Support wrangler pages functions build-env (#5279)

.changeset/hungry-teachers-poke.md

@@ -0,0 +1,5 @@
+---
+"wrangler": minor
+---
+
+feat: Support the hidden command `wrangler pages functions build-env`

packages/wrangler/src/__tests__/pages-build-env.test.ts

@@ -0,0 +1,158 @@
+/* eslint-disable turbo/no-undeclared-env-vars */
+import { mockConsoleMethods } from "./helpers/mock-console";
+import { runInTempDir } from "./helpers/run-in-tmp";
+import { runWrangler } from "./helpers/run-wrangler";
+import writeWranglerToml from "./helpers/write-wrangler-toml";
+
+describe("pages-build-env", () => {
+	const std = mockConsoleMethods();
+	runInTempDir();
+	const originalEnv = process.env;
+
+	afterEach(() => {
+		process.env = originalEnv;
+	});
+
+	it("should render empty object", async () => {
+		writeWranglerToml({
+			pages_build_output_dir: "./dist",
+			vars: {},
+		});
+		await runWrangler("pages functions build-env");
+		expect(std).toMatchInlineSnapshot(`
+		Object {
+		  "debug": "",
+		  "err": "",
+		  "info": "",
+		  "out": "{}",
+		  "warn": "",
+		}
+	`);
+	});
+
+	it("should fail with no config file", async () => {
+		await expect(
+			runWrangler("pages functions build-env")
+		).rejects.toThrowErrorMatchingInlineSnapshot(
+			`"No Pages config file found"`
+		);
+	});
+
+	it("should return top-level by default", async () => {
+		writeWranglerToml({
+			pages_build_output_dir: "./dist",
+			vars: {
+				VAR1: "VALUE1",
+				VAR2: "VALUE2",
+				JSON: { json: true },
+			},
+			env: {
+				production: {
+					vars: {
+						VAR1: "PROD_VALUE1",
+						VAR2: "PROD_VALUE2",
+						PROD_VAR3: "PROD_VALUE3",
+						JSON: { json: true },
+					},
+				},
+				preview: {
+					vars: {
+						VAR1: "PREVIEW_VALUE1",
+						VAR2: "PREVIEW_VALUE2",
+						PREVIEW_VAR3: "PREVIEW_VALUE3",
+						JSON: { json: true },
+					},
+				},
+			},
+		});
+		await runWrangler("pages functions build-env");
+		expect(std).toMatchInlineSnapshot(`
+		Object {
+		  "debug": "",
+		  "err": "",
+		  "info": "",
+		  "out": "{\\"VAR1\\":\\"VALUE1\\",\\"VAR2\\":\\"VALUE2\\"}",
+		  "warn": "",
+		}
+	`);
+	});
+	it("should return production", async () => {
+		process.env.PAGES_ENVIRONMENT = "production";
+		writeWranglerToml({
+			pages_build_output_dir: "./dist",
+			vars: {
+				VAR1: "VALUE1",
+				VAR2: "VALUE2",
+				JSON: { json: true },
+			},
+			env: {
+				production: {
+					vars: {
+						VAR1: "PROD_VALUE1",
+						VAR2: "PROD_VALUE2",
+						PROD_VAR3: "PROD_VALUE3",
+						JSON: { json: true },
+					},
+				},
+				preview: {
+					vars: {
+						VAR1: "PREVIEW_VALUE1",
+						VAR2: "PREVIEW_VALUE2",
+						PREVIEW_VAR3: "PREVIEW_VALUE3",
+						JSON: { json: true },
+					},
+				},
+			},
+		});
+		await runWrangler("pages functions build-env");
+		expect(std).toMatchInlineSnapshot(`
+		Object {
+		  "debug": "",
+		  "err": "",
+		  "info": "",
+		  "out": "{\\"VAR1\\":\\"PROD_VALUE1\\",\\"VAR2\\":\\"PROD_VALUE2\\",\\"PROD_VAR3\\":\\"PROD_VALUE3\\"}",
+		  "warn": "",
+		}
+	`);
+	});
+
+	it("should return preview", async () => {
+		process.env.PAGES_ENVIRONMENT = "preview";
+		writeWranglerToml({
+			pages_build_output_dir: "./dist",
+			vars: {
+				VAR1: "VALUE1",
+				VAR2: "VALUE2",
+				JSON: { json: true },
+			},
+			env: {
+				production: {
+					vars: {
+						VAR1: "PROD_VALUE1",
+						VAR2: "PROD_VALUE2",
+						PROD_VAR3: "PROD_VALUE3",
+						JSON: { json: true },
+					},
+				},
+				preview: {
+					vars: {
+						VAR1: "PREVIEW_VALUE1",
+						VAR2: "PREVIEW_VALUE2",
+						PREVIEW_VAR3: "PREVIEW_VALUE3",
+						JSON: { json: true },
+					},
+				},
+			},
+		});
+		await runWrangler("pages functions build-env");
+		expect(std).toMatchInlineSnapshot(`
+		Object {
+		  "debug": "",
+		  "err": "",
+		  "info": "",
+		  "out": "{\\"VAR1\\":\\"PREVIEW_VALUE1\\",\\"VAR2\\":\\"PREVIEW_VALUE2\\",\\"PREVIEW_VAR3\\":\\"PREVIEW_VALUE3\\"}",
+		  "warn": "",
+		}
+	`);
+	});
+});

packages/wrangler/src/config/config.ts

@@ -364,7 +364,7 @@ export const defaultWranglerConfig: Config = {
 	},
 	usage_model: undefined,
 	rules: [],
-	build: {},
+	build: { command: undefined, watch_dir: "./src", cwd: undefined },
 	no_bundle: undefined,
 	minify: undefined,
 	node_compat: undefined,

packages/wrangler/src/config/index.ts

@@ -84,7 +84,7 @@ export function readConfig<CommandArgs>(
 	// If we detected a Pages project, run config file validation against
 	// Pages specific validation rules
 	if (isPagesConfig) {
-		logger.info(
+		logger.debug(
 			`Configuration file belonging to ⚡️ Pages ⚡️ project detected.`
 		);
 

packages/wrangler/src/config/validation-pages.ts

@@ -32,6 +32,8 @@ const supportedPagesConfigFields = [
 	"analytics_engine_datasets",
 	"ai",
 	"dev",
+	// normalizeAndValidateConfig() sets this value
+	"configPath",
 ] as const;
 
 export function validatePagesConfig(

packages/wrangler/src/pages/build-env.ts

@@ -0,0 +1,31 @@
+import { readConfig } from "../config";
+import { FatalError } from "../errors";
+import { logger } from "../logger";
+import type {
+	CommonYargsArgv,
+	StrictYargsOptionsToInterface,
+} from "../yargs-types";
+
+export type PagesBuildEnvArgs = StrictYargsOptionsToInterface<typeof Options>;
+
+export function Options(yargs: CommonYargsArgv) {
+	return yargs;
+}
+
+export const Handler = async (args: PagesBuildEnvArgs) => {
+	const config = readConfig(undefined, {
+		...args,
+		// eslint-disable-next-line turbo/no-undeclared-env-vars
+		env: process.env.PAGES_ENVIRONMENT,
+	});
+	if (!config.pages_build_output_dir) {
+		throw new FatalError("No Pages config file found");
+	}
+
+	// Ensure JSON variables are not included
+	const textVars = Object.fromEntries(
+		Object.entries(config.vars).filter(([_, v]) => typeof v === "string")
+	);
+
+	logger.log(JSON.stringify(textVars));
+};

packages/wrangler/src/pages/index.ts

@@ -1,6 +1,7 @@
 /* eslint-disable no-shadow */
 
 import * as Build from "./build";
+import * as BuildEnv from "./build-env";
 import * as Deploy from "./deploy";
 import * as DeploymentTails from "./deployment-tails";
 import * as Deployments from "./deployments";
@@ -42,6 +43,12 @@ export function pages(yargs: CommonYargsArgv) {
 						Build.Options,
 						Build.Handler
 					)
+					.command(
+						"build-env",
+						"Render a list of environment variables from the config file",
+						BuildEnv.Options,
+						BuildEnv.Handler
+					)
 					.command(
 						"optimize-routes [routesPath] [outputRoutesPath]",
 						"Consolidate and optimize the route paths declared in _routes.json",