source: SRUAggregator/trunk/src/main/java/eu/clarin/sru/fcs/aggregator/app/Aggregator.java @ 6123

package eu.clarin.sru.fcs.aggregator.app;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.optimaize.langdetect.LanguageDetector;
import com.optimaize.langdetect.LanguageDetectorBuilder;
import com.optimaize.langdetect.ngram.NgramExtractors;
import com.optimaize.langdetect.profiles.LanguageProfile;
import com.optimaize.langdetect.profiles.LanguageProfileReader;
import com.optimaize.langdetect.text.*;
import eu.clarin.sru.fcs.aggregator.search.Search;
import eu.clarin.sru.fcs.aggregator.scan.ScanCrawlTask;
import eu.clarin.sru.fcs.aggregator.scan.Corpora;
import eu.clarin.sru.client.SRUVersion;
import eu.clarin.sru.client.fcs.ClarinFCSClientBuilder;
import eu.clarin.sru.client.fcs.ClarinFCSEndpointDescriptionParser;
import eu.clarin.sru.fcs.aggregator.client.ThrottledClient;
import eu.clarin.sru.fcs.aggregator.scan.Corpus;
import eu.clarin.sru.fcs.aggregator.rest.RestService;
import eu.clarin.sru.fcs.aggregator.scan.Statistics;
import eu.clarin.sru.fcs.aggregator.util.LanguagesISO693;
import io.dropwizard.Application;
import io.dropwizard.assets.AssetsBundle;
import io.dropwizard.setup.Bootstrap;
import io.dropwizard.setup.Environment;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.atomic.AtomicReference;
import org.eclipse.jetty.server.session.SessionHandler;
import org.slf4j.LoggerFactory;

/**
 * Main component of the Aggregator application intended to provide users access
 * to CLARIN-FCS resources.
 *
 * The webapp base URL corresponds to the default behavior of displaying the
 * main aggregator page, where the user can enter query, select the resources of
 * CQL endpoints (as specified in the Clarin center registry), and search in
 * these resources. The endpoints/resources selection is optional, by default
 * all the endpoints root resources are selected.
 *
 * If invoked with 'x-aggregation-context' and 'query' parameter, the aggregator
 * will pre-select provided resources and fill in the query field. This
 * mechanism is currently used by VLO.
 *
 * Example: POST
 * http://weblicht.sfs.uni-tuebingen.de/Aggregator HTTP/1.1
 * query = bellen & x-aggregation-context =
 * {"http://fedora.clarin-d.uni-saarland.de/sru/":["hdl:11858/00-246C-0000-0008-5F2A-0"]}
 *
 * If the Aggregator web page has the URL query string parameter 'mode'
 * set to the string 'search', and the 'query' parameter is set,
 * then the aggregator search results for this query are immediately displayed
 * (i.e. users don't need to click 'search' in the aggregator page).
 * This feature has been requested initially by Martin Wynne from CLARIN ERIC
 *
 * @author Yana Panchenko
 * @author edima
 *
 * TODO: improve help page text
 *
 * TODO: update comments everywhere
 *
 * TODO: add some basic docs
 *
 * TODO: Export search results to personal workspace using oauth
 *
 * TODO: websockets
 *
 * TODO: show multiple hits on the same result in multiple rows, linked visually
 *
 * TODO: optimise page load
 *
 * TODO: test it in IE, other browsers
 *
 * TODO: tri-state for parent collections; search + message implications
 *
 */
public class Aggregator extends Application<AggregatorConfiguration> {

        private static final org.slf4j.Logger log = LoggerFactory.getLogger(Aggregator.class);

        final int SEARCHES_SIZE_GC_THRESHOLD = 1000;
        final int SEARCHES_AGE_GC_THRESHOLD = 60;

        private static final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
        private static Aggregator instance;
        private AggregatorConfiguration.Params params;

        private AtomicReference<Corpora> scanCacheAtom = new AtomicReference<Corpora>(new Corpora());
        private AtomicReference<Statistics> scanStatsAtom = new AtomicReference<Statistics>(new Statistics());
        private AtomicReference<Statistics> searchStatsAtom = new AtomicReference<Statistics>(new Statistics());

        private LanguageDetector languageDetector;
        private TextObjectFactory textObjectFactory;

        private ThrottledClient sruScanClient = null;
        private ThrottledClient sruSearchClient = null;
        private Map<Long, Search> activeSearches = Collections.synchronizedMap(new HashMap<Long, Search>());

        public static void main(String[] args) throws Exception {
                new Aggregator().run(args);
        }

        @Override
        public String getName() {
                return "FCS Aggregator";
        }

        @Override
        public void initialize(Bootstrap<AggregatorConfiguration> bootstrap) {
                bootstrap.addBundle(new AssetsBundle("/assets", "/", "index.html", "static"));
        }

        @Override
        public void run(AggregatorConfiguration config, Environment environment) throws Exception {
                params = config.aggregatorParams;
                instance = this;

                List<String> wll = new ArrayList<String>();
                for (String l : config.aggregatorParams.weblichtConfig.getAcceptedTcfLanguages()) {
                        wll.add(LanguagesISO693.getInstance().code_3ForCode(l));
                }
                config.aggregatorParams.weblichtConfig.acceptedTcfLanguages = wll;

                System.out.println("Using parameters: ");
                try {
                        System.out.println(new ObjectMapper().writerWithDefaultPrettyPrinter().
                                        writeValueAsString(config.aggregatorParams));
                } catch (IOException xc) {
                }

                environment.getApplicationContext().setSessionHandler(new SessionHandler());
                environment.getApplicationContext().setErrorHandler(new ErrorHandler());
                environment.jersey().setUrlPattern("/rest/*");
                environment.jersey().register(new RestService());

                try {
                        init();
                } catch (Exception ex) {
                        log.error("INIT EXCEPTION", ex);
                        throw ex; // force exit
                }
        }

        public static Aggregator getInstance() {
                return instance;
        }

        public AggregatorConfiguration.Params getParams() {
                return params;
        }

        public Corpora getCorpora() {
                return scanCacheAtom.get();
        }

        public Statistics getScanStatistics() {
                return scanStatsAtom.get();
        }

        public Statistics getSearchStatistics() {
                return searchStatsAtom.get();
        }

        public void init() throws IOException {
                log.info("Aggregator initialization started.");
                sruScanClient = new ThrottledClient(
                                new ClarinFCSClientBuilder()
                                .setConnectTimeout(params.ENDPOINTS_SCAN_TIMEOUT_MS)
                                .setSocketTimeout(params.ENDPOINTS_SCAN_TIMEOUT_MS)
                                .addDefaultDataViewParsers()
                                .registerExtraResponseDataParser(
                                                new ClarinFCSEndpointDescriptionParser())
                                .enableLegacySupport()
                                .buildThreadedClient(),
                                params.SCAN_MAX_CONCURRENT_REQUESTS_PER_ENDPOINT
                );
                sruSearchClient = new ThrottledClient(
                                new ClarinFCSClientBuilder()
                                .setConnectTimeout(params.ENDPOINTS_SEARCH_TIMEOUT_MS)
                                .setSocketTimeout(params.ENDPOINTS_SEARCH_TIMEOUT_MS)
                                .addDefaultDataViewParsers()
                                .enableLegacySupport()
                                .buildThreadedClient(),
                                params.SEARCH_MAX_CONCURRENT_REQUESTS_PER_ENDPOINT
                );

                File corporaCacheFile = new File(params.AGGREGATOR_FILE_PATH);
                File corporaOldCacheFile = new File(params.AGGREGATOR_FILE_PATH_BACKUP);

                // init corpora from file
                {
                        Corpora corpora = null;
                        try {
                                corpora = new ObjectMapper().readValue(corporaCacheFile, Corpora.class);
                        } catch (Exception xc) {
                                log.error("Failed to load cached corpora from primary file:", xc);
                        }
                        if (corpora == null) {
                                try {
                                        corpora = new ObjectMapper().readValue(corporaOldCacheFile, Corpora.class);
                                } catch (Exception e) {
                                        log.error("Failed to load cached corpora from backup file:", e);
                                }
                        }
                        if (corpora != null) {
                                scanCacheAtom.set(corpora);
                                log.info("corpus list read from file; number of root corpora: " + scanCacheAtom.get().getCorpora().size());
                        }
                }

                LanguagesISO693.getInstance(); // force init
                initLanguageDetector();

                ScanCrawlTask task = new ScanCrawlTask(sruScanClient,
                                params.CENTER_REGISTRY_URL, params.SCAN_MAX_DEPTH,
                                params.additionalCQLEndpoints,
                                null, scanCacheAtom, corporaCacheFile, corporaOldCacheFile,
                                scanStatsAtom, searchStatsAtom);
                scheduler.scheduleAtFixedRate(task, params.SCAN_TASK_INITIAL_DELAY,
                                params.SCAN_TASK_INTERVAL, params.getScanTaskTimeUnit());

                log.info("Aggregator initialization finished.");
        }

        public void shutdown(AggregatorConfiguration config) {
                log.info("Aggregator is shutting down.");
                for (Search search : activeSearches.values()) {
                        search.shutdown();
                }
                shutdownAndAwaitTermination(config.aggregatorParams, sruScanClient, scheduler);
                shutdownAndAwaitTermination(config.aggregatorParams, sruSearchClient, scheduler);
                log.info("Aggregator shutdown complete.");
        }

        // this function should be thread-safe
        public Search startSearch(SRUVersion version, List<Corpus> corpora,
                        String searchString, String searchLang,
                        int firstRecord, int maxRecords) throws Exception {
                if (corpora.isEmpty()) {
                        // No corpora
                        return null;
                } else if (searchString.isEmpty()) {
                        // No query
                        return null;
                } else {
                        Search sr = new Search(sruSearchClient, version, searchStatsAtom.get(),
                                        corpora, searchString, searchLang, maxRecords);
                        if (activeSearches.size() > SEARCHES_SIZE_GC_THRESHOLD) {
                                List<Long> toBeRemoved = new ArrayList<Long>();
                                long t0 = System.currentTimeMillis();
                                for (Map.Entry<Long, Search> e : activeSearches.entrySet()) {
                                        long dtmin = (t0 - e.getValue().getCreatedAt()) / 1000 / 60;
                                        if (dtmin > SEARCHES_AGE_GC_THRESHOLD) {
                                                log.info("removing search " + e.getKey() + ": " + dtmin + " minutes old");
                                                toBeRemoved.add(e.getKey());
                                        }
                                }
                                for (Long l : toBeRemoved) {
                                        activeSearches.remove(l);
                                }
                        }
                        activeSearches.put(sr.getId(), sr);
                        return sr;
                }
        }

        public Search getSearchById(Long id) {
                return activeSearches.get(id);
        }

        private static void shutdownAndAwaitTermination(AggregatorConfiguration.Params params,
                        ThrottledClient sruClient, ExecutorService scheduler) {
                try {
                        sruClient.shutdown();
                        scheduler.shutdown();
                        Thread.sleep(params.EXECUTOR_SHUTDOWN_TIMEOUT_MS);
                        sruClient.shutdownNow();
                        scheduler.shutdownNow();
                        Thread.sleep(params.EXECUTOR_SHUTDOWN_TIMEOUT_MS);
                } catch (InterruptedException ie) {
                        sruClient.shutdownNow();
                        scheduler.shutdownNow();
                        Thread.currentThread().interrupt();
                }
        }

        public void initLanguageDetector() throws IOException {
                List<LanguageProfile> languageProfiles = new LanguageProfileReader().readAll();
                languageDetector = LanguageDetectorBuilder
                                .create(NgramExtractors.standard())
                                .withProfiles(languageProfiles)
                                .build();

                textObjectFactory = CommonTextObjectFactories.forDetectingOnLargeText();
        }

        public String detectLanguage(String text) {
                return languageDetector.detect(textObjectFactory.forText(text)).orNull();
        }
}