Refine default enablement of gRPC health service

spring-grpc-docs/src/main/antora/modules/ROOT/pages/health.adoc

@@ -7,6 +7,8 @@ The health service is registered with the gRPC server and a `HealthStatusManager
 
 IMPORTANT: The health service resides in the `io.grpc:grpc-services` library which is marked as `optional` by Spring gRPC. You must add this dependency to your application in order for it to be autoconfigured.
 
+NOTE: Server-side gRPC health is enabled by default when the application defines at least one  `BindableService`. If no server-side gRPC services are present, health is disabled by default and must be explicitly enabled using `spring.grpc.server.health.enabled=true`.
+
 == Actuator Health
 When Spring Boot Actuator is added to your project and the {spring-boot-docs}/actuator/endpoints.html#actuator.endpoints.health[Health endpoint] is available, the framework will automatically periodically update the health status of a configured list of Spring Boot {spring-boot-docs}/actuator/endpoints.html#actuator.endpoints.health.auto-configured-health-indicators[health indicators], including any ({spring-boot-docs}/actuator/endpoints.html#actuator.endpoints.health.writing-custom-health-indicators[custom indicators]).
 By default, the aggregate status of the individual indicators is also used to update the overall server status (`""`).

spring-grpc-server-spring-boot-autoconfigure/src/main/java/org/springframework/boot/grpc/server/autoconfigure/health/GrpcServerHealthAutoConfiguration.java

@@ -24,7 +24,6 @@
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionMessage;
 import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
@@ -55,13 +54,14 @@
  *
  * @author Daniel Theuke (daniel.theuke@heuboe.de)
  * @author Chris Bono
+ * @author Andrey Litvitski
  * @since 1.0.0
  */
 @AutoConfiguration(before = GrpcServerFactoryAutoConfiguration.class)
 @ConditionalOnSpringGrpc
 @ConditionalOnClass(HealthStatusManager.class)
 @ConditionalOnGrpcServerEnabled("health")
-@ConditionalOnBean(BindableService.class)
+@Conditional(GrpcServerHealthAutoConfiguration.OnHealthDefaultEnablementCondition.class)
 public final class GrpcServerHealthAutoConfiguration {
 
 	@Bean(destroyMethod = "enterTerminalState")
@@ -129,4 +129,25 @@ public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeM
 
 	}
 
+	static class OnHealthDefaultEnablementCondition extends SpringBootCondition {
+
+		@Override
+		public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
+			String propertyName = "spring.grpc.server.health.enabled";
+			BindResult<Boolean> enabled = Binder.get(context.getEnvironment()).bind(propertyName, Boolean.class);
+			if (enabled.isBound()) {
+				return enabled.get() ? ConditionOutcome.match("Health explicitly enabled")
+						: ConditionOutcome.noMatch("Health explicitly disabled");
+			}
+			if (context.getBeanFactory() == null) {
+				return ConditionOutcome.noMatch("Context bean factory is null");
+			}
+			String[] bindableServices = context.getBeanFactory()
+				.getBeanNamesForType(BindableService.class, false, false);
+			return (bindableServices.length > 0) ? ConditionOutcome.match("BindableService found")
+					: ConditionOutcome.noMatch("No BindableService found and health not explicitly enabled");
+		}
+
+	}
+
 }

spring-grpc-server-spring-boot-autoconfigure/src/test/java/org/springframework/boot/grpc/server/autoconfigure/health/GrpcServerHealthAutoConfigurationTests.java

@@ -130,6 +130,19 @@ void whenServerEnabledPropertySetTrueThenAutoConfigurationIsNotSkipped() {
 			.run((context) -> assertThat(context).hasSingleBean(GrpcServerHealthAutoConfiguration.class));
 	}
 
+	@Test
+	void whenNoBindableServiceAndHealthPropertyNotSetDoesNotAutoConfigureBeans() {
+		new ApplicationContextRunner().withConfiguration(AutoConfigurations.of(GrpcServerHealthAutoConfiguration.class))
+			.run((context) -> assertThat(context).doesNotHaveBean(GrpcServerHealthAutoConfiguration.class));
+	}
+
+	@Test
+	void whenNoBindableServiceAndHealthPropertyTrueAutoConfiguresBeans() {
+		new ApplicationContextRunner().withConfiguration(AutoConfigurations.of(GrpcServerHealthAutoConfiguration.class))
+			.withPropertyValues("spring.grpc.server.health.enabled=true")
+			.run((context) -> assertThat(context).hasSingleBean(GrpcServerHealthAutoConfiguration.class));
+	}
+
 	@Disabled("Will be tested in an integration test once the Actuator adapter is implemented")
 	@Test
 	void enterTerminalStateIsCalledWhenStatusManagerIsStopped() {