Implementing Grok


Posted: 2013-12-02 13:20   |   Source   |  More posts about python grok zope planetpython

Towards the First Grok Sprint

I got the idea for Grok in the summer of 2006. In the fall I still hadn't done anything yet about it. Then I gave a talk at a German Zope User Group (DZUG) conference (the video of that now appears to have sadly disappeared off the internet; if it's still somewhere I'd appreciate to get the link!). This was the series of conferences that a few years ago got broadened into the wider PyCon.DE (German PyCON) conferences. I chatted about Grok with Christian Theune of Gocept. He suggested we hold a sprint to build Grok at the Gocept offices.

So later on that fall I and my wife Felicia flew to Berlin and from there were taken by Christian to the Gocept offices in Halle. There were four of us at the sprint: myself, Christian, Philipp von Weitershausen, and Wolfgang Schnerring. The first three were very familiar with Zope both old and new. Wolfgang was new to it all, but had experience with Ruby on Rails, so could offer us an interesting different perspective.

Quadruple Programming

This sprint, we didn't do the pair programming that was pretty standard in Zope sprints, but quadruple programming. How did that work?

We used a video projector to project the screen of somebody's laptop onto the wall. The person at the keyboard was mostly either Philipp or Wolfgang. The rest would look at the projection and give directions. Christian made sure we didn't forget test cases by writing them down on a whiteboard. I sat or paced around and just talked. People who know me know I do that a lot anyway. I actually did not edit a single line of code during the entire weeklong sprint myself, but I'd seen all of it and was thoroughly familiar with it when I went home afterwards.

After a week of sprinting we got Grok from a design document to a working implementation. We built the traditional wiki application with it to try it all out in the end.

Starting Grok in a sprint like this made it a community project straight from the start. This was beneficial when we went home and had to cooperate online.

I wrote a report about the sprint and Grok to my blog back then; it may be interesting reading for some.

Grok the Caveman

None of the other sprinters liked my proposed name 'Grok' for the project. It was too nerdy, too obscure. Perhaps, it was proposed, we should name it something like "Easy Zope" (I forget the exact name proposed, but 'easy' was part of it). I protested and formulated what Philipp later dubbed "Faassen's law":

Don't use the name 'easy' or 'simple' in software, as it likely won't be and people will make fun of it.

Somehow during dinner we were discussing and imitating "Hulk talk", i.e. "Hulk smash". People are silly like that, especially people like me. I suddenly hit on the idea that Grok was actually a caveman, and that he talked like this: "me Grok smash ZCML". Everybody immediately liked this idea, as it had a sense of fun and fit the theme of Grok simplifying the new Zope.

We had the luck that my wife Felicia was there. She's a graphics designer, so we asked her Grok the Caveman, so we would have a mascot for the project. She made several drawings and showed them to the group. One of them was everybody's favorite. "But that one looks like me!" I protested. "Exactly," they said, grinning. And thus Grok the caveman was born.

Having a friendly caveman as a mascot/logo for your project actually helped attract people to it. Having such a character gives a project a face and gives people something to relate to. The web site theme was inspired by it, and even a stand-up wooden version of the caveman was made and used at various open source conventions.

I've been toying for a while with the idea of creating an elf character for the Obviel project...

While I did mention cave women in my original blog post on Grok, I wonder now whether our slogan "now even cavemen can use Zope 3" was sufficiently inclusive of women, given all the attention given to gendered language now... The word "cavepersons" would take away a bit of the charm of the ridiculously ahistorical but familiar caveman concept.

Grok Innovation

After I'd gone home from the first Grok sprint I could immediatetely pick up the code and continue working with it. I factored out a library, which contained what I think now was the most important innovation of Grok. This was the notion of scanning Python modules for things (classes, instances, decorators) that needed to be registered with the system. This, we discovered, allowed us to do metaclass-like things with Grok without the need for using actual metaclasses -- particularly picking up and registering relevant classes with the Zope configuration system. Avoiding metaclasses is good if you can get away with it, as they can lead to other unexpected behavior in subclasses. I called the library Martian, to fit the 'grok' theme.

When Chris McDonough started what later became the Pyramid project he used Martian to pick up configuration. Later on he reimagined Martian and he created the Venusian library, which I'm using today in Morepath. But that's another story.

Grok as an Open Source project

Grok as an open source project was moderately successful. A little community of people formed. It managed to attract a few people unfamiliar with Zope technology, and also made the new Zope technology more appealing to people who were already familiar with Zope. We got quite a few contributions, too.

We had regular Grok sprints that helped push Grok forward. We also participated in the Google summer of code for a few years, under the wider banner of the Zope project.

I was lucky enough that quickly after the initial creation of Grok I could start using Grok in my professional life on customer projects. I've been using it as the underpinnings in several large web applications since then.

Various contributors also refactored Grok technology so it could be plugged into the old Zope. From there the Plone community started using it; it's still widely used there today. This whole old Zope compatibility project was entirely pushed by contributors who weren't part of the original group -- a sign of open source success.

Grok and Zope

Grok was built on the new Zope. This gave Grok a running start and a built-in community to draw from, and this was definitely part of Grok's success. But many other Zope developers were not interested in Grok, and quite satisfied with the original ways of doing things. Grok could not have worked as a project to improve Zope itself -- there was insufficient consensus. To create something new, we had to go around the center.

Grok was successful at least for me personally: it made it possible for me to use the new Zope technology without much of the pain. But was Grok successful in being attractive to beginners? We certainly attracted some. But there were problems.

While Grok was simple enough on the surface, its learning curve was not as smooth as we'd have liked. Grok was too much like an iceberg; beneath the surface lurked the vast codebase of the new Zope. If we wanted to make Grok smaller and more comprehensible all the way down, we would need to fix this.

This blog entry is a part of a series on Zope and my involvement with it. Previous. Next.

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