Writing Your Own Spring Boot Starter

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Writing Your Own Spring Boot Starter

By Dieter Hubau@dhubau

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A little bit about me• Dieter Hubau - @dhubau

• Java Consultant at Ordina Belgium

• Cloud and PaaS Competence Lead

• Spring Lover

• Games, Blogs, Coding

• Soccer!

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Spring Boot“Opinionated view of building production-ready Spring applications”

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• Up and running as quickly as possible

• “Convention over configuration”

• Production-ready features such as metrics, health checks and

externalized configuration

• No more XML

• Starter POMs simplify configuration in MavenSTART.SPRING.IO

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Spring Boot Starter

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Quick Example

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Spring Boot Starter - How?“Is it magic?”

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Yes. Yes it is. That was a lie

Everything will be explained

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Spring Boot Starter - Example“Let’s make a minimal Spring Boot application, see what happens”

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Business Case“Let’s get to work!”

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• The FREP Handheld Business Case has concluded that the overall net cost/benefit of a Handheld is unacceptable and is significantly different from the current Non-Handheld.

• Initially, we were optimistic that a handheld deployment phase would be valuable for FREP but due to the characteristics of FREP and the recommendations from the Vivid Solutions study, this business case has identified an NPV difference of $500K.

• Most of the significant benefits are delivered with FREP online application in Release 1. This application provides significant data quality improvements with business data rules in the system and there is only incremental value to push this out to handhelds.

I LIED AGAIN

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(not so much) Business Case“Rock Paper Scissors Lizard Spock”

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• Scissors cuts Paper• Paper covers Rock• Rock crushes Lizard• Lizard poisons Spock• Spock smashes Scissors• Scissors decapitates Lizard• Lizard eats Paper• Paper disproves Spock• Spock vaporizes Rock• (and as it always has) Rock crushes Scissors

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(not so much) Business Case“Rock Paper Scissors Lizard Spock”

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• Lightweight

• Stateless

• Cloud Native

• Authentication over Twitter

• No JDBC

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(very much) Backup Plan“Josh Long Pokémon”

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• Spring Boot Starter

• Provide endpoint to retrieve Josh Long’s Pokémon

• Make it somewhat configurable

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RecapAutoConfiguration is not magic!

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• @SpringBootApplication enables AutoConfiguration• SpringFactoriesLoader removes the need for classpath scanning• @ConditionalOnClass/Bean allows for flexibility and overriding• Do not start your artifact name with spring-boot-starter!• Autoconfigurations are executed after the regular beans• Control the priority of your starters with @AutoconfigureBefore/After• Check out the autoconfig in debug mode with —debug parameter• Or include the actuator and browse to /autoconfig and /beans

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Any Questions?

Now go and try to create your own Spring Boot Starter

Check out the demo code at https://github.com/Turbots/SpringOne2016

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