Author: John McCaffrey

What is the ideal Senior Developer skillset?

John McCaffrey, Wednesday, November 11, 2009 @ 4:21 pm

We're currently in the process of interviewing candidates for 1-2 Senior, and 2-3 junior level Rails Developers, and I'm wondering about the skills that are most critical, and how best to identify the best candidates.

My normal interview process flows like this:

1. Quick Phone screen evaluating basic development skills, background, availability, personality
2. Basic coding problem (less than 1hr to complete)
3. Phone call to review coding problem, 'how would you handle X?' questions, etc
4. On site interview targeting: Communication, Communication, Communication, (and tech)
5. Final decision

Independent of the language they will be working with, I've found decent success with having candidates answer some standard dev questions, solve a basic coding problem, and demonstrate their ability to whiteboard a design.

The problem is that it doesn't scale. When we've opened up positions in the past, either Senior or Junior, there have been so many applications that its hard to contact them all. This leads to a reshuffling of the tasks and matching criteria, in an attempt to identify the 'best' matches, and 'filter out' the others.  So instead of calling each candidate first, we might simply reply to them with the details of the coding assignment. I've seen 40 people send the "I'm an extremely hard worker, very interested in your position and would do anything to join your wonderful company" cover letter and resume, and then get whittled down to only 10 candidates that actually submit the assignment.  (Note to applicants: 'showing up' is an important first step!)

I came across an interesting post titled '11 tips on hiring a rails developer' which mentioned some 'filtering' criteria to identify the best candidates

You can read the full description of each one, but there are a few of these that I wanted to highlight:

1. Don't use Monster.com or recruitment agencies.
2. Poach Talent from other companies!
   
3. Don't hire someone that doesn't know Rails at all.
4. Look for open source contributions.
5. A personal Rails blog is required.
6. A university degree is not important.
7. Be wary of holes in proficiency.
8. Avoid brand-name superstars.
9. Hire perpetually.
10. Have a company Rails blog
11. Special compensation.

So each of these tips is meant as a heuristic or proxy of the true underlying ability. Any time you are making generalizations you are going to miss out on a few exceptions, but hopefully you end up with what you are looking for.

Starting with the most controversial first, (#5) while I like the idea of giving a strong preference to someone that has a rails blog, and loves  Ruby, Rails, and Web Development enough to be opinionated and spend their own time ranting about it, I'm not sure I could make it a filtering criteria. Doesn't that seem a bit strong?

I feel the same about (#4) Open Source contribution. I think its great if they have it, but I'm not sure I would reject any candidates that haven't contributed to open source.

While I've met many systems administrators that (#6) don't have a degree, and are very good at their craft, I haven't really encountered many solid developers that don't have a degree. That's not to say they aren't out there, I'm just saying I've never encountered them, and I'm reluctant to use it as a filter. Do you think that there are many strong Rails developers out there without degrees? (I don't care if they have a CS degree, but I think I prefer that they have some kind of degree)

As it relates to (#1) and (#11), I know for sure that the economics of finding a candidate through your own network and contacts can be less expensive than the recruiter fees (assuming you find a decent candidate and don't waste a lot of your own time doing it), and if you are able to find someone directly, it frees up cash for such amenities as 'New Macbook Pro', 'RailsConf', and 'Fridge full of XXX'.

If I was in charge of everything

I really like what Andy Singleton describes regarding how his team at Assembla is organized and tackles Agile Development, and on the right project, I'd really like take his advice and try this one:

"Don’t interview. Just pay people to join a project, pull a task from the queue, and find out what they can do."

Anyways,  I'd be very interested in your thoughts regarding what makes for a Solid Rails developer, where you find them, how you keep them, and what you've learned.

(Oh, and if you know any passionate Rails Developers in the Chicago area, send them over!)

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Rails DateTime.to_time, Time, and a case of ‘Why do you need to do that?’

John McCaffrey, Wednesday, September 23, 2009 @ 1:24 pm

The problem: I needed to display a warning to a user if the data they were looking at was more than 90 days old.

The solution: Create a method that takes 2 dates (either DateTime or Time), and returns the number of days, or hours between them.

  def self.difference_in_dates(date1, date2, unit = 1.day)
    return nil if date1.nil? || date2.nil? || unit == 0
      (( date1.to_time - date2.to_time ) / unit).round.abs
  end

The problem was simple enough, and my tests were all passing, so I moved on to my next task.

That code has been out in production for several months, but earlier this week, a new developer told me he got an error when running the test:

  NoMethodError: undefined method `to_f'
    for Mon, 21 Sep 2009 14:29:38 -0500:DateTime

(we're running this in Rails 2.0.2)

I looked at the code, knowing it was working before, ran the unit tests myself, and didn't see the issue. Now I'm on Windows and everyone else is on a mac, so as soon as I run into an issue that no one else has seen I want to prove if its a Windows problem. But wait, this test has been running in our Continuous Integration server (Hudson) for months, and no one else on the team ever had any issues with it, and the code has been working in production without any errors in the logs.

I jumped into rails script/console to see what's up, and here's what I found:

 >> x = DateTime.now
=> Wed, 23 Sep 2009 00:00:00 +0000
>>; x.to_time
=> Wed Sep 23 00:00:00 UTC 2009
>> x.to_time.to_f
=> 1253664000.0

Which is what I expected, but when I asked the other developer to run that same instruction, he got an error.

>> DateTime.now.to_time.to_f
NoMethodError: undefined method `to_f'
  for Mon, 21 Sep 2009 14:29:38 -0500:DateTime

What's up with that? We're running the same code, and all of our libraries are the same version. Looking at the date value in his error, I saw the timezone, and decided to try this variation locally:

>>  x = DateTime.parse("2009-09-21T14:29:38-0500")
=> Mon, 21 Sep 2009 14:29:38 -0500
>> x.to_time.class
=>; DateTime

So I'm gathering that when there is a timezone and you ask DateTime.to_time, its just going to give you back a DateTime.
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Chiphone Meeting: Chicago iPhone user group gets its TDD on

John McCaffrey, Friday, August 28, 2009 @ 10:25 am

Eric Smith from 8th light gave a hands-on TDD presentation at last night's Chiphone meeting, hosted at Obtiva's downtown office, (conveniently located near the the train).

There was a good crowd of people, most attendees have 'played around' with iphone development, 4 have actively developed apps (3 people have live apps in the store).  From my quick survey of those that have submitted apps, it seems most of them were free utility apps or simple games, with at least one commercial app Dash for Confluence. It also seemed that no one had yet needed to do any animation beyond the basics, with just a bit of core-animation, but no need for more lower-level openGL or animation engines.

Eric started off by saying that he's given talks on iPhone testing, but that just telling people what to do is not the same as letting them experience it for themselves,  so we did a Randori, where a pair starts working on some code, and every 3 minutes one person from the pair swaps out and chooses his replacement from the crowd.

What I liked about this was that I felt like I got to know the audience better, and actually watch people reason their way through the code or a testing/mocking issue.  (You know how sometimes you go to a user group, and it can be hard to get a chance to talk to others, or sometimes there is a 'know-it-all' guy, and you just want him to shut up. Knowing that you are going to have to go up there and code is a great way to silence those types)

When it was my turn,  there was an interesting issue with one of the tests that had us all stumped for a bit, but ultimately ended up being one of those problems where you need to deconstruct everything and build it back up. (The issue was that while we were trying to set fooController.textView.text = @"foobar", we hadn't instantiated a textView object, or set it on the controller yet.)
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Javascript debugging and testing in the wild (Prototype bug when using array.flatten in IE)

John McCaffrey, Wednesday, August 19, 2009 @ 10:49 am

I had to dig into a production issue the other day that presented itself like this:
There was a piece of javascript code that iterated over some dom elements, gathered ids into 2 arrays, ran a validation check, and then flattened the arrays to add them to the url.

On firefox, opera, and chrome this was working correctly, and had been tested by the developers, but on IE 7 it isn't working, and the problem wasn't detected until it made it out to production. (Which raises a point about testing in IE during QA, which I'll get to in a sec).

I started my investigation doing what I'd call "poor man's debugging", putting some alerts in, breaking up the code a bit to make it easier to inspect, etc. Normally I don't do this when testing in Firefox, because I have Firebug, but in IE I always seem to start with the basics to get my bearings, then quickly move to a more pragmatic approach.

Then I started using firebug-lite, confirming that I can see the info I need, and I reverted my changes to the code so that I could verify that I hadn't introduced any issues.
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What’s the best way to programmatically edit a pdf in ruby?

John McCaffrey, Tuesday, July 21, 2009 @ 3:59 pm

I've been doing a good deal of PDF generation in Rails, and had to go through the process of comparing all the available techniques and frameworks in order to find the right solution for my needs.

Its great that there are so many tools out there, but it can be a daunting task to figure out which is best, which will scale, which will continue to grow and improve, and to evaluate the true 'cost' of free vs. commercial.

With all this info finally digested and sorted out,  I was surprised when I got a client request to be able to add a banner to an existing pdf, and from what I can  recall, none of the libraries I know about seem able to do this.  Right now, I'm in the middle of googling the hell out of it, but haven't found my silver-bullet answer yet.  (maybe I should ask jeeves?)

I've done various searches and have come across a few categories of PDF tools:

1. Wrappers to existing pdf generation tools like fpdf, and iText
2. PDF Template tools where you build a pdf skeleton file, and bind values to it programmatically
3. Pure Ruby PDF Generation tools
4. PDF Readers and inspection tools

I did find a discussion about how this could work on Google Groups between Greg Brown creator of Prawn and Ruport, and James Healey developer of PDF::Reader, but that discussion basically ended with, "Yeah, that would be cool!".

At this point I'm looking into the Origami library which is actually designed for pdf 'security' and testing, and isn't explicitly designed for editing pdfs in this way, but at the moment its the leading candidate in my list.

Have I missed something? Is there an obvious way to do this in ruby/rails that I'm completely overlooking? (I haven't looked very deeply at tools that shell out to the bigger libraries, but I wouldn't rule them out)

The initial requirement was to be able to add a banner/header to an existing PDF, but I can see the complexities of determining how to shift the existing content down without screwing up all the formatting, so I think even being able to insert a coverpage might be a suffcient implementation for now. (Maybe I should be searching for pdf 'merging' instead of editing)

I'll update you with my final solution in an upcoming blog post, and I'll be covering all of the info I've learned on PDF Generation tools for Ruby and Rails  at this year's WindyCityRails Conference on September 12th. Drop by http://windycityrails.org to register. (early registration ends Aug 1st)

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ChicagoRuby meeting ‘Test Prescriptions’ recap

John McCaffrey, Wednesday, June 24, 2009 @ 12:41 pm

The ChicagoRuby users group (not to be confused with chirb.org another great Chicago Ruby user group) held their second meeting at their downtown location.

While the meetings out in Elmhurst are always informative and helpful,  the downtown location may allow for a bigger crowd, and the weekday time might work better for more people. Plus, the Illinois Technology Association - Tech Nexus is right next to Union Station which works great for people that still have to go out to the suburbs.

Noel Rappin's talk covered some of the most common questions he gets through the Pathfinder Development Blog, and his own site RailsPrescriptions site RailsRX.com dedicated exclusivly to testing.

There's too much detail to cover here, but at a high-level, Noel covered:

• The why, how, when, and where questions that make the foundation of a good testing approach
• Testing techniques for legacy projects
• A good review of the different testing frameworks, what their differences are, and some discussion about each (test::unit, shoulda, rspec, cucumber)
• A solid review of different factory tools that go beyond standard fixtures (Factory Girl, Fixture Replacement, Machinist, and Object Daddy)
• Strategies for migrating from Fixtures
• Differences between the mocking frameworks:  Flexmock, mocha, rspec, and RR (double ruby)
• Finding the right balance, and avoiding the pitfalls of 'over mocking'
• Cucumber testing workflow (and where cucumber doesn't work well)

The audience seemed to have a wide range of experience, but all had opinions to share about what they've learned about testing.  After the talk everyone seemed fell into small groups to network and exchange ideas and contact info, and a group gathered around Ray and Noel as they tossed around some ideas on potential future meeting topics "Ruby IDE/Editor review", "Rails Jumpstart", "Coding Dojo".

The organizers took a stab at hosting the meeting virtually over gotomeeting (not sure if it was recorded or not).

Their next meeting is scheduled for July 18th, details can be found in their meetup.com group.

The organizers of the ChicagoRuby.com group are also the organizers of the 2nd annual WindyCityRails Conference right here in Chicago, on Sept, 12th, which Noel will be presenting at.

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Mowing the grass, Revisited

John McCaffrey, Wednesday, June 24, 2009 @ 12:17 am

photo credit: great_sea

A few weeks ago Alice Toth and I had a conversation about how we can better serve our clients, and while we normally delve into project efficiencies like communication, developer training, and good QA practices, this time we both concluded that we need to do a better job of helping our clients reach their goals in the most efficient way possible, and sometimes that means talking them 'down' from the specific implementation idea they have, and finding a faster way to get there.

I said that one of our challenges is that sometimes our clients feel they've hired us to just  'Mow the Grass', not discuss the landscape architecture, so we're not always in a place to be heard when it comes to discussing the fundamentals of a project.  Alice wrote a nice post about what 'Just Mow the Grass' meant to her, and the strategy she's devised to find a nice middle ground.

Here's how I see it

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5 things I can do with my windows mobile phone that you can’t do with your iPhone

John McCaffrey, Tuesday, June 16, 2009 @ 6:15 pm

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Web app security checklist (Braindump)

John McCaffrey, Thursday, May 14, 2009 @ 3:21 pm

In Yesterday's post I said I'd put together a quick list of things to think about around web application security. This is by no means an exhaustive list, but its a set of categories and things I start to look at when doing a security assessment on an app.

Web Application Security Checklist
Account management

• Password management (validation, expiration, previous passwords, etc)
• Account lockout (number of tries, IP auditing, etc)
• Role management

Data management

• Don't Leak sensitive user info (SSNs, account numbers, other identity info) in URLs, cookies, sessions, logs, or printable pages.
• User Auditing (who changed what, and when)

Browser hacks

• Cross Site Scripting (XSS)
• Cross Site Request Forgery (XSRF)

Encrypted transport (make sure Ajax calls are secure)
Encrypted storage (credit cards, ssns, etc)
Server configuration (firewalls, web/app server, db)

I actually have a longer list, but its not formatted/organized very well,  so this is my first cut at sharing it with others.

What other areas do you look at when doing security checks for your web apps?

What tools do you use?

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Avoid the last minute security review

John McCaffrey, Wednesday, May 13, 2009 @ 4:10 am

Photo Credit:
Amagill under Creative Commons Attribution

Security is hard

Security is often an after thought, slated towards the end of a project, or after some big issue has been discovered, but the nature of security functionality, rules, roles, auditing, etc make it hard to layer in to an existing codebase effectively.

Oh, and if the code base isn't sufficiently tested, you're in for a world of hurt.

If you are a developer that was just asked to 'do a quick security check and plug any holes', you are now in the difficult position of managing the expectation that a two-week security review means "we're covered". Be realistic about what you can accomplish, setting out some short-term and long-term goals.

Do More With Less. Start with a research 'Spike'

Instead of pushing for more time to be able to 'cover it all' (even though you have no idea what 'it all' is yet), it might be better to start with a shorter analysis phase, where you detail your findings, identify any trends, and include recommendations for process change. I've found that even the most demanding manager is appreciative and understanding when you ask for a small amount of time in order to produce a better estimate, than to just immediately demand more time without any evidence as to why.

Plan for success

With your analysis and recommendations in hand,
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Bugs can’t be estimated

John McCaffrey, Tuesday, May 5, 2009 @ 11:37 pm

In an earlier post about the benefits of Agile and Scrum, I made a statement that bugs by their nature are not the same as normal features, and I wanted to take a moment to try and make my point a little clearer. Bugs and estimation have been a hot topic with us lately, but interestingly we are all working on different projects and actually have a slightly different take on the subject.

My definition of a bug is: A feature that was specified, and you attempted to deliver, but is not working according to your intentions. (ie. "I thought it WAS saving to the database")

Not a bug: A feature or variation that you hadn't intended to create in the first place. ("Oh, I didn't know it was supposed to do that when you clicked the back button")

And with that understanding I say "Bugs can't be estimated"
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Adopt a non-techie. Help your business team move faster

John McCaffrey, Wednesday, April 8, 2009 @ 4:00 am

I've been spending some time with our internal sales and marketing team to hash out some of our goals for the year, and it became quite clear to me that non-developers are on their computers all day long facing some of the same technical challenges we do.

Some of the tasks they have to do:

• "take the data out of the spreadsheet for last quarter and compare it to this quarter"
• "gather the bounced emails from our newsletter posting, and update our list, pulling out duplicates"
• "replace all the names and addresses from our NDA agreement each time it is sent to a new client"
• "slice and dice google ad-words and google analytics data"

So I've resolved to take some time each week to 'Adopt a non-techie', and help them spend less time 'screwing around with the computer' and more time on the most valuable tasks they do.

In the same way that developers need to be as efficient as possible with the tools they use, Continue reading »

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Can your Selenium do that? Testing flash/flex and silverlight in web apps with iMacros

John McCaffrey, Wednesday, April 8, 2009 @ 4:00 am

Having learned a long time ago the value of automated testing tools like Selenium, jMeter, and soapUI, I'm always on the lookout for new improvements in these tools. While I love Selenium and other frameworks like it, it has the limitation of not being able to test Flash/Flex/Silverlight or Java Applets. But if you need to test flash and silverlight components of your web app, in an automated way, the  iMacros testing tool might be worth checking out.

No Free Ride

While the free version of the iMacros plugins for InternetExplorer and Firefox allow powerful web scripting similar to Selenium, to be able to do the flash/flex and silverlight, you have to get the paid version or the 30-day trial. I downloaded the trial version to see how it compares to Selenium and what kind of damage I could to.

Going through some of the online demos, Continue reading »

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Scrum defined in under 10 minutes

John McCaffrey, Thursday, January 22, 2009 @ 4:26 pm

Hamid Shojaee from www.axosoft.com put together a great video to introduce the core concepts of scrum and Agile practices called "Scrum in under 10 minutes"

I really like what he said particularly the focus on the importance and simplicity of the burndown chart which helps to :

• Visually show the hours remaining, and help anyone see "are we there yet?"

• Allows decision-makers to make adjustments if needed

A simple burndown chart quickly shows the impact of some of the most common efficiency killers or blockers

1.    late-breaking requirements changes
2.    waiting for business decision
3.    waiting for tech. partner (ssl keys, ops. vendor, etc)

He mentioned the standup, but didn't cover the 3 questions (What did you do?, What are you going to do? What do you Need in order to accomplish it?), or the idea that only people that have work can speak (Chickens vs. pigs)

I also liked his take on bugs, that you should plan a sprint to tackle them, and any bugs that come up during a sprint should be tackled immediately.

That's actually something that a lot of teams struggle with, "How do you plan for and estimate the time necessary to fix bugs?"

I always say Bugs Can't be estimated. While you may be able to plan how much time you will allocate to working on bugs, you can't really estimate how long it will take to fix bugs unless you have already looked at them, and have figured out the problem. From my point of view its the "looking at it and figuring out what's wrong", that takes the longest, and is the part that needs to be accounted for.

How do you plan for bugs?
Do you let bugs accumulate and then have a final sprint before a Release where you tackle all of the bugs? (How would you know that you can fix all the bugs in time for the release?)

Do you tackle all High-Priority bugs as soon as they come up, and leave the medium and small priority bugs for later?

Do you have a 'zero-bug' policy, where you fix any bugs that are opened?

UPDATE: I've expanded on this discussion a little more in a new post Bugs Can't be estimated, and after having some discussions around how best to plan for bugs, I was asked to do a last minute Security Analysis, and I wrote a post about How to avoid the last minute security review, and I think that the planning part can actually apply to how you manage a big list of bugs as well.

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Book Review: Core Animation for Mac OS X and the iPhone

John McCaffrey, Friday, January 16, 2009 @ 3:04 pm

Related Services: iPhone Application Development, Custom Software Development

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