Technical Debt - osbridge

Technical DebtElizabeth NaramoreOpen Source Bridge

June 2011

Technical Debt

1. What is it?

Technical Debt

2. Why should we care?

Technical Debt

3. What do we do about it?

“Shipping first time code is like going into debt. A little debt speeds development so long as it is paid back promptly with a rewrite...

The danger occurs when the debt is not repaid. Every minute spent on non-quite-right code counts as interest on that debt.”

--Ward Cunningham, 1992

“I think that there were plenty of cases where people would rush software out the door and learn things but never put that learning back into the program, and that by analogy, was borrowing money thinking that you never had to pay it back.... eventually all your income goes to interest and your purchasing power goes to zero.”

--Ward Cunningham, 1992

1. What is Technical Debt?

Code or practicesthat will hinder your progressin the future.

2. Why should we care?

Too much technical debtcan cripple your teamor organization.

3. What can we do about it?

Easy there, tiger. We’ll get to that.

Where do wefind it?

In our own code.

For example...

Untested code.

You have technical debt if you have...

Untested code.

How much time is wasted when changes break stuff and create more bugs?


Suppressed errors.


Suppressed errors.

(Psst. This doesn’t really make the error go away. I’ve tried.)


Confusing code, inconsistencies & workarounds


Confusing code, inconsistencies & workarounds

How much time has been wasted trying to sort through spaghetti code?


Legacy code


Legacy code.

How much time has been wasted trying to sift through cruft?


Code that doesn’t follow standards.


Code that doesn’t follow standards.

Code that is hard to read takes time to read.


Duplicate code blocks.


Duplicate code blocks.

Good for quilts. Not so good for fixing mistakes in code.


In things that affect our code.

For example...

•Non-existent or improperly used VCS.•Unstable deployment process.•Individual code ownership.•Lack of documentation.•Unshared knowledge.•Third party code that needs updated/patched


Guess what?

We all have it.

Don’t panic.

Sometechnical debt

is ok.

It allows you to hit a deadline.

It might make sense if...

It allows you to experiment.


The code is rarely touched.


You are coding for reasonable expectations.


Your code is at the end of the life cycle.


This kind of debtis known as

prudenttechnical debt.

So when is debtnot ok?

All the other times.

This kind of debtis known as

recklesstechnical debt.

Sometimes we knowwe are taking

shortcuts,but we do it anyway.

This kind of debtis known asdeliberate

technical debt.

Sometimes we don’t know any better,

or the debt is not our fault.

This could come from:

•inexperienced team members•changing project requirements•post-release retrospectives•security patches or updates from third parties

This kind of debtis known asinadvertent

technical debt.

4 ways to classifytechnical debt:

prudent vs. recklessdeliberate vs. inadvertent

Martin Fowler’s Quadrant

By minimizing deliberate debt, we can better handle

inadvertent debt.

So now that we know what it is, let’s move on.

3. What can we do about it?

We tackle our debt with

D.E.B.T.(see what I did there?)

Discover

Where is our technical debt?

•Ask your developers•Use the list mentioned before•Use software like Sonar

Where is our technical debt?

Estimatehttp://sonarsource.org

http://sonarsource.com

http://sonarsource.com

Sonar

http://nemo.sonarsource.org



SonarApache Jackrabbit:

Sonar

Sonar + Technical Debt Plugin

EstimateHow much is it costing us?

The Simple-ish Formula

Amount of the “loan” = cost to fix“Interest Rate” = Adverse impact on

development

EstimateHow much is it costing us?

Determining the “interest rate” is hard.

Use estimation techniques that work for you.

Break Down

Break DownWhat do we do with this mass of technical debt?

All debt breaks down into 2 categories:

1. Debts where we continue to pay interest.2. Debts where we pay on the principal.

Task and Track

Task and Track

The key is making it visible.

Task and Track

Add tasks to bug trackerAdd to task board

Show progress to all

Paying it Off

Paying it Off

Focus on high interest items

OR

Focus on small tickets

Paying it OffDedicate time.

• Use time right after a release• Tech debt iteration/sprint• Time each day for tech debt• Refactor as you go• Use off-season time• Designated Debt Payer

Paying it Off

Keep track of your progress

AND

communicate to all.

Prevention

Prevention

• Break past habits • Group consensus & commitment• Teach your “children” well• Never file for bankruptcy• Live within your means• Anticipate your needs

A few words aboutchange

management.

You should read this.

Change Management

Change Management

1. Direct the rider.

Change Management

2. Motivate the elephant.

Change Management

3. Shape the path.

Want to contact me?

http://naramore.net/blog@ElizabethN

[email protected] IRC: ElizabethN

THANKS!

Image used with permission from Martin Fowler

mailto:[email protected]

mailto:[email protected]

Technical Debt - osbridge

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