How to connect to Linear Data from Spring Boot

Spring Boot is a framework that makes engineering Java web applications easier. It offers the ability to create standalone applications with minimal configuration. When paired with the CData JDBC driver for Linear, Spring Boot can work with live Linear data. This article shows how to configure data sources and retrieve data in your Java Spring Boot Application, using the CData JDBC Driver for Linear.

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 the Spring Boot Project in Java

In an IDE (in this tutorial, we use IntelliJ), choose a Maven project: In the generated project, go to the pom.xml file, and add the required dependencies for Spring Boot:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.7.2</version>
<relativePath/>
</parent>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<build>
<plugins>
	<plugin>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-maven-plugin</artifactId>
	</plugin>

	<plugin>
		<groupId>org.apache.maven.plugins</groupId>
		<artifactId>maven-install-plugin</artifactId>
		<version>2.5.1</version>
		<executions>
			<execution>
				<id>id.install-file</id>
				<phase>clean</phase>
				<goals>
					<goal>install-file</goal>
				</goals>
				<configuration>
					<file>C:\Program Files\CData\CData JDBC Driver for Linear ####\lib\cdata.jdbc.linear.jar</file>
					<groupId>org.cdata.connectors</groupId>
					<artifactId>cdata-linear-connector</artifactId>
					<version>23</version>
					<packaging>jar</packaging>
				</configuration>
			</execution>
		</executions>
	</plugin>
</plugins>
</build>

<dependencies>
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-jdbc</artifactId>
	<version>2.7.0</version>
</dependency>
<dependency>
	<groupId>org.cdata.connectors</groupId>
	<artifactId>cdata-linear-connector</artifactId>
	<version>23</version>
</dependency>

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-test</artifactId>
	<scope>test</scope>
</dependency>
</dependencies>



<distributionManagement>
<repository>
	<uniqueVersion>false</uniqueVersion>
	<id>test</id>
	<name>My Repository</name>
	<url>scp://repo/maven2</url>
	<layout>default</layout>
</repository>
</distributionManagement>

</project>

Note: The year (####) and the version number (as seen in the provided XML script) should be adjusted according to the current version of the CData JDBC driver being utilized.

Project Structure

In the java directory, create a new package. Usually the name of the package is the name of the groupId (com.example) followed by the artifactId (.MDS).

Mark the "java" directory as the "Sources Root" (denoted by a blue color). To do this, right-click the java directory and choose Mark Directory as -> Sources Root (As shown below). Additionally, mark the "resources" directory as the "Resources Root."

Store Database Connection Properties

Create an "application.properties" file to store the database connection properties. To do this, right-click on the "resources" folder, opt for New -> File, input the file name as "application.properties," and press Enter.

In the application.properties file, we set the configuration properties for the Linear JDBC Driver, using the Class name and JDBC URL:

	spring.datasource.driver=cdata.jdbc.linear.LinearDriver
	spring.datasource.url=jdbc:linear:AuthScheme=APIKey;APIKey=myAPIKey;

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

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.

After setting the properties in the application.properties file, we now configure them.

Data Source Configuration

First, we mark the Linear data source as our primary data source. Then, we create a Data Source Bean.

Create a DriverManagerDataSource.java file and create a Bean within it, as shown below. If @Bean gives an error, Spring Boot may not have loaded properly. To fix this, go to File -> Invalidate Caches and restart. Additionally, make sure that Maven has added the Spring Boot dependencies.

To create a data source bean, we use the DriverManagerDataSource Class. This class allows us to set the properties of the data source. To create this Java class, right-click on "com.example.MDS" package, and choose New -> Java Class.

The following code shows the bean definition of our data source. Each driver should have a bean.

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Primary;
import org.springframework.core.env.Environment;
import javax.sql.DataSource;

public class DriverManagerDataSource{
	@Autowired
	private static Environment env;

	@Bean(name ="Linear")
	@Primary
	public static DataSource LinearDataSource()
	{

	DataSourceBuilder<?> dataSourceBuilder = DataSourceBuilder.create();
		dataSourceBuilder.driverClassName("cdata.jdbc.linear.LinearDriver");
		dataSourceBuilder.url("jdbc:linear:AuthScheme=APIKey;APIKey=myAPIKey;");
		return dataSourceBuilder.build();
	}
	
	//@Override
	public void setEnvironment( final Environment environment) {
	env=environment;
	}
}

Next, move the Linear jar file to the Documents folder (see path in command below) - The idea is to have a path without any spaces for the jar file. Then, click the Maven icon (top right corner of IntelliJ) and click "Execute Maven Goal." Now, run the following command:

mvn install:install-file "-Dfile=C:\Program Files\CData\CData JDBC Driver for Linear ####\lib\cdata.jdbc.linear.jar" -DgroupId=org.cdata.connectors -DartifactId=cdata-linear-connector -Dversion=23 -Dpackaging=jar

Follow either of the given steps to run this command:

1. The "-Dfile location" can be kept as the default installation path of the CData JDBC Driver. Make sure to keep the path in quotations in this case. Also, change the year and "Dversion" based on the current version of the driver being used.
2. As mentioned earlier in the article, in case you relocate the jar file to the Documents folder, make sure to modify the path in the provided command. In such instances, avoid enclosing the Dfile location in quotations and edit "Dversion" based on the current version of the driver being used.

After pressing enter, we see the following output:

Testing the Connection

The last step is testing the connection. Create a new Java class following the format (e.g., "MDSApplication"). You have the flexibility to select any name for the application class. We call the data source in the main method of MDSApplication.java:

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import java.sql.Connection;
import java.sql.SQLException;
import static com.example.demo.DriverManagerDataSources.LinearDataSource;


@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
	public class MDSApplication {
		//remove the comment on the line below
		public static void main (){
		SpringApplication.run(DemoApplication.class, args);
		Connection conn = LinearDataSource().getConnection();
		System.out.println("Catalog: "+ conn.getCatalog());
	}
}

The output generated should look like this:

Free Trial & More Information

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