Environment agnostic applications with Spring Maciej Walkowiak !

" " " DEV TEST PROD How to write application for multiple different environments?

Maven profiles Approach #1:

Maven profiles mvn package -P prod

Maven profiles # # MySQL Oracle

Maven profiles # # MySQL Oracle

Maven profiles mvn package -P prod,oracle # # MySQL Oracle

Maven profiles $ new feature! with two variants

Maven profiles $ new feature! with two variants

Maven profiles $ new feature! with two variants

Maven profiles mvn package -P prod,oracle,feature-impl1 $ new feature! with two variants

Maven profiles mvn package -P prod,oracle,feature-impl1, jboss,sec,s3,dk,wtf %

Maven profiles mvn package -P prod,oracle,feature-impl1, jboss,sec,s3,dk,wtf % … and we’re still building one single artifact

Configure in runtime Approach #2:

• 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

• Each environment has it’s own properties file on classpath
 
 • Picked from environmental variable Simple solutions often work -Denv=dev

• 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”

Spring @Profiles

Spring @Profiles

Spring @Profiles %

Spring @Profiles -Dspring.profiles.active=prod,oracle,feature- impl1,sec,s3,dk,wtf %

Spring @Profiles -Dspring.profiles.active=prod,oracle,feature- impl1,sec,s3,dk,wtf % … too many profiles can hurt

Spring 4 @Conditionals • Conditionally creates bean • @ConditionalOnExpression! • @ConditionalOnProperty! • @ConditionalOnClass! • @ConditionalOnWebApplication! • …! • “@YourCustomConditional”! • @Profile is just a @Conditional specialisation Spring Boot

Spring 4 @Conditionals # one of: filesystem,s3,mongo
 storage=filesystem

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 {
 }

Spring Boot • Automatically picks up right application-${profile}.properties ! • YAML format support • Properties loading hierarchy Spring Boot

Demo Spring Boot @Value @PropertySource @Configuration Properties Logback

Build once run everywhere

• make build process as simple as possible • externalize application configuration • externalize logging configuration • provide defaults! • use Spring Boot Build once run everywhere

Q & A

Thank you! ' maciejwalkowiak.pl (@maciejwalkowiak