Jetty ssl factory using http2 doesn't work

Question

I have a simple spring boot project using jetty.

I run on port 443 and use http1.1 just fine

@Bean(name = "containerCustomizer")
public WebServerFactoryCustomizer containerCustomizer()
{
    return (container -> ((JettyServletWebServerFactory) container).addServerCustomizers(server -> {
        // HTTPS
        SslContextFactory.Server sslContextFactory = new SslContextFactory.Server();
        sslContextFactory.setKeyStoreResource(Resource.newResource(
                getClass().getClassLoader().getResource("keystore.jks")));
        sslContextFactory.setKeyStorePassword("password");
        sslContextFactory.setProtocol("TLS");
        sslContextFactory.setKeyStoreType("JKS");

        HttpConfiguration https = new HttpConfiguration();
        https.addCustomizer(new SecureRequestCustomizer());
        SslConnectionFactory sslFactory = new SslConnectionFactory(sslContextFactory,
                                                                   HttpVersion.HTTP_1_1.asString());
        ServerConnector sslConnector = new ServerConnector(server, sslFactory, new HttpConnectionFactory(https));
        sslConnector.setPort(443);
        server.setConnectors(new Connector[] {sslConnector});
    }));
}

However once I change to HTTP2 by replacing HttpVersion.HTTP_1_1.asString() with HttpVersion.HTTP_2.asString() then I get exception

Caused by: java.lang.IllegalStateException: No protocol factory for SSL next protocol: 'HTTP/2.0' in ServerConnector@61e45f87{SSL, (ssl, http/1.1)}{0.0.0.0:443}
    at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:317) ~[jetty-server-9.4.35.v20201120.jar:9.4.35.v20201120]
    at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:81) ~[jetty-server-9.4.35.v20201120.jar:9.4.35.v20201120]
    at org.eclipse.jetty.server.ServerConnector.doStart(ServerConnector.java:234) ~[jetty-server-9.4.35.v20201120.jar:9.4.35.v20201120]
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:73) ~[jetty-util-9.4.35.v20201120.jar:9.4.35.v20201120]
    at org.springframework.boot.web.embedded.jetty.JettyWebServer.start(JettyWebServer.java:174) ~[spring-boot-2.3.7.RELEASE.jar:2.3.7.RELEASE]
    ... 16 common frames omitted

Answer 1

Just changing the version string isn't sufficient.

You'll also need ...

• ALPNServerConnectionFactory - for processing the TLS layer (known as ALPN) that selects the HTTP/2 protocol
• HTTP2ServerConnectionFactory - for using HTTP/2 protocol

As seen in the embedded / Http2Server.java example

The key is that you will chain the connection types together, ALPN to HTTP2 to HTTPS.

// SSL Context Factory for HTTPS and HTTP/2
SslContextFactory sslContextFactory = new SslContextFactory.Server();
// configure sslContextFactory

// HTTPS Configuration
HttpConfiguration httpsConfig = new HttpConfiguration(httpConfig);
httpsConfig.addCustomizer(new SecureRequestCustomizer());

// HTTP/2 Connection Factory
HTTP2ServerConnectionFactory h2 = new HTTP2ServerConnectionFactory(httpsConfig);

ALPNServerConnectionFactory alpn = new ALPNServerConnectionFactory();
alpn.setDefaultProtocol(http.getDefaultProtocol());

// SSL Connection Factory
SslConnectionFactory ssl = new SslConnectionFactory(sslContextFactory, alpn.getProtocol());

// HTTP/2 Connector
ServerConnector http2Connector =
    new ServerConnector(server, ssl, alpn, h2, new HttpConnectionFactory(httpsConfig));
http2Connector.setPort(securePort);
server.addConnector(http2Connector);