Welcome to Fail FastSession By @AlSayedGamal

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Fail FastBy @AlSayedGamal

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Agenda

Fail Immediately!

Assertion!

Eliminate the debugger!

Fail fast and robust software.

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Q1:What’s the most annoying part of software development ?

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A: Debugging

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Q2:What are the most hated bugs ?

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A: Bugs that appear unexpectedly after a long time of operating

normally!

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Fail Fast is the solution

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Fail ImmediatelyFail Fast concept can be digested as failing

immediately and clearly.

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Can you debug this ?Imagine this in a web based app & the developer had a typo in config file

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What about debugging this ?Same typo will be spotted immediately.

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Fail Fast Fundamentals

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Assertions

What’s assertion ?!

Make sure that your language fails on assertion error.!

When is the most suitable time to do assertion.!

Assertion doesn’t conflict with logging.

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Design your assertionsOnly if your language doesn’t have a powerful one already

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بط هوين؟ *

*But when ?15

–Jim Shore

“However, it’s tough to know when to add assertions. One way to tell is to look for comments.”

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The Killing ExceptionWhen Assert.notNull() can save your life.

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Debug this.The hair pulling phase.

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but when ?*

*بط هوين ؟20

Assertion not required

Assertion required21

Rule of thumb

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Eliminate the debugger

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and even better

If the maxConnections wasn’t found or mistyped it will throw!something like this one:

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Fail fast robust software

Global exception handler

Summary

Don’t fail silently and save your time and out time.!

Assert whenever you comment.!

Assert.notNull(_instanceVariable).!

Fail with description.!

Use a global handler for users sake.

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References

http://www.martinfowler.com/ieeeSoftware/failFast.pdf!

en.wikipedia.org/wiki/Fail-fast

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Questions ?

@AlSayedGamal

Thank you!