HTTP/3 support

gradle/libs.versions.toml

@@ -67,6 +67,7 @@ managed-jackson-databind = "2.14.1"
 managed-maven-native-plugin = "0.9.13"
 managed-methvin-directory-watcher = "0.16.1"
 managed-netty = "4.1.87.Final"
+managed-netty-http3 = "0.0.16.Final"
 managed-reactive-streams = "1.0.4"
 # This should be kept aligned with https://github.com/micronaut-projects/micronaut-reactor/blob/master/gradle.properties from the BOM
 managed-reactor = "3.4.24"
@@ -115,6 +116,7 @@ managed-methvin-directoryWatcher = { module = "io.methvin:directory-watcher", ve
 managed-netty-buffer = { module = "io.netty:netty-buffer", version.ref = "managed-netty" }
 managed-netty-codec-http = { module = "io.netty:netty-codec-http", version.ref = "managed-netty" }
 managed-netty-codec-http2 = { module = "io.netty:netty-codec-http2", version.ref = "managed-netty" }
+managed-netty-incubator-codec-http3 = { module = "io.netty.incubator:netty-incubator-codec-http3", version.ref = "managed-netty-http3" }
 managed-netty-handler = { module = "io.netty:netty-handler", version.ref = "managed-netty" }
 managed-netty-handler-proxy = { module = "io.netty:netty-handler-proxy", version.ref = "managed-netty" }
 managed-netty-transport-native-epoll = { module = "io.netty:netty-transport-native-epoll", version.ref = "managed-netty" }

http-client-core/src/main/java/io/micronaut/http/client/HttpVersionSelection.java

@@ -40,6 +40,11 @@ public final class HttpVersionSelection {
      * ALPN protocol ID for HTTP/2.
      */
     public static final String ALPN_HTTP_2 = "h2";
+    /**
+     * ALPN protocol ID for HTTP/3. When this is selected, it must be the only ALPN ID, since we
+     * will connect via UDP.
+     */
+    public static final String ALPN_HTTP_3 = "h3";
 
     private static final HttpVersionSelection LEGACY_1 = new HttpVersionSelection(
         PlaintextMode.HTTP_1,
@@ -59,12 +64,17 @@ public final class HttpVersionSelection {
     private final boolean alpn;
     private final String[] alpnSupportedProtocols;
     private final boolean http2CipherSuites;
+    private final boolean http3;
 
     private HttpVersionSelection(@NonNull PlaintextMode plaintextMode, boolean alpn, @NonNull String[] alpnSupportedProtocols, boolean http2CipherSuites) {
         this.plaintextMode = plaintextMode;
         this.alpn = alpn;
         this.alpnSupportedProtocols = alpnSupportedProtocols;
         this.http2CipherSuites = http2CipherSuites;
+        this.http3 = Arrays.asList(alpnSupportedProtocols).contains(ALPN_HTTP_3);
+        if (http3 && alpnSupportedProtocols.length != 1) {
+            throw new IllegalArgumentException("When using HTTP 3, h3 must be the only ALPN protocol");
+        }
     }
 
     /**
@@ -181,6 +191,11 @@ public boolean isHttp2CipherSuites() {
         return http2CipherSuites;
     }
 
+    @Internal
+    public boolean isHttp3() {
+        return http3;
+    }
+
     /**
      * The connection mode to use for plaintext (non-TLS) connections.
      */

http-client-jdk/src/main/java/io/micronaut/http/client/jdk/AbstractJdkHttpClient.java

@@ -53,6 +53,8 @@
 import java.net.URISyntaxException;
 import java.net.http.HttpClient;
 import java.net.http.HttpRequest;
+import java.util.Arrays;
+import java.util.List;
 import java.util.Optional;
 
 import static io.micronaut.http.client.exceptions.HttpClientExceptionUtils.populateServiceId;
@@ -69,6 +71,8 @@
 abstract class AbstractJdkHttpClient {
 
     public static final String H2C_ERROR_MESSAGE = "H2C is not supported by the JDK HTTP client";
+    public static final String H3_ERROR_MESSAGE = "HTTP/3 is not supported by the JDK HTTP client";
+    public static final String WEIRD_ALPN_ERROR_MESSAGE = "The only supported ALPN modes are [" + HttpVersionSelection.ALPN_HTTP_1 + "] or [" + HttpVersionSelection.ALPN_HTTP_1 + "," + HttpVersionSelection.ALPN_HTTP_2 + "]";
 
     protected final LoadBalancer loadBalancer;
     protected final HttpVersionSelection httpVersion;
@@ -142,9 +146,22 @@ protected AbstractJdkHttpClient(
         if (httpVersionSelection.getPlaintextMode() == HttpVersionSelection.PlaintextMode.H2C) {
             throw new ConfigurationException(H2C_ERROR_MESSAGE);
         }
+        if (httpVersionSelection.isHttp3()) {
+            throw new ConfigurationException(H3_ERROR_MESSAGE);
+        }
 
-        if (httpVersionSelection.isAlpn() && httpVersionSelection.isHttp2CipherSuites()) {
-            builder.version(HttpClient.Version.HTTP_2);
+        if (httpVersionSelection.isAlpn()) {
+            List<String> supportedProtocols = Arrays.asList(httpVersionSelection.getAlpnSupportedProtocols());
+            if (supportedProtocols.size() == 2 &&
+                supportedProtocols.contains(HttpVersionSelection.ALPN_HTTP_1) &&
+                supportedProtocols.contains(HttpVersionSelection.ALPN_HTTP_2)) {
+                builder.version(HttpClient.Version.HTTP_2);
+            } else if (supportedProtocols.size() == 1 &&
+                supportedProtocols.get(0).equals(HttpVersionSelection.ALPN_HTTP_1)) {
+                builder.version(HttpClient.Version.HTTP_1_1);
+            } else {
+                throw new ConfigurationException(WEIRD_ALPN_ERROR_MESSAGE);
+            }
         } else {
             builder.version(HttpClient.Version.HTTP_1_1);
         }

http-client-jdk/src/test/groovy/io/micronaut/http/client/jdk/H2CSpec.groovy

@@ -25,4 +25,40 @@ class H2CSpec extends Specification {
         cleanup:
         ctx.close()
     }
+
+    def "h3 is not supported"() {
+        given:
+        def ctx = ApplicationContext.run(
+                'micronaut.http.client.alpn-modes': ['h3']
+        )
+
+        when:
+        ctx.getBean(HttpClient)
+
+        then:
+        def ex = thrown(BeanInstantiationException)
+        ex.cause instanceof ConfigurationException
+        ex.cause.message == AbstractJdkHttpClient.H3_ERROR_MESSAGE
+
+        cleanup:
+        ctx.close()
+    }
+
+    def "http2-only is not supported"() {
+        given:
+        def ctx = ApplicationContext.run(
+                'micronaut.http.client.alpn-modes': ['h2']
+        )
+
+        when:
+        ctx.getBean(HttpClient)
+
+        then:
+        def ex = thrown(BeanInstantiationException)
+        ex.cause instanceof ConfigurationException
+        ex.cause.message == AbstractJdkHttpClient.WEIRD_ALPN_ERROR_MESSAGE
+
+        cleanup:
+        ctx.close()
+    }
 }

http-client/build.gradle

@@ -17,6 +17,8 @@ dependencies {
     api project(":http-netty")
     api libs.managed.netty.handler.proxy
 
+    compileOnly libs.managed.netty.incubator.codec.http3
+
     testAnnotationProcessor platform(libs.test.boms.micronaut.validation)
     testAnnotationProcessor (libs.micronaut.validation.processor) {
         exclude group: 'io.micronaut'