Feature Toggles On Steroids

Feature Toggles On Steroids

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Feature Branches(aka Branch Based Development)

Quelle: http://geekswithblogs.net/Optikal/archive/2013/02/10/152069.aspx

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Problem 1: ...

Quelle: http://martinfowler.com/bliki/FeatureBranch.html

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Problem 1: ...

Quelle: http://martinfowler.com/bliki/FeatureBranch.html

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Problem 1: ...

Quelle: http://martinfowler.com/bliki/FeatureBranch.html

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Problem 1: ...

Quelle: http://martinfowler.com/bliki/FeatureBranch.html

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Problem 1: Merge Pain

Quelle: http://martinfowler.com/bliki/FeatureBranch.html

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Problem 2: Communication Islands

„Branches create distance between developers and we don’t want that“

Frank Compagner

Quelle: http://paulhammant.com/2014/09/24/a-functional-branch-by-abstraction-case-study/

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Problem 3: No Continuous Integration

Quelle: http://de.slideshare.net/eugenmartynov/flow-23558345

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Branch Based Development

Quelle: http://geekswithblogs.net/Optikal/archive/2013/02/10/152069.aspx

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Trunk Based Development

No Merge Pain

No Communication Islands

Continuous Integration

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Trunk Based Development

No Merge Pain

No Communication Islands

Continuous Integration

Refactoring Friendly

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Trunk Based Development

There are branches.

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Trunk Based Development

There are branches.

But there are no feature branches!

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Feature Branches ↔ Trunk Based Dev.

Merge Conflict Resolutioncosts time is error-prone

Communication Islands

No Continuous Integration

No Merge Pain

No Communication Islands

Continuous Integration

Refactoring Friendly

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Feature Branches ↔ Trunk Based Dev.

Merge Conflict Resolutioncosts time is error-prone

Communication Islands

No Continuous Integration

Stable trunk

No Merge Pain

No Communication Islands

Continuous Integration

Refactoring Friendly

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Feature Branches ↔ Trunk Based Dev.

Merge Conflict Resolutioncosts time is error-prone

Communication Islands

No Continuous Integration

Stable trunk

No Merge Pain

No Communication Islands

Continuous Integration

Refactoring Friendly

Unstable trunk

19 / 99Quelle: http://www.infoq.com/presentations/Development-at-Google

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Do you have pre-commit-verification?

21 / 99Quelle: http://paulhammant.com/2013/12/04/what_is_your_branching_model/

Use short lived issue branchesor personal branches instead.

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How do you prevent, that incomplete features are released?

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Feature Toggles

aka Feature Bits

aka Feature Flags

aka Feature Switches

aka Feature Flippers

aka Conditional Features

aka Latent Code Pattern

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Feature Toggles

Quelle: http://martinfowler.com/bliki/FeatureToggle.html

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IFEATURE TOGGLES

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Why Feature Toggles?

Hide unfinished features from users

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Why Feature Toggles?

Hide unfinished features from users

“Stable trunk” for visible functionality

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Why Feature Toggles?

Hide unfinished features from users

Separate Deployment and Release

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Why Feature Toggles?

Hide unfinished features from users

Separate Deployment and Release

Fearless Deployment

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Why Feature Toggles?

Hide unfinished features from users

Separate Deployment and Release

Fearless Deployment

No Big Bang Releases

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Granularity

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Granularity

● per environment (local, staging, live)● per server● per customer/mandator

- inherited if you have a hierarchy● per user

- a certain percentage of users● per country● per session

- a certain percentage of sessions● ...

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Granularity

● per environment (local, staging, live)● per server● per customer/mandator

- inherited if you have a hierarchy● per user

- a certain percentage of users● per country● per session

- a certain percentage of sessions● ...

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Granularity (example #1)

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Granularity (example #2)

Quelle: http://www.togglz.org/documentation/activation-strategies.html

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Granularity (example #3)

Quelle: http://abhishek-tiwari.com/post/decoupling-deployment-and-release-feature-toggles

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Why Feature Toggles?

Hide unfinished features from users

Separate Deployment and Release

Fearless Deployment

No Big Bang Releases

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Why Feature Toggles?

Hide unfinished features from users

Separate Deployment and Release

Fearless Deployment

No Big Bang Releases

Better Software Architecture

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Feature Toggle = Feature Toggle|

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Feature Toggle = Feature Toggle|

long lived,payed for by customer

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Feature Toggle = Feature Toggle|

long lived,payed for by customer

Business

Toggle

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Feature Toggle = Feature Toggle|

long lived,payed for by customer

short lived,payed for by your company

Business

Toggle

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Feature Toggle = Feature Toggle|

long lived,payed for by customer

short lived,payed for by your company

Business

ToggleBusiness

Toggle

ReleaseToggle

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Release Toggle = Release Toggle|

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Release Toggle = Release Toggle|

hides a new feature

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Release Toggle = Release Toggle|

hides a new feature

e.g. new functionality (new menu point, new dialog, ...)

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Release Toggle = Release Toggle|

hides a new feature

e.g. new functionality (new menu point, new dialog, ...)

hides a new implementation

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Release Toggle = Release Toggle|

hides a new feature

e.g. new functionality (new menu point, new dialog, ...)

hides a new implementatione.g. - new design - new backend technology (PHP → Java or Hibernate → MongoDB) - performance optimization (added caching or better algorithm) - ...

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Branch By Abstraction

Quelle: http://martinfowler.com/bliki/BranchByAbstraction.html

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Branch By Abstraction

Quelle: http://martinfowler.com/bliki/BranchByAbstraction.html

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Branch By Abstraction

Quelle: http://martinfowler.com/bliki/BranchByAbstraction.html

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Branch By Abstraction

Quelle: http://martinfowler.com/bliki/BranchByAbstraction.html

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Branch By Abstraction

Quelle: http://martinfowler.com/bliki/BranchByAbstraction.html

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Branch By Abstraction

Quelle: http://martinfowler.com/bliki/BranchByAbstraction.html

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Branch By Abstraction

Quelle: http://martinfowler.com/bliki/BranchByAbstraction.html

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Branch By Abstraction

Quelle: http://martinfowler.com/bliki/BranchByAbstraction.html

You wanna keep this

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Why Feature Toggles?

Hide unfinished features from users

Separate Deployment and Release

Fearless Deployment

No Big Bang Releases

Better Software Architecture

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Why Feature Toggles?

Hide unfinished features from users

Separate Deployment and Release

Fearless Deployment

No Big Bang Releases

Better Software Architecture

Testing in Live Environment with Live Data

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Why Feature Toggles?

Hide unfinished features from users

Separate Deployment and Release

Fearless Deployment

No Big Bang Releases

Better Software Architecture

Testing in Live Environment with Live Data

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Release Toggle = Release Toggle|

hides a new feature hides a new implementation

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Release Toggle = Release Toggle|

hides a new feature hides a new implementation

Dark Launching Pattern

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Dark Launching (example)

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Release Toggle = Release Toggle|

hides a new feature hides a new implementation

Dark Launching Pattern

Beta-TestingA/B-Testing

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Release Toggle = Release Toggle|

hides a new feature hides a new implementation

Dark Launching Pattern

Beta-TestingA/B-Testing

Verify Branch By Abstraction Pattern

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Branch By Abstraction

Quelle: http://www.stephen-smith.co.uk/application-pattern-verify-branch-by-abstraction/

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Branch By Abstraction

Quelle: http://www.stephen-smith.co.uk/application-pattern-verify-branch-by-abstraction/

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Verify Branch By Abstraction

Quelle: http://www.stephen-smith.co.uk/application-pattern-verify-branch-by-abstraction/

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Verify Branch By Abstraction

Quelle: http://www.stephen-smith.co.uk/application-pattern-verify-branch-by-abstraction/

● asynchronously(i.e. in the background, invisible for users)

● check for correctness● check for performance

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Implementation: 2 Feature Toggles

Use new implementation?

Verify new implementation?

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Implementation: 2 Feature Toggles

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

Use old code

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

Use old code

Use old code and

asynchronouslyverify new code

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

Use old code and

asynchronouslyverify new code

This costs!

Use old code

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

Use old code and

asynchronouslyverify new code

2x load?

Use old code

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

Use old code and

asynchronouslyverify new code

2x load?

Can you handle 100x load?

Use old code

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

Use old code and

asynchronouslyverify new code

Start small

Use old code

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

Use old code and

asynchronouslyverify new code

Restrictresourcesused byverifyUse old code

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

Use old code and

asynchronouslyverify new code

Use new code

Use old code

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Implementation: 2 Feature TogglesU

se n

ew im

ple

men

tatio

n?

Verify new implementation?

Use new code

Use new code and

asynchronouslyverify old code

Use old code and

asynchronouslyverify new code

Use old code

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Verify Pattern (example)

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Verify Pattern (example)

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Verify Pattern (example)

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Verify Pattern (example)

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Verify Pattern (example)

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Why Feature Toggles?

Hide unfinished features from users

Separate Deployment and Release

Fearless Deployment

No Big Bang Releases

Better Software Architecture

Testing in Live Environment with Live Data

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Some Questions Remain

● What should the system doif an asynchronous verify fails?

● Which library should you usefor Feature Toggles?(Should you use a library at all?)

● When do you deleteold Feature Toggles?

● How do you do testing withFeature Toggles?

● ...

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What should the system doif an asynchronous verify fails?

Logging Metriken

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What should the system doif an asynchronous verify fails?

Logging Metriken

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Which library should you usefor Feature Toggles?

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But here is a tip ...

Don't use Strings, Use an Enum.

Prevents typing errors

Code completion

You can easily add documentation

Makes it easy to remove a Feature Toggle

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When do you deleteold Feature Toggles?

When you are confident

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When do you deleteold Feature Toggles?

When you are confident

(probably serveral weeks after you activated the

Feature Toggle globally)

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Testing with Feature Toggles –Combinatorial Explosion?

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Testing with Feature Toggles(example #1)

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Testing with Feature Toggles(example #1)

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Testing with Feature Toggles(example #2)

Quelle: https://gist.github.com/MichaelTamm/d5a5a67460d7a2db08a4

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Testing with Feature Toggles(example #3)

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Main Takeaways

● Use short lived issue or personal branches ● Use fine-grained Feature Toggles● Verify new implementations

– asynchronously in the background on live systems

– in the background, but blocking on test systems

● Choose names for Feature Toggles with care● Use Enums for Feature Toggles