Distroless GraalVM Dropwizard

README.md

This is meant to be a tester for running compiling Dropwizard to a native app using GraalVM and then deploying it using docker and Google's Distroless containers. This means that our application startup time should be orders of magnitude faster and our application size (and attack/scan surface area) should be as small as is possible by todays standards.

Another way to make this smaller again is by running docker on top of alpine linux. This is probably as tiny as you can go.

NOTE:

• reflect.yml will need to be added to as docker has dependencies that use reflection heavily. This will depend on your use case but something to be wary of (in other words dont try this with Spring :P ). reflect.yml needs to be in a folder in src/main/docker/
• This is a work in progress. IT MAY NOT WORK (still in testing)

DemoApplication.java

package com.jdrew1303.tinywizard;

import io.dropwizard.Application;
import io.dropwizard.setup.Environment;

public class DemoApplication extends Application<DemoConfiguration> {
    public static void main(String[] args) throws Exception {
        new DemoApplication().run(args);
    }

    @Override
    public void run(DemoConfiguration config, Environment env) throws Exception {
        ExampleApi api = new ExampleApi();
        environment.jersey().register(api);
    }
}

DemoConfiguration.java

package com.jdrew1303.tinywizard;

import io.dropwizard.Configuration;

public class DemoConfiguration extends Configuration {
}

Dockerfile

FROM maven:3.6.0-jdk-8-alpine as builder
COPY  . /root/app/
WORKDIR /root/app
RUN mvn dependency:resolve
RUN mvn install

FROM oracle/graalvm-ce:1.0.0-rc14 as graalvm
COPY --from=builder /root/app/ /home/app/
WORKDIR /home/app
RUN native-image --no-server \
                 --class-path target/hello-world.jar \
                 -H:EnableURLProtocols=http \
                 -H:Name=hello-world \
                 -H:Class=com.jdrew1303.tinywizard.DemoApplication \
                 --allow-incomplete-classpath

# this is a special container for graalvm containing zlib, glibc, 
# libssl and openssl. these are used quite a bit by java applications
# (and graal applications).
FROM FROM cescoffier/native-base:latest
EXPOSE 8080
COPY --from=graalvm /application
ENTRYPOINT ["./application"]

ExampleApi.java

package com.jdrew1303.tinywizard;

import com.codahale.metrics.annotation.Timed;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

@Path("/")
@Produces(MediaType.TEXT_PLAIN)
public class ExampleApi {

    @GET
    @Timed
    public String hello() {
        return "Boom! It's a tiny wizard app! :) ";
    }

}

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/xsd/maven-4.0.0.xsd">
    
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.jdrew1303</groupId>
    <artifactId>dropwizard-graalvm-native-distroless</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <dropwizard.version>1.3.12</dropwizard.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>io.dropwizard</groupId>
            <artifactId>dropwizard-core</artifactId>
            <version>${dropwizard.version}</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>hello-world</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.2.1</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>com.jdrew1303.tinywizard.DemoApplication</mainClass>
                                </transformer>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

reflect.json

[
  {
    "name" : "io.dropwizard.jetty.ConnectorFactory",
    "allDeclaredConstructors" : true
  }
]