Environment agnostic applications with Spring

Slides from Szczecin Java User Group meetup that took place on the 17th of December 2014.

Story about building multienvironment applications, starting from Maven profiles, through simple property placeholder based solutions, Spring @Profiles and in the end Spring @Conditionals and Spring Boot

Transcript

1. Environment agnostic applications with Spring Maciej Walkowiak !
2. " " " DEV TEST PROD How to write application for multiple different environments?
3. Maven profiles Approach #1:
4. Maven profiles mvn package -P prod
5. Maven profiles # # MySQL Oracle
6. Maven profiles # # MySQL Oracle
7. Maven profiles mvn package -P prod,oracle # # MySQL Oracle
8. Maven profiles $ new feature! with two variants
9. Maven profiles $ new feature! with two variants
10. Maven profiles $ new feature! with two variants
11. Maven profiles mvn package -P prod,oracle,feature-impl1 $ new feature! with two variants
12. Maven profiles mvn package -P prod,oracle,feature-impl1, jboss,sec,s3,dk,wtf %
13. Maven profiles mvn package -P prod,oracle,feature-impl1, jboss,sec,s3,dk,wtf % … and we’re still building one single artifact
14. Configure in runtime Approach #2:
15. • Tell application how to behave when you run it, not when you build it. • No environment specific configuration in build time.
 Build as simple as: Configure in runtime mvn package
16. • Each environment has it’s own properties file on classpath
 
 • Picked from environmental variable Simple solutions often work <context:property-placeholder location="classpath:application-${env}.properties"/> -Denv=dev
17. • Since Spring 3.1 (December 2011) • Profiles tag group of beans into sets
 
 
 
 • There can be multiple profiles enabled at once • Activated by environmental variable Spring @Profiles -Dspring.profiles.active=dev & & & “dev” “test” “prod”
18. Spring @Profiles
19. Spring @Profiles
20. Spring @Profiles %
21. Spring @Profiles -Dspring.profiles.active=prod,oracle,feature- impl1,sec,s3,dk,wtf %
22. Spring @Profiles -Dspring.profiles.active=prod,oracle,feature- impl1,sec,s3,dk,wtf % … too many profiles can hurt
23. Spring 4 @Conditionals • Conditionally creates bean • @ConditionalOnExpression! • @ConditionalOnProperty! • @ConditionalOnClass! • @ConditionalOnWebApplication! • …! • “@YourCustomConditional”! • @Profile is just a @Conditional specialisation Spring Boot
24. Spring 4 @Conditionals # one of: filesystem,s3,mongo
 storage=filesystem
25. Spring 4 @Conditionals # one of: filesystem,s3,mongo
 storage=filesystem @ConditionalOnProperty(name = "storage", havingValue = "s3")
 class S3StorageService implements StorageService {
 }
 
 @ConditionalOnProperty(name = "storage", havingValue = "mongo")
 class MongoStorageService implements StorageService {
 }
 
 @ConditionalOnProperty(name = "storage", havingValue = "filesystem", matchIfMissing = true)
 class FileSystemStorageService implements StorageService {
 }
26. Spring Boot • Automatically picks up right application-${profile}.properties ! • YAML format support • Properties loading hierarchy Spring Boot
27. Demo Spring Boot @Value @PropertySource @Configuration Properties Logback
28. Build once run everywhere
29. • make build process as simple as possible • externalize application configuration • externalize logging configuration • provide defaults! • use Spring Boot Build once run everywhere
30. Q & A
31. Thank you! ' maciejwalkowiak.pl (@maciejwalkowiak