contacted the community in February and was immediately hooked. Initially I decided to make a proposal for addition of book reviews for CritiqueBrianz, but it was not possible because the BookBrainz web service was unstable and the CritiqueBrainz’s host didn’t have direct access to BookBrainz database. So I tried to pitch my own ideas. But then, in one of the weekly meetings, I saw great support and enthusiasm among the community members for rating system for reviews —and I personally liked the idea of the project and thought it would be a great addition to CritiqueBrainz. I submitted my proposal, got accepted and a treat to the friends was due!


The aim of the project was to add support for three types of reviews: text, rating, text+rating (CB supported only-text reviews).

The schema changes and data-access functions are completed and merged. The frontend part is mainly completed including the fundamental functionality along with additional features. It took a lot of time to select and modify the rating input plugin perfectly satisfying the project’s needs. There is still some work to be done, most of which is based on the rating scale conversion in db package. Similarly, most of the web service part is completed and is held up due to the rating scale conversion PR.


Schema changes

The schema changes done are quite different than what was mentioned in the proposal. My mentor for the project, Roman Tsukanov (Gentlecat), recommended some changes which would make keeping track of revisions a lot easier. You can see the schema here and the PR here.

Data-access functions

By the time I started working on the project, CB has migrated off the ORM. So, I wrote raw SQL queries and its tests. See the PR here. The rating scale was decided to be 1-5 but for storage a scale of 0-100 is used just like MusicBrainz keeping the possibility of migration of ratings from MB to CB in mind (more info at CB-245). This part is covered in the PR here.

Changes in user-interface

This plugin is used for rendering the rating star icons. The code can be seen in this PR. See the images below to get a good idea about the implementation.

Write review page:


Review page:


Entity page:


Revision comparison:


Web service

All the functionalities added to CritiqueBrainz had to be implemented in the web service (API) as well. All three types of reviews and other features are now supported via the web service. See the PR here.


The chief part of the documentation was to update the schema. Other than that, rating parameter and several notes were added to the API documentation. See the PR here.

Other PRs relevant to the project can be found here.

Future work

First of all, I will complete the leftover work. Web service and frontend PRs are dependent on the rating scale PR. Once it gets merged, it’s 2–3 days of work to complete the rest.

Other than that, I look forward to keep contributing to CritiqueBrainz and other MetaBrainz projects. I am sure many interesting ideas will be discussed at the annual MetaBrainz Summit in Barcelona.


It was quite an eventful summer and GSoC was the biggest of them. Thanks to Roman for his constant help and guidance over the entire summer and also to all the other community members. It was so cool to work on an open-source project and I would definitely suggest for any music and data lover to explore the MetaBrainz projects.

GSoC 2017: Hacking on ListenBrainz


I am Param Singh, an undergraduate at the National Institute of Technology, Hamirpur, India, and I worked on ListenBrainz over the summer as part of the Google Summer of Code program. I started contributing code to ListenBrainz in January 2017 and have been working on new features and bug fixes since. I’ll be writing about the work I did and my experience working on LB in this blog post.

After a few of my patches had made it in and I was comfortable with the ListenBrainz codebase (which was a really nice example of software architecture for me), I talked with the LB team about what possible contributions I could make over the summer, and we decided that a Google BigQuery based statistics system is something that would be useful to have in ListenBrainz after we release a beta and have listen data that is permanently archived. I made a proposal for adding statistics to ListenBrainz which got accepted! During the community bonding period, we decided to try to get a solid and stable beta of ListenBrainz released before starting with the relatively large code additions that would be required by my project proposal. We tracked issues that we wanted fixed before a release in the MetaBrainz ticket tracker here. This work of fixing release blocking issues went into the coding period and we decided to continue working on a solid beta instead of adding new features for the time being.

I started with fixing bugs and adding new features to get a beta released as soon as possible. Some cool stuff I worked on during this time was dockerizing MessyBrainz (see PR here), migrating the codebases of MessyBrainz and ListenBrainz to Python 3 (PRs here and here) and improving the startup resilience of various parts of ListenBrainz to make sure that the server is able to self-heal (partially) if some part of it like RabbitMQ goes down (ticket here).

Later on, I did a big refactor of the LB code so that adding new modules would be easier in the future (PR here). I also spent a lot of time fixing bugs in our listen deduplication. Relevant pull requests for this are here and here.

Another feature I added to ListenBrainz while working on the beta was incremental imports. Earlier, LB didn’t keep track of previous imports of a user and did a full Last.FM import every time. However, now we keep track of the last time each user imported listens and only import new data since then. The PR adding incremental imports is here.

My mentor, Robert Kaye (ruaok) set up a test instance of the ListenBrainz server that was used by the community and as the community kept throwing their data at us, bugs kept popping up. A particularly weird bug caused LB to lose data for users with special characters in their usernames. The PR to fix this took a lot of time to create.

We kept on fixing bugs for a long time and the biggest thing I took away from this period of GSoC was the Ninety-ninety rule: «The first 90 percent of the code accounts for the first 90 percent of the development time. The remaining 10 percent of the code accounts for the other 90 percent of the development time.» This summer has drilled this into my mind.

As soon as the beta was released, I started with writing code for statistics, making schema changes (PR here) and adding some user stats (PRs here and here). I’ll be continuing on the stats work after Summer of Code. The basic foundation of stats is mostly done and soon I’ll start with showing statistics to the users.

By the end of the official GSoC coding period, I have made 266 commits in the ListenBrainz codebase and have opened a total of 111 pull requests. The current production ListenBrainz running on https://listenbrainz.org has 253 commits by me, most of which were made during the GSoC period.

Over the summer, I have fallen in love with the MetaBrainz community and have learned a lot of stuff. I’m really looking forward to adding more features to ListenBrainz soon, so that the data that the community is contributing becomes useful to everyone. I loved working on a really cool open-source project like ListenBrainz this summer and am very thankful to Google for providing me this opportunity. I would encourage everyone reading this to give the ListenBrainz beta a try and contribute to ListenBrainz if possible.

GSoC 2017: Directly accessing MusicBrainz DB in CritiqueBrainz

Hello, everyone! This summer was fantastic for me!
I’m Suyash Garg, an undergraduate at National Institute of Technology, Hamirpur and I participated in Google Summer of Code 2017 contributing code to CritiqueBrainz. Alastair Porter mentored me during this GSoC programme. This post summarizes my contributions to the project and experiences that I had throughout the summer.

I started contributing to CritiqueBrainz in January, 2017 and before the start of the SoC programme, I mainly worked on writing raw SQL for retrieving data from the CB database and replacing the ORM code (CB-230). Other than that I worked on issues like CB-120, CB-235 and other minor bugs and issues. They were my first proper contributions to the open source world. Thank you MetaBrainz!!

For the Google Summer of Code 2017, my project involved retrieving data related to various entities (release-groups, artists, releases, events and places) directly from the MusicBrainz database instead of querying the MusicBrainz web service (CB-231). This became necessary as some pages on CB required to fetch too much data and thus made many requests to the MB web service. These pages were taking a long time to load. Thus, by connecting directly to the database, we could reduce the load time of these pages.

Here is a summary of my contributions to the project during the summer:

Accessing the MusicBrainz database
New Infrastructure is allowing us to easily read data directly from the MusicBrainz database. For accessing the database in the development environment, another service running the MusicBrainz database was added which uses an existing Docker image which the MusicBrainz project was already using. This allowed us to share resources between projects. I worked on adding an option to download the database dumps and import the data into the database (see PR#523). Also, I added the service in CB docker-compose files and updated the documentation for setting up the development environment (see PR#115 and PR#92).
Fetching data using mbdata.models
After setting up the development environment, my mentor suggested to me to use the mbdata package for writing queries to fetch data from the database instead of writing raw SQL. I worked on retrieving information for the entity: places and added helpers for fetching the relationship information. Following that, I worked on retrieving information for other entities (release-groups, releases, events, and artists). Also, since SQLAlchemy makes lazy queries to the database, a number of queries were being issued to the database. This could slow things down as for each query it was going to require one trip to the SQL server (network trip in production). So, as suggested by my mentor, I also worked on reducing the number of queries made for fetching data related to each entity (see PR#135). For pages that made a number of requests to the web service, I made this PR#121 for fetching information related to multiple entities at the same time.
For testing, the database queries are mocked using the unittest.mock Python package. The tests added make sure that the code (serializing RowProxy objects to dictionaries, caching, etc.) works properly (see PR#134). Adding up a new service (as a separate Docker container) in the test environment and running tests was taking too much time (in creating the tables and truncating them). So as suggested by my mentors, mocking the database queries was the best option. Throughout my GSoC period, I learned how important it was to write tests (especially when you break things more when you fix something) and make them run fast. I learned that «If tests don’t run fast, they would be a distraction rather than a help» (quoting from the book “The Art of Agile Development” by James Shore).

Other than these, I also worked on some UI/UX issues, namely CB-80 (adding option to filter releases with reviews), CB-84 (ordering release groups according to release year) and CB-261 (authenticating requests to Spotify Web API). CB-130 (reviewing entities with MBID redirects – see PR#145) was also solved while solving a production server issue.

This summer was awesome for me. I learned a lot of new things and techniques for writing better code. Thanks to my mentors, Alastair Porter and Roman Tsukanov. Also, great thanks to the lovely MetaBrainz community and Google for this opportunity. I’m really looking forward to keep contributing to CritiqueBrainz and to dive into other MetaBrainz projects.

Classical Community Cleanup #1: Debussy

The Metabrainz Classical Music Enthusiasts Team has kicked off to a strong start! If you are unaware about the formation and tasks at hand, you can read more about it on the forums.

It’s clear by the number of discussions and engagements in the forum that a community effort on classical music was long overdue! It’s thrilling and we are eager for the first mission: after some discussion and voting we decided that the first community effort would be a clean-up of all our data for Claude Debussy.

As a composer with a huge influence in 20th century music, yet with a relatively low amount of hard to edit compositions like operas, Debussy is a great first choice for the community of classical editors to start actively working together to improve the data. As such, if you’d like to help out, but are new to classical editing or not too active in the community yet, don’t hesitate to reach out and ask any questions. The classical community is active in its own forum category, and we’re hoping to see a lot of activity there with editors both asking and answering questions.

What will we be working on in this first classical cleanup project?

  • We will review the existing works and catalogues to make sure there are no duplicates and the info looks correct (several very active classical editors have already been working on this in preparation for this cleanup).
  • We will check the release list for anything that doesn’t follow the classical guidelines. Those should of course be fixed to follow the guidelines, and that’s usually a good sign of the recording and relationship info being incomplete as well.
  • We will work on the recording list. The only recordings that should be there by the end of the cleanup are of Debussy himself as a performer. Anything else currently there should have performer relationships added to it if missing, then the artist credits for the recording should be changed to list the main performers.
  • And we will add missing Debussy recordings! If you have enough info to add a release we’re missing that includes works by Debussy, that’s always useful. Just make sure to try to add as much info as possible from the get go, so we don’t have to clean that addition up as well!

Don’t know where to begin? Let us know and we can help find a starting point–or just jump in and help out! We can’t wait for Mr. Debussy to be a great example of how much information MusicBrainz can provide!

ListenBrainz data is live on BigQuery!

We’re pleased to announce that in cooperation with Google, we are live streaming our ListenBrainz data to Google’s BigQuery service!

ListenBrainz is a project is that has the potential to gather a lot of data quickly, which would require us to have a Big Data infrastructure, which can be expensive. In an effort to use our available cash wisely, we began to look around for ways to take advantage of other infrastructures with lower costs.

Two years ago at the Google Summer of Code mentor summit I met with a representative from the BigQuery team who said that Google was happy to host any public data set for free! I immediately took them up on this offer and started a conversation.  With much time passed, we finally managed to get the data set live!

If you wish to play with the data, please do!


You’ll need a Google account to log in with — once you’re logged in, every user gets 5TB of query traffic free per month. That is quite a lot for how large this dataset is currently. The schema for this table is defined here and what the data elements mean are defined in our API docs. To get you started, I’ve written a few sample queries:

BigQuery uses an SQL like syntax, so if you know some SQL then diving right in should be easy. The queries above should give you an idea of what you can do with this data. Now, please know that currently we have approaching 30M listens, so the dataset is still quite small. We’re very much interested to see what sort of things people can come up with in the near future.

Finally, some notes about openness and proprietary software: Given that we have limited resources, we aim to make the most things happen with the services that are at our disposal. Google has been extremely generous to us over the years and we’re very pleased to have access to BigQuery now.

That is not to say that we’re putting all of our eggs in one basket or forcing people to use BigQuery. Our InfluxDB database hosted on our own servers keeps the master archival copy of our listen data. Soon we hope to make dumps of this data available for anyone to download and play with using whatever tools they would like. With this setup we are not fully reliant on Google for keeping this project alive. We’re glad to have their support, but should circumstance change, we can find another BigData solution and load our master archival copy there.

Now, go play with this very promising data and post some of your favorite queries in the comments!