Configure the CData JDBC Driver for Linear in a Connection Pool in Tomcat

The CData JDBC Drivers support standard JDBC interfaces to integrate with Web applications running on the JVM. This article details how to connect to Linear data from a connection pool in Tomcat.

Connect to Linear Data through a Connection Pool in Tomcat

1. Copy the CData JAR and CData .lic file to $CATALINA_HOME/lib. The CData JAR is located in the lib subfolder of the installation directory.
2. Add a definition of the resource to the context. Specify the JDBC URL here.

   You can authenticate to Linear with a personal API key or with OAuth 2.0. The API key is the simplest option for connecting with your own Linear account.

   Authenticating with an API Key

   Set the following connection properties:

   • AuthScheme: Set this to APIKey.
   • APIKey: A Linear personal API key.

   To create a personal API key, log in to Linear, open Settings > Security & access > Personal API keys, select New API key, and create it. Copy the key immediately, because Linear shows it only once.

   Authenticating with OAuth

   OAuth requires a custom OAuth application registered in Linear (Settings > API > OAuth applications), which provides the OAuthClientId and OAuthClientSecret. Two flows are supported:

   • Authorization code: Set AuthScheme to OAuth, InitiateOAuth to GETANDREFRESH, and provide OAuthClientId, OAuthClientSecret, and the CallbackURL defined in your application (e.g., http://localhost:33333). The driver opens Linear in your browser so you can grant access.
   • Client credentials: Set AuthScheme to OAuthClient and provide OAuthClientId and OAuthClientSecret. This authenticates the application itself, with no browser interaction, and suits machine-to-machine integrations.

   By default, the driver requests the read,write scopes. The driver refreshes the access token automatically when it expires.

   Built-in Connection String Designer

   For assistance in constructing the JDBC URL, use the connection string designer built into the Linear JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

   
   java -jar cdata.jdbc.linear.jar
   

   Fill in the connection properties and copy the connection string to the clipboard.

   

   You can see the JDBC URL specified in the resource definition below.

   
   
   <Resource name="jdbc/linear"   auth="Container" type="javax.sql.DataSource" driverClassName="cdata.jdbc.linear.LinearDriver" factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" url="jdbc:linear:AuthScheme=APIKey;APIKey=myAPIKey;" maxActive="20" maxIdle="10" maxWait="-1" />
   

   To allow a single application to access Linear data, add the code above to the context.xml in the application's META-INF directory.

   For a shared resource configuration, add the code above to the context.xml located in $CATALINA_BASE/conf. A shared resource configuration provides connectivity to Linear for all applications.

3. Add a reference to the resource to the web.xml for the application.

   
   
     Linear data JSP
     jdbc/Linear
     javax.sql.DataSource
     Container
   
   

4. Initialize connections from the connection pool:

   
   Context initContext = new InitialContext();
   Context envContext  = (Context)initContext.lookup("java:/comp/env");
   DataSource ds = (DataSource)envContext.lookup("jdbc/Linear");
   Connection conn = ds.getConnection();
     

More Tomcat Integration

The steps above show how to connect to Linear data in a simple connection pooling scenario. For more use cases and information, see the JNDI Datasource How-To in the Tomcat documentation.