UrlsController/src/main/java/eu/openaire/urls_controller/controllers/ShutdownController.java

package eu.openaire.urls_controller.controllers;

import eu.openaire.urls_controller.models.WorkerInfo;
import eu.openaire.urls_controller.services.ShutdownService;
import eu.openaire.urls_controller.util.GenericUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;


@RestController
@RequestMapping("")
public class ShutdownController {

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

    @Autowired
    ShutdownService shutdownService;

    public static boolean shouldShutdownService = false;
    public static boolean shouldShutdownAllWorkers = false;


    @PostMapping("shutdownService")
    public ResponseEntity<?> shutdownServiceGracefully(HttpServletRequest request)
    {
        String initMsg = "Received a \"shutdownService\" request ";
        String remoteAddr = GenericUtils.getRequestorAddress(request);
        initMsg += "from [" + remoteAddr + "]. ";
        ResponseEntity<?> responseEntity = shutdownService.passSecurityChecks(remoteAddr, initMsg);
        if ( responseEntity != null )
            return responseEntity;

        String endingMsg;
        if ( shouldShutdownService ) {
            endingMsg = "The controller has already received a \"shutdownService\" request (which was not canceled afterwards).";
            logger.info(initMsg + endingMsg);
        } else {
            shouldShutdownService = true;
            endingMsg = "The service will shutdown, after finishing current work.";
            logger.info(initMsg + endingMsg);

            shutdownService.postShutdownOrCancelRequestsToAllWorkers(false);

            // That's it for now. The workers may take some hours to finish their work (including delivering the full-text files).
            // A scheduler monitors the shutdown of the workers. Once all worker have shutdown, the Controller shuts down as well.
        }

        return ResponseEntity.ok().body(endingMsg + GenericUtils.endOfLine);
    }


    @PostMapping("cancelShutdownService")
    public ResponseEntity<?> cancelShutdownServiceGracefully(HttpServletRequest request)
    {
        String initMsg = "Received a \"cancelShutdownService\" request ";
        String remoteAddr = GenericUtils.getRequestorAddress(request);
        initMsg += "from [" + remoteAddr + "]. ";
        ResponseEntity<?> responseEntity = shutdownService.passSecurityChecks(remoteAddr, initMsg);
        if ( responseEntity != null )
            return responseEntity;

        shouldShutdownService = false;
        String endingMsg = "Any previous \"shutdownService\"-request is canceled.";
        logger.info(initMsg + endingMsg);

        // Cancel the shutdown of the workers, if we are able to catch up with them before they have already shutdown..
        shutdownService.postShutdownOrCancelRequestsToAllWorkers(true);

        return ResponseEntity.ok().body(endingMsg + GenericUtils.endOfLine);
    }


    // The  "shutdownAllWorkers" and a "cancelShutdownAllWorkers" endpoints help when updating only the workers,
    // while keeping the Controller running and accepting bulk-import requests.

    @PostMapping("shutdownAllWorkers")
    public ResponseEntity<?> shutdownAllWorkersGracefully(HttpServletRequest request)
    {
        String initMsg = "Received a \"shutdownAllWorkers\" request ";
        String remoteAddr = GenericUtils.getRequestorAddress(request);
        initMsg += "from [" + remoteAddr + "]. ";
        ResponseEntity<?> responseEntity = shutdownService.passSecurityChecks(remoteAddr, initMsg);
        if ( responseEntity != null )
            return responseEntity;

        String endingMsg;
        if ( shouldShutdownAllWorkers ) {
            endingMsg = "The controller has already received a \"shutdownAllWorkers\" request (which was not canceled afterwards).";
            logger.info(initMsg + endingMsg);
        } else {
            shouldShutdownAllWorkers = true;
            endingMsg = "All workers will shutdown, after finishing current work.";
            logger.info(initMsg + endingMsg);

            shutdownService.postShutdownOrCancelRequestsToAllWorkers(false);

            // That's it for now. The workers may take some hours to finish their work (including delivering the full-text files).
            // The service will continue to run and handle bulk-import requests.
            // Once the workers are ready to work again, they can be started without any additional configuration.
        }

        return ResponseEntity.ok().body(endingMsg + GenericUtils.endOfLine);
    }


    @PostMapping("cancelShutdownAllWorkers")
    public ResponseEntity<?> cancelShutdownAllWorkersGracefully(HttpServletRequest request)
    {
        String initMsg = "Received a \"cancelShutdownAllWorkers\" request ";
        String remoteAddr = GenericUtils.getRequestorAddress(request);
        initMsg += "from [" + remoteAddr + "]. ";
        ResponseEntity<?> responseEntity = shutdownService.passSecurityChecks(remoteAddr, initMsg);
        if ( responseEntity != null )
            return responseEntity;

        shouldShutdownAllWorkers = false;
        String endingMsg = "Any previous \"shutdownAllWorkers\"-request is canceled.";
        logger.info(initMsg + endingMsg);

        // Cancel the shutdown of the workers, if we are able to catch up with them before they have already shutdown..
        shutdownService.postShutdownOrCancelRequestsToAllWorkers(true);

        return ResponseEntity.ok().body(endingMsg + GenericUtils.endOfLine);
    }


    @PostMapping("workerShutdownReport")
    public ResponseEntity<?> workerShutdownReport(@RequestParam String workerId, HttpServletRequest request)
    {
        String remoteAddr = GenericUtils.getRequestorAddress(request);
        String initMsg = "Received a \"workerShutdownReport\" from worker: \"" + workerId + "\" [IP: " + remoteAddr + "].";
        WorkerInfo workerInfo = UrlsController.workersInfoMap.get(workerId);
        if ( workerInfo == null ) {
            String errorMsg = "The worker with id \"" + workerId + "\" has not participated in the PDF-Aggregation-Service!";
            logger.warn(initMsg + GenericUtils.endOfLine + errorMsg);
            return ResponseEntity.badRequest().body(errorMsg);
        }

        if ( ! remoteAddr.equals(workerInfo.getWorkerIP()) ) {
            logger.error(initMsg + " The request came from an IP different from the one this worker was registered with: " + workerInfo.getWorkerIP());
            return ResponseEntity.status(HttpStatus.FORBIDDEN).build();
        }

        logger.info(initMsg);

        workerInfo.setHasShutdown(true);    // This will update the map.
        UrlsController.numOfActiveWorkers.decrementAndGet();

        // Return "HTTP-OK" to this worker. If this was part of a shutdown-service request, then wait for the scheduler to check and shutdown the service.
        return ResponseEntity.ok().build();
    }

}