Add isConnected to ServiceManager, use it in hub-extension

packages/application/src/lab.ts

@@ -4,6 +4,7 @@
 import { PageConfig } from '@jupyterlab/coreutils';
 import { Base64ModelFactory } from '@jupyterlab/docregistry';
 import { IRenderMime } from '@jupyterlab/rendermime-interfaces';
+import { ServiceManager } from '@jupyterlab/services';
 import { Token } from '@lumino/coreutils';
 import { JupyterFrontEnd, JupyterFrontEndPlugin } from './frontend';
 import { createRendermimePlugins } from './mimerenderers';
@@ -18,7 +19,17 @@ export class JupyterLab extends JupyterFrontEnd<ILabShell> {
    * Construct a new JupyterLab object.
    */
   constructor(options: JupyterLab.IOptions = { shell: new LabShell() }) {
-    super({ ...options, shell: options.shell || new LabShell() });
+    super({
+      ...options,
+      shell: options.shell || new LabShell(),
+      serviceManager:
+        options.serviceManager ||
+        new ServiceManager({
+          standby: () => {
+            return !this._info.isConnected || 'when-hidden';
+          }
+        })
+    });
     this.restored = this.shell.restored
       .then(() => undefined)
       .catch(() => undefined);
@@ -157,7 +168,7 @@ export class JupyterLab extends JupyterFrontEnd<ILabShell> {
     });
   }
 
-  private _info: JupyterLab.IInfo;
+  private _info: JupyterLab.IInfo = JupyterLab.defaultInfo;
   private _paths: JupyterFrontEnd.IPaths;
 }
 
@@ -207,6 +218,18 @@ export namespace JupyterLab {
      * Whether files are cached on the server.
      */
     readonly filesCached: boolean;
+
+    /**
+     * Every periodic network polling should be paused while this is set
+     * to `false`. Extensions should use this value to decide whether to proceed
+     * with the polling.
+     * The extensions may also set this value to `false` if there is no need to
+     * fetch anything from the server backend basing on some conditions
+     * (e.g. when an error message dialog is displayed).
+     * At the same time, the extensions are responsible for setting this value
+     * back to `true`.
+     */
+    isConnected: boolean;
   }
 
   /**
@@ -217,7 +240,8 @@ export namespace JupyterLab {
     deferred: { patterns: [], matches: [] },
     disabled: { patterns: [], matches: [] },
     mimeExtensions: [],
-    filesCached: PageConfig.getOption('cacheFiles').toLowerCase() === 'true'
+    filesCached: PageConfig.getOption('cacheFiles').toLowerCase() === 'true',
+    isConnected: true
   };
 
   /**

packages/docmanager-extension/src/index.ts

@@ -9,7 +9,8 @@ import {
   ILabShell,
   ILabStatus,
   JupyterFrontEnd,
-  JupyterFrontEndPlugin
+  JupyterFrontEndPlugin,
+  JupyterLab
 } from '@jupyterlab/application';
 import {
   Dialog,
@@ -89,7 +90,8 @@ const docManagerPlugin: JupyterFrontEndPlugin<IDocumentManager> = {
     ICommandPalette,
     ILabShell,
     ISessionContextDialogs,
-    IDocumentProviderFactory
+    IDocumentProviderFactory,
+    JupyterLab.IInfo
   ],
   activate: (
     app: JupyterFrontEnd,
@@ -99,7 +101,8 @@ const docManagerPlugin: JupyterFrontEndPlugin<IDocumentManager> = {
     palette: ICommandPalette | null,
     labShell: ILabShell | null,
     sessionDialogs: ISessionContextDialogs | null,
-    docProviderFactory: IDocumentProviderFactory | null
+    docProviderFactory: IDocumentProviderFactory | null,
+    info: JupyterLab.IInfo | null
   ): IDocumentManager => {
     const trans = translator.load('jupyterlab');
     const manager = app.serviceManager;
@@ -139,7 +142,13 @@ const docManagerPlugin: JupyterFrontEndPlugin<IDocumentManager> = {
       sessionDialogs: sessionDialogs || undefined,
       translator,
       collaborative: true,
-      docProviderFactory: docProviderFactory ?? undefined
+      docProviderFactory: docProviderFactory ?? undefined,
+      isConnectedCallback: () => {
+        if (info) {
+          return info.isConnected;
+        }
+        return true;
+      }
     });
 
     // Register the file operations commands.

packages/docmanager/src/manager.ts

@@ -42,6 +42,7 @@ export class DocumentManager implements IDocumentManager {
     this._collaborative = !!options.collaborative;
     this._dialogs = options.sessionDialogs || sessionContextDialogs;
     this._docProviderFactory = options.docProviderFactory;
+    this._isConnectedCallback = options.isConnectedCallback || (() => true);
 
     this._opener = options.opener;
     this._when = options.when || options.manager.ready;
@@ -477,6 +478,7 @@ export class DocumentManager implements IDocumentManager {
     });
     const handler = new SaveHandler({
       context,
+      isConnectedCallback: this._isConnectedCallback,
       saveInterval: this.autosaveInterval
     });
     Private.saveHandlerProperty.set(context, handler);
@@ -602,6 +604,7 @@ export class DocumentManager implements IDocumentManager {
   private _dialogs: ISessionContext.IDialogs;
   private _docProviderFactory: IDocumentProviderFactory | undefined;
   private _collaborative: boolean;
+  private _isConnectedCallback: () => boolean;
 }
 
 /**
@@ -657,6 +660,12 @@ export namespace DocumentManager {
      * If true, the context will connect through yjs_ws_server to share information if possible.
      */
     collaborative?: boolean;
+
+    /**
+     * Autosaving should be paused while this callback function returns `false`.
+     * By default, it always returns `true`.
+     */
+    isConnectedCallback?: () => boolean;
   }
 
   /**

packages/docmanager/src/savehandler.ts

@@ -17,6 +17,7 @@ export class SaveHandler implements IDisposable {
    */
   constructor(options: SaveHandler.IOptions) {
     this._context = options.context;
+    this._isConnectedCallback = options.isConnectedCallback || (() => true);
     const interval = options.saveInterval || 120;
     this._minInterval = interval * 1000;
     this._interval = this._minInterval;
@@ -89,7 +90,9 @@ export class SaveHandler implements IDisposable {
       return;
     }
     this._autosaveTimer = window.setTimeout(() => {
-      this._save();
+      if (this._isConnectedCallback()) {
+        this._save();
+      }
     }, this._interval);
   }
 
@@ -144,6 +147,7 @@ export class SaveHandler implements IDisposable {
   private _minInterval = -1;
   private _interval = -1;
   private _context: DocumentRegistry.Context;
+  private _isConnectedCallback: () => boolean;
   private _isActive = false;
   private _inDialog = false;
   private _isDisposed = false;
@@ -163,6 +167,12 @@ export namespace SaveHandler {
      */
     context: DocumentRegistry.Context;
 
+    /**
+     * Autosaving should be paused while this callback function returns `false`.
+     * By default, it always returns `true`.
+     */
+    isConnectedCallback?: () => boolean;
+
     /**
      * The minimum save interval in seconds (default is two minutes).
      */

packages/filebrowser-extension/src/index.ts

@@ -11,7 +11,8 @@ import {
   IRouter,
   ITreePathUpdater,
   JupyterFrontEnd,
-  JupyterFrontEndPlugin
+  JupyterFrontEndPlugin,
+  JupyterLab
 } from '@jupyterlab/application';
 import {
   Clipboard,
@@ -246,14 +247,20 @@ const factory: JupyterFrontEndPlugin<IFileBrowserFactory> = {
   id: '@jupyterlab/filebrowser-extension:factory',
   provides: IFileBrowserFactory,
   requires: [IDocumentManager, ITranslator],
-  optional: [IStateDB, IRouter, JupyterFrontEnd.ITreeResolver],
+  optional: [
+    IStateDB,
+    IRouter,
+    JupyterFrontEnd.ITreeResolver,
+    JupyterLab.IInfo
+  ],
   activate: async (
     app: JupyterFrontEnd,
     docManager: IDocumentManager,
     translator: ITranslator,
     state: IStateDB | null,
     router: IRouter | null,
-    tree: JupyterFrontEnd.ITreeResolver | null
+    tree: JupyterFrontEnd.ITreeResolver | null,
+    info: JupyterLab.IInfo | null
   ): Promise<IFileBrowserFactory> => {
     const { commands } = app;
     const tracker = new WidgetTracker<FileBrowser>({ namespace });
@@ -267,6 +274,12 @@ const factory: JupyterFrontEndPlugin<IFileBrowserFactory> = {
         manager: docManager,
         driveName: options.driveName || '',
         refreshInterval: options.refreshInterval,
+        refreshStandby: () => {
+          if (info) {
+            return !info.isConnected || 'when-hidden';
+          }
+          return 'when-hidden';
+        },
         state:
           options.state === null
             ? undefined

packages/filebrowser/src/model.ts

@@ -103,7 +103,7 @@ export class FileBrowserModel implements IDisposable {
         backoff: true,
         max: 300 * 1000
       },
-      standby: 'when-hidden'
+      standby: options.refreshStandby || 'when-hidden'
     });
   }
 
@@ -695,6 +695,11 @@ export namespace FileBrowserModel {
      */
     refreshInterval?: number;
 
+    /**
+     * When the model stops polling the API. Defaults to `when-hidden`.
+     */
+    refreshStandby?: Poll.Standby | (() => boolean | Poll.Standby);
+
     /**
      * An optional state database. If provided, the model will restore which
      * folder was last opened when it is restored.

packages/hub-extension/src/index.ts

@@ -11,7 +11,8 @@ import {
   ConnectionLost,
   IConnectionLost,
   JupyterFrontEnd,
-  JupyterFrontEndPlugin
+  JupyterFrontEndPlugin,
+  JupyterLab
 } from '@jupyterlab/application';
 import { Dialog, ICommandPalette, showDialog } from '@jupyterlab/apputils';
 import { URLExt } from '@jupyterlab/coreutils';
@@ -125,10 +126,12 @@ const hubExtensionMenu: JupyterFrontEndPlugin<void> = {
 const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
   id: '@jupyterlab/apputils-extension:connectionlost',
   requires: [JupyterFrontEnd.IPaths, ITranslator],
+  optional: [JupyterLab.IInfo],
   activate: (
     app: JupyterFrontEnd,
     paths: JupyterFrontEnd.IPaths,
-    translator: ITranslator
+    translator: ITranslator,
+    info: JupyterLab.IInfo | null
   ): IConnectionLost => {
     const trans = translator.load('jupyterlab');
     const hubPrefix = paths.urls.hubPrefix || '';
@@ -149,7 +152,12 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
       if (showingError) {
         return;
       }
+
       showingError = true;
+      if (info) {
+        info.isConnected = false;
+      }
+
       const result = await showDialog({
         title: trans.__('Server unavailable or unreachable'),
         body: trans.__(
@@ -161,7 +169,12 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
           Dialog.cancelButton({ label: trans.__('Dismiss') })
         ]
       });
+
+      if (info) {
+        info.isConnected = true;
+      }
       showingError = false;
+
       if (result.button.accept) {
         await app.commands.execute(CommandIDs.restart);
       }

packages/services/src/kernel/manager.ts

@@ -337,6 +337,6 @@ export namespace KernelManager {
     /**
      * When the manager stops polling the API. Defaults to `when-hidden`.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
   }
 }

packages/services/src/kernelspec/manager.ts

@@ -147,6 +147,6 @@ export namespace KernelSpecManager {
     /**
      * When the manager stops polling the API. Defaults to `when-hidden`.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
   }
 }

packages/services/src/manager.ts

@@ -254,6 +254,6 @@ export namespace ServiceManager {
     /**
      * When the manager stops polling the API. Defaults to `when-hidden`.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
   }
 }

packages/services/src/session/manager.ts

@@ -355,7 +355,7 @@ export namespace SessionManager {
     /**
      * When the manager stops polling the API. Defaults to `when-hidden`.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
 
     /**
      * Kernel Manager

packages/services/src/terminal/manager.ts

@@ -289,6 +289,6 @@ export namespace TerminalManager {
     /**
      * When the manager stops polling the API. Defaults to `when-hidden`.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
   }
 }