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Practical Applications of

Micro Services in MITK

Keno März

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Why do we need classes?

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Rene Aigner - Monolith

A

B

C

D

E

F

G

Core

1) No separation of concerns

2) Seperation into modules

3) Seperation into micro services

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The ideal Micro Service

• One process

• One concern

• One interface

• „Shared Nothing“

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Monolithic Software

A

B

C

D

E

F

G

Core

A

B

C

D 2.0

E

F

G

Core

A

B

C

D 2.0

E

F

G

Core

A

B

C

D 2.0

E

F

G

Core

A

B

C

D 2.0

E

F

G

Core

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Maintenance

A

BC

D

D 2.0

Registry

Core

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Scalability

A

BC

D 2.0

Registry

Core

D 2.0

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Flexibility

A

BC

D 2.0

Registry

Core

D 2.0

More on on

that later!

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Not a silver bullet

http://www.kassenzone.de/2016/04/21/microservices-einradfahren/

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Topics

1. Intro

2. Implementation in MITK

3. Use-Case 1: Reader and Writer

4. Use-Case 2: IGT Devices

5. Conclusion

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C++ Micro Services

• http://cppmicroservices.org/

• Coder: Sascha Zelzer*

• Pure C++ implementation

* Google this name for more info

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Three steps to your Micro Service

1. Implement it

2. Register it

3. Discover it

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Create a Microservice: Implement it

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Create a Microservice: Register it

• Example Implementation: mitk::USDevice

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Service properties

• Map<string, us::Any>

• Can be used for filtering! (LDAP-Format)

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Create a Microservice: Discover it

Two options available:

a) Search via ModuleContext

• Example: mitk::FileWriterRegistry

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Create a Microservice: Discover it

Two options available:

a) Listen via EventListeners

• Example: QmitkServiceListWidget

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Listening to changes

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Topics

1. Intro

2. Implementation in MITK

3. Use-Case 1: Reader and Writer

4. Use-Case 2: IGT Devices

5. Conclusion

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The Situation

• I/O managed centrally from core

• I/O Implemented in modules

• Painful for 3rd-party devs

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Design idea

• Microservice with properties:

• Supported MimeType

• Priority value (int)

• Additional registry classes for easy access

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The new IO Architecture

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3rd party creates reader

mitk::MyFileReader mitk::MyFileWriter

mitk::MyFileReaderAndWriter

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Mime Types

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Core

Implement new Reader

Registry

IOUtil

My Module

ASD Reader

ASD Mime

TypeFileReader

ServiceRegistry

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Core

Supercede a Reader

Registry

IOUtil PicReader

Priority:100

FileReader

ServiceRegistry

My Module

BetterPicReader

Priority:101

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Summary

• Micro ServicesG

• G give more control to 3rd party devs

• G make I/O process more dynamic

• G decouple decouple core I/O from modules

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Topics

1. Intro

2. Implementation in MITK

3. Use-Case 1: Reader and Writer

4. Use-Case 2: IGT Devices

5. Conclusion

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Situation

• IGT Tracking Toolbox:

• Great for tracking!

• Ultrasound Support:

• Great for ultrasound imaging!

• My Ultrasound Navigation Plugin

• I have to replicate it all again!

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MyDeviceConfigurator

Device design

1. Can be activated/deactivated

2. Has configuration plugin

3. Publishes pipeline endpoint

4. Registered as Micro Service

Device

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Combining Devices

IGT Tracking Toolbox

Tracking

Device

Ultrasound Support

Ultrasound

Device

Ultrasound NavigationOpen IGT Link

Tracking

Device

Ultrasound

Device

Tracking Device

US Device

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Summary

• MicroservicesG

• G facilitate reuse of workflows

• G enable sharing of instances across plugins

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Topics

1. Intro

2. Implementation in MITK

3. Use-Case 1: Reader and Writer

4. Use-Case 2: IGT Devices

5. Conclusion

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Where to start

• mitk::USDevice

• Basic Implementation

• Properties

• QmitkServiceListWidget

• Event Listening

• Filtering Micro Services

• mitk::FileReaderRegistry

• Active Micro Service search

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Conclusion

Micro ServicesG

• G help achieve decoupling

• G promote reusability

• G require careful interface design

• G should be used with common sense

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Future work

• Mappers as Micro Services:

• Smiliar to I/O scenario

• Micro Services for properties

• Distribute property resolution

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Next up 3.

Thank you for

your attention!

Further

information

on www.dkfz.de