How to connect to JNDI bound datasource from WSO2 Data Services?

Data Services allow you to define a JDBC connection pool. But what if you already have a connection pool defined somewhere else & want to use it?

All you have to do is expose that pool (Datasource) as a JNDI resource. WSO2 Data Services allows you to connect to Datasources exposed as JNDI resources.

In the following example, I explain how  to create a Datasource on a Jboss-4.0.2 instance & connect to that from a data service. (I am going to use 'default' configuration of jboss-4.0.2, hence all the changes should be done inside jboss-4.0.2/server/default folder).

Step 1: Sample Database

For this example, I use the database created during Step 1 of 'How to RESTify your data with WSO2 Data Services?'.

Step 2: Creating Datasource in Jboss

Create a xml file (name - 'mysql-ds.xml') containing following & drop it to $JBOSS_HOME/server/default/deploy folder.

<?xml version="1.0" encoding="UTF-8"?>
<datasources>
  <local-tx-datasource>
    <use-java-context>false</use-java-context>
    <jndi-name>MySqlDS</jndi-name>
    <connection-url>jdbc:mysql://localhost:3306/DATASERVICE_SAMPLE</connection-url>
    <driver-class>com.mysql.jdbc.Driver</driver-class>
    <user-name>dsuser</user-name>
    <password>user123</password>
    <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>
    <metadata>
       <type-mapping>mySQL</type-mapping>
    </metadata>
  </local-tx-datasource>
</datasources>

More details on creating a Datasource on Jboss can be found here & here.

Step 3: MySql JDBC driver

Add MySQL JDBC driver to jboss-4.0.2's classpath. You can simply do this by dropping (mysql-connector-java-VERSION-bin.jar) to jboss-4.0.2/server/default/lib folder.

Step 4: Start jboss-4.0.2

execute

$JBOSS_HOME/bin/run.sh

During start up you will see a message similar to following, which tells you that Datasource is configured correctly.

06:03:24,802 INFO  [WrapperDataSourceService] Bound connection factory for resource 
adapter for ConnectionManager 'jboss.jca:service=DataSourceBinding,name=MySqlDS 
to JNDI name 'java:MySqlDS'

Step 5: Jboss JNP client libraries

WSO2 Data Services need to have Jboss's jnp client libraries within it's classpath. In order to do this, copy jboss-4.0.2/client/jbossall-client.jar to $wso2-dataservices-VERSION-home/lib/extensions.

Step 6: Sample Dataservice configuration file

Listed bellow is a sample Dataservice configuration file that connects to the Jboss Datasource we defined in previous steps. As you can see, following properties are being used to create the bridge between Jboss & WSO2 Data Services.

<property name="jndi_context_class">org.jnp.interfaces.NamingContextFactory</property>
<property name="jndi_provider_url">jnp://localhost:1099</property>
<property name="jndi_resource_name">MySqlDS</property>

Note : 1099 is the default jnp port of jboss. If you have changed this, use the new one.

<data name="TestJNDI">
    <config id="conA">
        <property name="jndi_context_class">org.jnp.interfaces.NamingContextFactory</property>
        <property name="jndi_provider_url">jnp://localhost:1099</property>
        <property name="jndi_resource_name">MySqlDS</property>
        <property name="jndi_username"/>
        <property name="jndi_password"/>
    </config>
    <query id="query1" useConfig="conA">
        <sql>select productCode,buyPrice from Products</sql>
        <result element="Products" rowName="Product">
            <element name="Code" column="productCode"/>
            <element name="Price" column="buyPrice"/>
        </result>
    </query>
    <operation name="operation1">
        <call-query href="query1"/>
    </operation>
</data>