Add validation for local java runtime

src/commands/createNewProject/javaSteps/JavaVersionStep.ts

@@ -8,15 +8,23 @@ import { previewDescription } from "../../../constants";
 import { hasMinFuncCliVersion } from "../../../funcCoreTools/hasMinFuncCliVersion";
 import { localize } from "../../../localize";
 import { IJavaProjectWizardContext } from "./IJavaProjectWizardContext";
+import { getJavaVersion } from "./JavaVersions";
 
 export const java8: string = '8';
 export const java11: string = '11';
 export const java17: string = '17';
 
-const versionInfo: [string, string, string, string?][] = [
-    [java8, 'Java 8', '1.0.0'],
-    [java11, 'Java 11', '3.0.2630'],
-    [java17, 'Java 17', '4.0.0', previewDescription]
+type javaVersionInfo = {
+    label: string,
+    data: string,
+    description?: string,
+    miniFunc: string
+}
+
+const versionInfo: javaVersionInfo[] = [
+    { label: 'Java 8', data: java8, miniFunc: '1.0.0' },
+    { label: 'Java 11', data: java11, miniFunc: '3.0.2630' },
+    { label: 'Java 17', data: java17, miniFunc: '4.0.0', description: previewDescription }
 ];
 
 export class JavaVersionStep extends AzureWizardPromptStep<IJavaProjectWizardContext> {
@@ -33,12 +41,12 @@ export class JavaVersionStep extends AzureWizardPromptStep<IJavaProjectWizardCon
         context.javaVersion = (await context.ui.showQuickPick(picks, { placeHolder })).data;
     }
 
-    // todo: get runtime from Get Function App Stacks API and validate local java version
     async getPicks(context: IJavaProjectWizardContext): Promise<IAzureQuickPickItem<string>[]> {
+        const javaVersion: number = await getJavaVersion();
         const result: IAzureQuickPickItem<string>[] = [];
-        for (const [javaVersion, displayName, miniFunc, description] of versionInfo) {
-            if (await hasMinFuncCliVersion(context, miniFunc, context.version)) {
-                result.push({ label: displayName, data: javaVersion, description: description });
+        for (const version of versionInfo) {
+            if (await hasMinFuncCliVersion(context, version.miniFunc, context.version) && javaVersion >= Number(version.data)) {
+                result.push(version);
             }
         }
         return result;

src/commands/createNewProject/javaSteps/JavaVersions.ts

@@ -0,0 +1,69 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+import * as fse from 'fs-extra';
+import { localize } from '../../../localize';
+import { cpUtils } from "../../../utils/cpUtils";
+
+import path = require("path");
+
+export async function getJavaVersion(): Promise<number> {
+    const javaHome: string | undefined = process.env['JAVA_HOME'];
+    let javaVersion = javaHome ? await checkVersionInReleaseFile(javaHome) : undefined;
+    if (!javaVersion) {
+        javaVersion = await checkVersionByCLI(javaHome ? path.join(javaHome, 'bin', 'java') : 'java');
+    }
+    if (!javaVersion) {
+        const message: string = localize('javaNotFound', 'Failed to get java version, please ensure that java is installed and JAVA_HOME is set correctly.');
+        throw Error(message);
+    }
+    return javaVersion;
+}
+
+async function checkVersionInReleaseFile(javaHome: string): Promise<number | undefined> {
+    if (!javaHome) {
+        return undefined;
+    }
+    const releaseFile = path.join(javaHome, "release");
+    if (!fse.existsSync(releaseFile)) {
+        return undefined;
+    }
+
+    try {
+        const content = fse.readFileSync(releaseFile);
+        const regexp = /^JAVA_VERSION="(.*)"/gm;
+        const match = regexp.exec(content.toString());
+        return match ? flattenMajorVersion(match[1]) : undefined;
+    } catch (error) {
+        // ignore
+        return undefined;
+    }
+}
+
+async function checkVersionByCLI(javaExec: string): Promise<number | undefined> {
+    if (!javaExec) {
+        return undefined;
+    }
+    const result: cpUtils.ICommandResult = await cpUtils.tryExecuteCommand(undefined, undefined, javaExec, '-version');
+    const output: string = result.cmdOutputIncludingStderr;
+    const regexp = /version "(.*)"/g;
+    const match = regexp.exec(output);
+    return match ? flattenMajorVersion(match[1]) : undefined;
+}
+
+function flattenMajorVersion(version: string): number {
+    // Ignore '1.' prefix for legacy Java versions
+    if (version.startsWith("1.")) {
+        version = version.substring(2);
+    }
+
+    const regexp = /\d+/g;
+    const match = regexp.exec(version);
+    let javaVersion = 0;
+    if (match) {
+        javaVersion = parseInt(match[0], 10);
+    }
+
+    return javaVersion;
+}