UrlsWorker/src/main/java/eu/openaire/urls_worker/UrlsWorkerApplication.java

package eu.openaire.urls_worker;

import eu.openaire.publications_retriever.PublicationsRetriever;
import eu.openaire.publications_retriever.util.file.FileUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;

import javax.annotation.PreDestroy;
import java.io.File;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;


@SpringBootApplication
@EnableScheduling
public class UrlsWorkerApplication {

    private static final Logger logger = LoggerFactory.getLogger(UrlsWorkerApplication.class);

    private static final String controllerBaseUrlFilePath = FileUtils.workingDir + "controllerBaseUrl.txt";
    public static String controllerBaseUrl = null;  // BaseUrl template: "http://IP:PORT/api/"

    public static void main(String[] args) {

        setControllerBaseUrl(); // This may cause the Server to terminate early, in case the controllerBaseUrl cannot be found.

        SpringApplication.run(UrlsWorkerApplication.class, args);
    }

    @PreDestroy
    public static void preDestroy()
    {
        if ( PublicationsRetriever.executor != null )
        {
            PublicationsRetriever.executor.shutdown();	// Define that no new tasks will be scheduled.
            try {
                if ( !PublicationsRetriever.executor.awaitTermination(1, TimeUnit.MINUTES) ) {
                    logger.warn("The working threads did not finish on time! Stopping them immediately..");
                    PublicationsRetriever.executor.shutdownNow();
                }
            } catch (InterruptedException e) {
                PublicationsRetriever.executor.shutdownNow();
            }
        }
    }


    private static void setControllerBaseUrl()
    {
        // Take the controllerBaseUrl from the file.
        Scanner myReader = null;
        try {
            File controllerBaseUrlFile = new File(controllerBaseUrlFilePath);
            if ( !controllerBaseUrlFile.exists() ) {
                String errorMsg = "controllerBaseUrlFile \"" + controllerBaseUrlFilePath + "\" does not exists!";
                logger.error(errorMsg);
                System.err.println(errorMsg);
                System.exit(60);
            }

            myReader = new Scanner(controllerBaseUrlFile);
            if ( !myReader.hasNextLine() ) {
                String errorMsg = "The controllerBaseUrlFile is empty! No WorkerReports can be sent from this worker! Exiting..";
                logger.error(errorMsg);
                System.err.println(errorMsg);
                System.exit(61);
            }

            controllerBaseUrl = myReader.nextLine().trim();
            if ( !controllerBaseUrl.endsWith("/") )
                controllerBaseUrl += "/";   // Make sure the whole urls will not break later.

            logger.info("The controllerBaseUrl is: " + controllerBaseUrl);

        } catch (Exception e) {
            String errorMsg = "An error prevented the retrieval of the controllerBaseUrl from the file: " + controllerBaseUrlFilePath + "\n" + e.getMessage();
            logger.error(errorMsg);
            System.err.println(errorMsg);
            e.printStackTrace();
            System.exit(62);
        } finally {
            if ( myReader != null )
                myReader.close();
        }
    }

}