Spring-boot: Exclude Hikari configurations with property "spring.datasource.hikari.enabled=false"

[ferblaca]

As a suggestion, in case you want to use a connection pool other than Hikari it would be nice to be able to perform the Hikari exclusion with the property "spring.datasource.hikari.enabled = false", without having to do it in the following way :

     <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
        <exclusions>
            <exclusion>
                <groupId>com.zaxxer</groupId>
                <artifactId>HikariCP</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

Also, this is a problem if you want to exclude the Hikari dependency from dependencyManagement since the forces hardcode the spring-boot version:

<dependencyManagement>
    <dependencies>    
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
            <version>2.1.5.RELEASE</version>
            <exclusions>
                <exclusion>
                    <groupId>com.zaxxer</groupId>
                    <artifactId>HikariCP</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>
</dependencyManagement>

With the property spring.datasource.hikari.enabled you can evaluate the load of autoconfigurations that now continue to be loaded only by evaluating the simple presence of the class in the classpath:

DataSourceJmxConfiguration.Hikari matched:
- @ConditionalOnClass found required class 'com.zaxxer.hikari.HikariDataSource' (OnClassCondition)

DataSourcePoolMetadataProvidersConfiguration.HikariPoolDataSourceMetadataProviderConfiguration matched:
- @ConditionalOnClass found required class 'com.zaxxer.hikari.HikariDataSource' (OnClassCondition)

DataSourceConfiguration.Hikari:
Did not match:
- @ConditionalOnProperty (spring.datasource.type=com.zaxxer.hikari.HikariDataSource) found different value in property 'spring.datasource.type' (OnPropertyCondition)
Matched:
- @ConditionalOnClass found required class 'com.zaxxer.hikari.HikariDataSource' (OnClassCondition)

DataSourcePoolMetadataProvidersConfiguration.HikariPoolDataSourceMetadataProviderConfiguration matched:
- @ConditionalOnClass found required class 'com.zaxxer.hikari.HikariDataSource' (OnClassCondition)

It's just a suggestion. thank you

[juliojgd]

I think this "enabled" property would be useful because HikariCP is a "special" case as it is included by default as a "compile" dependency in spring-boot-starter-jdbc.
Other connection pool libraries like tomcat-pool or dbcp2 are not included so their "enabled" properties are not useful, you can just not include their dependency..

[snicoll]

@juliojgd Spring Boot already offers a spring.datasource.type property where you can specify the connection pool to use. If you're not happy excluding the dependency then you should give that a try. We don't offer enabled property for core features.