Show message if insufficient file watcher handles

CHANGELOG.md

@@ -11,7 +11,7 @@
   - This change triggers the context menu for a given shell tab-bar without the need to activate it
   - While registering a command, `Event` should be passed down, if not passed, then the commands will not work correctly as they no longer rely on the activation of tab-bar
 - [core] Moved `findTitle()` and `findTabBar()` from `common-frontend-contribution.ts` to `application-shell.ts`  [#6965](https://github.com/eclipse-theia/theia/pull/6965)
-
+- [filesystem] show Linux users a warning when Inotify handles have been exhausted, with link to instructions on how to fix [#8458](https://github.com/eclipse-theia/theia/pull/8458)
 
 ## v1.5.0 - 27/08/2020
 

packages/filesystem/src/browser/file-service.ts

@@ -65,6 +65,7 @@ import { UTF8, UTF8_with_bom } from '@theia/core/lib/common/encodings';
 import { EncodingService, ResourceEncoding, DecodeStreamResult } from '@theia/core/lib/common/encoding-service';
 import { Mutable } from '@theia/core/lib/common/types';
 import { readFileIntoStream } from '../common/io';
+import { FileSystemWatcherErrorHandler } from './filesystem-watcher-error-handler';
 
 export interface FileOperationParticipant {
 
@@ -247,6 +248,9 @@ export class FileService {
     @inject(ContributionProvider) @named(FileServiceContribution)
     protected readonly contributions: ContributionProvider<FileServiceContribution>;
 
+    @inject(FileSystemWatcherErrorHandler)
+    protected readonly watcherErrorHandler: FileSystemWatcherErrorHandler;
+
     @postConstruct()
     protected init(): void {
         for (const contribution of this.contributions.getContributions()) {
@@ -308,6 +312,7 @@ export class FileService {
 
         const providerDisposables = new DisposableCollection();
         providerDisposables.push(provider.onDidChangeFile(changes => this.onDidFilesChangeEmitter.fire(new FileChangesEvent(changes))));
+        providerDisposables.push(provider.onFileWatchError(() => this.handleFileWatchError()));
         providerDisposables.push(provider.onDidChangeCapabilities(() => this.onDidChangeFileSystemProviderCapabilitiesEmitter.fire({ provider, scheme })));
 
         return Disposable.create(() => {
@@ -1675,4 +1680,7 @@ export class FileService {
 
     // #endregion
 
+    protected handleFileWatchError(): void {
+        this.watcherErrorHandler.handleError();
+    }
 }

packages/filesystem/src/browser/filesystem-frontend-module.ts

@@ -34,6 +34,7 @@ import { TextDocumentContentChangeEvent } from 'vscode-languageserver-protocol';
 import { EnvVariablesServer } from '@theia/core/lib/common/env-variables';
 import { bindContributionProvider } from '@theia/core/lib/common/contribution-provider';
 import { RemoteFileServiceContribution } from './remote-file-service-contribution';
+import { FileSystemWatcherErrorHandler } from './filesystem-watcher-error-handler';
 import { UTF8 } from '@theia/core/lib/common/encodings';
 
 export default new ContainerModule(bind => {
@@ -50,6 +51,8 @@ export default new ContainerModule(bind => {
     bind(FileServiceContribution).toService(RemoteFileServiceContribution);
 
     bind(FileSystemWatcher).toSelf().inSingletonScope();
+    bind(FileSystemWatcherErrorHandler).toSelf().inSingletonScope();
+
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     bind(FileSystem).toDynamicValue(({ container }) => {
         const fileService = container.get(FileService);

packages/filesystem/src/browser/filesystem-watcher-error-handler.ts

@@ -0,0 +1,60 @@
+/********************************************************************************
+ * Copyright (C) 2020 Arm and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { injectable, inject } from 'inversify';
+import { environment } from '@theia/application-package/lib/environment';
+import { MessageService } from '@theia/core';
+import { WindowService } from '@theia/core/lib/browser/window/window-service';
+
+@injectable()
+export class FileSystemWatcherErrorHandler {
+
+    @inject(MessageService) protected readonly messageService: MessageService;
+    @inject(WindowService) protected readonly windowService: WindowService;
+
+    protected watchHandlesExhausted: boolean = false;
+
+    protected get instructionsLink(): string {
+        return 'https://code.visualstudio.com/docs/setup/linux#_visual-studio-code-is-unable-to-watch-for-file-changes-in-this-large-workspace-error-enospc';
+    }
+
+    public async handleError(): Promise<void> {
+        if (!this.watchHandlesExhausted) {
+            this.watchHandlesExhausted = true;
+            if (this.isElectron()) {
+                const instructionsAction = 'Instructions';
+                const action = await this.messageService.warn(
+                    'Unable to watch for file changes in this large workspace.  Please follow the instructions link to resolve this issue.',
+                    { timeout: 60000 },
+                    instructionsAction
+                );
+                if (action === instructionsAction) {
+                    this.windowService.openNewWindow(this.instructionsLink, { external: true });
+                }
+            } else {
+                await this.messageService.warn(
+                    'Unable to watch for file changes in this large workspace.  The information you see may not include recent file changes.',
+                    { timeout: 60000 }
+                );
+            }
+        }
+    }
+
+    protected isElectron(): boolean {
+        return environment.electron.is();
+    }
+
+}

packages/filesystem/src/common/delegating-file-system-provider.ts

@@ -31,13 +31,18 @@ export class DelegatingFileSystemProvider implements Required<FileSystemProvider
     private readonly onDidChangeFileEmitter = new Emitter<readonly FileChange[]>();
     readonly onDidChangeFile = this.onDidChangeFileEmitter.event;
 
+    private readonly onFileWatchErrorEmitter = new Emitter<void>();
+    readonly onFileWatchError = this.onFileWatchErrorEmitter.event;
+
     constructor(
         protected readonly delegate: FileSystemProvider,
         protected readonly options: DelegatingFileSystemProvider.Options,
         protected readonly toDispose = new DisposableCollection()
     ) {
         this.toDispose.push(this.onDidChangeFileEmitter);
         this.toDispose.push(delegate.onDidChangeFile(changes => this.handleFileChanges(changes)));
+        this.toDispose.push(this.onFileWatchErrorEmitter);
+        this.toDispose.push(delegate.onFileWatchError(changes => this.onFileWatchErrorEmitter.fire()));
     }
 
     dispose(): void {

packages/filesystem/src/common/files.ts

@@ -564,6 +564,7 @@ export interface FileSystemProvider {
     readonly onDidChangeCapabilities: Event<void>;
 
     readonly onDidChangeFile: Event<readonly FileChange[]>;
+    readonly onFileWatchError: Event<void>;
     watch(resource: URI, opts: WatchOptions): IDisposable;
 
     stat(resource: URI): Promise<Stat>;

packages/filesystem/src/common/filesystem-watcher-protocol.ts

@@ -40,6 +40,11 @@ export interface FileSystemWatcherClient {
      * Notify when files under watched uris are changed.
      */
     onDidFilesChanged(event: DidFilesChangedParams): void;
+
+    /**
+     * Notify when unable to watch files because of Linux handle limit.
+     */
+    onError(): void;
 }
 
 export interface WatchOptions {

packages/filesystem/src/common/remote-file-system-provider.ts

@@ -68,6 +68,7 @@ export interface RemoteFileStreamError extends Error {
 
 export interface RemoteFileSystemClient {
     notifyDidChangeFile(event: { changes: RemoteFileChange[] }): void;
+    notifyFileWatchError(): void;
     notifyDidChangeCapabilities(capabilities: FileSystemProviderCapabilities): void;
     onFileStreamData(handle: number, data: number[]): void;
     onFileStreamEnd(handle: number, error: RemoteFileStreamError | undefined): void;
@@ -108,6 +109,9 @@ export class RemoteFileSystemProvider implements Required<FileSystemProvider>, D
     private readonly onDidChangeFileEmitter = new Emitter<readonly FileChange[]>();
     readonly onDidChangeFile = this.onDidChangeFileEmitter.event;
 
+    private readonly onFileWatchErrorEmitter = new Emitter<void>();
+    readonly onFileWatchError = this.onFileWatchErrorEmitter.event;
+
     private readonly onDidChangeCapabilitiesEmitter = new Emitter<void>();
     readonly onDidChangeCapabilities = this.onDidChangeCapabilitiesEmitter.event;
 
@@ -151,6 +155,9 @@ export class RemoteFileSystemProvider implements Required<FileSystemProvider>, D
             notifyDidChangeFile: ({ changes }) => {
                 this.onDidChangeFileEmitter.fire(changes.map(event => ({ resource: new URI(event.resource), type: event.type })));
             },
+            notifyFileWatchError: () => {
+                this.onFileWatchErrorEmitter.fire();
+            },
             notifyDidChangeCapabilities: capabilities => this.setCapabilities(capabilities),
             onFileStreamData: (handle, data) => this.onFileStreamDataEmitter.fire([handle, Uint8Array.from(data)]),
             onFileStreamEnd: (handle, error) => this.onFileStreamEndEmitter.fire([handle, error])
@@ -338,6 +345,11 @@ export class FileSystemProviderServer implements RemoteFileSystemServer {
                 });
             }
         }));
+        this.toDispose.push(this.provider.onFileWatchError(() => {
+            if (this.client) {
+                this.client.notifyFileWatchError();
+            }
+        }));
     }
 
     async getCapabilities(): Promise<FileSystemProviderCapabilities> {

packages/filesystem/src/node/disk-file-system-provider.ts

@@ -95,6 +95,9 @@ export class DiskFileSystemProvider implements Disposable,
     private readonly onDidChangeFileEmitter = new Emitter<readonly FileChange[]>();
     readonly onDidChangeFile = this.onDidChangeFileEmitter.event;
 
+    private readonly onFileWatchErrorEmitter = new Emitter<void>();
+    readonly onFileWatchError = this.onFileWatchErrorEmitter.event;
+
     protected readonly toDispose = new DisposableCollection(
         this.onDidChangeFileEmitter
     );
@@ -112,7 +115,8 @@ export class DiskFileSystemProvider implements Disposable,
             onDidFilesChanged: params => this.onDidChangeFileEmitter.fire(params.changes.map(({ uri, type }) => ({
                 resource: new URI(uri),
                 type
-            })))
+            }))),
+            onError: () => this.onFileWatchErrorEmitter.fire()
         });
     }
 

packages/filesystem/src/node/filesystem-watcher-client.ts

@@ -41,6 +41,11 @@ export class FileSystemWatcherServerClient implements FileSystemWatcherServer {
                 if (this.client) {
                     this.client.onDidFilesChanged(e);
                 }
+            },
+            onError: () => {
+                if (this.client) {
+                    this.client.onError();
+                }
             }
         });
         this.toDispose.push(this.remote);

packages/filesystem/src/node/nsfw-watcher/nsfw-filesystem-watcher.spec.ts

@@ -57,6 +57,8 @@ describe('nsfw-filesystem-watcher', function (): void {
         const watcherClient = {
             onDidFilesChanged(event: DidFilesChangedParams): void {
                 event.changes.forEach(c => actualUris.add(c.uri.toString()));
+            },
+            onError(): void {
             }
         };
         watcherServer.setClient(watcherClient);
@@ -92,6 +94,8 @@ describe('nsfw-filesystem-watcher', function (): void {
         const watcherClient = {
             onDidFilesChanged(event: DidFilesChangedParams): void {
                 event.changes.forEach(c => actualUris.add(c.uri.toString()));
+            },
+            onError(): void {
             }
         };
         watcherServer.setClient(watcherClient);

packages/filesystem/src/node/nsfw-watcher/nsfw-filesystem-watcher.ts

@@ -131,6 +131,11 @@ export class NsfwFileSystemWatcherServer implements FileSystemWatcherServer {
             errorCallback: error => {
                 // see https://github.com/atom/github/issues/342
                 console.warn(`Failed to watch "${basePath}":`, error);
+                if (error === 'Inotify limit reached') {
+                    if (this.client) {
+                        this.client.onError();
+                    }
+                }
                 this.unwatchFileChanges(watcherId);
             },
             ...this.options.nsfwOptions

packages/plugin-ext/src/main/browser/file-system-main-impl.ts

@@ -160,6 +160,7 @@ class RemoteFileSystemProvider implements FileSystemProviderWithFileReadWriteCap
     private readonly _registration: IDisposable;
 
     readonly onDidChangeFile: Event<readonly FileChange[]> = this._onDidChange.event;
+    readonly onFileWatchError: Event<void> = new Emitter<void>().event;  // dummy, never fired
 
     readonly capabilities: FileSystemProviderCapabilities;
     readonly onDidChangeCapabilities: Event<void> = Event.None;