Add support for using the Vite plugin without a Wrangler config file (#11408)

* Add support for zero-config Vite use

* Remove e2e test for missing config

* Move worker name logic into wrangler

* Remove logger

Author: ascorbic

.changeset/curly-weeks-run.md

@@ -0,0 +1,5 @@
+---
+"wrangler": minor
+---
+
+Export unstable helpers useful for generating wrangler config

.changeset/public-baths-change.md

@@ -0,0 +1,7 @@
+---
+"@cloudflare/vite-plugin": minor
+---
+
+Support zero-config operation
+
+If the Vite plugin is used in a project without an existing Wrangler config file, it should be able to operate in "zero-config" mode by generating a default Wrangler configuration for an assets-only worker.

packages/vite-plugin-cloudflare/e2e/fixtures/no-wrangler-config/package.json

@@ -5,15 +5,6 @@ import { runLongLived, seed } from "./helpers";
 //       testing regarding the validation there are unit tests in src/__tests__/get-validated-wrangler-config-path.spec.ts
 
 describe("during development wrangler config files are validated", () => {
-	const noWranglerConfigProjectPath = seed("no-wrangler-config", "pnpm");
-	test("for the entry worker", async ({ expect }) => {
-		const proc = await runLongLived("pnpm", "dev", noWranglerConfigProjectPath);
-		expect(await proc.exitCode).not.toBe(0);
-		expect(proc.stderr).toMatch(
-			/Error: No config file found in the .*? directory/
-		);
-	});
-
 	const noWranglerConfigAuxProjectPath = seed(
 		"no-wrangler-config-for-auxiliary-worker",
 		"pnpm"

packages/vite-plugin-cloudflare/e2e/fixtures/no-wrangler-config/vite.config.ts

@@ -9,39 +9,40 @@ const isWindows = process.platform === "win32";
 
 describe("valid cases", () => {
 	test("should return the value of a found wrangler config", () => {
-		const path = getValidatedWranglerConfigPath(fixturesPath, undefined);
-		expect(normalize(path)).toMatch(
+		const result = getValidatedWranglerConfigPath(fixturesPath, undefined);
+		expect(result).toBeDefined();
+		expect(normalize(result!)).toMatch(
 			isWindows
 				? /\\__tests__\\fixtures\\wrangler\.jsonc/
 				: /\/__tests__\/fixtures\/wrangler\.jsonc/
 		);
 	});
 
 	test("should return the value of a requested wrangler config", () => {
-		const path = getValidatedWranglerConfigPath(
+		const result = getValidatedWranglerConfigPath(
 			fixturesPath,
 			join(fixturesPath, "simple-wrangler.jsonc")
 		);
-		expect(normalize(path)).toMatch(
+		expect(result).toBeDefined();
+		expect(normalize(result!)).toMatch(
 			isWindows
 				? /\\__tests__\\fixtures\\simple-wrangler\.jsonc/
 				: /\/__tests__\/fixtures\/simple-wrangler\.jsonc/
 		);
 	});
 });
 
-describe("invalid cases", () => {
-	test("should error with an helpful message if a wrangler config could not be found", () => {
-		expect(() => {
-			getValidatedWranglerConfigPath(
-				join(fixturesPath, "empty-dir"),
-				undefined
-			);
-		}).toThrowError(
-			/No config file found in the .*?empty-dir directory\. Please add a wrangler.\(jsonc\|json\|toml\) file\./
+describe("zero-config cases", () => {
+	test("should return undefined when no wrangler config is found (zero-config mode)", () => {
+		const result = getValidatedWranglerConfigPath(
+			join(fixturesPath, "empty-dir"),
+			undefined
 		);
+		expect(result).toBeUndefined();
 	});
+});
 
+describe("invalid cases", () => {
 	[false, true].forEach((forAuxiliaryWorker) => {
 		const testPrefix = forAuxiliaryWorker
 			? "[auxiliary worker]"

packages/vite-plugin-cloudflare/e2e/wrangler-configs-validation.test.ts

@@ -5,6 +5,7 @@ import * as vite from "vite";
 import { getWorkerConfigs } from "./deploy-config";
 import { hasNodeJsCompat, NodeJsCompat } from "./nodejs-compat";
 import {
+	getDefaultWorkerConfig,
 	getValidatedWranglerConfigPath,
 	getWorkerConfig,
 } from "./workers-configs";
@@ -137,14 +138,14 @@ export function resolvePluginConfig(
 		pluginConfig.configPath
 	);
 
-	const entryWorkerResolvedConfig = getWorkerConfig(
-		entryWorkerConfigPath,
-		cloudflareEnv,
-		{
-			visitedConfigPaths: configPaths,
-			isEntryWorker: true,
-		}
-	);
+	// Handle zero-config mode when no wrangler config file is found
+	const entryWorkerResolvedConfig =
+		entryWorkerConfigPath === undefined
+			? getDefaultWorkerConfig(root)
+			: getWorkerConfig(entryWorkerConfigPath, cloudflareEnv, {
+					visitedConfigPaths: configPaths,
+					isEntryWorker: true,
+				});
 
 	if (entryWorkerResolvedConfig.type === "assets-only") {
 		return {

packages/vite-plugin-cloudflare/playground/static/wrangler.jsonc

@@ -1,7 +1,12 @@
 import assert from "node:assert";
 import * as fs from "node:fs";
 import * as path from "node:path";
-import { unstable_readConfig } from "wrangler";
+import {
+	unstable_defaultWranglerConfig,
+	unstable_getDevCompatibilityDate,
+	unstable_getWorkerNameFromProject,
+	unstable_readConfig,
+} from "wrangler";
 import type { AssetsOnlyConfig, WorkerConfig } from "./plugin-config";
 import type { Optional } from "./utils";
 import type { Unstable_Config as RawWorkerConfig } from "wrangler";
@@ -342,6 +347,40 @@ export function getWorkerConfig(
 	};
 }
 
+/**
+ * Generates a default worker config for zero-config mode when no wrangler config file is found.
+ * The worker name is derived from package.json name or directory basename.
+ * The compatibility date is taken from the installed workerd runtime.
+ *
+ * @param root the root of the vite project
+ * @returns an assets-only worker config with sensible defaults
+ */
+export function getDefaultWorkerConfig(
+	root: string
+): AssetsOnlyWorkerResolvedConfig {
+	const workerName = unstable_getWorkerNameFromProject(root);
+	const compatibilityDate = unstable_getDevCompatibilityDate(undefined);
+
+	// Start with the full default config to ensure all required fields have proper defaults,
+	// then override the fields specific to this zero-config worker
+	const config: RawWorkerConfig = {
+		...unstable_defaultWranglerConfig,
+		topLevelName: workerName,
+		name: workerName,
+		compatibility_date: compatibilityDate,
+	};
+
+	return {
+		type: "assets-only",
+		raw: config,
+		config: config as AssetsOnlyConfig,
+		nonApplicable: {
+			replacedByVite: new Set(),
+			notRelevant: new Set(),
+		},
+	};
+}
+
 const ENTRY_MODULE_EXTENSIONS = [".js", ".mjs", ".ts", ".mts", ".jsx", ".tsx"];
 
 /**
@@ -373,13 +412,23 @@ function maybeResolveMain(main: string, configPath: string): string {
  * @param root the root of the vite project
  * @param requestedConfigPath the requested config path, if any
  * @param isForAuxiliaryWorker whether the config path is being requested for an auxiliary worker
- * @returns a valid path to a config file
+ * @returns a valid path to a config file, or undefined for entry workers when no config is found (zero-config mode)
  */
+export function getValidatedWranglerConfigPath(
+	root: string,
+	requestedConfigPath: string | undefined,
+	isForAuxiliaryWorker: true
+): string;
+export function getValidatedWranglerConfigPath(
+	root: string,
+	requestedConfigPath: string | undefined,
+	isForAuxiliaryWorker?: boolean
+): string | undefined;
 export function getValidatedWranglerConfigPath(
 	root: string,
 	requestedConfigPath: string | undefined,
 	isForAuxiliaryWorker = false
-) {
+): string | undefined {
 	if (requestedConfigPath) {
 		const configPath = path.resolve(root, requestedConfigPath);
 
@@ -423,12 +472,7 @@ export function getValidatedWranglerConfigPath(
 
 	const configPath = findWranglerConfig(root);
 
-	if (!configPath) {
-		throw new Error(
-			`No config file found in the ${root} directory. Please add a wrangler.(jsonc|json|toml) file.`
-		);
-	}
-
+	// Return undefined for zero-config mode when no config file is found
 	return configPath;
 }
 

packages/vite-plugin-cloudflare/src/__tests__/get-validated-wrangler-config-path.spec.ts

@@ -37,6 +37,8 @@ import type {
 export { getVarsForDev as unstable_getVarsForDev } from "../../../dev/dev-vars";
 export { readConfig as unstable_readConfig };
 export { getDurableObjectClassNameToUseSQLiteMap as unstable_getDurableObjectClassNameToUseSQLiteMap };
+export { getDevCompatibilityDate as unstable_getDevCompatibilityDate } from "../../../utils/compatibility-date";
+export { getWorkerNameFromProject as unstable_getWorkerNameFromProject } from "../../../autoconfig/details";
 export type {
 	Config as Unstable_Config,
 	RawConfig as Unstable_RawConfig,