AmitKumarDas / dropwizard-spring

Spring integration for Dropwizard

dropwizard-spring

dropwizard-spring provides a clean, easy way to integrate the spring framework with dropwizard-based web service projects.

With dropwizard-spring you configure your dropwizard components (resources, healthchecks, jersey providers, managed objects, etc.) entirely with spring, and tell the spring service which components to enable using a simple YAML configuration.

With dropwizard-spring it is not necessary to subclass com.yammer.dropwizard.Service, instead you reference the provided com.hmsonline.dropwizard.spring.SpringService class as your service class.

Maven Configuration

Maven Dependency

<dependency>
	<groupId>com.hmsonline</groupId>
	<artifactId>dropwizard-spring</artifactId>
	<version>0.1.0-SNAPSHOT</version>
</dependency>

Maven Shade Plugin Configuration

This is required to have maven build a "fat," executable jar file.

<plugin>
	<groupId>org.apache.maven.plugins</groupId>
	<artifactId>maven-shade-plugin</artifactId>
	<version>1.4</version>
	<configuration>
		<createDependencyReducedPom>true</createDependencyReducedPom>
		<filters>
			<filter>
				<artifact>*</artifact>
				<excludes>
					<exclude>META-INF/*.SF</exclude>
					<exclude>META-INF/*.RSA</exclude>
					<exclude>META-INF/*.INF</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>com.hmsonline.dropwizard.spring.SpringService</mainClass>
					</transformer>
					<transformer
						implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
						<resource>META-INF/spring.handlers</resource>
					</transformer>
					<transformer
						implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
						<resource>META-INF/spring.schemas</resource>
					</transformer>
				</transformers>
			</configuration>
		</execution>
	</executions>
</plugin>

Sample YAML Configuration

# dropwizard-spring sample service configuration

spring:
    # Spring Context Type (Required)
    # either "file" or "classpath"
    appContextType: file

    # Spring Config Locations (Required)
    # The location of one or more beans.xml files
    configLocations:
       - conf/dropwizard-beans.xml
   
    # JAX-RS Resources (Required if you want your service to do anything)
    # one or more spring beans that are JAX-RS resources
    resources:
       - myRestResourceBean
       - anotherRestResourceBean

    # DW Health Checks (Optional, but recommended)
    # list of health check beans (must extend com.yammer.metrics.core.HealthCheck)
    healthChecks:
       - myHealthCheckBean

    # Jersey Providers (Optional)
    # list of Jersey Provider beans (ExceptionMappers, etc.)
    jerseyProviders:
        - myExceptionMapper

    # DW Managed Objects (Optional)
    # one or more instance of com.yammer.dropwizard.lifecycle.Managed
    managed:
        - myManagedObjectBean

    # Jersey Life Cycles (Optional)
    # one or more life cycle instances
    lifeCycles:
        - myLifeCycleBean
    
    # DW Tasks (Optional)
    # one or more instance of com.yammer.dropwizard.tasks.Task
    tasks:
        - myDropwizardTaskBean
   

    # Enabled/Disabled Jersey Features (Optional)
    # list of Jersey features to enable/disable
    enabledJerseyFeatures:
        - com.sun.jersey.config.feature.CanonicalizeURIPath

    disabledJerseyFeatures:
       - com.sun.jersey.config.feature.DisableWADL

Accessing Dropwizard Configuration Values from Spring

In some cases it may be necessary for a spring-configured component to access values in the dropwizard configuration or the com.yammer.dropwizard.config.Environment instance. For example, referencing the port on which the service is configured to run.

To allow this, at startup the dropwizard-spring service injects a special "dropwizard" bean into the application context that contains both the dropwizard environment and configuration objects.

The spring beans.xml example below illustrates how to reference values from the dropwizard yaml configuration:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:util="http://www.springframework.org/schema/util"
	xmlns:jms="http://www.springframework.org/schema/jms" xmlns:amq="http://activemq.apache.org/schema/core"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/jms http://www.springframework.org/schema/jms/spring-jms.xsd
                           http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/activemq-core.xsd
                           http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.0.xsd">

	<bean id="helloResource" class="com.hmsonline.dropwizard.spring.sample.HelloResource">
		<property name="port">
		<util:property-path path="dropwizard.configuration.httpConfiguration.port"></util:property-path>
	</property>
	</bean>
</beans>