Category: Development

Calling all guinea pigs!

I come bringing good news! With the latest version of the server now out in the wild, we’re ready to move on to the next stage of MusicBrainz development. But first a quick refresher…

You may recall, many moons ago I (Oliver Charles aka aCiD2) began work on moving the mb_server codebase from our own in-house framework, to the tried and tested Catalyst framework – along with separating out the HTML into separate Template Toolkit templates. Well, after what seems like an age, it’s finally got to the time where I can start getting some critical feedback from the most important people – you!

As from now, test.musicbrainz.org is now running the development branch of this work. It’s important to realise that this new codebase currently has no javascript support. This decision was made because it’s very important we get the website fully functional, and then add bells and whistles on later. We’re starting from a mostly clean slate, so there’s a lot of chance of things breaking, and JavaScript was likely to be just one more headache.

Oh, and I’ve never deployed a server like this before, so please bare with me while I work out any problems running the server. I’m going to London tomorrow and coming back Saturday evening (slightly bad timing, I’m aware) – but I’ll do my best to check any messages that come my way!

However, before you jump straight in and overload us with work – I’d like to lay down some guidelines for providing us with feedback. This will (hopefully) ensure that we can see to these bugs as fast as possible.

Where to report:

Standard practice- report at our bugtracker – bugs.musicbrainz.org

What should you report?

The most important things to report are actions that cause errors to occur, invalid behaviour or features that are simply not available, but are from the main server. You should also report typos and other visual problems – but I will be encouraging people to help fix these themselves (more on this later!).

What information should you provide?

The most critical information is that you can provide us with as much context as possible. Please let us know:

  • Any steps to reproduce the problem
  • Whether you are logged in or not
  • The address of the page that caused the problem
  • As much information as possible from the top of the error page

The last point relates somewhat to Catalyst. Catalyst features improved error handling and can provide us with a stack trace. You should try and include this stack trace, and the errors at the top. Chances are, we’ll be able to reproduce this from the information you provide – but if not, the stack trace gives us one more pointer to where the problem is 🙂

How should you organise the report?

Generally speaking, just try to fill in as many of the fields as possible. I’ll be reading every single report that comes in, and re-filing it myself where necessary. Ideally, set the component to ‘MusicBrainz’, the milestone to ‘Server: TemplateToolkit’ and assign the bug to me 🙂

So…

Let the bug crunching begin!

Main server updated

We just completed pushing the latest changes out to the main servers! We had a bit of a bumpy ride to roll out the upgrade — we’re noticing quite a few problems with collections right now and the Last Update feature brought our database server to its knees. As a result, we’ve disabled the Dashboard — we’ll re-enable it once we figure out what the problem is.

If you encounter a problem with the server, please file a bug report and select the 2008-11-23 version. Also, please check the open bug list to see if your problem has been reported before.

For a complete list of things that changed for this release, please see the release page on the wiki.

This massive release was brought to you by the tireless efforts of: Luks, Murdos, Djce, Jugdish, Acid2, Niklas and myself. Loads and loads of good testing came from Voiceinsideyou and Nikki. Thanks to everyone who helped with this release!

Also, if you’ve used Jugdish’s enhanced voting GreaseMonkey script, please disable it as it may cause problems since that functionality was included in this server release.

Call for testing: November 23 server release

Murdos, Niklas, Luks, Dave Evans and I have all been working on the upcoming server release and we would like to invite you to help us test this massive release. Most of the features for this release have been debugged, but a few bugs are still outstanding.

The test server has been updated with all of the latest features and is ready for you to log in with your normal user account with the password ‘mb’. The list of features in this release is described in this blog post and this post.

Submit new bug reports to our bug tracker. Also see, the milestone for this release to see which bugs have been fixed and which bugs are still open. Please check the open bug list before reporting a new bug.

Thanks to everyone who helped take part in the development for this release!

One more feature from good measure: CD Stubs

The final feature to be included in the upcoming release are CD Stubs. From the documentation page:

Many times people would like to contribute CD data to MusicBrainz, but would prefer to not learn to be part of MusicBrainz. These people would rather just toss some data into a pile and go on with their lives to listen to their music or rip their CDs. CD Stubs enable users to do just that.

With this release people who come to look up a CD, but MusicBrainz does not know about that CD, will be given a choice to either enter the CD as a CD Stub or to join MusicBrainz and to enter the CD into MusicBrainz proper. (This is the red pill/blue pill decision point). Note that users who are logged in to MusicBrainz when looking up a CD will not be given the option to enter a CD Stub.

To submit a CD Stub to the test server, use any MusicBrainz enabled CD lookup application to submit a CD to MusicBrainz. You must not be logged into the test server, otherwise you will never be given the option to submit a CD Stub. Then follow the instructions for how to submit a CD Stub.

To retrieve the CD Stub you must use the XML Webservice. CD Stubs are not available via the old RDF web service. Use this URL to fetch data for CDs that will also return CD Stubs if no CDs are available in the main DB:

http://[test.]musicbrainz.org/ws/1/release?type=xml&discid=[discid]&toc=[toc]

This URL is also available via libdiscid and its example program discid.

Discography, ratings, enhanced voting, dashboard, timeline and related tags now on test server

Murdos has been busy merging the various development branches into trunk — thanks for your work. I’ve updated the test server with the latest codebase. Come check out the latest new features:

(to log in use your normal log in name and password ‘mb‘)

We’ve got more bug fixes coming in the next couple of weeks. Also, the next server release has been scheduled for 2008-11-23. As usual, please report bugs to our bug tracker.

UPDATE: I had to clear everyone’s collections because of a bug. That’s fixed now — please start over again.
UPDATE2: Due to complaints by stodgy brits, Music Newz is now called Music News. 🙂

Running mb_server on Apache2

A number of people have expressed interest in running mb_server on Apache 2, rather than Apache 1 as mb_server currently requires. Our current roadmap calls for the next mb_server release to stay on Apache 1 and the following Template Toolkit branch to move to Apache2. There will be a lot of changes to the codebase going to TT, so it makes sense to make the switch to Apache 2 at that time since we have to test everything anyway.

LAADHARI Saber has created a “quick and dirty” port of mb_server to apache2. The patch uses the Apache2 compat module and still has some problems with Auth.pm in the Web Service.

Given our roadmap, we’re not going to accept this patch into our codebase, but I wanted to offer up this patch to anyone who wanted to use it.

Thanks LAADHARI Saber!

Server roadmap: SVN branches

If you’re not interested in following server development as it pertains to our SVN repository, then skip this post.

Today, Lukáš, Oliver (acid2) and I had a bit of a chat, discussing how to proceed with branches in our SVN repository. The chat ambles along for a while, so I’ll recap our plans here:

  1. Oliver will revert some of the refactoring changes he has made to the TemplateToolkit branch, which throw a bit of a monkey wrench into starting new branches.
  2. Lukáš will merge the old 20071014 (current live) branch back to trunk and the start a new branch for my work on the next release.
  3. Lukáš will then port bits of the TT branch to trunk so that he can base his work for Release Groups on the object model work in the TT branch.
  4. Lukáš the proceeds to work on Release Groups.
  5. Oliver continues to work on TT, sans the refactorings.
  6. I continue to work the next release in my branch. Ratings, discography and enhanced voting will be merged into the next release branch, not into trunk.

This gives us the flexibility for each one of us to work into their direction and it doesn’t commit us to the TT branch. While all things point to TT being the basis for our next release, its good to keep our options open for now. I’ll post a follow up post once these branches have been properly put in place.

Thanks Lukáš and Oliver!

NGS: From here to there

[ Before reading this post, make sure to read the previous NGS related post ]

The question that is on my mind right now is how to build a coherent roadmap that gets us from the mb_server codebase that we’re running today to the NGS codebase, complete with new edit system. The factors that play into this are:

  1. mb_server codebase: This is the codebase that we’re running today. We’re updating it one more time this year and then early next year we hope to move to the Template Toolkit work.
  2. Template Toolkit: This is Oliver Charles’ work to clean up our codebase. Template Toolkit is available for perl and looks like it will be available for Python soon. Our hope is the clean up the codebase so that we’re ready to take on more developers to help with the development — especially as we move closer to NGS.
  3. NGS playground: See the previous post for details on this.
  4. NGS proper: This is the finished NGS that we roll out onto the MusicBrainz servers.

Finally, the BBC has been keen on getting what they are calling Cultural Identifiers. This name is a bit of a misnomer — essentially it would be the release related portions of NGS. Release groupings that allows us a more product centric approach to managing releases. Right now we list and identify releases with different track layouts as totally separate releases, even though they ought to be properly related. The BBC wishes this work to happen sooner than later and have indicated that they would be willing to sponsor this work.

That’s awesome, right??

Well, yes. But there is one problem. In the last post we concluded that we should move to NGS in one fell swoop. And now the BBC would like us to take an intermediate step? As much as we agreed that moving to NGS in one step, I think we must work with our most visible partner. Since we are severely resource constrained (we have just enough money to hire a part time University student right now) I feel compelled to find a way to get the BBC what they want as soon as possible while accepting money from them to boost our development funds. Taking money from the BBC may allow us to accelerate our development schedule towards NGS. But at the same time, it may slow us down getting to NGS.

I’m very much looking for feedback on how to best make this happen and how to best accomplish all these goals. Do you think that adding an intermediary step in exchange for funds from the BBC is an acceptable compromise?

Next generation schema: Where we are today

Sorry for the delay in continuing my MusicBrainz Server Roadmap updates — we’ve been wrestling with some server configuration nightmares…

I’ll start by giving some background on the Next Generation Schema (NGS). People have been calling for an improved schema that can intelligently handle classical music, proper artist attribution and support for packages of releases (among many other things). In 2005 we held a summit in Germany where we laid down some groundwork for the requirements for a new schema and created a first rough draft schema. Holes were quickly poked into that schema, but this let us find the weak points and let us do a better job of designing the schema for the next attempt. The next attempt was an invite only summit held in London in 2007, where we created a schema that should be pretty close to what we’re actually going to put in place.

Since then we’ve been debating how to make NGS a reality. And to say the least, its been a real pain so far. The change from the existing schema to NGS is a very large project and will be far from trivial. For instance, do we migrate to NGS in one step or take a few steps? Can we keep our existing edit system or do we need to rewrite it from scratch? Now that we have the schema done, what should the user interface look like? How can we make it simple for those users who want to do simple data changes? How can we allow more expert users to make all sorts of detailed changes while keeping the user interface simple? What would the best tools for building a new UI be?

To answer these questions, Lukáš has been working on the NGS playground in his spare time. The NGS playground is Lukáš’ attempt to answer these questions. So far, he has answered two questions:

  1. We should move to NGS in one step. Moving to NGS in multiple step steps will cause too many headaches and too much lost work. Each step would require extensive work to glue the old portions to the new portions and these glue layers would later be discarded. Overall, not a very efficient means of moving forward.
  2. We need to dump the edit system and start over. We’ve learned a lot about how to do an edit system right — and the existing system won’t cut it moving forward. Its time to start over.

In the process, Lukáš is trying out a bunch of new tools to see how they fare. He’s also working in Python to see if that is the proper language to move forward with. While I haven’t run the NGS playground yet, Lukáš has the schema finished except for the Works concept, which is pretty straightforward. Also, I believe that the script to convert an existing database to the new format is also done. However, Lukáš’ work is only a playground — its an attempt to see how we can pull off the user interface for NGS. That’s NGS in a nutshell today.

In my next post I will continue this thread with thoughts on how we go from today’s mb_server and the Template Toolkit work and move towards the NGS work that Lukáš is doing. For now, if you’re a computer geek who is interested in looking at NGS, please take a look at the NGS playground. There isn’t much documentation yet — so consider this a “some assembly required” project. We’re interested to hear your comments on the playground — please feel free to post them here.