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TOTD #9: Using JDBC connection pool/JNDI name from GlassFish in Rails Application

Using the instructions followed in JRuby Hack Day and taking some help from Nick, I figured out how to use the JDBC connection pools configured in GlassFish using the JNDI names.

All the commands given below are relevant for GlassFish but the same concept will work where ever you deploy your WARed up JRuby on Rails application.

1. Follow the bullet #1 and #2 from here to create a new application and database with the following exceptions:
   1. Use the name "jndi_rails" instead of "RailsApplication9" for the Project Name.
   2. Make sure to select "Access database using JDBC" in bullet # 2.2. This will bundle ActionRecord-JDBC plugin in your application.
2. Create database using bullet # 3 from here. Use the following command instead to create the database instead:
   
   mysqladmin -u root create jndi_rails_production
3. Create Model and Controller as described in bullet #4 here.
4. Configure Model and Controller
   1. Configure Model
      1. In the NetBeans IDE, expand "Database Configurations", "migrate" and open "001_create_greetings.rb". Change the "self.up" helper method such that it looks like:
         
         def self.up
  create_table :greetings do |t|
    t.column :data, :string
  end
end
      2. Expand "Configuration", open "database.yml", change the database name for development configuration from "jndi_rails_development" to "jndi_rails_production".
      3. Right-select the project, select 'Run Rake Target', 'db', 'migrate'. This generates the appropriate database tables and the following is shown in the output window:
         
         (in C:/Users/Arun Gupta/Documents/NetBeansProjects/jndi_rails)
== CreateGreetings: migrating =================================================
-- create_table(:greetings)
-> 0.2650s
== CreateGreetings: migrated (0.2650s) ========================================
      4. Add data to the database tables and give appropriate privileges using the following commands in a shell window:
         
         C:\Program Files\MySQL\MySQL Server 5.0\bin>mysql -u root
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 14
Server version: 5.0.45-community-nt MySQL Community Edition (GPL)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> use jndi_rails_production;
Database changed
mysql> insert into greetings values (1, "Hello from MySQL JNDI pool!");
Query OK, 1 row affected (0.03 sec)

mysql> grant all on jndi_rails_production.* to arun@localhost identified by 'noway';
Query OK, 0 rows affected (0.26 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.16 sec)

mysql> quit;
Bye
      5. Change the production database environment from:
         
         production:
  adapter: mysql
  database: jndi_rails_production
  username: root
  password:
  host: localhost
         
         to
         
         production:
  adapter: jdbc
  jndi: jdbc/jndi_rails
  driver: com.mysql.jdbc.Driver

Notice only JDBC adpater and JNDI name is specified in the database configuration. This ensures that the database is resolved using only the JNDI name. Although "database", "username" and "password" attributes may be specified in addition to "jndi" and "driver" attributes. In this case, the Rails configuration falls back to pure-Ruby MySQL adapter.
   2. Configure Controller using bullet # 5.2 from here.
5. Create the JDBC connection pool and resource
   1. In GLASSFISH_HOME\bin, create the JDBC connection pool by giving the following command:
      
      asadmin create-jdbc-connection-pool --datasourceclassname com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource --restype javax.sql.DataSource --property User=arun:Password=noway:URL=jdbc\:mysql\://localhost/jndi_rails_production jdbc/jndi_rails_pool
      
      The following output should be seen on the console:
      
      Command create-jdbc-connection-pool executed successfully.
   2. Create the JDBC resource by giving the following command:
      
      asadmin create-jdbc-resource --connectionpoolid jdbc/jndi_rails_pool jdbc/jndi_rails
      
      The following output should be seen on the console:
      
      Command create-jdbc-resource executed successfully.
6. Create a WAR file as described in bullet #6 here
7. Download, Install and Start GlassFish as described in bullet #7 here.
8. Download and Install MySQL/J Connector in a new directory. Copy the JAR file from the main installation directory to 'GLASSFISH_HOME/lib' directory.
9. Copy the WAR file (jndi_rails.war) in "domains/domain/autodeploy" directory.

The application is accessible at "http://localhost:8080/jndi_rails/say/hello".

An alternative approach to use the connection pools is discussed here. Lou also nicely describes the benefits of connection pooling.

Connecting to Oracle From Rails explains how to connect to Oracle (instead of JavaDB) with JRuby.

Please leave suggestions on other TOTD that you'd like to see. A complete archive is available here.

Technorati: totd rubyonrails jruby ruby netbeans glassfish connectionpooling jndi jdbc jrubyonglassfish mysql

Posted by Arun Gupta in web2.0  |  Comments[9]