Coffee & Gems

When you develop an action for Apache OpenWhisk it can become cumbersome and time-consuming to upload the action to your OpenWhisk instance in order to test it. This is especially the case when your (Node-based) action contains NPM dependencies. You can always use Node.js to run the action locally. However, ideally one wants to run in an environment as similar to the cloud as possible - in this case run within an OpenWhisk Docker image. This is where runtest.sh comes in handy: it does exactly this - run the action locally in an OpenWhisk container. I hope this tool will make it into wsk or a similar tool for local OpenWhisk action development.

Lately, I had a lot of conversations about multi-tenancy (MT). So I finally wrote up my thoughts on that term. In this post I will argue that MT is a value that depends on a continuous variable. Therefore, any statement about a system being “MT” can only be made in the context of the given requirements. It is not a property of the system itself . I will also show that perfect multi-tenancy is indistinguishable from single-tenancy (ST). MT is a value that depends on a continuous variable Imagine a step-function "ST-MT" (values are either 0 or 1) that determines if a given system is MT (1) or ST (0). That function will look like this: ST-MT = function (system, business requirements) Look at  the function’s arguments: the first one is obvious – the result will depend on the system itself. The second one is more interesting: it is the cumulative set of business requirements . Typically, these requirements will include: Resource sharing: systems typically declare...

At this week's IKS meeting at Paderborn the second FISE Hackathon took place. FISE is an open source semantic engine that provides semantic annotation algorithms like semantic lifting. The actual annotation algorithms are pluggable through OSGi. Existing CMSs can integrate the engine through an HTTP interface (inspired from Solr ). Last week, Bertrand gave an introductory talk about FISE that is available online . There was no explicitly set goal for the second Hackathon. Rather, the existing code base was extended in various different directions. Some examples: a language detection enhancement engine (I am particularly glad to see this - automatic language detection in CMSs is a pet passion of mine) a UI for FISE users that allows humans to resolve ambiguities myself, I coded a JCR-based storage engine for the content and annotations There was also a good amount of work done on the annotation structure used by FISE and documented on the IKS wiki . A complete report of the Hack...

Three days ago I had to chance to talk about NoSQL at the Internet Briefing's Developer Summit . On top of general ideas and concepts like the CAP theorem I chose to talk about Apache Jackrabbit , CouchDB and Cassandra . My slides are embedded below. It was a really good event with interesting speakers and a knowledgeable audience. I was especially pleased that when I talked about CouchDB's HTTP API someone from the audience mentioned that Apache Sling does something very similar for Jackrabbit. Special kudos to Christian Stocker of Liip for daring to do a live demo of the "real-time web" - he took a picture from his phone and had it pop up on Jabber and Twitter in about 5 secs. Vlad Trifa has posted a good summary of the whole event ( part 1 , part 2 ) - he also gave a great presentation about the application of the REST architectural style to the "Web of Things". No Sql View more presentations from mmarth .

CMS analyst Janus Boye has just published a post on CMS vendors that discontinue their products (because they get bought out or similar) During the past 10 years, a number of software products used by online professionals have been discontinued That sentence reminded me that I had given a talk almost 10 years ago (it was in 2001 exactly) that contained a slide on the CMS market at that time: The circles denote vendors that were part of CMS market overview articles by popular German IT magazines in that year (I wanted to show how differently the market place could be perceived). A vendor placed in any of the circles had enough attention to be part of at least one evaluation. The vendors outside of the circles were not part of any of these overview articles, but somehow present in the market place - at least I knew their names back then. It is interesting to look at the landscape from that time. Of course there are a number of well-known vendors that got bought (Vignette, Obtree, Gauss...

On the mp3 tagger post I have received quite a bit of feedback and feature requests. Therefore, I thought it might be a good idea to do "social coding" and put the code on GitHub where it can easily be forked (and the forks can be watched). Other than that, the latest version of the tagger contains these improvements: the Last.fm keys and secret are not stored in the code anymore, but entered on the first run and stored in ~/.mp3tagger.cfg you can run the script in two additional modes: simulation and ask. In simulation mode no changes to mp3s will be saved, in ask mode you will be asked to save each change. Start the script with flags "-m simulation" or "-m ask", respectively. It is now possible to specify a list of genre tags that will be considered (additionally to the mp3 default genre tags). The list needs to be stored in a config file at ~/.mp3tagger_genres.cfg (in the "generic" section of the file). The full format this file needs to hav...

Due to public demand here's a little recipe how to run last post's mp3 tagger without using the command line on OS X: Open Automator Start a new "Application" project Drag the "Run Shell Script" action into the right workflow panel, set the "pass input" drop-down to "as arguments" and edit the script to (see screenshot below): for f in "$@" do /opt/local/bin/python /Users/michaelmarth/Development/Code/mp3tagger/tag_groupings.py -d "$f" done (you will have to adapt the paths to your local setup) Save the application and happily start dropping mp3 folders onto the application's icon.

Now that I have started to seriously use iTunes I figured it might be nice to have the genre tag set in a meaningful way. Since I have a reasonably large collection of mp3s doing that manually was out of question - I wrote me a Python script to do that. There seems to be a large demand for such a functionality (at least I found a lot of questions on how to automatically set the genre tag) so maybe someone else finds the script useful. It is pasted below. General Strategy The basic idea is to use Last.fm's tags for genre tagging. In iTunes the genre tag is IMO best used when it only contains one single genre, i.e. something like "Electronica", not something like "Electronica / Dance". On the other hand dropping all but one tag would lose a lot of information, so I decided to use the groupings tag for additional information that is contained in the list of tags that an artist has on Last.fm. In the example above that would be something like "Electronica, Dan...

Reto Hartinger of the Internet Briefing group has interviewed me about what I work on these days. The interview is in German.

Chances are you have not heard of Colayer , a Swiss-Indian company producing a SaaS-based collaboration software. I did a small project with the guys, that is how I got to know. When I first saw their product I immediately thought the guys are onto something good, so it is worthwhile to share a bit of their application concepts. They follow an approach I have not seen anywhere else. On first look Colayer seems to be a mixture between wikis and forums: the logical data structure resembles a hierarchical web-based forum and the forum entries are editable and versioned like in a wiki. But there is more: presence and real-time. All users that are currently logged in are visible and one can have real-time chats within the context of the page one is in or see updates to the page in real-time (similar as in Google Docs). These chats are treated as atomic page elements (called sems in Colayer parlance) just like the forum entries or other texts. Through this mechanism, all communication around...

Here is a small bit about the asynchronous nature of the Flex layout mechanisms that I learned while slapping together a presales demo yesterday: When changing properties of UIComponents listen for FlexEvent.UPDATE_COMPLETE events. They get fired when the change is actually done. In my case I needed to get the textWidth of a Label after changing the label text. Right after calling the setter of text the getter of textWidth will still return the old value. [Some background reading ]

Yesterday, I gave a talk at the Java User Group Switzerland (JUGS) titled "Agile RESTful Web Development". It was about the REST style in principle and hands-on RESTful development with Apache Sling. I enjoyed giving the talk and think that it was well received. Here's the slide deck: Agile RESTful Web Development View more documents from mmarth .

I just wrote a small Ruby script to generate a Google sitemap out of file directory. I thought that it might come handy as a quick start for someone, so here is the code (requires the builder gem) require 'builder' htmlfiles = Dir.glob("*.html") x = Builder::XmlMarkup.new(:target => $stdout, :indent => 1) x.instruct! x.urlset( "xmlns" => "http://www.sitemaps.org/schemas/sitemap/0.9" ) { for file in htmlfiles do x.url{x.loc "http://www.example.com/#{file}"; x.lastmod "2009-09-17"; x.changefreq "monthly"; x.priority "0.8"} end }

(cross-posting from here ) OK, I admit it, declaring that " the RDBMS is dead " is a meme that has been going around the software industry for a while. Remember object-oriented data bases that were supposed to replace the relational ones? Well, guess who is still here. However, despite the RDBMS's amazing survival skills I would like to propose a related prediction: I believe that the year 2009 will go down in history as the year when the " relational model default " ended. The term "relational model default" was coined by me to describe a peculiar thing that goes on in application development: start talking to your average application developer about some arbitrary business requirement and chances are that simultaneously he mentally constructs a relational model to fit those requirements. That relational approach to modeling your problem may or may not be suitable. The real problem is that all too often this default does not get challenged. As a conse...

The slides shown in my Jazoon talk are now online: Jazoon 2009 View more presentations from mmarth .

On Thursday, I will give a talk at the Jazoon conference in Zurich. It will be about Apache Sling, the web framework for content-centric applications. The agenda is: Scalable Agile Web Development: REST meets JCR meets OSGI This session is a very hands-on lab that shows how a real web application is developed from scratch in a very agile fashion leveraging a heavy-weight enterprise ready back-end yet allowing for unprecedented agility in development in building rest-style web applications. Thinking of a classic j2ee stack this may sound like a contradiction. Agility of development begins with the amount of tooling and setup we need to get started, so expect to see the entire walk-through from installation of the server software to the development of a complete application within the time constraints of the session. Agenda: (1) Web architecture, think outside the box. (2) Meet: apache sling. (3) Building a real-life webapp from scratch. The full conference agenda is here . I shall also ...

It has been a while since I have been on a standards committee (the last one was OMTP ), but I have now joined the Technical Committee of CMIS : Content Management Interoperability Services. Better interop is certainly something the CMS world is in dire need of.

Today, I am happy to announce that minimeme.org is finally "officially" going live. minimeme is a news aggregator focused on tech and software development news. minimeme was born out of a personal frustration of mine: each morning I would skim through my feed reader only to find the relevant items twice or more times. On the other hand the signal to noise ratio of many feeds was way too low. I felt like a machine trying to retrieve the important items. So I decided to build a machine to do that for me. There is no human intervention in the news selection - it is all done in a bias-free, neutral algorithm. Hence there is the claim "little Switzerland of tech news", minimeme is supposed to be neutral like Switzerland. Having tested the algorithm for a couple of months I believe minimeme is now stable enough to be officially let loose. On top of the two currently implemented sections " dev " ( feed ) and " valley " ( feed ) there is a Twitter accou...

(cross-posting from here ) CMS analyst Janus Boye has blogged about the expected lifetime of a CMS installation , i.e. for how long an installed CMS can be expected to be in production. His guess is a lifetime of 3 years. On the blog's comments Janus and I got into a discussion about the accuracy of that guess where he asked Day to publish actual real data about this topic. I like this idea because publishing this data provides a benefit to our potential new customers: a reliable indicator (without any hand-waving or gut feelings) of the CMS's lifetime that can be used in business plan The data The data I have used is taken from Day's support contracts. Only customer data from outside ouf Europe was used (simply because it was available to me). This selection is likely to bias the results towards shorter lifetimes as Day's oldest customers are based in Europe. The basic assumption is that the life time of the CMS is equivalent to the duration of the support contract...

Stefan Tilkov brilliantly sums up the out-of-band information problem in REST's HATEOAS constraint on the REST-discuss group : Given the representation contains <link rel="some-concept" ref="/some-uri"> you don't hardcode the string "/some-uri" into your client, but rather the string "some-concept".