The document provides insights into accelerating development using organizational opinions and Spring Boot's autoconfiguration features. It emphasizes the importance of maintaining a streamlined developer experience by implementing standardized practices for configuration and logging. Strategies for customizing behaviors, such as enabling request logging by default and various configuration options, are discussed, along with testing methodologies to ensure correct functionality.

1. Accelerating Development
with Organizational Opinions
October 7–10, 2019
Austin Convention Center

2. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
MUST CODE
FASTER!

3. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
LESS CODE

4. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
What are Organizational Opinions?
Spring Boot is “Opinionated”
• Investigates its environment (configuration, libraries, etc.)
• Instantiates beans and executes logic to establish default behavior
• Delivered through Spring Boot autoconfiguration
Organizational Opinions
• Implementation of standards through autoconfiguration
• Security, Operations, etc.
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5. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Goal: Keep developers focused on…
Business Functionality

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We get to enjoy…
• Predictability
• Typical behavior by default
• Consistency
• Easy for them to do the right thing
• Manage the 20%
• Supportability
• Operations out-of-the-box
• Sleep

7. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Developer Experience
What should be the Developer Experience?
• Should they have any choice?
How do they communicate intended behavior?
• Declared through an annotation?
• Bean construction?
How can they customize behavior?
• Configuration properties?
• Bean construction?
What about Operations?
• Should it include a HealthCheck bean?
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8. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Opinion Ownership
Opinions come in many forms…
Enterprise-wide
• Logging, Tracing
Technology-specific
• Configuration, Platform Security
Departmental
• Application-nuanced, layered on Enterprise/Technology
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9. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Lets Pair On an Example!

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Developer Experience – Acceptance Criteria
• RestTemplate Beans should be configured to log all outbound requests when
Bean is annotated with “@RequestLogging”
• Request logging should be enabled by default and should be disabled by
setting the property “request.logging.enabled=false”
1
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11. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Developer Experience
@Configuration
public class ExampleApplicationConfiguration {
@Bean
@RequestLogging
public RestTemplate restTemplate() {
return new RestTemplate();
}
}
@Qualifier
public @interface RequestLogging {}

12. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Option 1 - BeanPostProcessor
@Configuration
public class RequestLoggingConfiguration {
public BeanPostProcessor postProcessor() {
return new BeanPostProcessor() {
@Override
public Object postProcessAfterInitialization(Object bean, String beanName)
throws BeansException {
if (bean instanceof RestTemplate) {
...
}
return bean;
}
};
}
}

13. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Option 2 - SmartInitializingSingleton
@Configuration
public class RequestLoggingConfiguration {
@Autowired(required = false)
@RequestLogging
private List<RestTemplate> restTemplates;
@Bean
public SmartInitializingSingleton requestLoggingRestTemplateInitializer() {
return () -> this.restTemplate.forEach(restTemplate -> {…});
}
}

14. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
WE ARE DONE!

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Oh No!

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Developer Experience – Acceptance Criteria
• Request logging should be enabled by default and should be disabled by
setting the property `request.logging.enabled=false`
1
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Option 1 - @Enable* Annotation
@Configuration
@EnableRequestLogging
public class ExampleApplicationConfiguration {
}
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@Import(RequestLoggingConfiguration.class)
public @interface EnableRequestLogging {
}

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Option 2 – spring.factories
META-INF/spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=
com.acme.RequestLoggingAutoConfiguration
@Configuration
public class RequestLoggingAutoConfiguration {
…
}
1
8

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Option 2+ – conditional spring.factories
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META-INF/spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=
com.acme.RequestLoggingAutoConfiguration
@Configuration
@ConditionalOnProperty(name=“request.logging.enabled”, havingValue=“true”)
public class RequestLoggingAutoConfiguration {
…
}

20. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Testing
@Test
public void betterTestMethodNameHere() {
new ApplicationContextRunner()
.withUserConfiguration(RequestLoggingAutoConfiguration.class)
.withPropertyValues(”request.logging.enabled=false")
.run(context -> {
assertThat(context).doesNotHaveBean("initializingSingleton");
});
}

21. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
WE ARE FINALLY DONE!

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Recap
@Configuration
@ConditionalOnProperty(name=“request.logging.enabled”, havingValue=“true”)
public class RequestLoggingAutoConfiguration {
@Autowired(required = false)
@RequestLogging
private List<RestTemplate> restTemplates;
@Bean
public SmartInitializingSingleton requestLoggingRestTemplateInitializer() {
return () -> this.restTemplate.forEach(restTemplate -> {…});
}
}
META-INF/spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=
com.acme.RequestLoggingAutoConfiguration

23. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Recommendations
- Configuration Processor Library
- org.springframework.boot:spring-boot-configuration-processor
- Configuration Property IDE Hints
- Autoconfiguration Processor Library
- org.springframework.boot:spring-boot-autoconfigure-processor
- Indexes Auto-Configurations for Faster Application Start Times

24. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Additional Configuration Points
- EnvironmentPostProcessor
- Load Additional Property Sources
- ApplicationListeners
- Make changes based on application events
- ConfigurationPropertyBindingPostProcessor
- Makes changes to any @ConfigurationProperty Beans
- SecurityConfigurer
- Allows for Customizing Spring Security Configuration

25. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Additional Autoconfiguration Conditionals
- @Conditional
- @ConditionalOnBean
- @ConditionalOnMissingBean
- @ConditionalOnResource
- @ConditionalOnClass
- @ConditionalOnMissingClass
- @ConditionalOnCloudPlatform
- @ConditionalOnWebApplication
- @ConditionalOnExpression

26. Unless otherwise indicated, these slides are © 2013-2019 Pivotal Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
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