DEVit Conf 2016

Posted by Alexander Todorov on Wed 25 May 2016

It's been another busy week after DEVit conf took place in Thessaloniki. Here are my impressions.

DEVit 2016

Pre-conference

TechMinistry is Thessaloniki's hacker space which is hosted at a central location, near major shopping streets. I've attended an Open Source Wednesday meeting. From the event description I thought that there was going to be a discussion about getting involved with Firefox. However that was not the case. Once people started coming in they formed organic groups and started discussing various topics on their own.

I was also shown their 3D printer which IMO is the most precise of 3D printers I've seen so far. Imagine what it would be like to click Print, sometime in the future, and have your online orders appear on your desk over night. That would be quite cool!

I've met with Christos Bacharakis, a Mozilla representative for Greece, who gave me some goodies for my students at HackBulgaria!

On Thursday I spent the day merging pull requests for MrSenko/pelican-octopress-theme and attended the DEVit Speakers dinner at Massalia. Food and drinks were very good and I even found a new recipe for mushrooms with ouzo, of which I think I had a bit too many :).

I was also told that "a full stack developer is a developer who can introduce a bug to every layer of the software stack". I can't agree more!

DEVit

The conference day started with a huge delay due to long queues for registration. The fist talk I attended, and the best one IMO was Need It Robust? Make It Fragile! by Yegor Bugayenko (watch the video). There he talked about two different approaches to writing software: fail safe vs. fail fast.

He argues that when software is designed to fail fast bugs are discovered earlier in the development cycle/software lifetime and thus are easier to fix, making the whole system more robust and more stable. On the other hand when software is designed to hide failures and tries to recover auto-magically the same problems remain hidden for longer and when they are finally discovered they are harder to fix. This is mostly due to the fact that the original error condition is hidden and manifested in a different way which makes it harder to debug.

Yegor made several examples, all of which are valid code, which he considers bad practice. For example imagine we have a function that accepts a filename as parameter:

def read_file_fail_safe(fname):
    if not os.path.exists(fname):
        return -1

    # read the file, do something else
    ...
    return bytes_read


def read_file_fail_fast(fname):
    if not os.path.exists(fname):
        raise Exception('File does not exist')

    # read the file, do something else
    return bytes_read

In the first example read_file_fail_safe returns -1 on error. The trouble is whoever is calling this method may not check for errors thus corrupting the flow of the program further down the line. You may also want to collect metrics and update your database with the number of bytes processed - this will totally skew your metrics. C programmers out there will quickly remember at least one case when they didn't check the return code for errors!

The second example read_file_fail_fast will raise an exception the moment it encounters a problem. It's not its fault that the file doesn't exist and there's nothing it can do about it, nor is its job to do anything about it. Raising an exception will surface back to the caller and they will be notified about the problem, taking appropriate actions to resolve it.

Yegor was also unhappy that many books teach fail safe and even IDEs (for Java) generate fail safe boiler-plate code (need to check this)! Indeed it is me who asks the first question Are there any tools to detect fail safe code patterns? and it turns out there aren't (for the majority of cases that is). If you happen to know such a tool please post a link in the comments below.

I was a bit disappointed by the rest of the talks. They were all high-level overviews IMO and didn't go deep technical. Last year was better. I also wanted to attend the GitHub Patchwork workshop but looking at the agenda it looked like this is for users who are starting with git and GitHub (which I'm not).

The closing session of the day was "Real time front-end alchemy, or: capturing, playing, altering and encoding video and audio streams, without servers or plugins!" by Soledad Penades from Mozilla. There she gave a demo about the latest and greatest in terms of audio and video capturing, recording and mixing natively in the browser. This is definitively very cool for apps in the audio/video space but I can also imagine an application for us software testers.

Depending on computational and memory requirements you should be able to record everything the user does in their browser (while on your website) and send it back home when they want to report an error or contact support. Definitely better than screenshots and having to go back and forth until the exact steps to reproduce are established.

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