The document outlines configurations in Micronaut, focusing on creating and managing beans, conditional beans, and configuration properties. It highlights various features such as bean factories, bean replacement, and configuration injection through practical code examples. Additionally, it emphasizes the framework's extensibility and numerous options for enhancing productivity in application development.

1. Creating Micronaut Configurations
Iván Lopez - @ilopmar

2. About me...
➢ Iván Lopez Martín - @ilopmar
➢ Java/Groovy developer
Grails & Micronaut teams
at OCI
➢ @MadridGUG coordinator
https://madridgug.com
➢ Greach ex-organizer
https://greachconf.com
➢ Speaker: Devoxx, GeeCon, Codemotion, ConFoo,
JavaCro, RigaDevDays, SpringOne 2GX,...

3. What is a
configuration?

4. Micronaut Features (configurations)
annotation-api
aws-api-gateway
aws-api-gateway-graal
cassandra
config-consul
discovery-consul
discovery-eureka
file-watch
flyway
graal-native-image
groovy
grpc
hibernate-gorm
hibernate-jpa
http-client
http-server
java
jdbc-dbcp
jdbc-hikari
jdbc-tomcat
jib
jrebel
junit
kafka
kafka-streams
kotlin
liquibase
management
micrometer
micrometer-atlas
micrometer-graphite
micrometer-prometheus
micrometer-statsd
mongo-gorm
mongo-reactive
neo4j-bolt
neo4j-gorm
netflix-archaius
netflix-hystrix
netflix-ribbon
picocli
postgres-reactive
rabbitmq
redis-lettuce
security-jwt
security-session
spek
spock
springloaded
swagger-groovy
swagger-java
swagger-kotlin
tracing-jaeger
tracing-zipkin

5. Creating app with CLI
$ mn create-app greach
--features=discovery-consul,
management,
graal-native-image,
tracing-zipkin

6. It is “just”
creating beans...

7. ...although it’s
not

8. Creating a configuration
- Bean Factories
- Conditional Beans
- Bean Replacement
- Bean Configuration
- Configuration Properties
- Configuration Builder
- Each Property
- Each Bean
- More options

9. Bean Factories
public class FooLibrary {
// Do stuff
}
@Singleton
public class FooLibrary {
// Do stuff
}
@Factory
public class FooFactory {
@Bean
public FooLibrary createFoo() {
return new FooLibrary();
}
}

10. Conditional Beans
@Requires(beans = DataSource.class)
@Requires(property = "datasource.url")
@Singleton
public class JdbcBookService implements BookService {
DataSource dataSource;
public JdbcBookService(DataSource dataSource) {
this.dataSource = dataSource;
}
}

11. Conditional Beans (II)
@Requires(classes = DataSource.class)
@Requires(missing = JdbcRowSet.class)
@Requires(beans = DataSource.class)
@Requires(missingBeans = DataSource.class)
@Requires(env = Environment.TEST)
@Requires(notEnv = Environment.TEST)
@Requires(configuration = "some.config")
@Requires(missingConfigurations = "other.config")
@Requires(sdk = Requires.Sdk.JAVA, value = "1.8")
@Requires(entities = javax.persistence.Entity.class)
@Requires(property = "data-source.url")
@Requires(missingProperty = "data-source.url")
@Requires(property="foo", value="John", defaultValue="John")
@Requires(condition = FlywayCondition.class)
public class Foo {
}

12. Bean Replacement
@Singleton
@Requires(beans = DataSource.class)
@Requires(property = "datasource.url")
public class JdbcBookService implements BookService {
DataSource dataSource;
public JdbcBookService(DataSource dataSource) {
this.dataSource = dataSource;
}
}

13. Bean Replacement
@Singleton
@Requires(beans = DataSource.class)
@Requires(property = "datasource.url")
public class JdbcBookService implements BookService {
DataSource dataSource;
public JdbcBookService(DataSource dataSource) {
this.dataSource = dataSource;
}
}
@Singleton
@Replaces(JdbcBookService.class)
@Requires(property = "spec.name", value = "foo")
public class MockBookService implements BookService {
Map<String, Book> bookMap = new LinkedHashMap<>();
@Override
public Book findBook(String title) {
return bookMap.get(title);
}
}

14. Bean Configuration
// package-info.java
@Configuration
@Requires(property = "flyway.enabled", notEquals = "false")
package io.micronaut.configuration.dbmigration.flyway;
@Configuration
@Requires(classes = {Channel.class, Connection.class,
ConnectionFactory.class})
package io.micronaut.configuration.rabbitmq;

15. Configuration injection
@Singleton
public class ApiService {
@Value("${api.key}")
protected String apiKey;
@Value("${api.secret}")
protected String apiSecret;
@Value("${api.results:10}")
protected int results;
@Value("${api.url:`https://api.foo.com`}")
protected URL url;
}

16. Configuration injection (II)
@Controller("/api/${api.version:v1}")
public class ApiController {
// ...
}
@Client("${api.server-url:`http://localhost:8080`}")
public interface ApiClient {
// ...
}

17. Configuration injection (III)
# application.yml
datasources:
default:
name: 'mydb'
jpa:
default:
properties:
hibernate:
hbm2ddl:
auto: 'update'
show_sql: true
@Property(name = "jpa.default.properties")
Map<String, Object> jpaProperties;

18. Configuration Properties
@ConfigurationProperties('my.engine')
class EngineConfig {
@NotBlank
String manufacturer = "Ford"
@Min(1L)
int cylinders
CrankShaft crankShaft = new CrankShaft()
@ConfigurationProperties('crank-shaft')
static class CrankShaft {
Optional<Double> rodLength = Optional.empty()
}
}
# application.yml
my:
engine:
manufacturer: Toyota
cylinders: 4
crank-shaft:
rod-length: 4

19. Configuration Builder
@ConfigurationProperties('my.engine')
class EngineConfig {
@ConfigurationBuilder(prefixes = "with")
EngineImpl.Builder builder = EngineImpl.builder()
@ConfigurationBuilder(prefixes = "with", configurationPrefix = "crank-shaft")
CrankShaft.Builder crankShaft = CrankShaft.builder()
SparkPlug.Builder sparkPlug = SparkPlug.builder()
@ConfigurationBuilder(prefixes = "with", configurationPrefix = "spark-plug")
void setSparkPlug(SparkPlug.Builder sparkPlug) {
this.sparkPlug = sparkPlug
}
}

20. Configuration Builder
@ConfigurationProperties('my.engine')
class EngineConfig {
@ConfigurationBuilder(prefixes = "with")
EngineImpl.Builder builder = EngineImpl.builder()
@ConfigurationBuilder(prefixes = "with", configurationPrefix = "crank-shaft")
CrankShaft.Builder crankShaft = CrankShaft.builder()
SparkPlug.Builder sparkPlug = SparkPlug.builder()
@ConfigurationBuilder(prefixes = "with", configurationPrefix = "spark-plug")
void setSparkPlug(SparkPlug.Builder sparkPlug) {
this.sparkPlug = sparkPlug
}
}
class EngineImpl implements Engine {
//...
static Builder builder() {
return new Builder()
}
static final class Builder {
private String manufacturer = "Ford"
private int cylinders
Builder withManufacturer(String manufacturer) {
this.manufacturer = manufacturer
this
}
Builder withCylinders(int cylinders) {
this.cylinders = cylinders
this
}
EngineImpl build(CrankShaft.Builder crankShaft, SparkPlug.Builder sparkPlug) {
new EngineImpl(manufacturer, cylinders, crankShaft.build(), sparkPlug.build())
}
}
}

21. Configuration Builder
@ConfigurationProperties('my.engine')
class EngineConfig {
@ConfigurationBuilder(prefixes = "with")
EngineImpl.Builder builder = EngineImpl.builder()
@ConfigurationBuilder(prefixes = "with", configurationPrefix = "crank-shaft")
CrankShaft.Builder crankShaft = CrankShaft.builder()
SparkPlug.Builder sparkPlug = SparkPlug.builder()
@ConfigurationBuilder(prefixes = "with", configurationPrefix = "spark-plug")
void setSparkPlug(SparkPlug.Builder sparkPlug) {
this.sparkPlug = sparkPlug
}
}

22. Configuration Builder
# application.yml
my:
engine:
cylinders: 4
manufacturer: 'Subaru'
crank-shaft:
rod-length': 4
spark-plug:
name: '6619 LFR6AIX'
type: 'Iridium'
companyName: 'NGK'
@ConfigurationProperties('my.engine')
class EngineConfig {
@ConfigurationBuilder(prefixes = "with")
EngineImpl.Builder builder = EngineImpl.builder()
@ConfigurationBuilder(prefixes = "with", configurationPrefix = "crank-shaft")
CrankShaft.Builder crankShaft = CrankShaft.builder()
SparkPlug.Builder sparkPlug = SparkPlug.builder()
@ConfigurationBuilder(prefixes = "with", configurationPrefix = "spark-plug")
void setSparkPlug(SparkPlug.Builder sparkPlug) {
this.sparkPlug = sparkPlug
}
}

23. @EachProperty
@EachProperty("flyway.datasources")
public class FlywayConfigurationProperties {
private final DataSource dataSource;
private final String nameQualifier;
public FlywayConfigurationProperties(@Nullable @Parameter DataSource dataSource,
@Parameter String name) {
this.dataSource = dataSource;
this.nameQualifier = name;
}
...
}
# application.yml
flyway:
datasources:
default:
async: true
locations: classpath:databasemigrations
books:
locations: classpath:bookmigrations
enabled: false

24. @EachProperty
@EachProperty("flyway.datasources")
public class FlywayConfigurationProperties {
private final DataSource dataSource;
private final String nameQualifier;
public FlywayConfigurationProperties(@Nullable @Parameter DataSource dataSource,
@Parameter String name) {
this.dataSource = dataSource;
this.nameQualifier = name;
}
...
}
# application.yml
flyway:
datasources:
default:
async: true
locations: classpath:databasemigrations
books:
locations: classpath:bookmigrations
enabled: false

25. @EachProperty (II)
public class FlywayEndpoint {
private final ApplicationContext applicationContext;
private final Collection<FlywayConfigurationProperties> flywayConfigurationProperties;
public FlywayEndpoint(ApplicationContext applicationContext,
Collection<FlywayConfigurationProperties> flywayConfigurationProperties) {
this.applicationContext = applicationContext;
this.flywayConfigurationProperties = flywayConfigurationProperties;
}
...
}
Optional<FlywayConfigurationProperties> optionConfig =
applicationContext
.findBean(FlywayConfigurationProperties.class,
Qualifiers.byName(“books”));

26. @EachBean
@Factory
public class FlywayFactory {
@Requires(condition = FlywayCondition.class)
@EachBean(FlywayConfigurationProperties.class)
public Flyway flyway(FlywayConfigurationProperties config) {
FluentConfiguration fluentConfiguration = config.fluentConfiguration;
fluentConfiguration.dataSource(config.getDataSource());
return fluentConfiguration.load();
}
}
Flyway flyway = applicationContext
.getBean(Flyway.class,
Qualifiers.byName(“books”));

27. More options
- Filters
- Endpoints
- Aspect Oriented Programming (AOP)
- Annotation Mapper
- Controllers
- Fire events
- Execute something on startup

28. Show me the
code!

29. Summary
Configurations (features)
out-of-the-box
Easy to create Extend the
Framework
Lots of different options The sky is the limit Increase productivity

30. SLIDE TITLE 27 PT ALL CAPS
Thank you!
@ilopmar
lopez.ivan@gmail.com
https://github.com/ilopmar
Iván López
http://bit.ly/greach-micronaut
Questions?