Add Spring gRPC support

buildSrc/src/main/java/org/springframework/boot/build/context/properties/DocumentConfigurationProperties.java

@@ -58,6 +58,7 @@ void documentConfigurationProperties() throws IOException {
 		Snippets snippets = new Snippets(this.configurationPropertyMetadata);
 		snippets.add("application-properties.core", "Core Properties", this::corePrefixes);
 		snippets.add("application-properties.cache", "Cache Properties", this::cachePrefixes);
+		snippets.add("application-properties.grpc", "gRPC Properties", this::grpcPrefixes);
 		snippets.add("application-properties.mail", "Mail Properties", this::mailPrefixes);
 		snippets.add("application-properties.json", "JSON Properties", this::jsonPrefixes);
 		snippets.add("application-properties.data", "Data Properties", this::dataPrefixes);
@@ -159,6 +160,10 @@ private void dataMigrationPrefixes(Config prefix) {
 		prefix.accept("spring.sql.init");
 	}
 
+	private void grpcPrefixes(Config prefix) {
+		prefix.accept("spring.grpc");
+	}
+
 	private void integrationPrefixes(Config prefix) {
 		prefix.accept("spring.activemq");
 		prefix.accept("spring.artemis");

config/checkstyle/checkstyle-suppressions.xml

@@ -50,6 +50,7 @@
 	<suppress files="OutputCaptureRuleTests" checks="SpringJUnit5" />
 	<suppress files="[\\/]smoke-test[\\/]" checks="SpringJavadoc" message="\@since" />
 	<suppress files="[\\/]smoke-test[\\/]spring-boot-smoke-test-testng[\\/]" checks="SpringJUnit5" />
+	<suppress files="[\\/]smoke-test[\\/]spring-boot-smoke-test-grpc[\\/]build[\\/]generated[\\/]sources[\\/]proto" checks=".*" />
 	<suppress files="[\\/]test-support[\\/]" checks="SpringJavadoc" message="\@since" />
 	<suppress files="[\\/]src[\\/]dockerTest[\\/]java[\\/]" checks="JavadocPackage" />
 	<suppress files="[\\/]src[\\/]dockerTest[\\/]java[\\/]" checks="SpringJavadoc" message="\@since" />

documentation/spring-boot-docs/build.gradle

@@ -102,6 +102,8 @@ dependencies {
 	implementation(project(path: ":module:spring-boot-data-redis-test"))
 	implementation(project(path: ":module:spring-boot-devtools"))
 	implementation(project(path: ":module:spring-boot-graphql-test"))
+	implementation(project(path: ":module:spring-boot-grpc-client"))
+	implementation(project(path: ":module:spring-boot-grpc-server"))
 	implementation(project(path: ":module:spring-boot-health"))
 	implementation(project(path: ":module:spring-boot-hibernate"))
 	implementation(project(path: ":module:spring-boot-http-converter"))
@@ -195,6 +197,7 @@ dependencies {
 	implementation("org.springframework.data:spring-data-r2dbc")
 	implementation("org.springframework.graphql:spring-graphql")
 	implementation("org.springframework.graphql:spring-graphql-test")
+	implementation("org.springframework.grpc:spring-grpc-core")
 	implementation("org.springframework.kafka:spring-kafka")
 	implementation("org.springframework.kafka:spring-kafka-test")
 	implementation("org.springframework.pulsar:spring-pulsar")

module/spring-boot-grpc-client/build.gradle

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2012-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the License);
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+plugins {
+	id "java-library"
+	id "org.springframework.boot.auto-configuration"
+	id "org.springframework.boot.configuration-properties"
+	id "org.springframework.boot.deployed"
+	id "org.springframework.boot.optional-dependencies"
+}
+
+description = "Spring Boot gRPC Client"
+
+
+dependencies {
+	api(project(":core:spring-boot"))
+	api("org.springframework.grpc:spring-grpc-core")
+
+	compileOnly("com.fasterxml.jackson.core:jackson-annotations")
+
+	optional(project(":core:spring-boot-autoconfigure"))
+	optional(project(":module:spring-boot-actuator"))
+	optional(project(":module:spring-boot-actuator-autoconfigure"))
+	optional(project(":module:spring-boot-health"))
+	optional(project(":module:spring-boot-micrometer-observation"))
+	optional(project(":module:spring-boot-security"))
+	optional(project(":module:spring-boot-security-oauth2-client"))
+	optional(project(":module:spring-boot-security-oauth2-resource-server"))
+	optional("io.grpc:grpc-servlet-jakarta")
+	optional("io.grpc:grpc-stub")
+	optional("io.grpc:grpc-netty")
+	optional("io.grpc:grpc-netty-shaded")
+	optional("io.grpc:grpc-inprocess")
+	optional("io.grpc:grpc-kotlin-stub") {
+		exclude group: "javax.annotation", module: "javax.annotation-api"
+	}
+	optional("io.micrometer:micrometer-core")
+	optional("io.netty:netty-transport-native-epoll")
+	optional("io.projectreactor:reactor-core")
+	optional("jakarta.servlet:jakarta.servlet-api")
+	optional("org.springframework:spring-web")
+	optional("org.springframework.security:spring-security-config")
+	optional("org.springframework.security:spring-security-oauth2-client")
+	optional("org.springframework.security:spring-security-oauth2-resource-server")
+	optional("org.springframework.security:spring-security-oauth2-jose")
+	optional("org.springframework.security:spring-security-web")
+
+	testCompileOnly("com.fasterxml.jackson.core:jackson-annotations")
+
+	testImplementation(project(":core:spring-boot-test"))
+	testImplementation(project(":test-support:spring-boot-test-support"))
+
+	testRuntimeOnly("ch.qos.logback:logback-classic")
+}

module/spring-boot-grpc-client/src/main/java/org/springframework/boot/grpc/client/autoconfigure/ChannelBuilderCustomizers.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2012-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.grpc.client.autoconfigure;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import io.grpc.ManagedChannelBuilder;
+
+import org.springframework.boot.util.LambdaSafe;
+import org.springframework.grpc.client.GrpcChannelBuilderCustomizer;
+
+/**
+ * Invokes the available {@link GrpcChannelBuilderCustomizer} instances for a given
+ * {@link ManagedChannelBuilder}.
+ *
+ * @author Chris Bono
+ */
+class ChannelBuilderCustomizers {
+
+	private final List<GrpcChannelBuilderCustomizer<?>> customizers;
+
+	ChannelBuilderCustomizers(List<? extends GrpcChannelBuilderCustomizer<?>> customizers) {
+		this.customizers = (customizers != null) ? new ArrayList<>(customizers) : Collections.emptyList();
+	}
+
+	/**
+	 * Customize the specified {@link ManagedChannelBuilder}. Locates all
+	 * {@link GrpcChannelBuilderCustomizer} beans able to handle the specified instance
+	 * and invoke {@link GrpcChannelBuilderCustomizer#customize} on them.
+	 * @param <T> the type of channel builder
+	 * @param authority the target authority of the channel
+	 * @param channelBuilder the builder to customize
+	 * @return the customized builder
+	 */
+	@SuppressWarnings("unchecked")
+	<T extends ManagedChannelBuilder<?>> T customize(String authority, T channelBuilder) {
+		LambdaSafe.callbacks(GrpcChannelBuilderCustomizer.class, this.customizers, channelBuilder)
+			.withLogger(ChannelBuilderCustomizers.class)
+			.invoke((customizer) -> customizer.customize(authority, channelBuilder));
+		return channelBuilder;
+	}
+
+}

module/spring-boot-grpc-client/src/main/java/org/springframework/boot/grpc/client/autoconfigure/ClientPropertiesChannelBuilderCustomizer.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2012-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.grpc.client.autoconfigure;
+
+import java.time.Duration;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+
+import io.grpc.ManagedChannelBuilder;
+
+import org.springframework.boot.context.properties.PropertyMapper;
+import org.springframework.boot.grpc.client.autoconfigure.GrpcClientProperties.ChannelConfig;
+import org.springframework.grpc.client.GrpcChannelBuilderCustomizer;
+import org.springframework.grpc.client.interceptor.DefaultDeadlineSetupClientInterceptor;
+import org.springframework.util.unit.DataSize;
+
+/**
+ * A {@link GrpcChannelBuilderCustomizer} that maps {@link GrpcClientProperties client
+ * properties} to a channel builder.
+ *
+ * @param <T> the type of the builder
+ * @author David Syer
+ * @author Chris Bono
+ */
+class ClientPropertiesChannelBuilderCustomizer<T extends ManagedChannelBuilder<T>>
+		implements GrpcChannelBuilderCustomizer<T> {
+
+	private final GrpcClientProperties properties;
+
+	ClientPropertiesChannelBuilderCustomizer(GrpcClientProperties properties) {
+		this.properties = properties;
+	}
+
+	@Override
+	public void customize(String authority, T builder) {
+		ChannelConfig channel = this.properties.getChannel(authority);
+		PropertyMapper mapper = PropertyMapper.get();
+		mapper.from(channel.getUserAgent()).to(builder::userAgent);
+		if (!authority.startsWith("unix:") && !authority.startsWith("in-process:")) {
+			mapper.from(channel.getDefaultLoadBalancingPolicy()).to(builder::defaultLoadBalancingPolicy);
+		}
+		mapper.from(channel.getMaxInboundMessageSize()).asInt(DataSize::toBytes).to(builder::maxInboundMessageSize);
+		mapper.from(channel.getMaxInboundMetadataSize()).asInt(DataSize::toBytes).to(builder::maxInboundMetadataSize);
+		mapper.from(channel.getKeepAliveTime()).to(durationProperty(builder::keepAliveTime));
+		mapper.from(channel.getKeepAliveTimeout()).to(durationProperty(builder::keepAliveTimeout));
+		mapper.from(channel.getIdleTimeout()).to(durationProperty(builder::idleTimeout));
+		mapper.from(channel.isKeepAliveWithoutCalls()).to(builder::keepAliveWithoutCalls);
+		Map<String, Object> defaultServiceConfig = new HashMap<>(channel.getServiceConfig());
+		if (channel.getHealth().isEnabled()) {
+			String serviceNameToCheck = (channel.getHealth().getServiceName() != null)
+					? channel.getHealth().getServiceName() : "";
+			defaultServiceConfig.put("healthCheckConfig", Map.of("serviceName", serviceNameToCheck));
+		}
+		if (!defaultServiceConfig.isEmpty()) {
+			builder.defaultServiceConfig(defaultServiceConfig);
+		}
+		if (channel.getDefaultDeadline() != null && channel.getDefaultDeadline().toMillis() > 0L) {
+			builder.intercept(new DefaultDeadlineSetupClientInterceptor(channel.getDefaultDeadline()));
+		}
+	}
+
+	Consumer<Duration> durationProperty(BiConsumer<Long, TimeUnit> setter) {
+		return (duration) -> setter.accept(duration.toNanos(), TimeUnit.NANOSECONDS);
+	}
+
+}

module/spring-boot-grpc-client/src/main/java/org/springframework/boot/grpc/client/autoconfigure/CompositeChannelFactoryAutoConfiguration.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2012-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.grpc.client.autoconfigure;
+
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.boot.autoconfigure.AutoConfiguration;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnSingleCandidate;
+import org.springframework.boot.autoconfigure.condition.NoneNestedConditions;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Conditional;
+import org.springframework.context.annotation.Primary;
+import org.springframework.grpc.client.CompositeGrpcChannelFactory;
+import org.springframework.grpc.client.GrpcChannelFactory;
+
+/**
+ * {@link EnableAutoConfiguration Auto-configuration} for a
+ * {@link CompositeGrpcChannelFactory}.
+ *
+ * @author Chris Bono
+ * @since 4.0.0
+ */
+@AutoConfiguration
+@ConditionalOnGrpcClientEnabled
+@Conditional(CompositeChannelFactoryAutoConfiguration.MultipleNonPrimaryChannelFactoriesCondition.class)
+public final class CompositeChannelFactoryAutoConfiguration {
+
+	@Bean
+	@Primary
+	CompositeGrpcChannelFactory compositeChannelFactory(ObjectProvider<GrpcChannelFactory> channelFactoriesProvider) {
+		return new CompositeGrpcChannelFactory(channelFactoriesProvider.orderedStream().toList());
+	}
+
+	static class MultipleNonPrimaryChannelFactoriesCondition extends NoneNestedConditions {
+
+		MultipleNonPrimaryChannelFactoriesCondition() {
+			super(ConfigurationPhase.REGISTER_BEAN);
+		}
+
+		@ConditionalOnMissingBean(GrpcChannelFactory.class)
+		static class NoChannelFactoryCondition {
+
+		}
+
+		@ConditionalOnSingleCandidate(GrpcChannelFactory.class)
+		static class SingleInjectableChannelFactoryCondition {
+
+		}
+
+	}
+
+}

module/spring-boot-grpc-client/src/main/java/org/springframework/boot/grpc/client/autoconfigure/ConditionalOnGrpcClientEnabled.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.grpc.client.autoconfigure;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import io.grpc.stub.AbstractStub;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.context.annotation.Conditional;
+
+/**
+ * {@link Conditional @Conditional} that only matches when the {@code io.grpc:grpc-stub}
+ * module is in the classpath and the {@code spring.grpc.client.enabled} property is not
+ * explicitly set to {@code false}.
+ *
+ * @author Freeman Freeman
+ * @author Chris Bono
+ * @since 4.0.0
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.TYPE, ElementType.METHOD })
+@ConditionalOnClass(AbstractStub.class)
+@ConditionalOnProperty(prefix = "spring.grpc.client", name = "enabled", matchIfMissing = true)
+public @interface ConditionalOnGrpcClientEnabled {
+
+}