Moved the NodeJS version of the application to the app/ directory.

app/Dockerfile

@@ -0,0 +1,34 @@
+FROM node:24-trixie-slim AS build
+
+WORKDIR /app
+
+COPY app-new/backend/package*.json backend/
+COPY app-new/frontend/package*.json frontend/
+RUN cd backend && npm ci
+RUN cd frontend && npm ci
+
+COPY app-new .
+
+RUN cd backend && npm run build
+RUN cd frontend && npm run build
+RUN cd backend && npm prune --omit=dev
+
+FROM node:24-trixie-slim AS runtime
+
+WORKDIR /app
+ENV NODE_ENV=production
+ENV PORT=3000
+
+COPY --from=build /app/dist dist
+COPY --from=build /app/templates templates
+COPY --from=build /app/templates.json templates.json
+COPY --from=build /app/backend/node_modules dist/backend/node_modules
+
+WORKDIR /app
+COPY entrypoint.sh entrypoint.sh
+COPY healthcheck.js healthcheck.js
+RUN chmod +x entrypoint.sh
+
+EXPOSE 3000
+HEALTHCHECK --interval=30s --timeout=5s --start-period=15s --retries=3 CMD ["node", "/app/healthcheck.js"]
+ENTRYPOINT ["./entrypoint.sh"]

app/backend/package.json

@@ -0,0 +1,30 @@
+{
+  "name": "azure-image-chooser-backend",
+  "version": "0.1.0",
+  "private": true,
+  "type": "commonjs",
+  "scripts": {
+    "build": "tsc -p tsconfig.json",
+    "dev": "tsx watch src/server.ts",
+    "start": "node ../dist/backend/server.js",
+    "test": "vitest run"
+  },
+  "dependencies": {
+    "@azure/arm-compute": "^23.3.0",
+    "@azure/identity": "^4.13.1",
+    "cors": "^2.8.5",
+    "dotenv": "^17.2.3",
+    "express": "^5.2.1",
+    "nunjucks": "^3.2.4",
+    "zod": "^4.3.6"
+  },
+  "devDependencies": {
+    "@types/cors": "^2.8.19",
+    "@types/express": "^5.0.3",
+    "@types/nunjucks": "^3.2.6",
+    "@types/node": "^24.9.1",
+    "typescript": "^6.0.3",
+    "tsx": "^4.20.6",
+    "vitest": "^3.2.4"
+  }
+}

app/backend/src/azure-service.ts

@@ -0,0 +1,130 @@
+import { ComputeManagementClient } from "@azure/arm-compute";
+import { DefaultAzureCredential } from "@azure/identity";
+import { MemoryCache } from "./cache";
+import { sortImageVersionsIfSemantic } from "./version";
+import type { LocationOption } from "./types";
+
+const CACHE_TTL_MS = 5 * 60 * 1000;
+
+export class AzureImageService {
+  private readonly credential = new DefaultAzureCredential();
+
+  private readonly computeClient: ComputeManagementClient;
+
+  private readonly cache = new MemoryCache();
+
+  public constructor(private readonly subscriptionId: string) {
+    this.computeClient = new ComputeManagementClient(this.credential, subscriptionId);
+  }
+
+  public async getLocations(): Promise<LocationOption[]> {
+    const cacheKey = "locations";
+    const cached = this.cache.get<LocationOption[]>(cacheKey);
+    if (cached) {
+      return cached;
+    }
+
+    const token = await this.credential.getToken("https://management.azure.com/.default");
+    const url = `https://management.azure.com/subscriptions/${this.subscriptionId}/locations?api-version=2022-12-01`;
+    const response = await fetch(url, {
+      headers: {
+        Authorization: `Bearer ${token?.token ?? ""}`
+      }
+    });
+
+    if (!response.ok) {
+      throw new Error(`Failed to fetch Azure locations: ${response.status} ${response.statusText}`);
+    }
+
+    const payload = (await response.json()) as {
+      value?: Array<{ name?: string; displayName?: string; metadata?: { regionType?: string } }>;
+    };
+
+    const allLocations = (payload.value ?? [])
+      .filter((loc) => Boolean(loc.name))
+      .map((loc) => ({
+        name: loc.name as string,
+        displayName: loc.displayName ?? (loc.name as string),
+        regionType: loc.metadata?.regionType
+      }));
+
+    const physical = allLocations.filter((loc) => loc.regionType?.toLowerCase() === "physical");
+    const locations = (physical.length > 0 ? physical : allLocations).map((loc) => ({
+      name: loc.name,
+      displayName: loc.displayName
+    }));
+
+    locations.sort((a, b) => a.name.localeCompare(b.name));
+    this.cache.set(cacheKey, locations, CACHE_TTL_MS);
+    return locations;
+  }
+
+  public async getPublishers(location: string): Promise<string[]> {
+    const cacheKey = `publishers:${location}`;
+    const cached = this.cache.get<string[]>(cacheKey);
+    if (cached) {
+      return cached;
+    }
+
+    const response = await this.computeClient.virtualMachineImages.listPublishers(location);
+    const publishers = this.extractNames(response).sort((a, b) => a.localeCompare(b));
+
+    this.cache.set(cacheKey, publishers, CACHE_TTL_MS);
+    return publishers;
+  }
+
+  public async getOffers(location: string, publisher: string): Promise<string[]> {
+    const cacheKey = `offers:${location}:${publisher}`;
+    const cached = this.cache.get<string[]>(cacheKey);
+    if (cached) {
+      return cached;
+    }
+
+    const response = await this.computeClient.virtualMachineImages.listOffers(location, publisher);
+    const offers = this.extractNames(response).sort((a, b) => a.localeCompare(b));
+
+    this.cache.set(cacheKey, offers, CACHE_TTL_MS);
+    return offers;
+  }
+
+  public async getSkus(location: string, publisher: string, offer: string): Promise<string[]> {
+    const cacheKey = `skus:${location}:${publisher}:${offer}`;
+    const cached = this.cache.get<string[]>(cacheKey);
+    if (cached) {
+      return cached;
+    }
+
+    const response = await this.computeClient.virtualMachineImages.listSkus(location, publisher, offer);
+    const skus = this.extractNames(response).sort((a, b) => a.localeCompare(b));
+
+    this.cache.set(cacheKey, skus, CACHE_TTL_MS);
+    return skus;
+  }
+
+  public async getVersions(location: string, publisher: string, offer: string, sku: string): Promise<string[]> {
+    const cacheKey = `versions:${location}:${publisher}:${offer}:${sku}`;
+    const cached = this.cache.get<string[]>(cacheKey);
+    if (cached) {
+      return cached;
+    }
+
+    const response = await this.computeClient.virtualMachineImages.list(location, publisher, offer, sku);
+    const versions = this.extractNames(response);
+
+    const sorted = sortImageVersionsIfSemantic(versions);
+    this.cache.set(cacheKey, sorted, CACHE_TTL_MS);
+    return sorted;
+  }
+
+  private extractNames(source: unknown): string[] {
+    const items = Array.isArray(source)
+      ? source
+      : typeof source === "object" && source !== null && "value" in source && Array.isArray((source as { value?: unknown }).value)
+        ? ((source as { value: unknown[] }).value as unknown[])
+        : [];
+
+    return items
+      .map((item) => (typeof item === "object" && item !== null && "name" in item ? (item as { name?: string }).name : undefined))
+      .filter((value): value is string => Boolean(value));
+  }
+}

app/backend/src/cache.ts

@@ -0,0 +1,29 @@
+type CacheEntry<T> = {
+  value: T;
+  expiresAt: number;
+};
+
+export class MemoryCache {
+  private readonly store = new Map<string, CacheEntry<unknown>>();
+
+  public get<T>(key: string): T | undefined {
+    const hit = this.store.get(key);
+    if (!hit) {
+      return undefined;
+    }
+
+    if (Date.now() >= hit.expiresAt) {
+      this.store.delete(key);
+      return undefined;
+    }
+
+    return hit.value as T;
+  }
+
+  public set<T>(key: string, value: T, ttlMs: number): void {
+    this.store.set(key, {
+      value,
+      expiresAt: Date.now() + ttlMs
+    });
+  }
+}

app/backend/src/server.ts

@@ -0,0 +1,195 @@
+import { existsSync } from "node:fs";
+import { join } from "node:path";
+import cors from "cors";
+import express from "express";
+import { z } from "zod";
+import { AzureImageService } from "./azure-service";
+import { TemplateService } from "./template-service";
+
+const findAppNewRoot = (): string => {
+  const candidates = [join(__dirname, "../../.."), join(__dirname, "../..")];
+
+  for (const candidate of candidates) {
+    if (existsSync(join(candidate, "templates.json"))) {
+      return candidate;
+    }
+  }
+
+  throw new Error("Unable to resolve app-new root");
+};
+
+const queryLocation = z.object({ location: z.string().min(1) });
+const queryOffer = z.object({ location: z.string().min(1), publisher: z.string().min(1) });
+const querySku = z.object({ location: z.string().min(1), publisher: z.string().min(1), offer: z.string().min(1) });
+const queryVersion = z.object({ location: z.string().min(1), publisher: z.string().min(1), offer: z.string().min(1), sku: z.string().min(1) });
+
+const renderBody = z.object({
+  templateFile: z.string().min(1),
+  selection: z.object({
+    location: z.string().min(1),
+    publisher: z.string().min(1),
+    offer: z.string().min(1),
+    sku: z.string().min(1),
+    version: z.string().min(1)
+  })
+});
+
+const makeApp = () => {
+  const app = express();
+  const port = Number.parseInt(process.env.PORT ?? "3000", 10);
+  const subscriptionId = process.env.AZURE_SUBSCRIPTION_ID;
+
+  app.use(cors());
+  app.use(express.json());
+
+  const azure = subscriptionId ? new AzureImageService(subscriptionId) : null;
+  const templates = new TemplateService();
+
+  app.get("/api/health", (_req, res) => {
+    if (!subscriptionId) {
+      res.status(500).json({
+        status: "error",
+        message: "Missing AZURE_SUBSCRIPTION_ID"
+      });
+      return;
+    }
+
+    res.json({ status: "ok" });
+  });
+
+  const requireAzure = (): AzureImageService => {
+    if (!azure) {
+      throw new Error("Missing AZURE_SUBSCRIPTION_ID");
+    }
+
+    return azure;
+  };
+
+  app.get("/api/locations", async (_req, res, next) => {
+    try {
+      res.json(await requireAzure().getLocations());
+    } catch (error) {
+      next(error);
+    }
+  });
+
+  app.get("/api/publishers", async (req, res, next) => {
+    try {
+      const { location } = queryLocation.parse(req.query);
+      res.json(await requireAzure().getPublishers(location));
+    } catch (error) {
+      next(error);
+    }
+  });
+
+  app.get("/api/offers", async (req, res, next) => {
+    try {
+      const { location, publisher } = queryOffer.parse(req.query);
+      res.json(await requireAzure().getOffers(location, publisher));
+    } catch (error) {
+      next(error);
+    }
+  });
+
+  app.get("/api/skus", async (req, res, next) => {
+    try {
+      const { location, publisher, offer } = querySku.parse(req.query);
+      res.json(await requireAzure().getSkus(location, publisher, offer));
+    } catch (error) {
+      next(error);
+    }
+  });
+
+  app.get("/api/versions", async (req, res, next) => {
+    try {
+      const { location, publisher, offer, sku } = queryVersion.parse(req.query);
+      res.json(await requireAzure().getVersions(location, publisher, offer, sku));
+    } catch (error) {
+      next(error);
+    }
+  });
+
+  app.get("/api/templates", (_req, res) => {
+    res.json(templates.getTemplates());
+  });
+
+  app.post("/api/render", (req, res, next) => {
+    try {
+      const payload = renderBody.parse(req.body);
+      const rendered = templates.render(payload.templateFile, payload.selection);
+      res.json({ rendered });
+    } catch (error) {
+      next(error);
+    }
+  });
+
+  app.get("/api/sku-export", async (req, res, next) => {
+    try {
+      const { location, publisher, offer } = querySku.parse(req.query);
+      const skus = await requireAzure().getSkus(location, publisher, offer);
+      res.json({ rendered: templates.buildSkuExport(skus) });
+    } catch (error) {
+      next(error);
+    }
+  });
+
+  app.use((err: unknown, _req: express.Request, res: express.Response, _next: express.NextFunction) => {
+    if (err instanceof z.ZodError) {
+      res.status(400).json({ message: "Invalid request", issues: err.issues });
+      return;
+    }
+
+    const message = err instanceof Error ? err.message : "Unexpected error";
+    res.status(500).json({ message });
+  });
+
+  const frontendRoot = join(findAppNewRoot(), "dist/frontend");
+  if (existsSync(frontendRoot)) {
+    app.use(express.static(frontendRoot));
+    app.get(/^(?!\/api).*/, (_req, res) => {
+      res.sendFile(join(frontendRoot, "index.html"));
+    });
+  }
+
+  return { app, port };
+};
+
+if (require.main === module) {
+  const { app, port } = makeApp();
+  const server = app.listen(port, () => {
+    // eslint-disable-next-line no-console
+    console.log(`azure-image-chooser listening on ${port}`);
+  });
+
+  let shuttingDown = false;
+  const shutdown = (signal: NodeJS.Signals) => {
+    if (shuttingDown) {
+      return;
+    }
+
+    shuttingDown = true;
+    // eslint-disable-next-line no-console
+    console.log(`received ${signal}, shutting down`);
+    server.close((error) => {
+      if (error) {
+        // eslint-disable-next-line no-console
+        console.error("graceful shutdown failed", error);
+        process.exit(1);
+      }
+
+      process.exit(0);
+    });
+
+    // Force-exit if connections do not close in time.
+    setTimeout(() => {
+      // eslint-disable-next-line no-console
+      console.error("shutdown timeout reached, forcing exit");
+      process.exit(1);
+    }, 10_000).unref();
+  };
+
+  process.on("SIGTERM", shutdown);
+  process.on("SIGINT", shutdown);
+}
+
+export { makeApp };

app/backend/src/template-service.ts

@@ -0,0 +1,41 @@
+import { existsSync, readFileSync } from "node:fs";
+import { join } from "node:path";
+import nunjucks from "nunjucks";
+import type { ImageSelection, UsageTemplate } from "./types";
+
+const findAppNewRoot = (): string => {
+  const candidates = [join(__dirname, "../../.."), join(__dirname, "../..")];
+
+  for (const candidate of candidates) {
+    if (existsSync(join(candidate, "templates.json"))) {
+      return candidate;
+    }
+  }
+
+  throw new Error("Unable to resolve app-new template root");
+};
+
+export class TemplateService {
+  private readonly appNewRoot = findAppNewRoot();
+
+  private readonly env = nunjucks.configure(join(this.appNewRoot, "templates"), {
+    autoescape: false,
+    noCache: true
+  });
+
+  private readonly templates: UsageTemplate[] = JSON.parse(
+    readFileSync(join(this.appNewRoot, "templates.json"), "utf8")
+  ) as UsageTemplate[];
+
+  public getTemplates(): UsageTemplate[] {
+    return this.templates;
+  }
+
+  public render(templateFile: string, selection: ImageSelection): string {
+    return this.env.render(templateFile, selection);
+  }
+
+  public buildSkuExport(skus: string[]): string {
+    return `[\n${skus.map((sku) => `\t\"${sku}\"`).join(",\n")}\n]`;
+  }
+}

app/backend/src/types.ts

@@ -0,0 +1,18 @@
+export type LocationOption = {
+  name: string;
+  displayName: string;
+};
+
+export type UsageTemplate = {
+  label: string;
+  language: string;
+  file: string;
+};
+
+export type ImageSelection = {
+  location: string;
+  publisher: string;
+  offer: string;
+  sku: string;
+  version: string;
+};

app/backend/src/version.ts

@@ -0,0 +1,22 @@
+const SEMVER_PATTERN = /^[0-9]+\.[0-9]+\.[0-9]+$/;
+
+const semverSortKey = (value: string): number[] => value.split(".").map((part) => Number.parseInt(part, 10));
+
+export const sortImageVersionsIfSemantic = (versions: string[]): string[] => {
+  if (!versions.every((value) => SEMVER_PATTERN.test(value))) {
+    return [...versions].sort((a, b) => a.localeCompare(b, undefined, { numeric: true, sensitivity: "base" }));
+  }
+
+  return [...versions].sort((a, b) => {
+    const aParts = semverSortKey(a);
+    const bParts = semverSortKey(b);
+
+    for (let i = 0; i < aParts.length; i += 1) {
+      if (aParts[i] !== bParts[i]) {
+        return aParts[i] - bParts[i];
+      }
+    }
+
+    return 0;
+  });
+};

app/backend/test/version.test.ts

@@ -0,0 +1,14 @@
+import { describe, expect, it } from "vitest";
+import { sortImageVersionsIfSemantic } from "../src/version";
+
+describe("sortImageVersionsIfSemantic", () => {
+  it("sorts only semantic versions", () => {
+    const sorted = sortImageVersionsIfSemantic(["1.10.0", "1.2.0", "2.0.0"]);
+    expect(sorted).toEqual(["1.2.0", "1.10.0", "2.0.0"]);
+  });
+
+  it("sorts non-semantic versions naturally", () => {
+    const original = ["latest", "1.0.0", "beta"];
+    expect(sortImageVersionsIfSemantic(original)).toEqual(["1.0.0", "beta", "latest"]);
+  });
+});

app/backend/tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "Node16",
+    "moduleResolution": "Node16",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "rootDir": "src",
+    "outDir": "../dist/backend",
+    "types": ["node", "vitest/globals"]
+  },
+  "include": ["src"]
+}

app/entrypoint.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env sh
+set -eu
+
+exec node /app/dist/backend/server.js

app/frontend/index.html

@@ -0,0 +1,12 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Azure Image Chooser</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>

app/frontend/package.json

@@ -0,0 +1,31 @@
+{
+  "name": "azure-image-chooser-frontend",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -p tsconfig.json && vite build",
+    "preview": "vite preview",
+    "test": "vitest run"
+  },
+  "dependencies": {
+    "@emotion/react": "^11.14.0",
+    "@emotion/styled": "^11.14.1",
+    "@mui/material": "^9.0.0",
+    "@tanstack/react-query": "^5.99.2",
+    "react": "^19.2.5",
+    "react-dom": "^19.2.5"
+  },
+  "devDependencies": {
+    "@testing-library/jest-dom": "^6.9.1",
+    "@testing-library/react": "^16.3.0",
+    "@types/react": "^19.2.14",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^6.0.1",
+    "jsdom": "^27.0.1",
+    "typescript": "^6.0.3",
+    "vite": "^8.0.8",
+    "vitest": "^3.2.4"
+  }
+}

app/frontend/src/App.tsx

@@ -0,0 +1,292 @@
+import { useEffect, useMemo, useState } from "react";
+import {
+  Alert,
+  Autocomplete,
+  Box,
+  Button,
+  Card,
+  CardContent,
+  CircularProgress,
+  Container,
+  FormControl,
+  Grid,
+  InputLabel,
+  MenuItem,
+  Select,
+  Stack,
+  TextField,
+  Typography
+} from "@mui/material";
+import { useQuery } from "@tanstack/react-query";
+import { api } from "./api";
+import type { SelectionState } from "./types";
+
+const EMPTY_SELECTION: SelectionState = {
+  location: "",
+  publisher: "",
+  offer: "",
+  sku: "",
+  version: ""
+};
+
+const App = () => {
+  const [selection, setSelection] = useState<SelectionState>(EMPTY_SELECTION);
+  const [templateFile, setTemplateFile] = useState("");
+  const [renderedUsage, setRenderedUsage] = useState("");
+  const [skuExport, setSkuExport] = useState("");
+  const [renderError, setRenderError] = useState("");
+
+  const healthQuery = useQuery({ queryKey: ["health"], queryFn: api.health });
+  const locationsQuery = useQuery({ queryKey: ["locations"], queryFn: api.locations });
+  const publishersQuery = useQuery({
+    queryKey: ["publishers", selection.location],
+    queryFn: () => api.publishers(selection.location),
+    enabled: Boolean(selection.location)
+  });
+  const offersQuery = useQuery({
+    queryKey: ["offers", selection.location, selection.publisher],
+    queryFn: () => api.offers(selection.location, selection.publisher),
+    enabled: Boolean(selection.location && selection.publisher)
+  });
+  const skusQuery = useQuery({
+    queryKey: ["skus", selection.location, selection.publisher, selection.offer],
+    queryFn: () => api.skus(selection.location, selection.publisher, selection.offer),
+    enabled: Boolean(selection.location && selection.publisher && selection.offer)
+  });
+  const versionsQuery = useQuery({
+    queryKey: ["versions", selection.location, selection.publisher, selection.offer, selection.sku],
+    queryFn: () => api.versions(selection.location, selection.publisher, selection.offer, selection.sku),
+    enabled: Boolean(selection.location && selection.publisher && selection.offer && selection.sku)
+  });
+  const templatesQuery = useQuery({ queryKey: ["templates"], queryFn: api.templates });
+
+  useEffect(() => {
+    setSelection((previous) => ({ ...previous, publisher: "", offer: "", sku: "", version: "" }));
+    setRenderedUsage("");
+    setSkuExport("");
+  }, [selection.location]);
+
+  useEffect(() => {
+    setSelection((previous) => ({ ...previous, offer: "", sku: "", version: "" }));
+    setRenderedUsage("");
+    setSkuExport("");
+  }, [selection.publisher]);
+
+  useEffect(() => {
+    setSelection((previous) => ({ ...previous, sku: "", version: "" }));
+    setRenderedUsage("");
+  }, [selection.offer]);
+
+  useEffect(() => {
+    setSelection((previous) => ({ ...previous, version: "" }));
+    setRenderedUsage("");
+  }, [selection.sku]);
+
+  const canRender = useMemo(
+    () => Boolean(selection.location && selection.publisher && selection.offer && selection.sku && selection.version && templateFile),
+    [selection, templateFile]
+  );
+
+  const publishers = useMemo(
+    () => [...(publishersQuery.data ?? [])].sort((a, b) => a.localeCompare(b)),
+    [publishersQuery.data]
+  );
+  const offers = useMemo(
+    () => [...(offersQuery.data ?? [])].sort((a, b) => a.localeCompare(b)),
+    [offersQuery.data]
+  );
+  const skus = useMemo(
+    () => [...(skusQuery.data ?? [])].sort((a, b) => a.localeCompare(b)),
+    [skusQuery.data]
+  );
+  const versions = useMemo(
+    () => [...(versionsQuery.data ?? [])].sort((a, b) => a.localeCompare(b, undefined, { numeric: true, sensitivity: "base" })),
+    [versionsQuery.data]
+  );
+
+  const containsFilter = (options: string[], inputValue: string) => {
+    const query = inputValue.trim().toLowerCase();
+    if (!query) {
+      return options;
+    }
+
+    return options.filter((option) => option.toLowerCase().includes(query));
+  };
+
+  const onRender = async () => {
+    setRenderError("");
+    try {
+      const [usage, skuBlock] = await Promise.all([
+        api.render(templateFile, selection),
+        api.skuExport(selection.location, selection.publisher, selection.offer)
+      ]);
+      setRenderedUsage(usage);
+      setSkuExport(skuBlock);
+    } catch (error) {
+      setRenderError(error instanceof Error ? error.message : "Unexpected render error");
+    }
+  };
+
+  const loading = locationsQuery.isLoading || templatesQuery.isLoading;
+  const healthError = healthQuery.error instanceof Error ? healthQuery.error.message : "";
+  const appNotConfigured = healthError.includes("Missing AZURE_SUBSCRIPTION_ID");
+  const locationsError = locationsQuery.error instanceof Error ? locationsQuery.error.message : "Failed to load locations";
+
+  return (
+    <Box sx={{ minHeight: "100vh", py: 4 }}>
+      <Container maxWidth="lg">
+        <Stack spacing={3}>
+          <Typography variant="h4" sx={{ fontWeight: 500 }}>
+            Azure Image Chooser
+          </Typography>
+          <Typography color="text.secondary">
+            Select a marketplace image and generate reusable snippets.
+          </Typography>
+
+          {appNotConfigured ? (
+            <Alert severity="warning">
+              App is not configured. Set AZURE_SUBSCRIPTION_ID (and Azure credentials) in the container start environment, then restart the app.
+            </Alert>
+          ) : null}
+
+          {loading ? (
+            <CircularProgress />
+          ) : locationsQuery.isError ? (
+            <Alert severity={appNotConfigured ? "warning" : "error"}>{locationsError}</Alert>
+          ) : (
+            <Card>
+              <CardContent>
+                <Grid container spacing={2}>
+                  <Grid size={{ xs: 12, md: 6 }}>
+                    <FormControl fullWidth>
+                      <InputLabel id="location-label">Location</InputLabel>
+                      <Select
+                        labelId="location-label"
+                        label="Location"
+                        value={selection.location}
+                        onChange={(event) => setSelection((prev) => ({ ...prev, location: event.target.value }))}
+                      >
+                        {(locationsQuery.data ?? []).map((location) => (
+                          <MenuItem key={location.name} value={location.name}>
+                            {location.displayName}
+                          </MenuItem>
+                        ))}
+                      </Select>
+                    </FormControl>
+                  </Grid>
+
+                  <Grid size={{ xs: 12, md: 6 }}>
+                    <Autocomplete
+                      options={publishers}
+                      value={selection.publisher || null}
+                      disabled={!selection.location}
+                      onChange={(_event, value) => setSelection((prev) => ({ ...prev, publisher: value ?? "" }))}
+                      filterOptions={(options, state) => containsFilter(options, state.inputValue)}
+                      renderInput={(params) => <TextField {...params} label="Publisher" />}
+                    />
+                  </Grid>
+
+                  <Grid size={{ xs: 12, md: 4 }}>
+                    <Autocomplete
+                      options={offers}
+                      value={selection.offer || null}
+                      disabled={!selection.publisher}
+                      onChange={(_event, value) => setSelection((prev) => ({ ...prev, offer: value ?? "" }))}
+                      filterOptions={(options, state) => containsFilter(options, state.inputValue)}
+                      renderInput={(params) => <TextField {...params} label="Offer" />}
+                    />
+                  </Grid>
+
+                  <Grid size={{ xs: 12, md: 4 }}>
+                    <Autocomplete
+                      options={skus}
+                      value={selection.sku || null}
+                      disabled={!selection.offer}
+                      onChange={(_event, value) => setSelection((prev) => ({ ...prev, sku: value ?? "" }))}
+                      filterOptions={(options, state) => containsFilter(options, state.inputValue)}
+                      renderInput={(params) => <TextField {...params} label="SKU" />}
+                    />
+                  </Grid>
+
+                  <Grid size={{ xs: 12, md: 4 }}>
+                    <FormControl fullWidth disabled={!selection.sku}>
+                      <InputLabel id="version-label">Version</InputLabel>
+                      <Select
+                        labelId="version-label"
+                        label="Version"
+                        value={selection.version}
+                        onChange={(event) => setSelection((prev) => ({ ...prev, version: event.target.value }))}
+                      >
+                        {versions.map((version) => (
+                          <MenuItem key={version} value={version}>
+                            {version}
+                          </MenuItem>
+                        ))}
+                      </Select>
+                    </FormControl>
+                  </Grid>
+
+                  <Grid size={{ xs: 12, md: 8 }}>
+                    <FormControl fullWidth>
+                      <InputLabel id="template-label">Usage scenario</InputLabel>
+                      <Select
+                        labelId="template-label"
+                        label="Usage scenario"
+                        value={templateFile}
+                        onChange={(event) => setTemplateFile(event.target.value)}
+                      >
+                        {(templatesQuery.data ?? []).map((template) => (
+                          <MenuItem key={template.file} value={template.file}>
+                            {template.label}
+                          </MenuItem>
+                        ))}
+                      </Select>
+                    </FormControl>
+                  </Grid>
+
+                  <Grid size={{ xs: 12, md: 4 }}>
+                    <Button fullWidth variant="contained" sx={{ height: "100%" }} color="primary" onClick={onRender} disabled={!canRender}>
+                      Generate usage
+                    </Button>
+                  </Grid>
+                </Grid>
+              </CardContent>
+            </Card>
+          )}
+
+          {renderError ? <Alert severity="error">{renderError}</Alert> : null}
+
+          {renderedUsage ? (
+            <Card>
+              <CardContent>
+                <Typography variant="h6">Usage snippet</Typography>
+                <Box
+                  component="pre"
+                  sx={{ overflowX: "auto", p: 2, bgcolor: "grey.100", color: "text.primary", borderRadius: 1, border: 1, borderColor: "divider" }}
+                >
+                  {renderedUsage}
+                </Box>
+              </CardContent>
+            </Card>
+          ) : null}
+
+          {skuExport ? (
+            <Card>
+              <CardContent>
+                <Typography variant="h6">Available SKUs</Typography>
+                <Box
+                  component="pre"
+                  sx={{ overflowX: "auto", p: 2, bgcolor: "grey.100", color: "text.primary", borderRadius: 1, border: 1, borderColor: "divider" }}
+                >
+                  {skuExport}
+                </Box>
+              </CardContent>
+            </Card>
+          ) : null}
+        </Stack>
+      </Container>
+    </Box>
+  );
+};
+
+export default App;

app/frontend/src/api.ts

@@ -0,0 +1,55 @@
+import type { LocationOption, SelectionState, UsageTemplate } from "./types";
+
+const json = async <T>(path: string): Promise<T> => {
+  const response = await fetch(path);
+  if (!response.ok) {
+    let details = "";
+    try {
+      const payload = (await response.json()) as { message?: string };
+      details = payload.message ?? "";
+    } catch {
+      // Ignore non-JSON error payloads.
+    }
+
+    throw new Error(details || `Request failed for ${path} (${response.status})`);
+  }
+
+  return (await response.json()) as T;
+};
+
+export const api = {
+  health: () => json<{ status: string; message?: string }>("/api/health"),
+  locations: () => json<LocationOption[]>("/api/locations"),
+  publishers: (location: string) => json<string[]>(`/api/publishers?location=${encodeURIComponent(location)}`),
+  offers: (location: string, publisher: string) =>
+    json<string[]>(`/api/offers?location=${encodeURIComponent(location)}&publisher=${encodeURIComponent(publisher)}`),
+  skus: (location: string, publisher: string, offer: string) =>
+    json<string[]>(
+      `/api/skus?location=${encodeURIComponent(location)}&publisher=${encodeURIComponent(publisher)}&offer=${encodeURIComponent(offer)}`
+    ),
+  versions: (location: string, publisher: string, offer: string, sku: string) =>
+    json<string[]>(
+      `/api/versions?location=${encodeURIComponent(location)}&publisher=${encodeURIComponent(publisher)}&offer=${encodeURIComponent(offer)}&sku=${encodeURIComponent(sku)}`
+    ),
+  templates: () => json<UsageTemplate[]>("/api/templates"),
+  render: async (templateFile: string, selection: SelectionState): Promise<string> => {
+    const response = await fetch("/api/render", {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ templateFile, selection })
+    });
+
+    if (!response.ok) {
+      throw new Error("Failed to render template");
+    }
+
+    const payload = (await response.json()) as { rendered: string };
+    return payload.rendered;
+  },
+  skuExport: async (location: string, publisher: string, offer: string): Promise<string> => {
+    const payload = await json<{ rendered: string }>(
+      `/api/sku-export?location=${encodeURIComponent(location)}&publisher=${encodeURIComponent(publisher)}&offer=${encodeURIComponent(offer)}`
+    );
+    return payload.rendered;
+  }
+};

app/frontend/src/main.tsx

@@ -0,0 +1,16 @@
+import { StrictMode } from "react";
+import { createRoot } from "react-dom/client";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { CssBaseline } from "@mui/material";
+import App from "./App";
+
+const queryClient = new QueryClient();
+
+createRoot(document.getElementById("root")!).render(
+  <StrictMode>
+    <QueryClientProvider client={queryClient}>
+      <CssBaseline />
+      <App />
+    </QueryClientProvider>
+  </StrictMode>
+);

app/frontend/src/types.ts

@@ -0,0 +1,18 @@
+export type LocationOption = {
+  name: string;
+  displayName: string;
+};
+
+export type UsageTemplate = {
+  label: string;
+  language: string;
+  file: string;
+};
+
+export type SelectionState = {
+  location: string;
+  publisher: string;
+  offer: string;
+  sku: string;
+  version: string;
+};

app/frontend/test/app.test.tsx

@@ -0,0 +1,57 @@
+import { render, screen } from "@testing-library/react";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { ThemeProvider, createTheme } from "@mui/material";
+import { beforeEach, afterEach, describe, expect, it, vi } from "vitest";
+import App from "../src/App";
+
+const originalFetch = globalThis.fetch;
+
+const createResponse = (payload: unknown) =>
+  new Response(JSON.stringify(payload), {
+    status: 200,
+    headers: { "Content-Type": "application/json" }
+  });
+
+describe("App", () => {
+  beforeEach(() => {
+    globalThis.fetch = vi.fn((url: string) => {
+      if (url === "/api/locations") {
+        return Promise.resolve(createResponse([{ name: "westeurope", displayName: "West Europe" }]));
+      }
+
+      if (url === "/api/templates") {
+        return Promise.resolve(createResponse([{ label: "Azure CLI", language: "shell", file: "shell.tpl" }]));
+      }
+
+      return Promise.resolve(createResponse([]));
+    }) as typeof fetch;
+  });
+
+  afterEach(() => {
+    globalThis.fetch = originalFetch;
+  });
+
+  it("renders application heading", async () => {
+    const client = new QueryClient({
+      defaultOptions: {
+        queries: {
+          retry: false,
+          gcTime: 0
+        }
+      }
+    });
+    const theme = createTheme();
+
+    const view = render(
+      <QueryClientProvider client={client}>
+        <ThemeProvider theme={theme}>
+          <App />
+        </ThemeProvider>
+      </QueryClientProvider>
+    );
+
+    expect(await screen.findByText("Azure Image Chooser")).toBeInTheDocument();
+    view.unmount();
+    client.clear();
+  });
+});

app/frontend/test/setup.ts

@@ -0,0 +1 @@
+import "@testing-library/jest-dom/vitest";

app/frontend/tsconfig.json

@@ -0,0 +1,15 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "jsx": "react-jsx",
+    "strict": true,
+    "skipLibCheck": true,
+    "noEmit": true,
+    "resolveJsonModule": true,
+    "types": ["vite/client", "vitest/globals"]
+  },
+  "include": ["src", "test", "vite.config.ts"]
+}

app/frontend/vite.config.ts

@@ -0,0 +1,19 @@
+import { defineConfig } from "vite";
+import react from "@vitejs/plugin-react";
+
+export default defineConfig({
+  plugins: [react()],
+  build: {
+    outDir: "../dist/frontend",
+    emptyOutDir: true
+  },
+  server: {
+    port: 5173,
+    proxy: {
+      "/api": {
+        target: "http://localhost:3000",
+        changeOrigin: true
+      }
+    }
+  }
+});

app/frontend/vitest.config.ts

@@ -0,0 +1,8 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    environment: "jsdom",
+    setupFiles: ["./test/setup.ts"]
+  }
+});

app/healthcheck.js

@@ -0,0 +1,39 @@
+#!/usr/bin/env node
+"use strict";
+
+const http = require("node:http");
+
+const port = Number.parseInt(process.env.PORT || "3000", 10);
+const path = process.env.HEALTHCHECK_PATH || "/api/health";
+const timeoutMs = Number.parseInt(process.env.HEALTHCHECK_TIMEOUT_MS || "3000", 10);
+
+const req = http.request(
+  {
+    host: "127.0.0.1",
+    port,
+    path,
+    method: "GET",
+    timeout: timeoutMs
+  },
+  (res) => {
+    // Drain the response so the socket can close cleanly.
+    res.resume();
+
+    if (res.statusCode && res.statusCode >= 200 && res.statusCode < 400) {
+      process.exit(0);
+      return;
+    }
+
+    process.exit(1);
+  }
+);
+
+req.on("timeout", () => {
+  req.destroy(new Error("healthcheck timeout"));
+});
+
+req.on("error", () => {
+  process.exit(1);
+});
+
+req.end();

app/templates.json

@@ -0,0 +1,22 @@
+[
+  {
+    "label": "Terraform VM image reference",
+    "language": "hcl",
+    "file": "azurerm_hcl.tpl"
+  },
+  {
+    "label": "Azure CLI",
+    "language": "shell",
+    "file": "shell.tpl"
+  },
+  {
+    "label": "Azure Resource Manager Template",
+    "language": "json",
+    "file": "arm_vm.jsonc"
+  },
+  {
+    "label": "Bicep VM image reference",
+    "language": "bicep",
+    "file": "bicep_vm.tpl"
+  }
+]

app/templates/arm_vm.jsonc

@@ -0,0 +1,17 @@
+{
+    // This is a partial Azure virtual machine resource template.
+    "type": "Microsoft.Compute/virtualMachines",
+    "apiVersion": "2022-03-01",
+    "name": "example-vm",
+    "location": "westeurope",
+    "properties": {
+        "storageProfile": {
+            "imageReference": {
+                "publisher": "{{ publisher }}",
+                "offer": "{{ offer }}",
+                "sku": "{{ sku }}",
+                "version": "{{ version }}"
+            }
+        }
+    }
+}

app/templates/azurerm_hcl.tpl

@@ -0,0 +1,6 @@
+source_image_reference = {
+    publisher = "{{ publisher }}"
+    offer     = "{{ offer }}"
+    sku       = "{{ sku }}"
+    version   = "{{ version }}"
+}

app/templates/bicep_vm.tpl

@@ -0,0 +1,14 @@
+resource virtualMachine 'Microsoft.Compute/virtualMachines@2024-03-01' = {
+  name: 'example-vm'
+  location: resourceGroup().location
+  properties: {
+    storageProfile: {
+      imageReference: {
+        publisher: '{{ publisher }}'
+        offer: '{{ offer }}'
+        sku: '{{ sku }}'
+        version: '{{ version }}'
+      }
+    }
+  }
+}

app/templates/shell.tpl

@@ -0,0 +1 @@
+az create -n MyVM -g MyResourceGroup --image {{ publisher }}:{{ offer }}:{{ sku }}:{{ version }}