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;


    @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\" (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);

            // Send "shutdownWorker" requests to all active Workers.
            for ( String workerId : UrlsController.workersInfoMap.keySet() ) {
                WorkerInfo workerInfo = UrlsController.workersInfoMap.get(workerId);
                if ( ! workerInfo.getHasShutdown() )    // A worker may have shutdown on its own (by sending it a shutDown request manually), so it will have told the Controller when it shut down. In case of a Worker-crash, the Controller will not know about it.
                    shutdownService.postShutdownOrCancelRequestToWorker(workerId, workerInfo.getWorkerIP(), false);
                else
                    logger.warn("Will not post ShutdownRequest to Worker \"" + workerId + "\", since is it has already shutdown.");
            }

            // 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);

        // Send "cancelShutdownWorker" requests to all active Workers.
        for ( String workerId : UrlsController.workersInfoMap.keySet() ) {
            WorkerInfo workerInfo = UrlsController.workersInfoMap.get(workerId);
            if ( ! workerInfo.getHasShutdown() )    // A worker may have shutdown on its own (by sending it a shutDown request manually), so it will have told the Controller when it shut down. In case of a Worker-crash, the Controller will not know about it.
                shutdownService.postShutdownOrCancelRequestToWorker(workerId, workerInfo.getWorkerIP(), true);
            else
                logger.warn("Will not post CancelShutdownRequest to Worker \"" + workerId + "\", since is it has already shutdown.");
        }

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


    @PostMapping("workerShutdownReport")
    public ResponseEntity<?> workerShutdownReport(@RequestParam String workerId, HttpServletRequest request)
    {
        String initMsg = "Received a \"workerShutdownReport\" from worker: \"" + workerId + "\".";
        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);
        }

        String remoteAddr = GenericUtils.getRequestorAddress(request);
        if ( ! remoteAddr.equals(workerInfo.getWorkerIP()) ) {
            logger.error(initMsg + " The request came from another IP: " + remoteAddr + " | while this worker was registered with this IP: " + workerInfo.getWorkerIP());
            return ResponseEntity.status(HttpStatus.FORBIDDEN).build();
        }

        logger.info(initMsg);

        workerInfo.setHasShutdown(true);    // This will update the map.
        UrlsController.numOfWorkers.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();
    }

}