Add bandwidthSaveMode to ServiceManager, use it in hub-extension

packages/docmanager/src/manager.ts

@@ -485,7 +485,8 @@ export class DocumentManager implements IDocumentManager {
     });
     const handler = new SaveHandler({
       context,
-      saveInterval: this.autosaveInterval
+      saveInterval: this.autosaveInterval,
+      services: this.services
     });
     Private.saveHandlerProperty.set(context, handler);
     void context.ready.then(() => {

packages/docmanager/src/savehandler.ts

@@ -5,6 +5,8 @@ import { IDisposable } from '@lumino/disposable';
 
 import { Signal } from '@lumino/signaling';
 
+import { ServiceManager } from '@jupyterlab/services';
+
 import { DocumentRegistry } from '@jupyterlab/docregistry';
 
 /**
@@ -19,6 +21,7 @@ export class SaveHandler implements IDisposable {
    */
   constructor(options: SaveHandler.IOptions) {
     this._context = options.context;
+    this._services = options.services;
     const interval = options.saveInterval || 120;
     this._minInterval = interval * 1000;
     this._interval = this._minInterval;
@@ -91,7 +94,9 @@ export class SaveHandler implements IDisposable {
       return;
     }
     this._autosaveTimer = window.setTimeout(() => {
-      this._save();
+      if (!this._services.bandwidthSaveMode) {
+        this._save();
+      }
     }, this._interval);
   }
 
@@ -146,6 +151,7 @@ export class SaveHandler implements IDisposable {
   private _minInterval = -1;
   private _interval = -1;
   private _context: DocumentRegistry.Context;
+  private _services: ServiceManager.IManager;
   private _isActive = false;
   private _inDialog = false;
   private _isDisposed = false;
@@ -169,5 +175,10 @@ export namespace SaveHandler {
      * The minimum save interval in seconds (default is two minutes).
      */
     saveInterval?: number;
+
+    /**
+     * A service manager instance.
+     */
+    services: ServiceManager.IManager;
   }
 }

packages/docmanager/test/savehandler.spec.ts

@@ -38,7 +38,7 @@ describe('docregistry/savehandler', () => {
       factory,
       path: UUID.uuid4() + '.txt'
     });
-    handler = new SaveHandler({ context });
+    handler = new SaveHandler({ context, services: manager });
     return context.initialize(true);
   });
 

packages/filebrowser/src/model.ts

@@ -113,7 +113,9 @@ export class FileBrowserModel implements IDisposable {
         backoff: true,
         max: 300 * 1000
       },
-      standby: 'when-hidden'
+      standby: () => {
+        return services.bandwidthSaveMode || 'when-hidden';
+      }
     });
   }
 

packages/hub-extension/src/index.ts

@@ -153,6 +153,7 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
         return;
       }
       showingError = true;
+      manager.bandwidthSaveMode = true;
       const result = await showDialog({
         title: trans.__('Server unavailable or unreachable'),
         body: trans.__(
@@ -164,6 +165,7 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
           Dialog.cancelButton({ label: trans.__('Dismiss') })
         ]
       });
+      manager.bandwidthSaveMode = false;
       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

@@ -37,7 +37,12 @@ export class ServiceManager implements ServiceManager.IManager {
     const defaultDrive = options.defaultDrive;
     const serverSettings =
       options.serverSettings ?? ServerConnection.makeSettings();
-    const standby = options.standby ?? 'when-hidden';
+
+    const standby =
+      options.standby ??
+      (() => {
+        return this.bandwidthSaveMode || 'when-hidden';
+      });
     const normalized = { defaultDrive, serverSettings, standby };
 
     const kernelManager = new KernelManager(normalized);
@@ -158,6 +163,23 @@ export class ServiceManager implements ServiceManager.IManager {
     return this._readyPromise;
   }
 
+  /**
+   * Every periodic network polling should be paused while
+   * this is set to true. Extensions should use this value
+   * to decide whether to proceed with the polling.
+   * The extensions may also set this value to true 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 false.
+   */
+  get bandwidthSaveMode(): boolean {
+    return this._bandwidthSaveMode;
+  }
+  set bandwidthSaveMode(value: boolean) {
+    this._bandwidthSaveMode = value;
+  }
+
   private _onConnectionFailure(sender: any, err: Error): void {
     this._connectionFailure.emit(err);
   }
@@ -166,6 +188,7 @@ export class ServiceManager implements ServiceManager.IManager {
   private _readyPromise: Promise<void>;
   private _connectionFailure = new Signal<this, Error>(this);
   private _isReady = false;
+  private _bandwidthSaveMode = false;
 }
 
 /**
@@ -235,6 +258,18 @@ export namespace ServiceManager {
      * A signal emitted when there is a connection failure with the server.
      */
     readonly connectionFailure: ISignal<IManager, Error>;
+
+    /**
+     * Every periodic network polling should be paused while
+     * this is set to true. Extensions should use this value
+     * to decide whether to proceed with the polling.
+     * The extensions may also set this value to true 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 false.
+     */
+    bandwidthSaveMode: boolean;
   }
 
   /**
@@ -252,8 +287,8 @@ export namespace ServiceManager {
     readonly defaultDrive?: Contents.IDrive;
 
     /**
-     * When the manager stops polling the API. Defaults to `when-hidden`.
+     * When the manager stops polling the API.
      */
-    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);
   }
 }