Provide documentation on hover, in .kafka files

Fixes jlandersen#149

Signed-off-by: azerr <[email protected]>

CHANGELOG.md

@@ -7,6 +7,7 @@ All notable changes to `Tools for Apache Kafka®` are documented in this file.
 - Hide internal [strimzi](https://strimzi.io/) topics/consumers by default. See [#176](https://github.com/jlandersen/vscode-kafka/pull/176).
 - Validation for available topics in `.kafka` files. See [#153](https://github.com/jlandersen/vscode-kafka/issues/153).
 - Simplify snippets. See [#180](https://github.com/jlandersen/vscode-kafka/pull/180).
+- Hover support in `.kafka` files. See [#149](https://github.com/jlandersen/vscode-kafka/issues/149).
 
 ## [0.12.0] - 2021-04-26
 ### Added

src/kafka-file/kafkaFileClient.ts

@@ -164,6 +164,12 @@ export function startLanguageClient(
     const diagnostics = new KafkaFileDiagnostics(kafkaFileDocuments, languageService, clusterSettings, clientAccessor, modelProvider, workspaceSettings);
     context.subscriptions.push(diagnostics);
 
+    // Hover
+    const hover = new KafkaFileHoverProvider(kafkaFileDocuments, languageService);
+    context.subscriptions.push(
+        vscode.languages.registerHoverProvider(documentSelector, hover)
+    );
+
     // Open / Close document
     context.subscriptions.push(vscode.workspace.onDidOpenTextDocument(e => {
         if (e.languageId === 'kafka') {
@@ -277,7 +283,7 @@ class KafkaFileCompletionItemProvider extends AbstractKafkaFileFeature implement
         return runSafeAsync(async () => {
             const kafkaFileDocument = this.getKafkaFileDocument(document);
             return this.languageService.doComplete(document, kafkaFileDocument, this.workspaceSettings.producerFakerJSEnabled, position);
-        }, new vscode.CompletionList(), `Error while computing code lenses for ${document.uri}`, token);
+        }, new vscode.CompletionList(), `Error while computing completion for ${document.uri}`, token);
     }
 
 }
@@ -359,3 +365,13 @@ class KafkaFileDiagnostics extends AbstractKafkaFileFeature implements vscode.Di
         this.diagnosticCollection.dispose();
     }
 }
+
+class KafkaFileHoverProvider extends AbstractKafkaFileFeature implements vscode.HoverProvider {
+    provideHover(document: vscode.TextDocument, position: vscode.Position, token: vscode.CancellationToken): vscode.ProviderResult<vscode.Hover> {
+        return runSafeAsync(async () => {
+            const kafkaFileDocument = this.getKafkaFileDocument(document);
+            return this.languageService.doHover(document, kafkaFileDocument, position);
+        }, null, `Error while computing hover for ${document.uri}`, token);       
+    }
+
+}

src/kafka-file/languageservice/kafkaFileLanguageService.ts

@@ -1,11 +1,12 @@
-import { CodeLens, CompletionList, Diagnostic, Position, TextDocument, Uri } from "vscode";
+import { CodeLens, CompletionList, Diagnostic, Hover, Position, TextDocument, Uri } from "vscode";
 import { ClientState, ConsumerLaunchState } from "../../client";
 import { BrokerConfigs } from "../../client/config";
 import { ProducerLaunchState } from "../../client/producer";
 import { KafkaFileDocument, parseKafkaFile } from "./parser/kafkaFileParser";
 import { KafkaFileCodeLenses } from "./services/codeLensProvider";
 import { KafkaFileCompletion } from "./services/completion";
 import { KafkaFileDiagnostics } from "./services/diagnostics";
+import { KafkaFileHover } from "./services/hover";
 
 /**
  * Provider API which gets the state for a given producer.
@@ -49,6 +50,7 @@ export interface TopicProvider {
  *
  */
 export interface LanguageService {
+
     /**
      * Parse the given text document and returns an AST.
      *
@@ -85,6 +87,15 @@ export interface LanguageService {
      * @param kafkaFileDocument the parsed AST.
      */
     doDiagnostics(document: TextDocument, kafkaFileDocument: KafkaFileDocument, producerFakerJSEnabled: boolean): Promise<Diagnostic[]>;
+
+    /**
+     * Returns the hover result for the given text document and parsed AST at given position.
+     *
+     * @param document the text document.
+     * @param kafkaFileDocument the parsed AST.
+     * @param position the position where the hover was triggered.
+     */
+    doHover(document: TextDocument, kafkaFileDocument: KafkaFileDocument, position: Position): Promise<Hover | undefined>;
 }
 
 /**
@@ -100,10 +111,18 @@ export function getLanguageService(producerLaunchStateProvider: ProducerLaunchSt
     const codeLenses = new KafkaFileCodeLenses(producerLaunchStateProvider, consumerLaunchStateProvider, selectedClusterProvider);
     const completion = new KafkaFileCompletion(selectedClusterProvider, topicProvider);
     const diagnostics = new KafkaFileDiagnostics(selectedClusterProvider, topicProvider);
+    const hover = new KafkaFileHover(selectedClusterProvider, topicProvider);
     return {
         parseKafkaFileDocument: (document: TextDocument) => parseKafkaFile(document),
         getCodeLenses: codeLenses.getCodeLenses.bind(codeLenses),
         doComplete: completion.doComplete.bind(completion),
-        doDiagnostics: diagnostics.doDiagnostics.bind(diagnostics)
+        doDiagnostics: diagnostics.doDiagnostics.bind(diagnostics),
+        doHover: hover.doHover.bind(hover)
     };
 }
+
+export function createTopicDocumentation(topic: TopicDetail): string {
+    return `Topic \`${topic.id}\`\n` +
+        ` * partition count: \`${topic.partitionCount}\`\n` +
+        ` * replication factor: \`${topic.replicationFactor}\`\n`;
+}

src/kafka-file/languageservice/parser/kafkaFileParser.ts

@@ -17,7 +17,9 @@ export enum NodeKind {
 export interface Node {
     start: Position;
     end: Position;
+    range(): Range;
     findNodeBefore(offset: Position): Node;
+    findNodeAt(offset: Position): Node;
     lastChild: Node | undefined;
     parent: Node | undefined;
     kind: NodeKind;
@@ -32,10 +34,20 @@ class BaseNode implements Node {
 
     }
 
+    public range(): Range {
+        const start = this.start;
+        const end = this.end;
+        return new Range(start, end);
+    }
+
     public findNodeBefore(offset: Position): Node {
         return this;
     }
 
+    public findNodeAt(offset: Position): Node {
+        return this;
+    }
+
     public get lastChild(): Node | undefined { return undefined; }
 }
 
@@ -65,6 +77,17 @@ class ChildrenNode<T extends Node> extends BaseNode {
         return this;
     }
 
+    public findNodeAt(offset: Position): Node {
+        const idx = findFirst(this.children, c => offset.isBeforeOrEqual(c.start)) - 1;
+        if (idx >= 0) {
+            const child = this.children[idx];
+            if (offset.isAfter(child.start) && offset.isBeforeOrEqual(child.end)) {
+                return child.findNodeAt(offset);
+            }
+        }
+        return this;
+    }
+
     public get lastChild(): Node | undefined { return this.children.length ? this.children[this.children.length - 1] : void 0; };
 }
 
@@ -84,6 +107,7 @@ export class Chunk extends BaseNode {
     constructor(public readonly content: string, start: Position, end: Position, kind: NodeKind) {
         super(start, end, kind);
     }
+
 }
 
 export class Property extends BaseNode {
@@ -106,12 +130,6 @@ export class Property extends BaseNode {
         return this.value?.content.trim();
     }
 
-    public get propertyRange(): Range {
-        const start = this.start;
-        const end = this.end;
-        return new Range(start, end);
-    }
-
     public get propertyKeyRange(): Range {
         const start = this.start;
         const end = this.assignerCharacter ? new Position(this.start.line, this.assignerCharacter) : this.end;
@@ -159,6 +177,13 @@ export class Property extends BaseNode {
         }
         return true;
     }
+
+    findNodeAt(position : Position) : Node {
+        if (this.isBeforeAssigner(position)) {
+            return this.key?.findNodeAt(position) || this;
+        }
+        return this.value?.findNodeAt(position) || this;
+    }
 }
 
 export abstract class Block extends ChildrenNode<Property | Chunk> {

src/kafka-file/languageservice/services/completion.ts

@@ -1,5 +1,5 @@
 import { TextDocument, Position, CompletionList, CompletionItem, SnippetString, MarkdownString, CompletionItemKind, Range } from "vscode";
-import { SelectedClusterProvider, TopicDetail, TopicProvider } from "../kafkaFileLanguageService";
+import { createTopicDocumentation, SelectedClusterProvider, TopicProvider } from "../kafkaFileLanguageService";
 import { consumerModel, fakerjsAPIModel, Model, ModelDefinition, producerModel } from "../model";
 import { Block, BlockType, Chunk, ConsumerBlock, KafkaFileDocument, MustacheExpression, NodeKind, ProducerBlock, Property } from "../parser/kafkaFileParser";
 
@@ -235,19 +235,14 @@ export class KafkaFileCompletion {
             return;
         }
 
-        function createDocumentation(topic: TopicDetail): string {
-            return `Topic \`${topic.id}\`\n` +
-                ` * partition count: \`${topic.partitionCount}\`\n` +
-                ` * replication factor: \`${topic.replicationFactor}\`\n`;
-        }
         const valueRange = property.propertyValueRange;
         try {
             const topics = await this.topicProvider.getTopics(clusterId);
             topics.forEach((topic) => {
                 const value = topic.id;
                 const item = new CompletionItem(value);
                 item.kind = CompletionItemKind.Value;
-                item.documentation = new MarkdownString(createDocumentation(topic));
+                item.documentation = new MarkdownString(createTopicDocumentation(topic));
                 const insertText = new SnippetString(' ');
                 insertText.appendText(value);
                 item.insertText = insertText;

src/kafka-file/languageservice/services/diagnostics.ts

@@ -208,14 +208,14 @@ export class KafkaFileDiagnostics {
         const assigner = property.assignerCharacter;
         if (!assigner) {
             // Error => topic
-            const range = property.propertyRange;
+            const range = property.range();
             diagnostics.push(new Diagnostic(range, `Missing ':' sign after '${propertyName}'`, DiagnosticSeverity.Error));
             return;
         }
         // 1.2. property must declare a key
         if (!propertyName) {
             // Error => :string
-            const range = property.propertyRange;
+            const range = property.range();
             diagnostics.push(new Diagnostic(range, "Property must define a name before ':' sign", DiagnosticSeverity.Error));
             return;
         }
@@ -280,7 +280,7 @@ export class KafkaFileDiagnostics {
                     // The topic validation is done, only when the cluster is connected
                     if (!await this.topicProvider.getTopic(clusterId, topicId)) {
                         // The topic doesn't exist, report an error
-                        const range = topicProperty.propertyTrimmedValueRange || topicProperty.propertyRange;
+                        const range = topicProperty.propertyTrimmedValueRange || topicProperty.range();
                         const autoCreate = await this.topicProvider.getAutoCreateTopicEnabled(clusterId);
                         const errorMessage = getTopicErrorMessage(topicId, autoCreate, blockType);
                         const severity = getTopicErrorSeverity(autoCreate);