Spring-balancing-datasource

Redundant abstraction over multiple datasources. Gives functionality like MariaDB'sjdbc:mysql:replication//..... or Oracle's jdbc:oracle:thin:@(DESCRIPTION = (FAILOVER=on) to any databases and datasources without messing with the availability definition of each database vendor.

Balancing datasources are defined as system properties under spring.balancing-config property section.

By default each declared datasource is created as HikariCP datasource. If different javax.sql.DataSource implementation is needed, then own bean implementation of the interface io.ankburov.spring.balancing.datasource.factory.DataSourceFactory should be used.

Download

Gradle

repositories {
    jcenter()
}

dependencies {
    compile "io.ankburov:spring-balancing-datasource:<version>"
}

Usage

Add @EnableBalancingDataSource annotation to your Spring boot configuration:

@Configuration
@EnableBalancingDataSource
public class JdbcAdapterConfiguration {}

Define minimal configuration in properties. All available properties are defined in BalancingDataSourceConfiguration or in generated spring-configuration-metadata.json

application.yaml example:

spring:
    balancing-config:
        datasources:
            main_oracle:
                url: jdbc:oracle:thin:@localhost:1521:xe
                username: system
                password: oracle
                name: whatever
            standby_oracle:
                url: jdbc:oracle:thin:@localhost:1525:xe
                username: system
                password: oracle
                name: jdbc-adapter-local-test

After that all JDBC connections from dataSource bean with an implementation as BalancingDataSource will be balanced across defined datasources according to used BalancingStrategy - in failover manner or load-balancing one.

Ignoring datasources

Sometimes in strict deployment environments number of used properties is rigid (for example in Ansible's deployments where there is one or several playbooks and a number of different environments around them - some with one datasource, some with many). To overcome this datasources can be ignored. It means that they will be ignored on an initialization of BalancingDataSource and won't be created as javax.sql.DataSource instances.

To do that, url property of ignoring datasources should have value IGNORE:

spring:
    balancing-config:
        datasources:
            main_oracle:
                url: jdbc:oracle:thin:@localhost:1521:xe
                username: system
                password: oracle
                name: main_oracle
            ignored_datasource:
                url: IGNORE

With such configuration only one instance of javax.sql.DataSource with the name main_oracle will be created

Additional properties can also be ignored. Additional property is ignored when its value is set to IGNORE