Spring BOOT & microservices
@ladislavGazo
gazo@seges.sk
monolithic architecture
Microservices
PROS
Each microservice is relatively small
Easier for a developer to understand
-
The IDE is faster making developers more productive
- The web container starts faster
Easier to scale development.
- Each team can develop, deploy and scale their service independently of all of the other teams.
PROS 2
Improved fault isolation
-
In comparison, one misbehaving component of a monolithic architecture can bring down the entire system.
Each service can be developed and deployed independently
Eliminates any long-term commitment to a technology stack
BUT...
(there is always at least one...)
Developers must deal with the additional complexity of creating a distributed system
- testing
- transactions
- use-cases span multiple microservices
Deployment complexity In production
Increased memory consumption
... TACKLE WITH
when to split to multiple microservices
what should be inside one microservice
single responsibility principle
...
it is the art
Spring BOOT
opinionated way how to do modern applications
Very easy to start
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.1.8.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>ta-daaaa .... web app built :)
APP CODE
package hello;
import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.stereotype.*;
import org.springframework.web.bind.annotation.*;
@Controller
@EnableAutoConfiguration
public class SampleController {
@RequestMapping("/")
@ResponseBody
String home() {
return "Hello World!";
}
public static void main(String[] args) throws Exception {
SpringApplication.run(SampleController.class, args);
}
}... the beauty of autoconfiguration
3 options
JRebel
jHipster Reloader
Spring Loaded
jHipster reloader
-javaagent:/home/user/.m2/repository/io/github/jhipster/loaded/agent/0.12/agent-0.12.jar
<profiles>
<profile>
<id>reloaded</id>
<dependencies>
<dependency>
<groupId>io.github.jhipster.loaded</groupId>
<artifactId>agent</artifactId>
<version>0.12</version>
<exclusions>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
</dependency>
</dependencies>
</profile>
</profiles>
Interesting dependencies
benefit of Spring Boot
- MVC
- data access
- templating
- security
- ...
... anything from the Spring stack
REST
@RestController
based on Spring MVC
TEMPLATING
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>using Thymeleaf
Spring Security
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>@EnableWebMvcSecurity
@EnableGlobalMethodSecurity
http.authorizeRequests().antMatchers("/identity/login", "/page/**", "/client/**", "/user/**").permitAll().anyRequest().authenticated();
http.csrf().disable();
http.sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS);
http.addFilterBefore(new AuthenticationTokenFilter(identityService), AnonymousAuthenticationFilter.class);
http.exceptionHandling().authenticationEntryPoint(new UnauthorizedEntryPoint());MIGRATIONS
<dependency>
<groupId>org.flywaydb</groupId>
<artifactId>flyway-core</artifactId>
</dependency>migration files
V1.1__init.sql
V1.2__data.sql
...
DATA ACCESS
<dependency><groupId>com.h2database</groupId> <artifactId>h2</artifactId> </dependency>
<dependency><groupId>org.postgresql</groupId> <artifactId>postgresql</artifactId> </dependency>
autodetection of the driver
DATA ACCESS II.
spring.datasource.url: jdbc:postgresql://localhost/mydb
spring.datasource.username: myuser
spring.datasource.password: mypass
spring.datasource.driverClassName: org.postgresql.Driver<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>CONFIGURATION
driven mainly by:
Spring Java Configuration
Spring Annotations
Spring Profiles
simple YAML / properties file
Cherry
@Component
@ConfigurationProperties(prefix="connection")
public class ConnectionSettings {
private String username;
private InetAddress remoteAddress;
// ... getters and setters
}# application.yml
connection:
username: admin
remoteAddress: 192.168.1.1Kontanjere
SKALA
giter8 template
curl https://raw.githubusercontent.com/n8han/conscript/master/setup.sh | sh# add to your path ~/bin cs n8han/giter8 g8 lgazo/scala-boot
Questions?
@ladislavGazo
gazo@seges.sk
Thank YOu... for...
ATTENTION
Spring Boot and Microservices
By lgazo
Spring Boot and Microservices
How to start building microservices with Spring Boot
