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Posts tagged ‘Programming’

Leading Snowflakes – Inspiration codified in a book

Oren Ellenbogen taught me so much along the years. He was my manager/team lead for a year, and I’ve learned from and worked with him on several other occaisions. I would love to co-found a startup with him one day.

Engineering management has been his passion and dedication for years. Finally – he achieved his dream and codified his passion into an eBook & package: Leading Snowflakes, The Engineering Manager Handbook. I highly recommend it for anyone wishing to increase their leadership abilities.

If you don’t want to commit or don’t have the time right now, you can start by subscribing to his weekly newsletter – Software Lead Weekly – it’s one of the most known newsletter that investigates and teaches engineering management.

Wanted: CTO

Want to be the CTO of a new Israeli Bitcoin Startup?

Head over to jobs.bitblu.com and learn more.

Things are moving.
Teams are assembling.
Join the revolution!

(Even if you’re not familiar with Bitcoin, but looking for an interesting CTO position, feel free to approach – we’ll teach you all you need to know about Bitcoin)
(Even if not relevant to you, we’ll appreciate a like/share/referral)

How to do a production hotfix

Situation
It’s Thursday/Friday evening, the daily version / master branch was deemed too risky to install, and you decide to wait for Sunday/Monday with the deploy to production.

There’s a new critical bug found in production.
We do not want to install the bug on top of all the other changes, because of the risk factor.

What do we do?
Develop the fix on top of the production branch, in our local machine, git push, and deploy the fix, without all the other changes.

How can I do this?

My example uses a Play Framework service, but that’s immaterial.

  1. gitk –all – review the situation
  2. Suppose the latest version deployed in prod is 1.2.3, and master has some commits after that.
  3. You checkout this version:

    git checkout 1.2.3

  4. Create a new branch for this hotfix.

    git checkout -b 1.2.3_hotfix1

  5. Fix the bug locally, and commit.
  6. Test it locally.
  7. git push
  8. On the production machine:
    1. git fetch (not pull!)
    2. sudo service play stop
    3. git checkout 1.2.3_hotfix1
    4. sudo service play start
  9. Test on production
  10. Merge the fix back to master:
    1. git checkout master
    2. git merge 1.2.3_hotfix1
    3. git push
  11. Clean up the local branch:


    git branch -d 1.2.3_hotfix1


    (Note: the branch will still be saved on origin, you’re not losing any information by deleting it locally)

Summary of JavaScript Weekly – Issue 86

I recently subscribed to Javascript Weekly, a weekly newsletter (yes, no RSS! or RSS feed) rather high quality weekly collection of Javascript cool stuff.

I’ve been picking the best links and sending to people at work, when I thought … hmm, I actually have a blog, why not summarize it here instead?
So, whenever I feel like it, I’ll be posting my own picks out the this week’s JS weekly.

Today, we have:

Interviewing? Keep it simple, stupid!

If any of you are intereview for a job any time soon, please take this advice to heart – just like KISS is a good principle in your every day job, it’s a great principle in a job interview.

Some people like to boast their skills when interviewing.

“I’m a Java Guru”

“I’m excellent at Big Data analysis on a NoSQL system in the cloud”

“I like well designed code … here are my favorite design patterns, I use them all the time”

Some of the above statements could apply to you … but be sure to be relevant to the job you’re interviewing for, and the tests you’re given. If you are asked to do a simple hands on coding session, know that your interviewer just want to see you code, he doesn’t need to you implement Map Reduce or show off your Uber Design Pattern skills.

Sure, it’s nice to sprinkle in good design, unit tests, and write scalable code … but before you do all those things, make sure you get the job done, on time, without bugs. Do the important stuff first, and show off later, if you have the time.

First Java & JVM Tel Aviv Tools Night!

After a few months of gathering forces, we have a critical mass of people interesting in learning and teaching about Java & JVM related technologies.

Our first Tools Night is this upcoming Sunday (29/04), in Sears Israeli (Hertzelia Pituah).

Please check out the schdeule on EventBrite, and subscribe if you’re interested. Also don’t forget to subscribe to the google group.

A few jQuery tricks from a newb

Hi all, this is your newb web developer talking again. While some of the following might be obvious to the more experienced web devs among you, this is a post that I wish I’d read when I just started using jQuery.

Write your own jQuery plugins

The word “plugin” usually entails something complicated and with some non-trivial learning curve (e.g. how many of you ever wrote a Chrome of Firefox plugin?) Well, in jQuery, this is really not the case. Here is how you write a simple jQuery plugin:

$.fn.enable = function() {
  $(this).prop("disabled", false);
};
 
$.fn.disable = function() {
  $(this).prop("disabled", true);
};

I find it useful to wrap even simple one liners such as .prop(“disabled”, false) with a plugin, because the semantics of writing $(“#foo”).disable() is much nicer than playing with properties/attributes directly. I haven’t written a lot of plugins yet, but it’s something to keep in mind as a useful tool to wrap actions on specific DOM elements.

Know the commonly used plugins
There are a ton … I still know very few of them. Here are a bunch of useful ones (and the ones I personally know and use).

A lot of plugins are very easy to use, and have good documentation and demos, so not using them and rolling your own solution is usually just a result of ignorance. Take the time to educate yourself!

UI Queues
For a long time I’ve that you can do things like $(“#mydiv”).show(), $(“#mydiv”).hide() and even $(“#mydiv”).show(1000) for a simple animation. Only recently I discovered you can actually chain these using Event Queues:

$("#mydiv")
  .hide(1000)
  .delay(500)
  .show(200)
  .fadeOut();

Each call to an animation method gets queued up and executes after the previous one.

Deferred
jQuery Deferred is a little gem. It lets you write fluent code similar to the queue example above. Here is how you use it:

$.when($.post('http://api.com/request_1'), 
       $.post('http://api.com/request_2'))
  .then(function(){alert("Got two responses")});

You can also use them with the event queue:

  $("#mydiv")
    .show(1000)
    .delay(500)
    .promise()
    .then(function(){/*do something */});

That’s all I have for now. Have any essential tips & tricks that I’m missing out on?

Javascript refactoring is hard

I’ve been refactoring code all my professional career. I started from C/C++, and when I hit C# (Resharper) and Java (IntelliJ), my productivity at refactoring was boosted by a few factors by the wonderful IDEs and refactoring tools that these languages have.

I am rather confident when I write “dirty code” in Java or C#, because I know that I can swiftly refactor it into beautiful code without too much trouble. Both aforementioned IDEs are so great at this, that it’s painless. You can take an ugly 300 line method and break it into several methods, break a long class into several classes, inline, move, and otherwise shape your code.

Enters javascript and web development.

Last year I’ve made the plunge and officially started working on front end web development, first at Google, and recently at Commerce Sciences. And I’ve recently discovered that … refactoring javascript and frontend code is hard.

The language is dynamically typed

Compilers and IDEs can help you less when the language is dynamic. They can make less assurances about your code, making reasoning and refactoring harder. Safely moving a method from class Foo to class Baz is an easy feat in a statically typed language, and a difficult or impossible one in a dynamic language.

Classes are not first-class citizens

While you can do OOP in javascript, classes are not first class citizens, but rather they’re implemented using functions, objects and prototypes. Automatically reasoning about “classes” without having an equivalent of keyword class is difficult.

Your code is not just Javascript, it’s HTML & CSS as well

Web development is not just about javascript, it’s a combination of JS, HTML & CSS (not to mention other potential technologies such as LESS/SCSS, HAML, JSON, and whatever language your backend is written in). Unless you’re already a web development ace and perfectly design your codebase … you will get these mixed up. Refactoring is about changing the design of your program, and when that design is split up between three or four different technology domains, design mistakes are harder to rectify.

You can’t (at least not yet) do an automatic refactoring to “move inline css into an external css file”, or to “convert static html snippet into a javascript DOM manipulation method”. The makers of IDEs and refactoring tools don’t have javascript completely figured out yet, no wonder they haven’t gotten around to building cross-domain refactoring!

Again, if you “know what you’re doing”, you can structure your program perfectly in the first place, and won’t ever have to do this kind of “cross domain refactoring”. Sadly, we’re not all born with this kind of experience.

It’s harder to know when you’ve broken something

Backend code is so much easier to test than frontend code. While frontend testing is important, and growing, it is by no means as well understood or practiced as classical “backend TDD, this is a calculator, assertEquals(30, calc.plus(10, 20))”.

So, since BE code has much wider test coverage than FE code, and is bloody compiled for Java & C#, when you refactor FE code it has a much greater chance of breaking down, often in subtle ways you’ll only notice on IE 8, or when the network is slow, or whatever edge case surfaces your particular bug.

 

 

So … how do we manage?

  • Refactor less – Since we know refactoring is hard, we try to do less refactoring and more pre-factoring. Think a little more than usual before coding. While I’ve grown the habit of “code first, think about design later” over the years due to power of refactoring, it’s less useful in FE dev, so I need to take the time before coding and try harder to get it the design right on my first attempt.
  • Still .. refactor – IntelliJ and Resharper both offer some refactoring capabilities. I’m most comfortable with “limited scope refactoring” – those that affect one function like Extract Variable. Use the tools you do have, instead of whining about the tools you don’t.
  • Try to think harder about the different problem domains (JS/HTML/CSS), and to develop a better understanding of how to structure your program in a way that won’t force you do to refactoring across problem domains.

Please do share your own experience with refactoring in web dev!