This tutorial shows how to create components that consume a REST API. The component developed as example in this tutorial is an input component that provides a search functionality for zendesk using its Search API. Lombok is used to avoid writing getter, setter and constructor methods. You can generate a project using the Talend Components Kit starter, as described in this tutorial. The input component relies on zendesk Search API and requires an HTTP client to consume it. The zendesk Search API takes the following parameters on the /api/v2/search.json endpoint. query : The search query. sort_by : The sorting type of the query result. Possible values are updated_at, created_at, priority, status, ticket_type, or relevance. It defaults to relevance. sort_order: The sorting order of the query result. Possible values are asc (for ascending) or desc (for descending). It defaults to desc. Talend Component Kit provides a built-in service to create an easy-to-use HTTP client in a declarative manner, using Java annotations. No additional implementation is needed for the interface, as it is provided by the component framework, according to what is defined above. This HTTP client can be injected into a mapper or a processor to perform HTTP requests. This example uses the basic authentication that supported by the API. The first step is to set up the configuration for the basic authentication. To be able to consume the Search API, the zendesk instance URL, the username and the password are needed. The data store is now configured. It provides a basic authentication token. Once the data store is configured, you can define the dataset by configuring the search query. It is that query that defines the records processed by the input component. Your component is configured. You can now create the component logic. Mappers defined with this tutorial don’t implement the split part because HTTP calls are not split on many workers in this case. Once the component logic implemented, you can create the source in charge of performing the HTTP request to the search API and converting the result to JsonObject records. You now have created a simple Talend component that consumes a REST API. To learn how to test this component, refer to this tutorial.

Testing code that consumes REST APIs can sometimes present many constraints: API rate limit, authentication token and password sharing, API availability, sandbox expiration, API costs, and so on. As a developer, it becomes critical to avoid those constraints and to be able to easily mock the API response. The component framework provides an API simulation tool that makes it easy to write unit tests. This tutorial shows how to use this tool in unit tests. As a starting point, the tutorial uses the component that consumes zendesk Search API and that was created in a previous tutorial. The goal is to add unit tests for it. For this tutorial, four tickets that have the open status have been added to the zendesk test instance used in the tests. To learn more about the testing methodology used in this tutorial, refer to Component JUnit testing. Create a unit test that performs a real HTTP request to the zendesk Search API instance. You can learn how to create a simple unit test in this tutorial. the authentication configuration using zendesk instance URL and credentials. the search query configuration to get all the open ticket, ordered by creation date and sorted in descending order. The test is now complete and working. It performs a real HTTP request to the zendesk instance. As an alternative, you can use mock results to avoid performing HTTP requests every time on the development environment. The real HTTP requests would, for example, only be performed on an integration environment. To transform the unit test into a mocked test that uses a mocked response of the zendesk Search API: Add the two following JUnit rules provided by the component framework. JUnit4HttpApi: This rule starts a simulation server that acts as a proxy and catches all the HTTP requests performed in the tests. This simulation server has two modes : capture : This mode forwards the captured HTTP request to the real server and captures the response. simulation : this mode returns a mocked response from the responses already captured. This rule needs to be added as a class rule. JUnit4HttpApi: This rule has a reference to the first rule. Its role is to configure the simulation server for every unit test. It passes the context of the running test to the simulation server. This rule needs to be added as a simple (method) rule. Example to run in a simulation mode: Make the test run in capture mode to catch the real API responses that can be used later in the simulated mode. To do that, set a new talend.junit.http.capture environment variable to true. This tells the simulation server to run in a capture mode. The captured response is saved in the resources/talend.testing.http package in a JSON format, then reused to perform the API simulation.

This tutorial shows how to adapt the test configuration of the zendesk search component that was done in this previous tutorial to make it work in a Continuous Integration environment. In the test, the zendesk credentials are used directly in the code to perform a first capture of the API response. Then, fake credentials are used in the simulation mode because the real API is not called anymore. However, in some cases, you can require to continue calling the real API on a CI server or on a specific environment. To do that, you can adapt the test to get the credentials depending on the execution mode (simulation/passthrough). These instructions concern the CI server or on any environment that requires real credentials. This tutorial uses: A Maven server that supports password encryption as a credential provider. Encryption is optional but recommended. The MavenDecrypterRule test rule provided by the framework. This rule lets you get credentials from Maven settings using a server ID. To create encrypted server credentials for the zendesk instance: Create a master password using the command: mvn --encrypt-master-password . Store this master password in the settings-security.xml file of the ~/.m2 folder. Encrypt the zendesk instance password using the command: mvn --encrypt-password <zendesk-password>. Create a server entry under servers in Maven settings.xml file located in the ~/.m2 folder. You can store the settings-security.xml and settings.xml files elsewhere that the default location (~/.m2). To do that, set the path of the directory containing the files in the talend.maven.decrypter.m2.location environment variable. Add the MavenDecrypterRule rule to the test class. This rule allows to inject server information stored in Maven settings.xml file to the test. The rule also decrypts credentials if they are encrypted. Inject the zendesk server to the test. To do that, add a new field to the class with the @DecryptedServer annotation, that holds the server ID to be injected. The MavenDecrypterRule is able to inject the server instance into this class at runtime. The server instance contains the username and the decrypted password. Use the server instance in the test to get the real credentials in a secured manner. Once modified, the complete test class looks as follows: This test will continue to work in simulation mode, because the API simulation proxy is activated. This tutorial shows how to set up a CI server in passthrough mode using Jenkins. Log in to Jenkins. Click New Item to create a new build job. Enter an Item name (Job name) and choose the freestyle job. Then click OK. In the Source Code Management section, enter your project repository URL. A GitHub repository is used in this tutorial. Specify the master branch as Branches to build. In the Build section, click Add build step and choose Invoke top-level Maven targets. Choose your Maven version and enter the Maven build command. In this case: clean install. Then, click Save. The -Dtalend.junit.http.passthrough=true option is part of the build command. This option tells the API simulation proxy to run in passthrough mode. This way, all the HTTP requests made in the test are forwarded to the real API server. The MavenDecrypterRule rule allows to get the real credentials. You can configure the passthrough mode globally on your CI server by setting the talend.junit.http.passthrough environment variable to true. Test the job by selecting Build now, and check that the job has built correctly. Now your tests run in a simulation mode on your development environment and in a passthrough mode on your CI server.

The following tutorials are designed to help you understand the main principles of component development using Talend Component Kit. With this set of tutorials, get your hands on project creation using the Component Kit Starter and implement the logic of different types of components. Creating your first component Generating a project from the starter Creating a Hazelcast input component Creating a Hazelcast output component Creating a zendesk REST API connector Handling component version migration With this set of tutorials, learn the different approaches to test the components created in the previous tutorials. Testing a zendesk REST API connector Testing a Hazelcast component Testing in a continuous integration environment