Document gRPC support

Closes gh-49291

Author: philwebb

buildSrc/src/main/java/org/springframework/boot/build/antora/AntoraAsciidocAttributes.java

@@ -161,6 +161,9 @@ private void addVersionAttributes(Map<String, String> attributes, Map<String, St
 		});
 		attributes.put("version-native-build-tools", (String) this.projectProperties.get("nativeBuildToolsVersion"));
 		attributes.put("version-graal", (String) this.projectProperties.get("graalVersion"));
+		attributes.put("version-protobuf-gradle-plugin",
+				(String) this.projectProperties.get("protobufGradlePluginVersion"));
+		addDependencyVersion(attributes, "grpc-api", "io.grpc:grpc-api");
 		addDependencyVersion(attributes, "jackson-annotations", "com.fasterxml.jackson.core:jackson-annotations");
 		addDependencyVersion(attributes, "jackson-core", "tools.jackson.core:jackson-core");
 		addDependencyVersion(attributes, "jackson-databind", "tools.jackson.core:jackson-databind");

buildSrc/src/main/resources/org/springframework/boot/build/antora/antora-asciidoc-attributes.properties

@@ -26,6 +26,7 @@ url-gradle-docs-java-plugin={url-gradle-docs}/java_plugin.html
 url-gradle-docs-war-plugin={url-gradle-docs}/war_plugin.html
 url-gradle-dsl=https://docs.gradle.org/current/dsl
 url-gradle-javadoc=https://docs.gradle.org/current/javadoc
+url-grpc-api-javadoc=https://javadoc.io/doc/io.grpc/grpc-api/{version-grpc-api}
 url-kotlin-docs-kotlin-plugin={url-kotlin-docs}/using-gradle.html
 url-micrometer-docs-concepts={url-micrometer-docs}/concepts
 url-micrometer-docs-implementations={url-micrometer-docs}/implementations
@@ -82,6 +83,8 @@ url-jackson-databind-javadoc=https://javadoc.io/doc/tools.jackson.core/jackson-d
 url-jackson-dataformat-xml-javadoc=https://javadoc.io/doc/tools.jackson.dataformat/jackson-dataformat-xml/{version-jackson-dataformat-xml}
 url-jackson2-databind-javadoc=https://javadoc.io/doc/com.fasterxml.jackson.core/jackson-databind/{version-jackson2-databind}
 
+https://javadoc.io/doc/io.grpc/grpc-api/latest/io/grpc/package-summary.html
+
 # === Javadoc Locations ===
 
 javadoc-location-com-fasterxml-jackson-annotation={url-jackson-annotations-javadoc}
@@ -104,6 +107,7 @@ javadoc-location-org-springframework-data-rest={url-spring-data-rest-javadoc}
 javadoc-location-tools-jackson-core={url-jackson-core-javadoc}
 javadoc-location-tools-jackson-databind={url-jackson-databind-javadoc}
 javadoc-location-tools-jackson-dataformat-xml={url-jackson-dataformat-xml-javadoc}
+javadoc-location-io-grpc={url-grpc-api-javadoc}
 
 # === API References ===
 

buildSrc/src/test/java/org/springframework/boot/build/antora/AntoraAsciidocAttributesTests.java

@@ -286,6 +286,7 @@ private Map<String, String> mockDependencyVersions(String version) {
 		addMockJacksonCoreVersion(versions, "jackson-core", version);
 		addMockJacksonCoreVersion(versions, "jackson-databind", version);
 		addMockJacksonCoreVersion(versions, "jackson-databind", version);
+		versions.put("io.grpc:grpc-api", version);
 		versions.put("org.apache.pulsar:pulsar-client-api", version);
 		versions.put("tools.jackson.dataformat:jackson-dataformat-xml", version);
 		return versions;

documentation/spring-boot-docs/build.gradle

@@ -149,6 +149,8 @@ dependencies {
 	implementation("ch.qos.logback:logback-classic")
 	implementation("com.redis:testcontainers-redis")
 	implementation("com.zaxxer:HikariCP")
+	implementation("io.grpc:grpc-stub")
+	implementation("io.grpc:grpc-netty")
 	implementation("io.micrometer:micrometer-jakarta9")
 	implementation("io.micrometer:micrometer-tracing")
 	implementation("io.micrometer:micrometer-registry-graphite")