org.apache.zeppelin.notebook.Notebook.java Source code

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.zeppelin.notebook;

import com.google.common.collect.Sets;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
import javax.inject.Inject;
import org.apache.commons.lang.StringUtils;
import org.apache.zeppelin.conf.ZeppelinConfiguration;
import org.apache.zeppelin.conf.ZeppelinConfiguration.ConfVars;
import org.apache.zeppelin.display.AngularObject;
import org.apache.zeppelin.display.AngularObjectRegistry;
import org.apache.zeppelin.interpreter.Interpreter;
import org.apache.zeppelin.interpreter.InterpreterException;
import org.apache.zeppelin.interpreter.InterpreterFactory;
import org.apache.zeppelin.interpreter.InterpreterGroup;
import org.apache.zeppelin.interpreter.InterpreterNotFoundException;
import org.apache.zeppelin.interpreter.InterpreterSetting;
import org.apache.zeppelin.interpreter.InterpreterSettingManager;
import org.apache.zeppelin.interpreter.ManagedInterpreterGroup;
import org.apache.zeppelin.notebook.repo.NotebookRepo;
import org.apache.zeppelin.notebook.repo.NotebookRepoSync;
import org.apache.zeppelin.notebook.repo.NotebookRepoWithVersionControl;
import org.apache.zeppelin.notebook.repo.NotebookRepoWithVersionControl.Revision;
import org.apache.zeppelin.search.SearchService;
import org.apache.zeppelin.user.AuthenticationInfo;
import org.apache.zeppelin.user.Credentials;
import org.quartz.CronScheduleBuilder;
import org.quartz.CronTrigger;
import org.quartz.JobBuilder;
import org.quartz.JobDetail;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.quartz.JobKey;
import org.quartz.SchedulerException;
import org.quartz.TriggerBuilder;
import org.quartz.impl.StdSchedulerFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * High level api of Notebook related operations, such as create, move & delete note/folder.
 * It will also do other thing which is caused by these operation, such as update index,
 * refresh cron and update InterpreterSetting, these are done through NoteEventListener.
 *
 */
public class Notebook {
    private static final Logger LOGGER = LoggerFactory.getLogger(Notebook.class);

    private NoteManager noteManager;

    private InterpreterFactory replFactory;
    private InterpreterSettingManager interpreterSettingManager;
    private ZeppelinConfiguration conf;
    private StdSchedulerFactory quertzSchedFact;
    org.quartz.Scheduler quartzSched;
    private ParagraphJobListener paragraphJobListener;
    private NotebookRepo notebookRepo;
    private SearchService noteSearchService;
    private NotebookAuthorization notebookAuthorization;
    private List<NoteEventListener> noteEventListeners = new ArrayList<>();
    private Credentials credentials;

    /**
     * Main constructor \w manual Dependency Injection
     *
     * @throws IOException
     * @throws SchedulerException
     */
    public Notebook(ZeppelinConfiguration conf, NotebookRepo notebookRepo, InterpreterFactory replFactory,
            InterpreterSettingManager interpreterSettingManager, SearchService noteSearchService,
            NotebookAuthorization notebookAuthorization, Credentials credentials)
            throws IOException, SchedulerException {
        this.noteManager = new NoteManager(notebookRepo);
        this.conf = conf;
        this.notebookRepo = notebookRepo;
        this.replFactory = replFactory;
        this.interpreterSettingManager = interpreterSettingManager;
        this.noteSearchService = noteSearchService;
        this.notebookAuthorization = notebookAuthorization;
        this.credentials = credentials;
        quertzSchedFact = new org.quartz.impl.StdSchedulerFactory();
        quartzSched = quertzSchedFact.getScheduler();
        quartzSched.start();
        CronJob.notebook = this;

        this.noteEventListeners.add(this.noteSearchService);
        this.noteEventListeners.add(this.notebookAuthorization);
        this.noteEventListeners.add(this.interpreterSettingManager);
    }

    @Inject
    public Notebook(ZeppelinConfiguration conf, NotebookRepo notebookRepo, InterpreterFactory replFactory,
            InterpreterSettingManager interpreterSettingManager, SearchService noteSearchService,
            NotebookAuthorization notebookAuthorization, Credentials credentials,
            NoteEventListener noteEventListener) throws IOException, SchedulerException {
        this(conf, notebookRepo, replFactory, interpreterSettingManager, noteSearchService, notebookAuthorization,
                credentials);
        if (null != noteEventListener) {
            this.noteEventListeners.add(noteEventListener);
        }
        this.paragraphJobListener = (ParagraphJobListener) noteEventListener;
    }

    /**
     * This method will be called only NotebookService to register {@link *
     * org.apache.zeppelin.notebook.ParagraphJobListener}.
     */
    public void setParagraphJobListener(ParagraphJobListener paragraphJobListener) {
        this.paragraphJobListener = paragraphJobListener;
    }

    /**
     * Creating new note. defaultInterpreterGroup is not provided, so the global
     * defaultInterpreterGroup (zeppelin.interpreter.group.default) is used
     *
     * @param notePath
     * @param subject
     * @return
     * @throws IOException
     */
    public Note createNote(String notePath, AuthenticationInfo subject) throws IOException {
        return createNote(notePath, interpreterSettingManager.getDefaultInterpreterSetting().getName(), subject);
    }

    /**
     * Creating new note.
     *
     * @param notePath
     * @param defaultInterpreterGroup
     * @param subject
     * @return
     * @throws IOException
     */
    public Note createNote(String notePath, String defaultInterpreterGroup, AuthenticationInfo subject)
            throws IOException {
        Note note = new Note(notePath, defaultInterpreterGroup, replFactory, interpreterSettingManager,
                paragraphJobListener, credentials, noteEventListeners);
        saveNote(note, subject);
        fireNoteCreateEvent(note, subject);
        return note;
    }

    /**
     * Export existing note.
     *
     * @param noteId - the note ID to clone
     * @return Note JSON
     * @throws IOException, IllegalArgumentException
     */
    public String exportNote(String noteId) throws IOException {
        Note note = getNote(noteId);
        if (note == null) {
            throw new IOException(noteId + " not found");
        }
        return note.toJson();
    }

    /**
     * import JSON as a new note.
     *
     * @param sourceJson - the note JSON to import
     * @param notePath   - the path of the new note
     * @return note ID
     * @throws IOException
     */
    public Note importNote(String sourceJson, String notePath, AuthenticationInfo subject) throws IOException {
        Note oldNote = Note.fromJson(sourceJson);
        if (notePath == null) {
            notePath = oldNote.getName();
        }
        Note newNote = createNote(notePath, subject);
        List<Paragraph> paragraphs = oldNote.getParagraphs();
        for (Paragraph p : paragraphs) {
            newNote.addCloneParagraph(p, subject);
        }
        return newNote;
    }

    /**
     * Clone existing note.
     *
     * @param sourceNoteId - the note ID to clone
     * @param newNotePath  - the path of the new note
     * @return noteId
     * @throws IOException, CloneNotSupportedException, IllegalArgumentException
     */
    public Note cloneNote(String sourceNoteId, String newNotePath, AuthenticationInfo subject) throws IOException {
        Note sourceNote = getNote(sourceNoteId);
        if (sourceNote == null) {
            throw new IOException("Source note: " + sourceNoteId + " not found");
        }
        Note newNote = createNote(newNotePath, subject);
        List<Paragraph> paragraphs = sourceNote.getParagraphs();
        for (Paragraph p : paragraphs) {
            newNote.addCloneParagraph(p, subject);
        }
        return newNote;
    }

    public void removeNote(String noteId, AuthenticationInfo subject) throws IOException {
        LOGGER.info("Remove note " + noteId);
        Note note = getNote(noteId);
        noteManager.removeNote(noteId, subject);
        fireNoteRemoveEvent(note, subject);
    }

    public Note getNote(String id) {
        try {
            Note note = noteManager.getNote(id);
            if (note == null) {
                return null;
            }
            note.setInterpreterFactory(replFactory);
            note.setInterpreterSettingManager(interpreterSettingManager);
            note.setParagraphJobListener(paragraphJobListener);
            note.setNoteEventListeners(noteEventListeners);
            note.setCredentials(credentials);
            for (Paragraph p : note.getParagraphs()) {
                p.setNote(note);
            }
            return note;
        } catch (IOException e) {
            LOGGER.warn("Fail to get note: " + id, e);
            return null;
        }
    }

    public void saveNote(Note note, AuthenticationInfo subject) throws IOException {
        noteManager.saveNote(note, subject);
        fireNoteUpdateEvent(note, subject);
    }

    public boolean containsNote(String notePath) {
        return noteManager.containsNote(notePath);
    }

    public boolean containsFolder(String folderPath) {
        return noteManager.containsFolder(folderPath);
    }

    public void moveNote(String noteId, String newNotePath, AuthenticationInfo subject) throws IOException {
        LOGGER.info("Move note " + noteId + " to " + newNotePath);
        noteManager.moveNote(noteId, newNotePath, subject);
    }

    public void moveFolder(String folderPath, String newFolderPath, AuthenticationInfo subject) throws IOException {
        LOGGER.info("Move folder from " + folderPath + " to " + newFolderPath);
        noteManager.moveFolder(folderPath, newFolderPath, subject);
    }

    public void removeFolder(String folderPath, AuthenticationInfo subject) throws IOException {
        LOGGER.info("Remove folder " + folderPath);
        // TODO(zjffdu) NotebookRepo.remove is called twice here
        List<Note> notes = noteManager.removeFolder(folderPath, subject);
        for (Note note : notes) {
            fireNoteRemoveEvent(note, subject);
        }
    }

    public void emptyTrash(AuthenticationInfo subject) throws IOException {
        LOGGER.info("Empty Trash");
        removeFolder("/" + NoteManager.TRASH_FOLDER, subject);
    }

    public void restoreAll(AuthenticationInfo subject) throws IOException {
        NoteManager.Folder trash = noteManager.getTrashFolder();
        // restore notes under trash folder
        for (NoteManager.NoteNode noteNode : trash.getNotes().values()) {
            moveNote(noteNode.getNoteId(), noteNode.getNotePath().replace("/~Trash", ""), subject);
        }
        // restore folders under trash folder
        for (NoteManager.Folder folder : trash.getFolders().values()) {
            moveFolder(folder.getPath(), folder.getPath().replace("/~Trash", ""), subject);
        }
    }

    public Revision checkpointNote(String noteId, String noteName, String checkpointMessage,
            AuthenticationInfo subject) throws IOException {
        if (((NotebookRepoSync) notebookRepo).isRevisionSupportedInDefaultRepo()) {
            return ((NotebookRepoWithVersionControl) notebookRepo).checkpoint(noteId, noteName, checkpointMessage,
                    subject);
        } else {
            return null;
        }
    }

    public List<Revision> listRevisionHistory(String noteId, String noteName, AuthenticationInfo subject)
            throws IOException {
        if (((NotebookRepoSync) notebookRepo).isRevisionSupportedInDefaultRepo()) {
            return ((NotebookRepoWithVersionControl) notebookRepo).revisionHistory(noteId, noteName, subject);
        } else {
            return null;
        }
    }

    public Note setNoteRevision(String noteId, String noteName, String revisionId, AuthenticationInfo subject)
            throws IOException {
        if (((NotebookRepoSync) notebookRepo).isRevisionSupportedInDefaultRepo()) {
            return ((NotebookRepoWithVersionControl) notebookRepo).setNoteRevision(noteId, noteName, revisionId,
                    subject);
        } else {
            return null;
        }
    }

    public Note getNoteByRevision(String noteId, String noteName, String revisionId, AuthenticationInfo subject)
            throws IOException {
        if (((NotebookRepoSync) notebookRepo).isRevisionSupportedInDefaultRepo()) {
            return ((NotebookRepoWithVersionControl) notebookRepo).get(noteId, noteName, revisionId, subject);
        } else {
            return null;
        }
    }

    @SuppressWarnings("rawtypes")
    public Note loadNoteFromRepo(String id, AuthenticationInfo subject) {
        Note note = null;
        try {
            note = noteManager.getNote(id);
        } catch (IOException e) {
            LOGGER.error("Failed to load " + id, e);
        }
        if (note == null) {
            return null;
        }

        //Manually inject ALL dependencies, as DI constructor was NOT used
        note.setCredentials(this.credentials);

        note.setInterpreterFactory(replFactory);
        note.setInterpreterSettingManager(interpreterSettingManager);

        note.setParagraphJobListener(this.paragraphJobListener);
        note.setCronSupported(getConf());

        if (note.getDefaultInterpreterGroup() == null) {
            note.setDefaultInterpreterGroup(conf.getString(ConfVars.ZEPPELIN_INTERPRETER_GROUP_DEFAULT));
        }

        Map<String, SnapshotAngularObject> angularObjectSnapshot = new HashMap<>();

        // restore angular object --------------
        Date lastUpdatedDate = new Date(0);
        for (Paragraph p : note.getParagraphs()) {
            p.setNote(note);
            if (p.getDateFinished() != null && lastUpdatedDate.before(p.getDateFinished())) {
                lastUpdatedDate = p.getDateFinished();
            }
        }

        Map<String, List<AngularObject>> savedObjects = note.getAngularObjects();

        if (savedObjects != null) {
            for (String intpGroupName : savedObjects.keySet()) {
                List<AngularObject> objectList = savedObjects.get(intpGroupName);

                for (AngularObject object : objectList) {
                    SnapshotAngularObject snapshot = angularObjectSnapshot.get(object.getName());
                    if (snapshot == null || snapshot.getLastUpdate().before(lastUpdatedDate)) {
                        angularObjectSnapshot.put(object.getName(),
                                new SnapshotAngularObject(intpGroupName, object, lastUpdatedDate));
                    }
                }
            }
        }

        note.setNoteEventListeners(this.noteEventListeners);

        for (String name : angularObjectSnapshot.keySet()) {
            SnapshotAngularObject snapshot = angularObjectSnapshot.get(name);
            List<InterpreterSetting> settings = interpreterSettingManager.get();
            for (InterpreterSetting setting : settings) {
                InterpreterGroup intpGroup = setting.getInterpreterGroup(subject.getUser(), note.getId());
                if (intpGroup != null && intpGroup.getId().equals(snapshot.getIntpGroupId())) {
                    AngularObjectRegistry registry = intpGroup.getAngularObjectRegistry();
                    String noteId = snapshot.getAngularObject().getNoteId();
                    String paragraphId = snapshot.getAngularObject().getParagraphId();
                    // at this point, remote interpreter process is not created.
                    // so does not make sense add it to the remote.
                    //
                    // therefore instead of addAndNotifyRemoteProcess(), need to use add()
                    // that results add angularObject only in ZeppelinServer side not remoteProcessSide
                    registry.add(name, snapshot.getAngularObject().get(), noteId, paragraphId);
                }
            }
        }

        return note;
    }

    /**
     * Reload all notes from repository after clearing `notes` and `folders`
     * to reflect the changes of added/deleted/modified notes on file system level.
     *
     * @throws IOException
     */
    public void reloadAllNotes(AuthenticationInfo subject) throws IOException {
        this.noteManager.reloadNotes();

        if (notebookRepo instanceof NotebookRepoSync) {
            NotebookRepoSync mainRepo = (NotebookRepoSync) notebookRepo;
            if (mainRepo.getRepoCount() > 1) {
                mainRepo.sync(subject);
            }
        }
    }

    private class SnapshotAngularObject {
        String intpGroupId;
        AngularObject angularObject;
        Date lastUpdate;

        SnapshotAngularObject(String intpGroupId, AngularObject angularObject, Date lastUpdate) {
            super();
            this.intpGroupId = intpGroupId;
            this.angularObject = angularObject;
            this.lastUpdate = lastUpdate;
        }

        String getIntpGroupId() {
            return intpGroupId;
        }

        AngularObject getAngularObject() {
            return angularObject;
        }

        Date getLastUpdate() {
            return lastUpdate;
        }
    }

    public List<NoteInfo> getNotesInfo() {
        return noteManager.getNotesInfo().entrySet().stream()
                .map(entry -> new NoteInfo(entry.getKey(), entry.getValue())).collect(Collectors.toList());
    }

    public List<Note> getAllNotes() {
        List<Note> noteList = noteManager.getAllNotes();
        Collections.sort(noteList, Comparator.comparing(Note::getPath));
        return noteList;
    }

    public List<Note> getAllNotes(Set<String> userAndRoles) {
        final Set<String> entities = Sets.newHashSet();
        if (userAndRoles != null) {
            entities.addAll(userAndRoles);
        }
        return getAllNotes().stream().filter(note -> notebookAuthorization.isReader(note.getId(), entities))
                .collect(Collectors.toList());
    }

    public List<NoteInfo> getNotesInfo(Set<String> userAndRoles) {
        final Set<String> entities = Sets.newHashSet();
        if (userAndRoles != null) {
            entities.addAll(userAndRoles);
        }
        String homescreenNoteId = conf.getString(ConfVars.ZEPPELIN_NOTEBOOK_HOMESCREEN);
        boolean hideHomeScreenNotebookFromList = conf.getBoolean(ConfVars.ZEPPELIN_NOTEBOOK_HOMESCREEN_HIDE);

        synchronized (noteManager.getNotesInfo()) {
            List<NoteInfo> notesInfo = noteManager.getNotesInfo().entrySet().stream()
                    .filter(entry -> notebookAuthorization.isReader(entry.getKey(), entities)
                            && ((!hideHomeScreenNotebookFromList) || ((hideHomeScreenNotebookFromList)
                                    && !entry.getKey().equals(homescreenNoteId))))
                    .map(entry -> new NoteInfo(entry.getKey(), entry.getValue())).collect(Collectors.toList());

            notesInfo.sort((note1, note2) -> {
                String name1 = note1.getId();
                if (note1.getPath() != null) {
                    name1 = note1.getPath();
                }
                String name2 = note2.getId();
                if (note2.getPath() != null) {
                    name2 = note2.getPath();
                }
                return name1.compareTo(name2);
            });
            return notesInfo;
        }
    }

    public List<InterpreterSetting> getBindedInterpreterSettings(String noteId) {
        Note note = getNote(noteId);
        if (note != null) {
            Set<InterpreterSetting> settings = new HashSet<>();
            for (Paragraph p : note.getParagraphs()) {
                try {
                    Interpreter intp = p.getBindedInterpreter();
                    settings.add(((ManagedInterpreterGroup) intp.getInterpreterGroup()).getInterpreterSetting());
                } catch (InterpreterNotFoundException e) {
                    // ignore this
                }
            }
            // add the default interpreter group
            InterpreterSetting defaultIntpSetting = interpreterSettingManager
                    .getByName(note.getDefaultInterpreterGroup());
            if (defaultIntpSetting != null) {
                settings.add(defaultIntpSetting);
            }
            return new ArrayList<>(settings);
        } else {
            return new LinkedList<>();
        }
    }

    /**
     * Cron task for the note.
     */
    public static class CronJob implements org.quartz.Job {
        public static Notebook notebook;

        @Override
        public void execute(JobExecutionContext context) throws JobExecutionException {

            String noteId = context.getJobDetail().getJobDataMap().getString("noteId");
            Note note = notebook.getNote(noteId);
            if (note.haveRunningOrPendingParagraphs()) {
                LOGGER.warn("execution of the cron job is skipped because there is a running or pending "
                        + "paragraph (note id: {})", noteId);
                return;
            }

            if (!note.isCronSupported(notebook.getConf())) {
                LOGGER.warn("execution of the cron job is skipped cron is not enabled from Zeppelin server");
                return;
            }

            runAll(note);

            boolean releaseResource = false;
            String cronExecutingUser = null;
            try {
                Map<String, Object> config = note.getConfig();
                if (config != null) {
                    if (config.containsKey("releaseresource")) {
                        releaseResource = (boolean) config.get("releaseresource");
                    }
                    cronExecutingUser = (String) config.get("cronExecutingUser");
                }
            } catch (ClassCastException e) {
                LOGGER.error(e.getMessage(), e);
            }
            if (releaseResource) {
                for (InterpreterSetting setting : notebook.getInterpreterSettingManager()
                        .getInterpreterSettings(note.getId())) {
                    try {
                        notebook.getInterpreterSettingManager().restart(setting.getId(), noteId,
                                cronExecutingUser != null ? cronExecutingUser : "anonymous");
                    } catch (InterpreterException e) {
                        LOGGER.error("Fail to restart interpreter: " + setting.getId(), e);
                    }
                }
            }
        }

        void runAll(Note note) {
            String cronExecutingUser = (String) note.getConfig().get("cronExecutingUser");
            String cronExecutingRoles = (String) note.getConfig().get("cronExecutingRoles");
            if (null == cronExecutingUser) {
                cronExecutingUser = "anonymous";
            }
            AuthenticationInfo authenticationInfo = new AuthenticationInfo(cronExecutingUser,
                    StringUtils.isEmpty(cronExecutingRoles) ? null : cronExecutingRoles, null);
            note.runAll(authenticationInfo, true);
        }
    }

    public void refreshCron(String id) {
        removeCron(id);
        Note note = getNote(id);
        if (note == null || note.isTrash()) {
            return;
        }
        Map<String, Object> config = note.getConfig();
        if (config == null) {
            return;
        }

        if (!note.isCronSupported(getConf())) {
            LOGGER.warn("execution of the cron job is skipped cron is not enabled from Zeppelin server");
            return;
        }

        String cronExpr = (String) note.getConfig().get("cron");
        if (cronExpr == null || cronExpr.trim().length() == 0) {
            return;
        }

        JobDetail newJob = JobBuilder.newJob(CronJob.class).withIdentity(id, "note").usingJobData("noteId", id)
                .build();

        Map<String, Object> info = note.getInfo();
        info.put("cron", null);

        CronTrigger trigger = null;
        try {
            trigger = TriggerBuilder.newTrigger().withIdentity("trigger_" + id, "note")
                    .withSchedule(CronScheduleBuilder.cronSchedule(cronExpr)).forJob(id, "note").build();
        } catch (Exception e) {
            LOGGER.error("Error", e);
            info.put("cron", e.getMessage());
        }

        try {
            if (trigger != null) {
                quartzSched.scheduleJob(newJob, trigger);
            }
        } catch (SchedulerException e) {
            LOGGER.error("Error", e);
            info.put("cron", "Scheduler Exception");
        }

    }

    public void removeCron(String id) {
        try {
            quartzSched.deleteJob(new JobKey(id, "note"));
        } catch (SchedulerException e) {
            LOGGER.error("Can't remove quertz " + id, e);
        }
    }

    public InterpreterFactory getInterpreterFactory() {
        return replFactory;
    }

    public InterpreterSettingManager getInterpreterSettingManager() {
        return interpreterSettingManager;
    }

    public NotebookAuthorization getNotebookAuthorization() {
        return notebookAuthorization;
    }

    public ZeppelinConfiguration getConf() {
        return conf;
    }

    public void close() {
        this.notebookRepo.close();
        this.noteSearchService.close();
    }

    public void addNotebookEventListener(NoteEventListener listener) {
        noteEventListeners.add(listener);
    }

    private void fireNoteCreateEvent(Note note, AuthenticationInfo subject) throws IOException {
        for (NoteEventListener listener : noteEventListeners) {
            listener.onNoteCreate(note, subject);
        }
    }

    private void fireNoteUpdateEvent(Note note, AuthenticationInfo subject) throws IOException {
        for (NoteEventListener listener : noteEventListeners) {
            listener.onNoteUpdate(note, subject);
        }
    }

    private void fireNoteRemoveEvent(Note note, AuthenticationInfo subject) throws IOException {
        for (NoteEventListener listener : noteEventListeners) {
            listener.onNoteRemove(note, subject);
        }
    }

    public Boolean isRevisionSupported() {
        if (notebookRepo instanceof NotebookRepoSync) {
            return ((NotebookRepoSync) notebookRepo).isRevisionSupportedInDefaultRepo();
        } else if (notebookRepo instanceof NotebookRepoWithVersionControl) {
            return true;
        } else {
            return false;
        }
    }
}