# Create a Java Lambda function

To create a Lambda function, we will be using the AWS toolkit with Eclipse.

Download and setup AWS Toolkit with Eclipse on your laptop using instructions at https://aws.amazon.com/en/eclipse/.

Once configured, use Eclipse to create a new Lambda Java project:

## Procedure

1. Click File > New > Project.

   ![](https://help.qlik.com/talend/en-US/integrate-data-integration-with-s3-lambda/Resources/images/273993775_project.png)
2. In the New Project Wizard, click AWS > AWS Lambda Java Project.

   ![](https://help.qlik.com/talend/en-US/integrate-data-integration-with-s3-lambda/Resources/images/273993775_select.png)
3. Click Next.
4. Set the values as below:
   * Project Name = TalendLambdaProject
   * Package Name = com.talend.lambda.handlers
   * Class Name = S3LambdaFunctionHandler
   * Output type = Object ![](https://help.qlik.com/talend/en-US/integrate-data-integration-with-s3-lambda/Resources/images/273993775_class.png)
5. Click Finish.

   The README guide is displayed. Take some time to read it and get familiar with the steps to create, develop and deploy a Lambda function.

   ![](https://help.qlik.com/talend/en-US/integrate-data-integration-with-s3-lambda/Resources/images/273993775_readme.png)
6. In Project Explorer view, navigate through TalendLambdaProject > src > com.talend.lambda.handlers.

   ![](https://help.qlik.com/talend/en-US/integrate-data-integration-with-s3-lambda/Resources/images/273993775_explorer.png)
7. Double click on S3LambdaFunctionHandler.java to open. As you can see, a sample basic code has been generated for you.

   ![](https://help.qlik.com/talend/en-US/integrate-data-integration-with-s3-lambda/Resources/images/273993775_andler.png)
8. Remove all generated content and update your Lambda class to use the code below:
   ```
   package com.talend.lambda.handlers;
   import java.io.IOException;
   import java.util.Base64;
   import java.util.List;
   import org.apache.http.client.ClientProtocolException;
   import org.apache.http.client.methods.CloseableHttpResponse;
   import org.apache.http.client.methods.HttpGet;
   import org.apache.http.impl.client.CloseableHttpClient;
   import org.apache.http.impl.client.HttpClients;
   import org.apache.http.util.EntityUtils;
   import com.amazonaws.services.lambda.runtime.Context;
   import com.amazonaws.services.lambda.runtime.RequestHandler;
   import com.amazonaws.services.lambda.runtime.events.S3Event;
   import com.amazonaws.services.s3.event.S3EventNotification.S3EventNotificationRecord;
   import com.fasterxml.jackson.databind.ObjectMapper;
   public class S3LambdaFunctionHandler implements RequestHandler<S3Event, Object> {
   	@Override
   	public Object handleRequest(S3Event pS3Event, Context context) {
   		final String v_tac_endpoint = System.getenv("tac_endpoint");
   		final String v_tac_username = System.getenv("tac_username");
   		final String v_tac_password = System.getenv("tac_password");
   		final String v_tac_task_name = System.getenv("tac_task_name");
   		
   		Integer vTaskId = null;
   		String v_bucket = null;
   		String v_object = null;
   		CloseableHttpClient v_http_client = null;
   		CloseableHttpResponse v_response = null;
   		S3EventNotificationRecord v_record = null;
   		
   		
   		// To keep things simple for this demo,
   		// we only handle the first S3 event notification in the list
   		List<S3EventNotificationRecord> v_liste_records = pS3Event.getRecords();
   		if (v_liste_records != null && v_liste_records.size() > 0) {
   			v_record = v_liste_records.get(0);
   		}
   		if (v_record != null) {
   			v_bucket = v_record.getS3().getBucket().getArn();
   			context.getLogger().log("bucket = " + v_bucket);
   			v_object = v_record.getS3().getObject().getKey();
   			context.getLogger().log("file = " + v_object);
   		}
   		// if an object has been uploaded in S3, call TAC Metaservlet to trigger
   		// Talend Job
   		if (v_object != null) {
   			v_http_client = HttpClients.createDefault();
   			// get the tac task id by name
   			String v_taskid_request = "{\"actionName\":\"getTaskIdByName\",\"authPass\":\""
   					+ v_tac_password + "\",\"authUser\":\"" + v_tac_username + "\",\"taskName\":\"" + v_tac_task_name
   					+ "\"}";
   			context.getLogger().log("Request being sent to Talend Administration Center : " + v_taskid_request);
   			String v_taskid_request_base64 = Base64.getEncoder().encodeToString(v_taskid_request.getBytes());
   			HttpGet v_http_get_taskid_request = new HttpGet(
   					v_tac_endpoint + "/metaServlet?" + v_taskid_request_base64);
   			try {
   				// send the HTTP request to remote TAC
   				v_response = v_http_client.execute(v_http_get_taskid_request);
   				// log response received from TAC
   				String v_json = EntityUtils.toString(v_response.getEntity());
   				context.getLogger().log("Response from Talend Administration Center : " + v_json);
   				// Extract response
   				ObjectMapper vObjectMapper = new ObjectMapper();
   				TacResponse response = vObjectMapper.readValue(v_json, TacResponse.class);
   				if(response != null){
   					vTaskId = response.taskId;
   				}
   			} catch (ClientProtocolException e_ClientProtocolException) {
   				context.getLogger().log(e_ClientProtocolException.toString());
   			} catch (IOException e_IOException) {
   				context.getLogger().log(e_IOException.toString());
   			}
   		}
   		
   		//if the task id has been retrieved
   		if (vTaskId != null) {
   			String v_tac_run_task_request = "{\"actionName\":\"runTask\",\"authPass\":\"" + v_tac_password
   					+ "\",\"authUser\":\"" + v_tac_username + "\",\"taskId\":" + vTaskId
   					+ ",\"mode\":\"asynchronous\"" + ",\"context\":{\"s3_file\":\"" + v_object + "\"}" + "}";
   			context.getLogger().log("Request being sent to Talend Administration Center : " + v_tac_run_task_request);
   			// encode the metaservlet request in base64
   			String v_request_base64 = Base64.getEncoder().encodeToString(v_tac_run_task_request.getBytes());
   			// construct an HTTP request
   			HttpGet v_http_get_request = new HttpGet(v_tac_endpoint + "/metaServlet?" + v_request_base64);
   			try {
   				// send the HTTP request to remote TAC
   				v_response = v_http_client.execute(v_http_get_request);
   				// log response received from TAC
   				context.getLogger()
   						.log("Response from Talend Administration Center : " + EntityUtils.toString(v_response.getEntity()));
   			} catch (ClientProtocolException e_ClientProtocolException) {
   				context.getLogger().log(e_ClientProtocolException.toString());
   			} catch (IOException e_IOException) {
   				context.getLogger().log(e_IOException.toString());
   			}
   		}
   		return null;
   	}
   }
   ```
9. Save your changes.

   The Lambda class will complain about an unknown *TacResponse* class. The class does not exist yet, so let's create it.
   1. Right-click on the package *com.talend.lambda.handlers*. ![](https://help.qlik.com/talend/en-US/integrate-data-integration-with-s3-lambda/Resources/images/273993775_create_a_new_class.png)
   2. Choose New &gt; Class.
   3. New Java Class: set the values as below:
      * Source folder = TalendLambdaProject/src
      * Package = com.talend.lambda.handlers
      * Name = TacResponse
      * Modifiers = public
      * Superclass = java.lang.Object
      * All other fields: leave as default. ![](https://help.qlik.com/talend/en-US/integrate-data-integration-with-s3-lambda/Resources/images/273993775_create_classs_tacresponse.png)
   4. Click Finish to create the new class.
   5. Open the class, remove the default content then copy/paste the code below:
      ```
      package com.talend.lambda.handlers;
      import com.fasterxml.jackson.annotation.JsonIgnoreType;
      public class TacResponse {
      	@JsonIgnoreType
      	public static class ExecutionTimeType{
      		public long millis;
      		public String seconds;
      	}
      	
      	public Integer returnCode;
      	public Integer taskId;
      	public ExecutionTimeType executionTime;
      	
      }
      ```
   6. Save changes.
   7. Check any eventual error inside both classes S3LambdaFunctionHandler.java and TacResponse.java. You should no longer have any error in these classes.