Integrate with Linear Data using Apache Camel2

Apache Camel is an open source integration framework that allows you to integrate various systems consuming or producing data. When paired with the CData JDBC Driver for Linear, you can write Java apps that use Camel routes that integrate with live Linear data. This article explains how to create an app in NetBeans that connects, queries, and routes Linear data to a JSON file.

With built-in optimized data processing, the CData JDBC Driver offers unmatched performance for interacting with live Linear data. When you issue complex SQL queries to Linear, the driver pushes supported SQL operations, like filters and aggregations, directly to Linear and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations). Its built-in dynamic metadata querying allows you to work with and analyze Linear data using native data types.

Creating A New Maven/Java Project

Follow the steps below to create a new Java project and add the appropriate dependencies:

1. Open NetBeans and create a new project.
2. Select Maven from the categories list and Java Application from the projects list, then click Next.
3. Name the project (and adjust any other properties) and click Finish.
4. In the source package, create a new Java class (we used App.java for this article) and add the main method to the class.

Adding Project Dependencies

With the project created, we can start adding the dependencies needed to work with live Linear data from our App. If you have not already done so, install Maven in your environment, as it is required to add the JAR file for the CData JDBC Driver to your project.

Installing the CData JDBC Driver for Linear with Maven

1. Download the CData JDBC Driver for Linear installer, unzip the package, and run the JAR file to install the driver.
2. Use Maven to install the JDBC Driver as a connector.

   mvn install:install-file 
   	-Dfile="C:\Program Files\CData\CData JDBC Driver for Linear 2019\lib\cdata.jdbc.linear.jar" 
   	-DgroupId="org.cdata.connectors" 
   	-DartifactId="cdata-linear-connector" 
   	-Dversion="19" 
   	-Dpackaging=jar
   

Once the JDBC Driver is installed, we can add dependencies to our project. To add a dependency, you can either edit the pom.xml file or right-click the dependencies folder and click Add Dependency. The properties for each dependency follow, but you can search through the available libraries by typing the name of the dependency in the Query box in the Add Dependency wizard.

Required Dependencies

Accessing Linear Data in Java Apps with Camel

After adding the required dependencies, we can use the Java DSL (Domain Specific Language) to create routes with access to live Linear data. Code snippets follow. Download the sample project (zip file) to follow along (make note of the TODO comments).

Start by importing the necessary classes into our main class.

import org.apache.camel.CamelContext;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.impl.DefaultCamelContext;
import org.apache.camel.support.SimpleRegistry;
import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.log4j.BasicConfigurator;

Then in the main method, we configure logging, create a new BasicDataSource and add it to the registry, create a new CamelContext, and finally add a route to the context. In this sample, we route Linear data to a JSON file.

Configure Logging

BasicConfigurator.configure();

Create a BasicDataSource

Create a BasicDataSource and set the driver class name (cdata.jdbc.salesforce.SalesforceDriver) and URL (using the required connection properties).

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.

BasicDataSource basic = new BasicDataSource();
basic.setDriverClassName("cdata.jdbc.linear.LinearDriver");
basic.setUrl("jdbc:linear:AuthScheme=APIKey;APIKey=myAPIKey;");

The CData JDBC Driver includes a built-in connection string designer to help you configure the connection URL.

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.

Add the BasicDataSource to the Registry and Create a CamelContext

SimpleRegistry reg = new SimpleRegistry();
reg.bind("myDataSource", basic);

CamelContext context = new DefaultCamelContext(reg);

Add Routing to the CamelContext

The routing below uses a timer component to run one time and passes a SQL query to the JDBC Driver. The results are marshaled as JSON (and formatted for pretty print) and passed to a file component to write to disk as a JSON file.

context.addRoutes(new RouteBuilder() {
	@Override
	public void configure() {
		from("timer://foo?repeatCount=1")
			.setBody(constant("SELECT * FROM Account LIMIT 10"))
			.to("jdbc:myDataSource")
			.marshal().json(true)
			.to("file:C:\\Users\\USER\\Documents?fileName=account.json");
	}
});

Managing the CamelContext Lifecycle

With the route defined, start the CamelContext to begin the lifecycle. In this example, we wait 10 seconds and then shut down the context.

context.start();
Thread.sleep(10000);
context.stop();

Free Trial, Sample Project & Technical Support

Now, you have a working Java application that uses Camel to route data from Linear to a JSON file. Download a free, 30-day trial of the CData JDBC Driver for Linear and the sample project (make note of the TODO comments) and start working with your live Linear data in Apache Camel. Reach out to our Support Team if you have any questions.