HTTP/2 support

[Santiago Vitullo]

Hello dropwizard devs,

I'm trying to spin up a dropwizard instance that supports HTTP/2 and I'm not sure if my setup is right so I wanted to run it by you. 

Since I'm trying this in a dev environment, I'm trying to use HTTP/2 plain text as explained here: http://www.dropwizard.io/1.0.6/docs/manual/configuration.html#http-2-plain-text
And to make things easier I created a new project from scratch using dropwizard 1.0.6.

Here are the important details of the pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project
        xmlns="http://maven.apache.org/POM/4.0.0"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <prerequisites>
        <maven>3.0.0</maven>
    </prerequisites>

    <groupId>practice</groupId>
    <artifactId>dwtest</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>dw</name>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <dropwizard.version>1.0.6</dropwizard.version>
        <mainClass>practice.dwApplication</mainClass>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>io.dropwizard</groupId>
                <artifactId>dropwizard-bom</artifactId>
                <version>${dropwizard.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>io.dropwizard</groupId>
            <artifactId>dropwizard-core</artifactId>
        </dependency>
        <dependency>
            <groupId>io.dropwizard</groupId>
            <artifactId>dropwizard-http2</artifactId>
        </dependency>
    </dependencies>

    <!-- Note that more content goes here, but I decided to hide it for simplicity -->

</project>

Here's the yml file I use to start the application

logging:
  level: INFO
  loggers:
    practice: DEBUG

server:
  applicationConnectors:
    - type: h2c
      port: 8446
      maxConcurrentStreams: 1024
      initialStreamRecvWindow: 65535

The application class only registers a hello world resource

public static void main(final String[] args) throws Exception {
    new dwApplication().run(args);
}

@Override
public String getName() {
    return "dw";
}

@Override
public void initialize(final Bootstrap<dwConfiguration> bootstrap) {
    // TODO: application initialization
}

@Override
public void run(final dwConfiguration configuration,
                final Environment environment) {
    final HelloWorldResource resource = new HelloWorldResource();
    environment.jersey().register(resource);
}

And here's the resource.

@Path("/hello-world")
@Produces(MediaType.APPLICATION_JSON)
public class HelloWorldResource {
    private final AtomicLong counter;

    public HelloWorldResource() {
        this.counter = new AtomicLong();
    }

    @GET
    public String sayHello(@QueryParam("name") Optional<String> name) {
        return "dummy-test";
    }
}

I build the project with maven and I start the server by running: java -jar target/dwtest-1.0-SNAPSHOT.jar server config.yml

Now when I issue the following curl command: 

curl -I --http2 http://localhost:8446/hello-world

I get this in response:

HTTP/1.1 101 Switching Protocols

HTTP/2 200  

date: Tue, 07 Feb 2017 04:13:37 GMT

content-length: 10

content-type: application/json

And the logs of my dw instance display:

0:0:0:0:0:0:0:1 - - [07/Feb/2017:04:13:38 +0000] "HEAD /hello-world HTTP/1.1" 200 0 "-" "curl/7.52.1" 77

So the questions are:

1- Is the request handled as HTTP/2? I'm inclined to say no, based on the logs, but figured it is better to ask 

2- Is there any missing configuration in my setup?

3- Is the request I'm issuing to the server wrong?

Thanks in advance

[Jochen Schalanda]

Hi Santiago,

1- Is the request handled as HTTP/2? I'm inclined to say no, based on the logs, but figured it is better to ask 

Yes, see https://tools.ietf.org/html/rfc7540#section-3.2 for a description of the protocol upgrade from HTTP/1.1 to HTTP/2 in the same connection.

Cheers,

Jochen