Creating REST service using spring-data-cassandra and spring-data-rest-webmvc

[Jega A]

I am working on a POC -- creating a REST service to perform basic CRUD operations into Cassandra.

I am using spring-data-cassandra and spring-data-rest-web-mvc

I have created three Java files 

Contract.java -> Entity description of the Cassandra column family (Table)

ContractRepository.java -> Repository information

Application.java -> Contains the main

I am trying to follow some of the samples outlined in String Data website. Specifically the tutorials that show how to use REST/MongoDB  (http://spring.io/guides/gs/accessing-mongodb-data-rest/) 

Since there are no specific tutorial for Cassandra (as yet) I am trying to replicate the MongoDb description with Cassandra.  

I am trying to run the application without any configuration files and also using spring-boot -- similar to how the tutorials are done with Mongo.

I am using maven to do the compile/build and run. I am starting the run using "mvn spring-boot:run".

I am getting a run time exception while trying to run this.

The key error is the following:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'contractRepository': Cannot resolve reference to bean 'cassandraTemplate' while setting bean property 'cassandraTemplate'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'cassandraTemplate' defined in class cass_test3.Application: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: [Assertion failed] - this argument is required; it must not be null

The cassandraTemplate bean is not being created!

Here is the code 

Application.java

package cass_test3;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.EnableAutoConfiguration;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.Import;

import org.springframework.data.cassandra.repository.config.EnableCassandraRepositories;

import org.springframework.data.rest.webmvc.config.RepositoryRestMvcConfiguration;

@Configuration

@EnableCassandraRepositories

@Import(RepositoryRestMvcConfiguration.class)

@EnableAutoConfiguration

public class Application{

    public static void main(String[] args) {

        SpringApplication.run(Application.class, args);

    }

}

Contract.java 

package cass_test3;

import org.springframework.data.cassandra.mapping.PrimaryKey;

import org.springframework.data.cassandra.mapping.Column;

import org.springframework.data.cassandra.mapping.Table;

@Table(value="contracts")

public class Contract {

@PrimaryKey(value="id")

@Column(value="id")

private String id;

public String getId() {

return id;

}

public void setId(String id) {

this.id = id;

}

}

ContractRepository.java

package cass_test3;

import org.springframework.data.cassandra.repository.CassandraRepository;

import org.springframework.data.repository.query.Param;

import org.springframework.data.rest.core.annotation.RepositoryRestResource;

@RepositoryRestResource(collectionResourceRel = "contract", path = "contract")

public interface ContractRepository extends CassandraRepository<Contract> {

Contract findById(@Param("id") String id);

}

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>cass-test3</groupId>

<artifactId>cass-test3</artifactId>

<version>1.0-SNAPSHOT</version>

<parent>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>1.0.2.RELEASE</version>

</parent>

<repositories>

<repository>

<id>spring-libs-snapshot</id>

<url>http://repo.spring.io/libs-snapshot</url>

<snapshots>

<enabled>true</enabled>

</snapshots>

</repository>

<repository>

<id>spring-milestones</id>

<url>http://repo.spring.io/libs-snapshot</url>

<snapshots>

<enabled>true</enabled>

</snapshots>

</repository>

</repositories>

<dependencies>

<dependency>

<groupId>org.springframework.data</groupId>

<artifactId>spring-data-rest-webmvc</artifactId>

<version>2.1.0.RC1</version>

</dependency>

<dependency>

<groupId>org.springframework.data</groupId>

<artifactId>spring-data-cassandra</artifactId>

<version>1.0.0.RC1</version>

</dependency>

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

</dependency>

<dependency>

<groupId>org.springframework.data</groupId>

<artifactId>spring-data-solr</artifactId>

<version>1.1.0.RELEASE</version>

</dependency>

</dependencies>

</project>

I understand that a default cassandraTemplate bean should be created at run time using the standard defaults for the connection to ContractRepository.

Somehow that is not being created. Do I need to explicitly initialize the cassandraTemplate? If so how do I do it?

Thanks

Jega

[Matthew Adams]

I'd say that you at minimum need to configure a Cassandra Cluster, then a Session to give to the CassandraTemplate.  See org.springframework.data.cassandra.config.java.AbstractCassandraConfiguration for details.

I'm sorry to say that I'm not too familiar with Spring Boot yet.  If you find that we could automatically create a Cluster & Session with reasonable defaults (localhost, 9042) for use with Spring Boot, please enter an issue for that.

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[Jega A]

Thanks for your tip. I was able to get the code running by adding some initialization for the CassandraTemplate.

I think it would be nice to have a default implementation that uses localhost:9042 (similar to the spring-data-mongo and other implementations).

===============

Modified Application.java

public class Application extends AbstractCassandraConfiguration{

private static final String KEYSPACE_NAME = "contracts_ks";

private static final String CONTACT_POINTS = "192.168.72.100";

private static final int PORT = 9042;

private static final int MAX_POOL_CONNECTION = 50;

@Override

protected String getKeyspaceName() {

return KEYSPACE_NAME;

}

@Override

protected String getContactPoints() {

return CONTACT_POINTS;

}

@Override

protected int getPort() {

return PORT;

}

@Bean(name="casops")

public CassandraOperations operations() throws Exception {

return new CassandraTemplate(session().getObject(), new MappingCassandraConverter(new BasicCassandraMappingContext()));

--
Jega

[Matthew Adams]

Glad to hear!  Please enter an issue for us to track this.