What are the minimum requirements for Spring JPA

I am trying to setup a simple Spring JPA connection with Docker-Compose.

This is my docker-compose.yml:

services:
  postgres-database:
    image: postgres
    volumes:
    - ./data:/var/lib/postgresql/data
    environment:
      POSTGRES_USER: ${POSTGRES_USER}
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
      POSTGRES_DB: ${POSTGRES_DB}
    networks:
      - spring-app
  spring-app:
    image: spring-app
    build:
      context: ./
      dockerfile: Dockerfile
    environment:
      SPRING_DATASOURCE_URL: jdbc:postgresql://postgres-database:5432/${POSTGRES_DB}
      SPRING_DATASOURCE_DRIVER-CLASS-NAME: org.postgresql.Driver
      SPRING_DATASOURCE_USERNAME: ${POSTGRES_USER}
      SPRING_DATASOURCE_PASSWORD: ${POSTGRES_PASSWORD}
    depends_on:
      - postgres-database

    ports:
      - 8080:8080
    networks:
      - spring-app

My pom.xml looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.3.0.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>NaN</groupId>
  <artifactId>NaN</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>
  <name>spring-app</name>
  <properties>
    <java.version>11</java.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
    <dependency>
      <groupId>org.postgresql</groupId>
      <artifactId>postgresql</artifactId>
      <version>42.2.12</version>
      <scope>runtime</scope>
    </dependency>
    <dependency>
      <groupId>com.h2database</groupId>
      <artifactId>h2</artifactId>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-tomcat</artifactId>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
      <exclusions>
        <exclusion>
          <groupId>org.junit.vintage</groupId>
          <artifactId>junit-vintage-engine</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
    <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-test</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>

</project>

I’m used to see Spring trying to connect to a database before starting anything. I set up some temporary Repositories to make sure it had some Entities to work with.

The logging looks like this:

   .   ____          _            __ _ _
  /\ / ___'_ __ _ _(_)_ __  __ _    
 ( ( )___ | '_ | '_| | '_ / _` |    
  \/  ___)| |_)| | | | | || (_| |  ) ) ) )
   '  |____| .__|_| |_|_| |___, | / / / /
  =========|_|==============|___/=/_/_/_/
  :: Spring Boot ::        (v2.3.0.RELEASE)

 2020-06-03 14:43:36.810  INFO 1 --- [           main] n.p.p.o.SpringApplication   : Starting SpringApplication v0.0.1-SNAPSHOT on c41863fe7cb8 with PID 1 (/spring-app.jar started by root in /)
 2020-06-03 14:43:36.814  INFO 1 --- [           main] n.p.p.o.SpringApplication   : No active profile set, falling back to default profiles: default
 2020-06-03 14:43:38.750  INFO 1 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
 2020-06-03 14:43:38.781  INFO 1 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
 2020-06-03 14:43:38.782  INFO 1 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.35]
 2020-06-03 14:43:38.875  INFO 1 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
 2020-06-03 14:43:38.875  INFO 1 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1991 ms
 2020-06-03 14:43:39.338  INFO 1 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
 2020-06-03 14:43:39.663  INFO 1 --- [           main] o.s.b.a.e.web.EndpointLinksResolver      : Exposing 3 endpoint(s) beneath base path '/actuator'
 2020-06-03 14:43:39.734  INFO 1 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
 2020-06-03 14:43:39.757  INFO 1 --- [           main] n.p.p.o.SpringApplication   : Started SpringApplication in 3.975 seconds (JVM running for 4.953)
 2020-06-03 14:44:15.560  INFO 1 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
 2020-06-03 14:44:15.561  INFO 1 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
 2020-06-03 14:44:15.587  INFO 1 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 25 ms

What do I need to add to make sure Spring makes a connection to the database? I want to test this docker environment setup before continuing.

Answer

Take a look at Spring References.

To have a connection you just need to define the right properties in application.properties. To do a bit more you need to create at least one entity and call it.

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Answer