This guide walks you through building a simple Customer Service, Spring Boot application using Apache Geode to manage Customer interactions. You should already be familiar with Spring Boot and Apache Geode.

By the end of this lesson, you should have a better understanding of what Spring Boot for Apache Geode’s (SBDG) auto-configuration support actually does.

This guide compliments the Auto-configuration vs. Annotation-based configuration chapter with concrete examples.

Let’s begin.

This guide builds on the Simplifying Apache Geode with Spring Data presentation by John Blum during the 2017 SpringOne Platform conference. While this example as well as the example presented in the talk both use Spring Boot, only this example is using Spring Boot for Apache Geode (SBDG). This guide improves on the example from the presentation by using SBDG.

Back

1. Application Domain Classes

We will build the Spring Boot, Customer Service application from the ground up.

1.1. Customer class

Like any sensible application development project, we begin by modeling the data our application needs to manage, namely a Customer. For this example, the Customer class is implemented as follows:

Customer class
@Region("Customers")
@EqualsAndHashCode
@ToString(of = "name")
@RequiredArgsConstructor(staticName = "newCustomer")
public class Customer {

	@Id @NonNull @Getter
	private Long id;

	@NonNull @Getter
	private String name;

}

The Customer class uses Project Lombok to simplify the implementation so we can focus on the important details. Lombok is useful for testing or prototyping purposes. However, using Lombok is optional and in most production applications, I would not recommend it.

Additionally, the Customer class is annotated with Spring Data Geode’s (SDG) @Region annotation. @Region is a mapping annotation declaring the Apache Geode Region in which Customer data will be persisted.

Finally, the org.springframework.data.annotation.Id annotation was used to designate the Customer.id field as the identifier for Customer objects. The identifier is the Key used in the Entry stored in the Apache Geode Region. A Region is a distributed version of java.util.Map.

If the @Region annotation is not explicitly declared, then SDG uses the simple name of the class, which in this case is "Customer", to identify the Region. However, there is another reason we explicitly annotated the Customer class with @Region, which we will cover below.

1.2. CustomerRepository interface

Next, we create a Data Access Object (DAO) to persist Customers to Apache Geode. We create the DAO using Spring Data’s Repository abstraction:

CustomerRepository inteface
public interface CustomerRepository extends CrudRepository<Customer, Long> {

	Customer findByNameLike(String name);

}

CustomerRepository is a Spring Data CrudRepository. CrudRepository provides basic CRUD (Create, Read, Update, Delete) data access operations along with the ability to define simple queries on Customers.

Spring Data Geode will create a proxy implementation for your application-specific Repository interfaces, implementing any query methods you may have explicitly defined on the interface in addition to the data access operations provided in the CrudRepository interface extension.

In addition to the base CrudRepository operations, CustomerRepository has additionally defined a findByNameLike(:String):Customer query method. The Apache Geode OQL query is derived from the method declaration.

Though it is beyond the scope of this document, Spring Data’s Repository infrastructure is capable of generating data store specific queries (e.g. Apache Geode OQL) for Repository interface query method declarations just by introspecting the method signature. The query methods must conform to specific conventions. Alternatively, users may use @Query to annotate query methods to specify the raw query instead (i.e. OQL for Apache Geode, SQL for JDBC, and so on).

1.3. Customer Service Application (main class)

Now that we have created the basic domain classes of our Customer Service application, we need a main application class to drive the interactions with Customers:

CustomerServiceApplication class
@SpringBootApplication
@EnableEntityDefinedRegions(basePackageClasses = Customer.class, clientRegionShortcut = ClientRegionShortcut.LOCAL)
public class CustomerServiceApplication {

	public static void main(String[] args) {

		new SpringApplicationBuilder(CustomerServiceApplication.class)
			.web(WebApplicationType.NONE)
			.build()
			.run(args);
	}

	@Bean
	ApplicationRunner runner(CustomerRepository customerRepository) {

		return args -> {

			assertThat(customerRepository.count()).isEqualTo(0);

			Customer jonDoe = Customer.newCustomer(1L, "Jon Doe");

			System.err.printf("Saving Customer [%s]%n", jonDoe);

			jonDoe = customerRepository.save(jonDoe);

			assertThat(jonDoe).isNotNull();
			assertThat(jonDoe.getId()).isEqualTo(1L);
			assertThat(jonDoe.getName()).isEqualTo("Jon Doe");
			assertThat(customerRepository.count()).isEqualTo(1);

			System.err.println("Querying for Customer [SELECT * FROM /Customers WHERE name LIKE '%Doe']");

			Customer queriedJonDoe = customerRepository.findByNameLike("%Doe");

			assertThat(queriedJonDoe).isEqualTo(jonDoe);

			System.err.printf("Customer was [%s]%n", queriedJonDoe);
		};
	}
}

The CustomerServiceApplication class is annotated with @SpringBootApplication. Therefore, the main class is a proper Spring Boot application equipped with all the features of Spring Boot (e.g. auto-configuration).

Additionally, we use Spring Boot’s SpringApplicationBuilder in the main method to configure and bootstrap the Customer Service application.

Then, we declare a Spring Boot ApplicationRunner bean, which is invoked by Spring Boot after the Spring container (i.e. ApplicationContext) has been properly initialized and started. Our ApplicationRunner defines the Customer interactions performed by our Customer Service application.

Specifically, the runner creates a new Customer object ("Jon Doe"), saves him to the Apache Geode "Customers" Region, and then queries for "Jon Doe" using an OQL query with the predicate: name LIKE '%Doe'.

% is the wildcard for OQL text searches.

2. Auto-configuration for Apache Geode, Take One

"With great power comes great responsibility." - Uncle Ben

While it is not apparent (yet), there is a lot of hidden, intrinsic power provided by Spring Boot Data Geode (SBDG) in this example.

2.1. Cache instance

First, in order to put anything into Apache Geode, you need a cache instance. A cache instance is also required to create Regions which ultimately store the application’s data (state). Again, a Region is just a Key/Value data structure, like java.util.Map, mapping a Key to a Value, or an Object. A Region is actually much more than a simple Map since it is distributed. However, since Region implements java.util.Map, it can be treated as such.

A complete discussion of Region and it concepts are beyond the scope of this document. You may learn more by reading Apache Geode’s User Guide on Regions.

SBDG is opinionated and assumes most developer applications will be client applications in Apache Geode’s client/server topology. Therefore, SBDG auto-configures a ClientCache instance by default.

The intrinsic ClientCache auto-configuration provided by SBDG can be made apparent by disabling it:

Disabling ClientCache Auto-configuration
@SpringBootApplication(exclude = ClientCacheAutoConfiguration.class)
@EnableEntityDefinedRegions(basePackageClasses = Customer.class, clientRegionShortcut = ClientRegionShortcut.LOCAL)
public class CustomerServiceApplication {
  ...
}

Note the exclude on the ClientCacheAutoConfiguration.class.

With the correct log-level set, you will see an error message similar to:

Error resulting from no ClientCache instance
16:20:47.543 [main] DEBUG o.s.b.d.LoggingFailureAnalysisReporter - Application failed to start due to an exception
org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'example.app.crm.repo.CustomerRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1509) ~[spring-beans-5.0.13.RELEASE.jar:5.0.13.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1104) ~[spring-beans-5.0.13.RELEASE.jar:5.0.13.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.13.RELEASE.jar:5.0.13.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:819) ~[spring-beans-5.0.13.RELEASE.jar:5.0.13.RELEASE]
	...
16:20:47.548 [main] ERROR o.s.b.d.LoggingFailureAnalysisReporter -

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

Description:

Parameter 0 of method runner in example.app.crm.CustomerServiceApplication required a bean of type 'example.app.crm.repo.CustomerRepository' that could not be found.

Essentially, the CustomerRepository could not be injected into our CustomerServiceApplication class, ApplicationRunner bean method because the CustomerRepository, which depends on the "Customers" Region, could not be created. The CustomerRepository could not be created because the "Customers" Region could not be created. The "Customers" Region could not be created because there was no cache instance available (e.g. ClientCache) to create Regions, resulting in the trickling effect.

The ClientCache auto-configuration is equivalent to the following:

Equivalent ClientCache configuration
@SpringBootApplication
@ClientCacheApplication
@EnableEntityDefinedRegions(basePackageClasses = Customer.class, clientRegionShortcut = ClientRegionShortcut.LOCAL)
public class CustomerServiceApplication {
  ...
}

That is, you would need to explicitly declare the @ClientCacheApplication annotation if you were not using SBDG.

2.2. Repository instance

We are also using the Spring Data (Geode) Repository infrastructure in the Customer Service application. This should be evident from our definition and declaration of the application-specific CustomerRepository interface.

If we disable the Spring Data Repository auto-configuration:

Disabling Spring Data Repositories Auto-configuration
@SpringBootApplication(exclude = RepositoriesAutoConfiguration.class)
@EnableEntityDefinedRegions(basePackageClasses = Customer.class, clientRegionShortcut = ClientRegionShortcut.LOCAL)
public class CustomerServiceApplication {
  ...
}

The application would throw a similar error on startup:

Error resulting from no proxied CustomerRepository instance
17:31:21.231 [main] DEBUG o.s.b.d.LoggingFailureAnalysisReporter - Application failed to start due to an exception
org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'example.app.crm.repo.CustomerRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1509) ~[spring-beans-5.0.13.RELEASE.jar:5.0.13.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1104) ~[spring-beans-5.0.13.RELEASE.jar:5.0.13.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.13.RELEASE.jar:5.0.13.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:819) ~[spring-beans-5.0.13.RELEASE.jar:5.0.13.RELEASE]
	...
17:31:21.235 [main] ERROR o.s.b.d.LoggingFailureAnalysisReporter -

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

Description:

Parameter 0 of method runner in example.app.crm.CustomerServiceApplication required a bean of type 'example.app.crm.repo.CustomerRepository' that could not be found.

In this case, there was simply no proxied implementation of the CustomerRepository interface provided by the framework since the auto-configuration was disabled. The ClientCache and "Customers" Region do exist in this case.

The Spring Data Repository auto-configuration even takes care of locating our application Repository interface definitions for us.

Without auto-configuration, you would need to explicitly:

Equivalent Spring Data Repositories configuration
@SpringBootApplication
@EnableEntityDefinedRegions(basePackageClasses = Customer.class, clientRegionShortcut = ClientRegionShortcut.LOCAL)
@EnableGemfireRepositories(basePackageClasses = CustomerRepository.class)
public class CustomerServiceApplication {
  ...
}

That is, you would need to explicitly declare the @EnableGemfireRepositories annotation and set the basePackages attribute, or the equivalent, type-safe basePackageClasses attribute, to the package containing your application Repository interfaces, if you were not using SBDG.

2.3. Entity-defined Regions

So far, the only explicit declaration of configuration in our Customer Service application is the @EnableEntityDefinedRegions annotation.

As was alluded to above, there was another reason we explicitly declared the @Region annotation on our Customer class.

We could have defined the client-local, "Customers" Region using Spring JavaConfig, explicitly:

JavaConfig Bean Defintion for the "Customers" Region
@Bean("Customers")
public ClientRegionFactoryBean<Long, Customer> customersRegion(GemFireCache gemfireCache) {

    ClientRegionFactoryBean<Long, Customer> customersRegion = new ClientRegionFactoryBean<>();

    customersRegion.setCache(gemfireCache);
    customersRegion.setClose(false);
    customersRegion.setShortcut(ClientRegionShortcut.LOCAL);

    return customersRegion;
}

Or, even define the "Customers" Region using Spring XML, explicitly:

XML Bean Definition for the "Customers" Region
<gfe:client-region id="Customers" shortcut="LOCAL"/>

But, using SDG’s @EnableEntityDefinedRegions annotation is very convenient and can scan for the Regions (whether client or server/peer Regions) required by your application based the entity classes themselves (e.g. Customer):

Annotation-based config for the "Customers" Region
@EnableEntityDefinedRegions(basePackageClasses = Customer.class, clientRegionShortcut = ClientRegionShortcut.LOCAL)

The basePackageClasses attribute is an alternative to basePackages, and a type-safe way to target the packages (and subpackages) containing the entity classes that your application will persist to Apache Geode. You need only choose 1 class in the top-level package from each package where you want the scan to begin. Spring Data Geode uses this class to determine the package to start the scan. 'basePackageClasses` accepts an array of Class types so you can specify multiple independent top-level packages. The annotation also includes the ability to filter types.

However, the @EnableEntityDefinedRegions annotation only works when the entity class (e.g. Customer) is explicitly annotated with the @Region annotation (e.g. @Region("Customers")), otherwise it ignores the class.

You will also notice that the data policy type (i.e. clientRegionShort, or simply shortcut) is set to LOCAL in our example. Why?

Well, initially we wanted to get up and running as quickly as possible, without a lot of ceremony and fuss. By using a LOCAL client Region initially, we are not required to start a server for the client to be able to store data.

While LOCAL client Regions can be useful for some purposes (e.g. local processing/querying), it is more common for a client to persist data in a cluster of servers, and for that data to be shared by multiple clients, especially as the application is scaled out to meet demand.

3. Switching to Client/Server

We continue with our example by switching from local to a client/server topology.

If you are rapidly prototyping your application and want to lift off the ground quickly, then it is useful to start locally and gradually migrate to a client/server architecture.

To switch to client/server, all you need to do is remove the clientRegionShortcut attribute:

Client/Server Topology Region Configuration
@EnableEntityDefinedRegions(basePackageClasses = Customer.class)

The default value for the clientRegionShortcut attribute is ClientRegionShortcut.PROXY. This means no data is stored locally. All data will be sent from the client to 1 or more servers in a cluster.

However, if we try to run the application, it will fail:

NoAvailableServersException
Caused by: org.apache.geode.cache.client.NoAvailableServersException
	at org.apache.geode.cache.client.internal.pooling.ConnectionManagerImpl.borrowConnection(ConnectionManagerImpl.java:234) ~[geode-core-1.2.1.jar:?]
	at org.apache.geode.cache.client.internal.OpExecutorImpl.execute(OpExecutorImpl.java:136) ~[geode-core-1.2.1.jar:?]
	at org.apache.geode.cache.client.internal.OpExecutorImpl.execute(OpExecutorImpl.java:115) ~[geode-core-1.2.1.jar:?]
	at org.apache.geode.cache.client.internal.PoolImpl.execute(PoolImpl.java:763) ~[geode-core-1.2.1.jar:?]
	at org.apache.geode.cache.client.internal.QueryOp.execute(QueryOp.java:58) ~[geode-core-1.2.1.jar:?]
	at org.apache.geode.cache.client.internal.ServerProxy.query(ServerProxy.java:70) ~[geode-core-1.2.1.jar:?]
	at org.apache.geode.cache.query.internal.DefaultQuery.executeOnServer(DefaultQuery.java:456) ~[geode-core-1.2.1.jar:?]
	at org.apache.geode.cache.query.internal.DefaultQuery.execute(DefaultQuery.java:338) ~[geode-core-1.2.1.jar:?]
	at org.springframework.data.gemfire.GemfireTemplate.find(GemfireTemplate.java:311) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
	at org.springframework.data.gemfire.repository.support.SimpleGemfireRepository.count(SimpleGemfireRepository.java:129) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
	...
	at example.app.crm.CustomerServiceApplication.lambda$runner$0(CustomerServiceApplication.java:59) ~[classes/:?]
	at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:783) ~[spring-boot-2.0.9.RELEASE.jar:2.0.9.RELEASE]

The client is expecting there to be a cluster of servers to communicate with and to store/access data. Clearly, there are no servers running yet.

There are several ways in which to start a cluster. For example, you may use Spring to configure and bootstrap the cluster, which has been demonstrated here.

Although, for this example, we are going to use the tools provided with Apache Geode, or Pivotal GemFire, i.e. Gfsh (GemFire/Geode Shell) for reasons that will become apparent later.

You need to download and install a full distribution of Apache Geode to make use of the provided tools. After installation, you will need to set the GEODE (or GEMFIRE) environment variable to the location of your installation. Additionally, add $GEODE/bin to your system $PATH.

Once Apache Geode has been successfully installed, you can open a command prompt (terminal) and do:

Running Gfsh
$ echo $GEMFIRE
/Users/jblum/pivdev/apache-geode-1.2.1


$ gfsh
    _________________________     __
   / _____/ ______/ ______/ /____/ /
  / /  __/ /___  /_____  / _____  /
 / /__/ / ____/  _____/ / /    / /
/______/_/      /______/_/    /_/    1.2.1

Monitor and Manage Apache Geode
gfsh>

You are set to go.

For your convenience, a Gfsh shell script is provided to start a cluster:

Gfsh shell script
# Gfsh shell script to start a simple GemFire/Geode cluster

start locator --name=LocatorOne --log-level=config
start server --name=ServerOne --log-level=config

Specifically, we are starting 1 Locator and 1 Server, all running with the default ports.

Execute the Gfsh shell script using:

Run Gfsh shell script
gfsh>run --file=/path/to/spring-boot-data-geode/samples/boot/configuration/src/main/resources/geode/bin/start-simple-cluster.gfsh
1. Executing - start locator --name=LocatorOne --log-level=config

Starting a Geode Locator in /Users/jblum/pivdev/lab/LocatorOne...
....
Locator in /Users/jblum/pivdev/lab/LocatorOne on 10.99.199.24[10334] as LocatorOne is currently online.
Process ID: 68425
Uptime: 2 seconds
Geode Version: 1.2.1
Java Version: 1.8.0_192
Log File: /Users/jblum/pivdev/lab/LocatorOne/LocatorOne.log
JVM Arguments: -Dgemfire.log-level=config -Dgemfire.enable-cluster-configuration=true -Dgemfire.load-cluster-configuration-from-dir=false -Dgemfire.launcher.registerSignalHandlers=true -Djava.awt.headless=true -Dsun.rmi.dgc.server.gcInterval=9223372036854775806
Class-Path: /Users/jblum/pivdev/apache-geode-1.2.1/lib/geode-core-1.2.1.jar:/Users/jblum/pivdev/apache-geode-1.2.1/lib/geode-dependencies.jar

Successfully connected to: JMX Manager [host=10.99.199.24, port=1099]

Cluster configuration service is up and running.

2. Executing - start server --name=ServerOne --log-level=config

Starting a Geode Server in /Users/jblum/pivdev/lab/ServerOne...
.....
Server in /Users/jblum/pivdev/lab/ServerOne on 10.99.199.24[40404] as ServerOne is currently online.
Process ID: 68434
Uptime: 2 seconds
Geode Version: 1.2.1
Java Version: 1.8.0_192
Log File: /Users/jblum/pivdev/lab/ServerOne/ServerOne.log
JVM Arguments: -Dgemfire.default.locators=10.99.199.24[10334] -Dgemfire.use-cluster-configuration=true -Dgemfire.start-dev-rest-api=false -Dgemfire.log-level=config -XX:OnOutOfMemoryError=kill -KILL %p -Dgemfire.launcher.registerSignalHandlers=true -Djava.awt.headless=true -Dsun.rmi.dgc.server.gcInterval=9223372036854775806
Class-Path: /Users/jblum/pivdev/apache-geode-1.2.1/lib/geode-core-1.2.1.jar:/Users/jblum/pivdev/apache-geode-1.2.1/lib/geode-dependencies.jar
You will need to change the path to the spring-boot-data-geode/samples/boot/configuration directory in the run --file=…​ Gfsh command above based on where you git cloned the spring-boot-data-geode project to your computer.

Now, our simple cluster with an Apache Geode Locator and (Cache) Server is running. We can verify by listing and describing the members:

List and Describe Members
gfsh>list members
   Name    | Id
---------- | ---------------------------------------------------
LocatorOne | 10.99.199.24(LocatorOne:68425:locator)<ec><v0>:1024
ServerOne  | 10.99.199.24(ServerOne:68434)<v1>:1025


gfsh>describe member --name=ServerOne
Name        : ServerOne
Id          : 10.99.199.24(ServerOne:68434)<v1>:1025
Host        : 10.99.199.24
Regions     :
PID         : 68434
Groups      :
Used Heap   : 27M
Max Heap    : 3641M
Working Dir : /Users/jblum/pivdev/lab/ServerOne
Log file    : /Users/jblum/pivdev/lab/ServerOne/ServerOne.log
Locators    : 10.99.199.24[10334]

Cache Server Information
Server Bind              : null
Server Port              : 40404
Running                  : true
Client Connections       : 0

What happens if we try to run the application now?

RegionNotFoundException
17:42:16.873 [main] ERROR o.s.b.SpringApplication - Application run failed
java.lang.IllegalStateException: Failed to execute ApplicationRunner
    ...
    at example.app.crm.CustomerServiceApplication.main(CustomerServiceApplication.java:51) [classes/:?]
Caused by: org.springframework.dao.DataAccessResourceFailureException: remote server on 10.99.199.24(SpringBasedCacheClientApplication:68473:loner):51142:f9f4573d:SpringBasedCacheClientApplication: While performing a remote query; nested exception is org.apache.geode.cache.client.ServerOperationException: remote server on 10.99.199.24(SpringBasedCacheClientApplication:68473:loner):51142:f9f4573d:SpringBasedCacheClientApplication: While performing a remote query
    at org.springframework.data.gemfire.GemfireCacheUtils.convertGemfireAccessException(GemfireCacheUtils.java:230) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
    at org.springframework.data.gemfire.GemfireAccessor.convertGemFireAccessException(GemfireAccessor.java:91) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
    at org.springframework.data.gemfire.GemfireTemplate.find(GemfireTemplate.java:329) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
    at org.springframework.data.gemfire.repository.support.SimpleGemfireRepository.count(SimpleGemfireRepository.java:129) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
    ...
    at example.app.crm.CustomerServiceApplication.lambda$runner$0(CustomerServiceApplication.java:59) ~[classes/:?]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:783) ~[spring-boot-2.0.9.RELEASE.jar:2.0.9.RELEASE]
	... 3 more
Caused by: org.apache.geode.cache.client.ServerOperationException: remote server on 10.99.199.24(SpringBasedCacheClientApplication:68473:loner):51142:f9f4573d:SpringBasedCacheClientApplication: While performing a remote query
    at org.apache.geode.cache.client.internal.AbstractOp.processChunkedResponse(AbstractOp.java:352) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.QueryOp$QueryOpImpl.processResponse(QueryOp.java:170) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.AbstractOp.processResponse(AbstractOp.java:230) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.AbstractOp.attempt(AbstractOp.java:394) ~[geode-core-1.2.1.jar:?]
	at org.apache.geode.cache.client.internal.AbstractOp.attemptReadResponse(AbstractOp.java:203) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.ConnectionImpl.execute(ConnectionImpl.java:275) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.pooling.PooledConnection.execute(PooledConnection.java:332) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.OpExecutorImpl.executeWithPossibleReAuthentication(OpExecutorImpl.java:900) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.OpExecutorImpl.execute(OpExecutorImpl.java:158) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.OpExecutorImpl.execute(OpExecutorImpl.java:115) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.PoolImpl.execute(PoolImpl.java:763) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.QueryOp.execute(QueryOp.java:58) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.ServerProxy.query(ServerProxy.java:70) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.query.internal.DefaultQuery.executeOnServer(DefaultQuery.java:456) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.query.internal.DefaultQuery.execute(DefaultQuery.java:338) ~[geode-core-1.2.1.jar:?]
    at org.springframework.data.gemfire.GemfireTemplate.find(GemfireTemplate.java:311) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
    at org.springframework.data.gemfire.repository.support.SimpleGemfireRepository.count(SimpleGemfireRepository.java:129) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
	...
    at example.app.crm.CustomerServiceApplication.lambda$runner$0(CustomerServiceApplication.java:59) ~[classes/:?]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:783) ~[spring-boot-2.0.9.RELEASE.jar:2.0.9.RELEASE]
	... 3 more
Caused by: org.apache.geode.cache.query.RegionNotFoundException: Region not found:  /Customers
    at org.apache.geode.cache.query.internal.DefaultQuery.checkQueryOnPR(DefaultQuery.java:599) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.query.internal.DefaultQuery.execute(DefaultQuery.java:348) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.query.internal.DefaultQuery.execute(DefaultQuery.java:319) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.BaseCommandQuery.processQueryUsingParams(BaseCommandQuery.java:121) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.BaseCommandQuery.processQuery(BaseCommandQuery.java:65) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.command.Query.cmdExecute(Query.java:91) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.BaseCommand.execute(BaseCommand.java:165) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.ServerConnection.doNormalMsg(ServerConnection.java:791) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.ServerConnection.doOneMessage(ServerConnection.java:922) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.ServerConnection.run(ServerConnection.java:1180) ~[geode-core-1.2.1.jar:?]
    ...

The application fails to run because we (deliberately) did not create a corresponding, server-side, "Customers" Region. In order for a client to send data via a client PROXY Region (a Region with no local state) to a server in a cluster, at least one server in the cluster must have a matching Region by name (i.e. "Customers").

Indeed, there are no Regions in the cluster:

List Regions
gfsh>list regions
No Regions Found

Of course, you could have created the matching server-side, "Customers" Region using Gfsh:

gfsh>create region --name=Customers --type=PARTITION

But, what if you have hundreds of domain objects each requiring a Region for persistence? It is not an unusual or unreasonable requirement in any practical enterprise application.

While it is not a "convention" in Spring Boot for Apache Geode (SBDG), Spring Data for Apache Geode (SDG) comes to our rescue. We simply only need to enable cluster configuration from the client:

Enable Cluster Configuration
@SpringBootApplication
@EnableEntityDefinedRegions(basePackageClasses = Customer.class)
@EnableClusterConfiguration(useHttp = true)
public class CustomerServiceApplication {
  ...
}

That is, we annotate our Customer Service application class with SDG’s @EnableClusterConfiguration annotation. Additionally, we have set the useHttp attribute to true. This sends the configuration meta-data from the client to the cluster via GemFire/Geode’s Management REST API.

This is useful when your GemFire/Geode cluster may be running behind a firewall, such as on public cloud infrastructure. However, there are other benefits to using HTTP as well. As stated, the client sends configuration meta-data to GemFire/Geode’s Management REST interface, which is a facade for the server-side Cluster Configuration Service. If another peer (e.g. server) is added to the cluster as a member, then this member will get the same configuration. If the entire cluster goes down, it will have the same configuration when it is restarted.

SDG is careful not to stomp on existing Regions since those Regions may have data already. Declaring the @EnableClusterConfiguration annotation is a useful development-time feature, but it is recommended that you explicitly define and declare your Regions in production environments, either using Gfsh or Spring confg.

Now, we can run our application again, and this time, it works!

Client/Server Run Successful
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.0.9.RELEASE)

Saving Customer [Customer(name=Jon Doe)]
Querying for Customer [SELECT * FROM /Customers WHERE name LIKE '%Doe']
Customer was [Customer(name=Jon Doe)]

Process finished with exit code 0

In the cluster (server-side), we will also see that the "Customers" Region was created successfully:

List & Describe Regions
gfsh>list regions
List of regions
---------------
Customers


gfsh>describe region --name=/Customers
..........................................................
Name            : Customers
Data Policy     : partition
Hosting Members : ServerOne

Non-Default Attributes Shared By Hosting Members

 Type  |    Name     | Value
------ | ----------- | ---------
Region | size        | 1
       | data-policy | PARTITION

We see that the "Customers" Region has a size of 1, containing "Jon Doe".

We can verify this by querying the "Customers" Region:

Query for all Customers
gfsh>query --query="SELECT customer.name FROM /Customers customer"
Result : true
Limit  : 100
Rows   : 1

Result
-------
Jon Doe

That was easy!

4. Auto-configuration for Apache Geode, Take Two

What may not be apparent in this example up to this point is how the data got from the client to the server. Certainly, our client did send Jon Doe to the server, but our Customer class is not java.io.Serializable. So, how was an instance of Customer streamed from the client to the server then (it is using a Socket)?

Any object sent over a network, between two Java processes, or streamed to/from disk, must be serializable.

Furthermore, when we started the cluster, we did not include any application domain classes on the classpath of any server in the cluster.

As further evidence, we an adjust our query slightly:

Invalid Query
gfsh>query --query="SELECT * FROM /Customers"
Message : Could not create an instance of a class example.app.crm.model.Customer
Result  : false

If you tried to perform a get, you would hit a similar error:

Region.get(key)
gfsh>get --region=/Customers --key=1 --key-class=java.lang.Long
Message : Could not create an instance of a class example.app.crm.model.Customer
Result  : false

So, how was the data sent, then?

Well, Apache Geode and Pivotal GemFire provide 2 proprietary serialization formats in addition to Java Serialization: Data Serialization and PDX, or Portable Data Exchange.

While Data Serialization is more efficient, PDX is more flexible (i.e. "portable"). PDX enables data to be queried in serialized form and is the format used to support both Java and native clients (C++, C#) simultaneously. Therefore, PDX is auto-configured in Spring Boot Data Geode (SBDG) by default.

This is convenient since you may not want to implement java.io.Serializable for all your application domain model types that you store in Apache Geode. In other cases, you may not even have control over the types referred to by your application domain model types to make they Serializable, such as when using a 3rd party library.

So, SBDG auto-configures PDX and uses Spring Data Geode’s MappingPdxSerializer as the PdxSerializer to de/serialize all application domain types.

If we disable PDX auto-configuration, we will see the effects of trying to serialize a non-serializable type, Customer.

First, let’s back up a few steps and destroy the server-side "Customers" Region:

Destroy "Customers" Region
gfsh>destroy region --name=/Customers
"/Customers"  destroyed successfully.


gfsh>list regions
No Regions Found

Then, we disable PDX auto-configuration:

Disable PDX Auto-configuration
@SpringBootApplication(exclude = PdxSerializationAutoConfiguration.class)
@EnableEntityDefinedRegions(basePackageClasses = Customer.class)
@EnableClusterConfiguration(useHttp = true)
public class CustomerServiceApplication {
  ...
}

When we re-run the application, we get the error we would expect:

NotSerializableException
Caused by: java.io.NotSerializableException: example.app.crm.model.Customer
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184) ~[?:1.8.0_192]
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[?:1.8.0_192]
    at org.apache.geode.internal.InternalDataSerializer.writeSerializableObject(InternalDataSerializer.java:2248) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.InternalDataSerializer.basicWriteObject(InternalDataSerializer.java:2123) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.DataSerializer.writeObject(DataSerializer.java:2936) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.util.BlobHelper.serializeTo(BlobHelper.java:66) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.Message.serializeAndAddPart(Message.java:396) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.Message.addObjPart(Message.java:340) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.Message.addObjPart(Message.java:319) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.PutOp$PutOpImpl.<init>(PutOp.java:281) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.PutOp.execute(PutOp.java:66) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.ServerRegionProxy.put(ServerRegionProxy.java:162) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.LocalRegion.serverPut(LocalRegion.java:3006) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.LocalRegion.cacheWriteBeforePut(LocalRegion.java:3115) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.ProxyRegionMap.basicPut(ProxyRegionMap.java:222) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.LocalRegion.virtualPut(LocalRegion.java:5628) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.LocalRegionDataView.putEntry(LocalRegionDataView.java:151) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.LocalRegion.basicPut(LocalRegion.java:5057) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.LocalRegion.validatedPut(LocalRegion.java:1595) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.LocalRegion.put(LocalRegion.java:1582) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.AbstractRegion.put(AbstractRegion.java:325) ~[geode-core-1.2.1.jar:?]
    at org.springframework.data.gemfire.GemfireTemplate.put(GemfireTemplate.java:193) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
    at org.springframework.data.gemfire.repository.support.SimpleGemfireRepository.save(SimpleGemfireRepository.java:86) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
    ...
    at example.app.crm.CustomerServiceApplication.lambda$runner$0(CustomerServiceApplication.java:70) ~[spring-samples-boot-configuration-1.0.0.RELEASE.jar]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:783) ~[spring-boot-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    ...

Our "Customers" Region is recreated, but is empty:

Empty "Customers" Region
gfsh>list regions
List of regions
---------------
Customers


gfsh>describe region --name=/Customers
..........................................................
Name            : Customers
Data Policy     : partition
Hosting Members : ServerOne

Non-Default Attributes Shared By Hosting Members

 Type  |    Name     | Value
------ | ----------- | ---------
Region | size        | 0
       | data-policy | PARTITION

So, SBDG takes care of all your serialization needs without you having to configure serialization or implement java.io.Serializable in all your application domain types, including types your application domain types refer to, which may not be possible.

If you were not using SBDG, then you would need to enable PDX serialization explicitly.

The PDX auto-configuration provided by SBDG is equivalent to:

Equivalent PDX Configuration
@SpringBootApplication
@ClientCacheApplication
@EnableEntityDefinedRegions(basePackageClasses = Customer.class)
@EnableClusterConfiguration(useHttp = true)
@EnablePdx
public class CustomerServiceApplication {
  ...
}

In addition to the @ClientCacheApplication annotation, you would need to include the @EnablePdx annotation, which is responsible for configuring PDX serialization and registering SDG’s MappingPdxSerializer.

5. Securing the Client & Server

The last bit of auto-configuration provided by SBDG that we will look at in this guide involves Security, and specifically, Authentication/Authorization (Auth) along with Transport Layer Security (TLS) using SSL.

In today’s age, Security is no laughing matter and making sure your applications are secure is a first-class concern. This is why SBDG takes Security very seriously and attempts to make this as simple as possible. You are definitely encouraged to read the relevant chapter in this Reference Documentation on the provided Security auto-configuration support.

We will now expand on our example to secure the client and server processes, with both Auth and TLS using SSL, and then see how SBDG helps us properly configure these concerns, easily and reliably.

5.1. Securing the server

First, we must secure the cluster (i.e. the Locator and Server).

In a nutshell, when using the Apache Geode API (with no help from Spring), you must do the following:

  1. (Auth) Implement the org.apache.geode.security.SecurityManager interface.

  2. (Auth) Configure your custom SecurityManager using the GemFire/Geode security-manager property in gemfire.properties.

  3. (Auth) Either create a gfsecurity.properties file and set the security-username and security-password properties, or…​

  4. (Auth) Implement the org.apache.geode.security.AuthInitialize interface and set the security-peer-auth-init property in gemfire.properties as described in Implementing Authentication of the Apache Geode User Guide.

  5. (SSL) Then, you must create Java KeyStore (jks) files for both the keystore and truststore used to configure the SSL Socket.

  6. (SSL) Configure the Java KeyStores using the GemFire/Geode ssl-keystore and ssl-truststore properties in gemfire.properties.

  7. (SSL) If you secured your Java KeyStores (recommended) then you must additionally set the ssl-keystore-password and ssl-truststore-password properties.

  8. (SSL) Optionally, configure the GemFire/Geode components that should be enabled with SSL using the ssl-enabled-components property (e.g. locator and server for client/server and Locator connections).

  9. Then launch the cluster, and its members using Gfsh in the proper order.

This is a lot of tedious work and if you get any bit of the configuration wrong, then either your servers will fail to start correctly, or worse, they will not be secure.

Fortunately, this sample provides Gfsh shell scripts to get you going:

Gfsh shell script to start a secure cluster
# Gfsh shell script to start a secure GemFire/Geode cluster

set variable --name=CLASSPATH --value=${SBDG_HOME}/apache-geode-extensions/build/libs/apache-geode-extensions-@[email protected]
set variable --name=GEMFIRE_PROPERTIES --value=${SBDG_HOME}/spring-geode-samples/boot/configuration/build/resources/main/geode/config/gemfire.properties

start locator --name=LocatorOne --classpath=${CLASSPATH} --properties-file=${GEMFIRE_PROPERTIES}
connect --user=test --password=test
start server --name=ServerOne --classpath=${CLASSPATH} --properties-file=${GEMFIRE_PROPERTIES}
SBDG does provide server-side, peer Security auto-configuration support. However, you must then configure and bootstrap your GemFire/Geode servers with Spring. Again, an example of configuring/bootstrapping GemFire/Geode servers with Spring is provided here.

5.2. Securing the client

5.2.1. Authentication

If you were to run the client, Customer Service application when SSL is not enabled, the application would throw the following error on startup:

AuthenticationRequiredException
15:26:10.598 [main] ERROR o.a.g.i.c.GemFireCacheImpl - org.apache.geode.security.AuthenticationRequiredException: No security credentials are provided
15:26:10.607 [main] ERROR o.s.b.SpringApplication - Application run failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'runner' defined in example.app.crm.CustomerServiceApplication: Unsatisfied dependency expressed through method 'runner' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'customerRepository': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'Customers': Cannot resolve reference to bean 'gemfireCache' while setting bean property 'cache'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'gemfireCache': FactoryBean threw exception on object creation; nested exception is java.lang.RuntimeException: Error occurred when initializing peer cache
    ....
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at example.app.crm.CustomerServiceApplication.main(CustomerServiceApplication.java:51) [main/:?]
....
Caused by: org.apache.geode.security.AuthenticationRequiredException: No security credentials are provided
    at org.apache.geode.internal.cache.tier.sockets.HandShake.readMessage(HandShake.java:1396) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.HandShake.handshakeWithServer(HandShake.java:1251) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.ConnectionImpl.connect(ConnectionImpl.java:117) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.ConnectionFactoryImpl.createClientToServerConnection(ConnectionFactoryImpl.java:136) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.QueueManagerImpl.initializeConnections(QueueManagerImpl.java:466) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.QueueManagerImpl.start(QueueManagerImpl.java:303) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.PoolImpl.start(PoolImpl.java:343) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.PoolImpl.finishCreate(PoolImpl.java:173) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.PoolImpl.create(PoolImpl.java:159) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.PoolFactoryImpl.create(PoolFactoryImpl.java:321) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.determineDefaultPool(GemFireCacheImpl.java:2922) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.initializeDeclarativeCache(GemFireCacheImpl.java:1369) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.initialize(GemFireCacheImpl.java:1195) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.basicCreate(GemFireCacheImpl.java:758) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.createClient(GemFireCacheImpl.java:731) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.ClientCacheFactory.basicCreate(ClientCacheFactory.java:262) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.ClientCacheFactory.create(ClientCacheFactory.java:212) ~[geode-core-1.2.1.jar:?]
    at org.springframework.data.gemfire.client.ClientCacheFactoryBean.createCache(ClientCacheFactoryBean.java:400) ~[spring-data-geode-2.0.14.RELEASE.jar:2.0.14.RELEASE]
	...

Even though SBDG provides auto-configuration support for client Security, and specifically Auth in this case, you still must supply a username and password, minimally.

This is as easy as setting a username/password in Spring Boot application.properties using Spring Data Geode’s (SDG) well-known and documented properties:

Application security configuration properties
# Security Configuration for Apache Geode/Pivotal GemFire using Spring Boot and Spring Data GemFire properties

spring.boot.data.gemfire.security.ssl.keystore.name=example-trusted-keystore.jks
spring.data.gemfire.security.username=test
spring.data.gemfire.security.password=test
spring.data.gemfire.security.ssl.keystore.password=s3cr3t
spring.data.gemfire.security.ssl.truststore.password=s3cr3t

The act of setting a username and password triggers the client Security auto-configuration provided by SBDG. There are many steps to configuring client Security in Apache Geode/Pivotal GemFire properly, as there was on the server. All you need to worry about is supplying the credentials. Easy!

To include the application-security.properties, simply enable the Spring "security" profile in your run configuration when running the CustomerServiceApplication class:

Enable Spring "security" Profile
-Dspring.profiles.active=security

By doing so, the application-security.properties file containing the configured username/password properties is included on application startup and our application is able to authenticate with the cluster successfully.

To illustrate that there is more to configuring Authentication than simply setting a username/password, if you were to disable the client Security auto-configuration:

Disabling Client Security Auto-configuration
@SpringBootApplication(exclude = ClientSecurityAutoConfiguration.class)
@EnableEntityDefinedRegions(basePackageClasses = Customer.class)
@EnableClusterConfiguration(useHttp = true)
public class CustomerServiceApplication {
  ...
}

Then, our application would not be able to authenticate with the cluster, and again, an error would be thrown:

AuthenticationRequiredException
Caused by: org.apache.geode.security.AuthenticationRequiredException: No security credentials are provided
    at org.apache.geode.internal.cache.tier.sockets.HandShake.readMessage(HandShake.java:1396) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.tier.sockets.HandShake.handshakeWithServer(HandShake.java:1251) ~[geode-core-1.2.1.jar:?]
    ....

Without the support of SBDG’s client Security auto-configuration, you would need to explicitly enable Security:

Explicitly Enable Security
@SpringBootApplication
@ClientCacheApplication
@EnableSecurity
@EnableEntityDefinedRegions(basePackageClasses = Customer.class)
@EnableClusterConfiguration(useHttp = true)
public class CustomerServiceApplication {
  ...
}

That is, in addition to the @ClientCacheApplication annotation, you would still need to 1) set the username/password properties in Spring Boot application.properties and 2) explicitly declare the @EnableSecurity annotation.

Therefore, SBDG (with help from SDG, under-the-hood) does the heavy lifting, automatically for you.

5.2.2. TLS with SSL

What about SSL?

With either SBDG SSL auto-configuration disabled:

Disable SSL Auto-configuration
@SpringBootApplication(exclude = SslAutoConfiguration.class)
@EnableEntityDefinedRegions(basePackageClasses = Customer.class)
@EnableClusterConfiguration(useHttp = true)
public class CustomerServiceApplication {
  ...
}

Or optionally, no explicit Java KeyStore configuration, iff necessary, such as:

Java KeyStore Configuration for SSL using SBDG
spring.boot.data.gemfire.security.ssl.keystore.name=myTrustedKeyStore.jks
spring.data.gemfire.security.ssl.keystore.password=s3cr3t
spring.data.gemfire.security.ssl.truststore.password=s3cr3t

Or possibly:

Java KeyStore Configuration for SSL using SDG
spring.data.gemfire.security.ssl.keystore=/file/system/path/to/trusted-keystore.jks
spring.data.gemfire.security.ssl.keystore.password=s3cr3t
spring.data.gemfire.security.ssl.keystore.type=JKS
spring.data.gemfire.security.ssl.truststore=/file/system/path/to/trusted-keystore.jks
spring.data.gemfire.security.ssl.truststore.password=s3cr3t

Then, the application will throw the following error:

Connectivity Exception
Caused by: org.apache.geode.security.AuthenticationRequiredException: Server expecting SSL connection
    at org.apache.geode.internal.cache.tier.sockets.HandShake.handshakeWithServer(HandShake.java:1222) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.ConnectionImpl.connect(ConnectionImpl.java:117) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.ConnectionFactoryImpl.createClientToServerConnection(ConnectionFactoryImpl.java:136) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.QueueManagerImpl.initializeConnections(QueueManagerImpl.java:466) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.PoolImpl.start(PoolImpl.java:343) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.QueueManagerImpl.start(QueueManagerImpl.java:303) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.PoolImpl.finishCreate(PoolImpl.java:173) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.internal.PoolImpl.create(PoolImpl.java:159) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.PoolFactoryImpl.create(PoolFactoryImpl.java:321) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.determineDefaultPool(GemFireCacheImpl.java:2922) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.initializeDeclarativeCache(GemFireCacheImpl.java:1369) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.initialize(GemFireCacheImpl.java:1195) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.basicCreate(GemFireCacheImpl.java:758) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.internal.cache.GemFireCacheImpl.createClient(GemFireCacheImpl.java:731) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.ClientCacheFactory.basicCreate(ClientCacheFactory.java:262) ~[geode-core-1.2.1.jar:?]
    at org.apache.geode.cache.client.ClientCacheFactory.create(ClientCacheFactory.java:212) ~[geode-core-1.2.1.jar:?]

With very minimal to no configuration, SBDG can automatically configure SSL, as explained in Transport Layer Security using SSL section under Security. In fact, no configuration is actually required if the trusted Java KeyStore file is named "trusted.keystore", is in the root of the classpath and the JKS file is unsecured, i.e. not protected by a password.

However, if the you named your Java KeyStore (JKS) file something other than "trusted.keystore", then you can set the spring-boot-data-gemfire.security.ssl.keystore.name property:

Delcaring the Java KeyStore filename
spring.boot.data.gemfire.security.ssl.keystore.name=myTrustedKeyStore.jks

If you Java KeyStore (JKS) file is secure, then you can specify the password:

Java KeyStore Configuration for SSL using SBDG
spring.data.gemfire.security.ssl.keystore.password=s3cr3t
spring.data.gemfire.security.ssl.truststore.password=s3cr3t

Or, if the Java KeyStore files for SSL are completely of a different variety:

Complete Java KeyStore Configuration for SSL using SDG
spring.data.gemfire.security.ssl.keystore=/file/system/path/to/trusted-keystore.pks11
spring.data.gemfire.security.ssl.keystore.password=s3cr3t
spring.data.gemfire.security.ssl.keystore.type=PKS11
spring.data.gemfire.security.ssl.truststore=/file/system/path/to/trusted-keystore.pks11
spring.data.gemfire.security.ssl.truststore.password=differentS3cr3t

Again, you can customize your configuration as much as needed or let SBDG handle things by following the defaults.

The SBDG SSL auto-configuration is equivalent to the following in SDG:

SDG SSL Configuration
@SpringBootApplication
@ClientCacheApplication
@EnableSsl
@EnableEntityDefinedRegions(basePackageClasses = Customer.class)
@EnableClusterConfiguration(useHttp = true)
public class CustomerServiceApplication {
  ...
}

In addition to the @ClientCacheApplication annotation, you must additional declare the @EnableSsl annotation along with the spring.data.gemfire.security.ssl.keystore and spring.data.gemfire.security.ssl.truststore properties in Spring Boot application.properties.

In total, it is just simpler to start with the defaults and then customize bits of the configuration as your UC and application requirements grow.

6. Conclusion

Hopefully this guide has now given you a better understanding of what the auto-configuration support provided by Spring Boot for Apache Geode/Pivotal GemFire (SBDG) is giving you when developing Apache Geode or Pivotal GemFire applications with Spring.

In this guide, we have seen that SBDG provides auto-configuration support for the following Spring Data for Apache Geode’s (SDG) annotations:

  • @ClientCacheApplication

  • @EnableGemfireRepositories

  • @EnablePdx

  • @EnableSecurity

  • @EnableSsl

While we also presented these additional SDG annotations, which are not auto-configured by SDG:

  • @EnableEntityDefinedRegions

  • @EnableClusterConfiguration

They are optional and were shown for pure convenience.

Technically, the only annotation you are required to declare when SBDG is on the classpath, is @SpringBootApplication, leaving our Customer Service application declaration as simple as:

Basic CustomerServiceApplication class
@SpringBootApplication
public class CustomerServiceApplication {
  ...
}

That is it! That is all! However, this guide is by no means complete.

This guide does not cover all the auto-configuration provided by SBDG. SBDG additionally provides auto-configuration for Spring’s Cache Abstraction, Continuous Query (CQ), Function Execution & Implementations, GemfireTemplates and Spring Session. However, the concepts and effects are similar to what has been presented above.

We leave it as an exercise for you to explore and understand the remaining auto-configuration bits using this guide as a reference for your learning purposes.

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