Changes to dropwizard-service-utils to make it a Dropwizard App for testing FreePortFinder implementations

App.java

package org.kiwiproject.dropwizard.util;

import lombok.extern.slf4j.Slf4j;

import org.kiwiproject.dropwizard.util.bundle.DynamicPortsBundle;
import org.kiwiproject.dropwizard.util.bundle.DynamicPortsConfiguration;
import org.kiwiproject.dropwizard.util.server.DropwizardConnectors;

import java.util.Map;
import java.time.Instant;

import io.dropwizard.core.Application;
import io.dropwizard.core.setup.Bootstrap;
import io.dropwizard.core.setup.Environment;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;
import jakarta.ws.rs.core.Response;

@Slf4j
public class App extends Application<AppConfig> {

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

    @Override
    public void initialize(Bootstrap<AppConfig> bootstrap) {
        var portsBundle = new DynamicPortsBundle<AppConfig>() {
            @Override
            public DynamicPortsConfiguration getDynamicPortsConfiguration(AppConfig configuration) {
                return configuration.getDynamicPorts();
            }
        };
        bootstrap.addBundle(portsBundle);
    }

    @Override
    public void run(AppConfig configuration, Environment environment) throws Exception {
        var applicationPorts = DropwizardConnectors.getApplicationPorts(configuration);
        var adminPorts = DropwizardConnectors.getAdminPorts(configuration);

        LOG.info("Application ports:");
        applicationPorts.forEach(port -> LOG.info("\t{}", port));

        LOG.info("Admin ports:");
        adminPorts.forEach(port -> LOG.info("\t{}", port));

        environment.jersey().register(new HelloResource());
    }

    @Path("/hello")
    @Produces(MediaType.APPLICATION_JSON)
    public static class HelloResource {
        @GET
        public Response sayHelloAndTime() {
            var entity = Map.of(
                "greeting", "Good morning",
                "time", Instant.now().toString()
            );
            return Response.ok(entity).build();
        }
    }
}

AppConfig.java

package org.kiwiproject.dropwizard.util;

import com.fasterxml.jackson.annotation.JsonProperty;

import lombok.Getter;
import lombok.Setter;

import org.kiwiproject.dropwizard.util.bundle.DynamicPortsConfiguration;

import io.dropwizard.core.Configuration;
import jakarta.validation.Valid;
import jakarta.validation.constraints.NotNull;

@Getter
@Setter
public class AppConfig extends Configuration {

    @NotNull
    @Valid
    @JsonProperty("dynamicPorts")
    private DynamicPortsConfiguration dynamicPorts;
}

config-adjacent.yml

---

dynamicPorts:
  minDynamicPort: 15000
  maxDynamicPort: 15100
  freePortFinder:
    type: adjacent
  useSecureDynamicPorts: false

logging:
  level: INFO
  loggers:
    org.kiwiproject.dropwizard.util.startup: TRACE
  appenders:
    - type: console

config-incrementing.yml

---

dynamicPorts:
  minDynamicPort: 15000
  maxDynamicPort: 15100
  freePortFinder:
    type: incrementing
  useSecureDynamicPorts: false

config-random.yml

---

dynamicPorts:
  minDynamicPort: 15000
  maxDynamicPort: 15100
  freePortFinder:
    type: random
  useSecureDynamicPorts: false

pom.xml

<!-- These are the CHANGES to make -->

<!-- 1. Change logback-classic to a required dependency by commenting out the test scope -->

<!-- 2. Add Maven Shade plugin -->

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.6.0</version>
                <configuration>
                    <createDependencyReducedPom>true</createDependencyReducedPom>
                    <filters>
                        <filter>
                            <artifact>*:*</artifact>
                            <excludes>
                                <exclude>META-INF/*.SF</exclude>
                                <exclude>META-INF/*.DSA</exclude>
                                <exclude>META-INF/*.RSA</exclude>
                            </excludes>
                        </filter>
                    </filters>
                </configuration>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer" />
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>org.kiwiproject.dropwizard.util.App</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

Steps to run the apps:

1. Build: mvn package -DskipTests
2. Make sure netcat (nc) is installed
3. In a terminal (tab), run: nc -l -p 15001
4. In a terminal (tab), run: nc -l -p 15003
5. In a terminal (tab), run: java -jar target/dropwizard-service-utilities-x.y.z-SNAPSHOT.jar server config-adjacent.yml (adjust x.y.z as necessary)
6. In a terminal (tab), run: java -jar target/dropwizard-service-utilities-x.y.z-SNAPSHOT.jar server config-incrementing.yml (adjust x.y.z as necessary)
7. In a terminal (tab), run: java -jar target/dropwizard-service-utilities-x.y.z-SNAPSHOT.jar server config-random.yml (adjust x.y.z as necessary)

The nc commands open a "server" listening on ports 15001 and 15003, which will not allow the adjacent port finder to use ports 15000 through 15003. So, the first (adjacent) app will take ports 15004 and 15005. The second (incrementing) app will use ports 15000 and 15002, since it is not limited to adjacent ports. And the third (random) app will search for two open ports at random between 15000 and 15100.