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Blog entries june 2009 [5]
 The semantic web technology conference is taking place every year in San Jose, California. It is meant to be the world's symposium on the business of semantic technologies. Essentially here we discuss about semantic search, how to improve access to the data and how we make sense of structured, but mainly unstructured content.
Some exhibitors were more NLP oriented, concepts extraction (such as SemanticV), others were more focused on providing a scalable storage (essentially RDF storage). Most of the solutions includes a data aggregator/unifier in order to combine multi-sources data into a single storage from which ontologies could be defined.
Then on top of that is the enhanced search engine. They concentrate on internal data within the enterprise and not that much about using the Web as a resource. For those who built a web application on top of the data, they choosed Flex as their framework ( Metatomix). Developped by Cambridge Semantics, in Java, Anzo suite, especially, Anzo on the web and Anzo collaboration server, is the closest tools to CubicWeb, providing a multi source data server and an AJAX/HTML interface to develop semantic web applications, customize views of the data using a templating language. It is available in open source.
The feature that I think was interesting is an assistant to load data into their application that then helps the users define the data model based on that data. The internal representation of the content is totally transparent to the user, types are inferred by the application, as well as relations.
 I did not get a demo of ORDI, but it was just mentionned to me as an open source equivalent to CubicWeb, which I am not too sure about after looking at their web site. It does data integration into RDF. Allegrograph RDF store is a potential candidate for another source type in CubicWeb . It is already supported by Jena and Sesame framework.
They developped a Python client API to attract pythonist in the Java world.
They all agreed on one thing : the use of SPARQL should be the standard query language. I quickly heard about Knowledge Interface Format (KIF) which seems to be an interesting representation of knowledge used for multi-lingual applications. If there was one buzz word to recall from the conference, I would choose ontology :) 
As you might have noticed we quite like munin. We use it quite a bit to monitor how our servers and services are doing. One of the things we like about munin is obviously that the plugins can be written in python (and perl, bash and ruby).
On a few recent servers we started playing with IPMI to sensor the temperature, watts, fan's rpms etc. So we went out looking for a munin plugin for that. We found Peter Palfrader's ruby plugins. There was one small glitch though, we came across a simple bug : the "ipmitool -I open sensor" can be real long to execute on certain machines, so configuring the plugin was a bit painful and running it too. Changing the ruby code was a bit tricky since we don't really know ruby... so we did a quick rewrite of the plugin in python... with a few optimizations.
It's not really complete but works for us, and might be useful to you, so we're publishing the hg repo. You can get the tgz or browse the source.
 The big event of the conference was the annoucement of Google Wave, a new online communication and collaboration tool, built on the Google Web Toolkit (GWT).
Another big thing the GWT, lots of application built with it, a delightful tool for Java developers. It was interesting to see that Google App Engine (GAE) will shortly provide an API to do offline processing, with objects called Task Queue.
Task queue are web hooks, tasks are pushed to the server, queued and they are pushed until the task is executed (which overpass the annoying well-known time out issue with Google App Engine).
It was introduced as asynchronous, enabling low latency, reliable and scalable (where are the buzz words?).
Of course, this news has been a huge relief for most of the developers in the public as that was a big missing part from GAE.
An nice presentation from the founders of FrontSeat.org about their current project Walk score. They introduced themselves as civic software developers, writing software in a civic manner.
They explained how they use GAE, and why they had to use Amazon EC2 to compensate GAE gaps. The gaps they listed here were the ranking non-ability of GAE, the too long reponse time for such computation they do, the fact that no cron jobs can be done (the arrival of Task Queue might change their opinion).  All the sessions have been recorded and are available here. And yes, as all the participants of this conference, I went back home with an Android phone :) I am pleased to introduce you to the latest kid of the Logilab team: hgview 1.0.0.
hgview is a very helpful tool for daily work using the excellent DVCS Mercurial (which we heavily use at Logilab). It allows to easily and visually navigate your hg repository revision graphlog. It is written in Python and pyqt.
This version is an almost complete rewrite of hgview 0.x which had two GUI backends, gtk and qt4. This 1.0 release drops the gtk backend (we may consider reintroducing it, we haven't decided yet... by the way, patches are always welcome). Some may not like this choice, but the immediate benefit of using qt4 is that hgview works like a charm on MacOS X systems.
Edit: there was a bug in hgview 1.0.0 on Ubuntu hardy. It's now fixed, and I've uploaded a 1.0.1 version deb package for hardy.
- 4 different viewers:
- repository navigator that displays the graphlog efficiently (works well with 10,000 changesets),
- filelog navigator that displays the filelog of a file (follows files through renames),
- filelog diff navigator that displays the filelog in diff mode to easily track changes between two revisions of a file,
- manifest viewer that navigates in the files hierarchy as it was at a given revision.
- Each viewer offers:
- easy keyboard navigation:
- up/down to change revision,
- left/right to change file (for the repo navigator only),
- return to display the diff viewer of the selected file,
- search quickbar (Ctrl+F or /): search in graphlog (search as you type in the currently displayed file or diff, plus a cancellable background search in the revision tree),
- goto quickbar (Ctrl+G): go to the given revision (accepts id or tag, with completion for tags),
- navigation history: alt+left/alt+right to navigate backward/forward in the history,
- can be used alone or as a hg extension,
- can be configured using standard hg rc files (system, user or per repository),
- possibility to declare users (with multiple mail addresses) and assign them a given color to make a given user look the same in all your repositories,
The source code is available as a tarball, or using our public hg repository of course.
To use it from the sources, you just have to add a line in your .hgrc file, in the [extensions] section:
hgext.hgview=/path/to/hgview/hgext/hgview.py
Debian and Ubuntu users can also easily install hgview (and Logilab other free software tools) using our deb package repositories.
I presented CubicWeb at several conferences recently and I used the following as an introduction.
Web version numbers:
- version 0 = the internet links computers
- version 1 = the web links documents
- version 2 = web applications
- version 3 = the semantic web links data [we are here!]
- version 4 = more personnalization and fix problems with privacy and security
- ... reach into physical world, bits of AI, etc.
In his blog at MIT, Tim Berners-Lee calls version 0 the International Information Infrastructure, version 1 the World Wide Web and version 3 the Giant Global Graph. Read the details about the Giant Global Graph on his blog.
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