feat: add properties to customize universeDomain and endpoint in KMS module

[mpeddada1]

This PR introduces the following changes:

• Introduces spring.cloud.gcp.kms.universe-domain and spring.cloud.gcp.kms.endpoint properties for customers to set the universe domain and endpoints to client settings if these values aren't null. If either universe domain or endpoint are empty then we will rely on the client library to throw an IllegalArgumentException.
• Adds unit tests in KmsAutoConfigurationTests verify that the client settings have been correctly set.
• Adds integration tests in KmsAutoConfigurationIntegrationTests to verify behavior of KmsTemplate methods with universeDomain being set to googleapis.com and endpoint to cloudkms.googleapis.com:443. Per offline discussion with @blakeli0 and @burkedavison, from spring framework for gcp's perspective, unit testing to ensure that we have set the universe domain and endpoints correctly in the client library provides us with sufficient coverage.

End-to-end verification with test environment endpoints have been documented in a separate test plan document.

[blakeli0]

Shall we consider empty String as well? Or this is the common practice?

[burkedavison]

The requirements doc suggests differentiating between null and empty string, but discussion has led to some implementation variation by language.

It is not standard practice to perform null || isEmpty checking in these AutoConfiguration classes. Search: https://github.com/search?q=repo%3AGoogleCloudPlatform%2Fspring-cloud-gcp+path%3A**AutoConfiguration.java+null&type=code

[mpeddada1]

[From offline discussion]If universe-domain is empty via spring.cloud.gcp.kms.universe-domain=:

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.google.cloud.kms.v1.KeyManagementServiceClient]: Factory method 'keyManagementClient' threw exception with message: The universe domain value cannot be empty.
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:177) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:644) ~[spring-beans-6.1.10.jar:6.1.10]
	... 33 common frames omitted
Caused by: java.lang.IllegalArgumentException: The universe domain value cannot be empty.
	at com.google.api.gax.rpc.EndpointContext$Builder.determineUniverseDomain(EndpointContext.java:237) ~[gax-2.50.0.jar:2.50.0]
	at com.google.api.gax.rpc.EndpointContext$Builder.build(EndpointContext.java:316) ~[gax-2.50.0.jar:2.50.0]
	at com.google.api.gax.rpc.StubSettings.buildEndpointContext(StubSettings.java:124) ~[gax-2.50.0.jar:2.50.0]
	at com.google.api.gax.rpc.StubSettings.<init>(StubSettings.java:106) ~[gax-2.50.0.jar:2.50.0]
	at com.google.cloud.kms.v1.stub.KeyManagementServiceStubSettings.<init>(KeyManagementServiceStubSettings.java:791) ~[google-cloud-kms-2.49.0.jar:2.49.0]
	at com.google.cloud.kms.v1.stub.KeyManagementServiceStubSettings$Builder.build(KeyManagementServiceStubSettings.java:1493) ~[google-cloud-kms-2.49.0.jar:2.49.0]
	at com.google.cloud.kms.v1.stub.KeyManagementServiceStubSettings$Builder.build(KeyManagementServiceStubSettings.java:830) ~[google-cloud-kms-2.49.0.jar:2.49.0]
	at com.google.api.gax.rpc.ClientSettings.<init>(ClientSettings.java:59) ~[gax-2.50.0.jar:2.50.0]
	at com.google.cloud.kms.v1.KeyManagementServiceSettings.<init>(KeyManagementServiceSettings.java:344) ~[google-cloud-kms-2.49.0.jar:2.49.0]
	at com.google.cloud.kms.v1.KeyManagementServiceSettings$Builder.build(KeyManagementServiceSettings.java:581) ~[google-cloud-kms-2.49.0.jar:2.49.0]
	at com.google.cloud.spring.autoconfigure.kms.GcpKmsAutoConfiguration.keyManagementClient(GcpKmsAutoConfiguration.java:83) ~[spring-cloud-gcp-autoconfigure-5.5.1-SNAPSHOT.jar:5.5.1-SNAPSHOT]
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:580) ~[na:na]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:140) ~[spring-beans-6.1.10.jar:6.1.10]
	... 34 common frames omitted

When endpoint is set to an empty string, the client library throws an exception:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'kmsUniverseDomain': Unsatisfied dependency expressed through constructor parameter 0: Error creating bean with name 'keyManagementClient' defined in class path resource [com/google/cloud/spring/autoconfigure/kms/GcpKmsAutoConfiguration.class]: Failed to instantiate [com.google.cloud.kms.v1.KeyManagementServiceClient]: Factory method 'keyManagementClient' threw exception with message: invalid endpoint, expecting "<host>:<port>"
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:795) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:237) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1357) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1194) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:562) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:522) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:337) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:335) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:975) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:962) ~[spring-context-6.1.10.jar:6.1.10]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:624) ~[spring-context-6.1.10.jar:6.1.10]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146) ~[spring-boot-3.3.1.jar:3.3.1]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754) ~[spring-boot-3.3.1.jar:3.3.1]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:456) ~[spring-boot-3.3.1.jar:3.3.1]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:335) ~[spring-boot-3.3.1.jar:3.3.1]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1363) ~[spring-boot-3.3.1.jar:3.3.1]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1352) ~[spring-boot-3.3.1.jar:3.3.1]
	at com.example.KmsUniverseDomain.main(KmsUniverseDomain.java:21) ~[classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'keyManagementClient' defined in class path resource [com/google/cloud/spring/autoconfigure/kms/GcpKmsAutoConfiguration.class]: Failed to instantiate [com.google.cloud.kms.v1.KeyManagementServiceClient]: Factory method 'keyManagementClient' threw exception with message: invalid endpoint, expecting "<host>:<port>"
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:648) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:636) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1337) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1167) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:562) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:522) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:337) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:335) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:254) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1443) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1353) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:904) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:782) ~[spring-beans-6.1.10.jar:6.1.10]
	... 19 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.google.cloud.kms.v1.KeyManagementServiceClient]: Factory method 'keyManagementClient' threw exception with message: invalid endpoint, expecting "<host>:<port>"
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:177) ~[spring-beans-6.1.10.jar:6.1.10]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:644) ~[spring-beans-6.1.10.jar:6.1.10]
	... 33 common frames omitted
Caused by: java.lang.IllegalArgumentException: invalid endpoint, expecting "<host>:<port>"
	at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.validateEndpoint(InstantiatingGrpcChannelProvider.java:905) ~[gax-grpc-2.51.0.jar:2.51.0]
	at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.withEndpoint(InstantiatingGrpcChannelProvider.java:217) ~[gax-grpc-2.51.0.jar:2.51.0]
	at com.google.api.gax.rpc.ClientContext.create(ClientContext.java:234) ~[gax-2.51.0.jar:2.51.0]
	at com.google.cloud.kms.v1.stub.GrpcKeyManagementServiceStub.create(GrpcKeyManagementServiceStub.java:482) ~[google-cloud-kms-2.50.0.jar:2.50.0]
	at com.google.cloud.kms.v1.stub.KeyManagementServiceStubSettings.createStub(KeyManagementServiceStubSettings.java:688) ~[google-cloud-kms-2.50.0.jar:2.50.0]
	at com.google.cloud.kms.v1.KeyManagementServiceClient.<init>(KeyManagementServiceClient.java:783) ~[google-cloud-kms-2.50.0.jar:2.50.0]
	at com.google.cloud.kms.v1.KeyManagementServiceClient.create(KeyManagementServiceClient.java:765) ~[google-cloud-kms-2.50.0.jar:2.50.0]
	at com.google.cloud.spring.autoconfigure.kms.GcpKmsAutoConfiguration.keyManagementClient(GcpKmsAutoConfiguration.java:83) ~[spring-cloud-gcp-autoconfigure-5.5.1-SNAPSHOT.jar:5.5.1-SNAPSHOT]
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:580) ~[na:na]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:140) ~[spring-beans-6.1.10.jar:6.1.10]
	... 34 common frames omitted

[blakeli0]

nit: Rename the variable as well since the type is changed. All the references in this method also need to be updated.

Suggested change

	KeyManagementServiceSettings.Builder settings =
	KeyManagementServiceSettings.Builder settingsBuilder =

[mpeddada1]

Done, thank you.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud