Unable to create Postgres datasource programatically using Spring

Question

I am trying to create a DataSource as is suggested in some Spring examples online this way:

    @Configuration
public class RepositoryConfiguration {

    @Primary
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }

}

I have an application.yml file that looks like this:

spring:
  datasource:
    driver-class-name: org.postgresql.Driver
    url: jdbc:postgresql://localhost:54320/mydb
    username: postgres
    password: somepassword

When I run the debugger and evaluate DataSourceBuilder.create().build(); the values don't seem to be set. Any idea what could be missing?

I am using version 2.2.4 of Spring boot

This is my build.gradle file

buildscript {
    repositories {
        mavenLocal()
        mavenCentral()
    }
    dependencies {
        classpath "org.postgresql:postgresql:42.2.11"
    }
}

plugins {
    id 'org.springframework.boot' version '2.2.4.RELEASE'
    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
    id 'java'
    id 'org.flywaydb.flyway' version '6.3.0'
    id 'nu.studer.jooq' version '4.1'
}

group 'com.solution.asclepius'
version '1.0-SNAPSHOT'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {

    annotationProcessor 'org.projectlombok:lombok:1.18.8'

    implementation 'org.jooq:jooq'
    implementation 'org.jooq:jooq-codegen'
    jooqRuntime 'org.postgresql:postgresql:42.2.11'
    implementation 'org.projectlombok:lombok:1.18.8'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.boot:spring-boot-starter-actuator'
    implementation 'org.springframework.boot:spring-boot-starter-jooq'
    implementation 'io.vavr:vavr:0.10.2'

    testCompile group: 'junit', name: 'junit', version: '4.12'
    testCompile group: 'org.mockito', name: 'mockito-core', version: '2.1.0'
    testCompile group: 'org.assertj', name: 'assertj-core', version: '3.15.0'

}

jooq {
    sample(sourceSets.main) {
        jdbc {
            driver = 'org.postgresql.Driver'
            url = 'jdbc:postgresql://localhost:54320/asclepiusdb'
            user = 'postgres'
            password = 'somepassword'
        }
        generator {
            database() {
                name = 'org.jooq.meta.postgres.PostgresDatabase'
                inputSchema = 'public'
                includes = '.*'
            }
            target {
                packageName = 'com.solution.asclepius'
                directory = 'build/generated/java'
            }
        }
    }
}

tasks.generateSampleJooqSchemaSource.with {
    def out = new ByteArrayOutputStream()
    javaExecSpec = { JavaExecSpec s ->
        s.standardOutput = out
        s.errorOutput = out
        s.ignoreExitValue = true
        s.jvmArgs '-Xmx512M'
    }
    execResultHandler = { ExecResult r ->
        if (r.exitValue != 0) {
            throw new RuntimeException('jOOQ source code generation failed:\n\n' + out.toString())
        }
    }
}

flyway {
    url = 'jdbc:postgresql://localhost:54320/asclepiusdb'
    user = 'postgres'
    password = 'somepassword'
    schemas = ['public']
    locations = ["filesystem:$project.projectDir/src/main/resources/db/migration"]
}

At the moment the app is failing to boot:

***************************
APPLICATION FAILED TO START
***************************

Description:

Failed to bind properties under 'spring.datasource' to javax.sql.DataSource:

    Property: spring.datasource.driver-class-name
    Value: org.postgresql.Driver
    Origin: class path resource [application.yml]:4:24
    Reason: Failed to load driver class org.postgresql.Driver in either of HikariConfig class loader or Thread context classloader

Action:

Update your application's configuration

Answer 1

@ConfigurationProperties is processed by ConfigurationPropertiesBindingPostProcessor after the bean creation.

So don't worry, your properties will be set later during app's initialization. You can set some breakpoints in that postprocessor or even in HikariConfig ( HikariDataSource is used by default in Spring Boot 2, it can be something else) and see the process.