Library for distributed spring config (outside springboot) - spring

Question

I am looking for solution for distributed spring configuration. I am thinking of storing it in zookeeper. https://github.com/spring-cloud/spring-cloud-zookeeper does have that functionality but apparently it requires to use spring-boot.
Is there any similar library that I can use outside spring-boot

Answer 1

Consul by HashiCorp
Consul is a popular option because it is:
Open Source
Includes Service Discovery & Configuration
Support Multi-Datacenter out of the box
Etc.

Answer 2

It doesn't require you to use Spring Boot, it just provides the auto-configurations in case you do decide to go with Spring Boot. In other words, if you're not using Spring Boot, none of the configurations will apply automatically, you'll have to provide the configuration yourself.
Zookeeper is a good option, go for it.
EDIT:
To use Zookeeper without Spring Boot, you'd need to register the appropriate beans either manually or by importing the auto-configuration classes that Spring Boot would import for you implicitly. This rule of thumb generally applies to all Spring Boot-enabled modules.
In your case, you'd most likely need to import just the ZookeeperConfigBootstrapConfiguration and ZookeeperConfigAutoConfiguration. The classes are to be found within spring-cloud-zookeeper-config module so no Spring Boot dependencies needed.
Alternatively, you should look at those classes and their #Imports and declare the beans manually.

Answer 3

I found a solution for using spring-cloud-zookeeper without Spring Boot, based on the idea provided here https://wenku.baidu.com/view/493cf9eba300a6c30d229f49.html
First, create a CloudEnvironement class that will create a PropertySource from Zookeeper :
CloudEnvironement.java
public class CloudEnvironment extends StandardServletEnvironment {
#Override
protected void customizePropertySources(MutablePropertySources propertySources) {
super.customizePropertySources(propertySources);
try {
propertySources.addLast(initConfigServicePropertySourceLocator(this));
}
catch (Exception ex) {
logger.warn("failed to initialize cloud config environment", ex);
}
}
private PropertySource<?> initConfigServicePropertySourceLocator(Environment environment) {
ZookeeperConfigProperties configProp = new ZookeeperConfigProperties();
ZookeeperProperties props = new ZookeeperProperties();
props.setConnectString("myzookeeper:2181");
CuratorFramework fwk = curatorFramework(exponentialBackoffRetry(props), props);
ZookeeperPropertySourceLocator propertySourceLocator = new ZookeeperPropertySourceLocator(fwk, configProp);
PropertySource<?> source= propertySourceLocator.locate(environment);
return source ;
}
private CuratorFramework curatorFramework(RetryPolicy retryPolicy, ZookeeperProperties properties) {
CuratorFrameworkFactory.Builder builder = CuratorFrameworkFactory.builder();
builder.connectString(properties.getConnectString());
CuratorFramework curator = builder.retryPolicy(retryPolicy).build();
curator.start();
try {
curator.blockUntilConnected(properties.getBlockUntilConnectedWait(), properties.getBlockUntilConnectedUnit());
}
catch (InterruptedException e) {
throw new RuntimeException(e);
}
return curator;
}
private RetryPolicy exponentialBackoffRetry(ZookeeperProperties properties) {
return new ExponentialBackoffRetry(properties.getBaseSleepTimeMs(),
properties.getMaxRetries(),
properties.getMaxSleepMs());
}
}
Then create a custom XmlWebApplicationContext class : it will enable to load the PropertySource from Zookeeper when your webapplication start and replace the bootsrap magic of Spring Boot:
MyConfigurableWebApplicationContext.java
public class MyConfigurableWebApplicationContext extends XmlWebApplicationContext {
#Override
protected ConfigurableEnvironment createEnvironment() {
return new CloudEnvironment();
}
}
Last, in your web.xml file add the following context-param for using your MyConfigurableWebApplicationContext class and bootstraping your CloudEnvironement.
<context-param>
<param-name>contextClass</param-name>
<param-value>com.kiabi.config.MyConfigurableWebApplicationContext</param-value>
</context-param>
If you use a standard property file configurer, it should still be loaded so you can have properties in both a local file and Zookeeper.
For all this to work you need to have spring-cloud-starter-zookeeper-config and curator-framework jar in your classpath with their dependancy, if you use maven you can add the following to your pom.xml
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-zookeeper-dependencies</artifactId>
<version>1.1.1.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-zookeeper-config</artifactId>
</dependency>
<dependency>
<groupId>org.apache.curator</groupId>
<artifactId>curator-framework</artifactId>
</dependency>
</dependencies>