Add feature to use environment variable for Hyperdrive local dev conn…

…ection string (#4900)

* hyperdrive: support HYPERDRIVE_LOCAL_CONNECTION_STRING

* hyperdrive: add changeset

* Fix build issues and add tests

* Use binding name in hyperdrive local string environment variable

* Fix changeset, use simpler method for grabbing environment variable

---------

Co-authored-by: Matt Silverlock <matt@eatsleeprepeat.net>

.changeset/khaki-feet-exist.md

@@ -0,0 +1,7 @@
+---
+"wrangler": patch
+---
+
+feature: allow hyperdrive users to set local connection string as environment variable
+
+Wrangler dev now supports the HYPERDRIVE_LOCAL_CONNECTION_STRING environmental variable for connecting to a local database instance when testing Hyperdrive in local development. This environmental variable takes precedence over the localConnectionString set in wrangler.toml.

packages/wrangler/e2e/dev.test.ts

@@ -435,6 +435,9 @@ describe("hyperdrive dev tests", () => {
 	beforeEach(async () => {
 		worker = await makeWorker();
 		server = nodeNet.createServer().listen();
+	});
+
+	it("matches expected configuration parameters", async () => {
 		let port = 5432;
 		if (server.address() && typeof server.address() !== "string") {
 			port = (server.address() as nodeNet.AddressInfo).port;
@@ -468,9 +471,6 @@ describe("hyperdrive dev tests", () => {
 					}
 					`,
 		}));
-	});
-
-	it("matches expected configuration parameters", async () => {
 		await worker.runDevSession("", async (session) => {
 			const { text } = await retry(
 				(s) => {
@@ -490,6 +490,39 @@ describe("hyperdrive dev tests", () => {
 	});
 
 	it("connects to a socket", async () => {
+		let port = 5432;
+		if (server.address() && typeof server.address() !== "string") {
+			port = (server.address() as nodeNet.AddressInfo).port;
+		}
+		await worker.seed((workerName) => ({
+			"wrangler.toml": dedent`
+					name = "${workerName}"
+					main = "src/index.ts"
+					compatibility_date = "2023-10-25"
+
+					[[hyperdrive]]
+					binding = "HYPERDRIVE"
+					id = "hyperdrive_id"
+					localConnectionString = "postgresql://user:pass@127.0.0.1:${port}/some_db"
+			`,
+			"src/index.ts": dedent`
+					export default {
+						async fetch(request, env) {
+							if (request.url.includes("connect")) {
+								const conn = env.HYPERDRIVE.connect();
+								await conn.writable.getWriter().write(new TextEncoder().encode("test string"));
+							}
+							return new Response(env.HYPERDRIVE?.connectionString ?? "no")
+						}
+					}`,
+			"package.json": dedent`
+					{
+						"name": "${workerName}",
+						"version": "0.0.0",
+						"private": true
+					}
+					`,
+		}));
 		const socketMsgPromise = new Promise((resolve, _) => {
 			server.on("connection", (sock) => {
 				sock.on("data", (data) => {
@@ -513,10 +546,76 @@ describe("hyperdrive dev tests", () => {
 		await socketMsgPromise;
 	});
 
+	it("uses HYPERDRIVE_LOCAL_CONNECTION_STRING for the localConnectionString variable in the binding", async () => {
+		let port = 5432;
+		if (server.address() && typeof server.address() !== "string") {
+			port = (server.address() as nodeNet.AddressInfo).port;
+		}
+		await worker.seed((workerName) => ({
+			"wrangler.toml": dedent`
+					name = "${workerName}"
+					main = "src/index.ts"
+					compatibility_date = "2023-10-25"
+
+					[[hyperdrive]]
+					binding = "HYPERDRIVE"
+					id = "hyperdrive_id"
+			`,
+			"src/index.ts": dedent`
+					export default {
+						async fetch(request, env) {
+							if (request.url.includes("connect")) {
+								const conn = env.HYPERDRIVE.connect();
+								await conn.writable.getWriter().write(new TextEncoder().encode("test string"));
+							}
+							return new Response(env.HYPERDRIVE?.connectionString ?? "no")
+						}
+					}`,
+			"package.json": dedent`
+					{
+						"name": "${workerName}",
+						"version": "0.0.0",
+						"private": true
+					}
+					`,
+		}));
+		const socketMsgPromise = new Promise((resolve, _) => {
+			server.on("connection", (sock) => {
+				sock.on("data", (data) => {
+					expect(new TextDecoder().decode(data)).toBe("test string");
+					server.close();
+					resolve({});
+				});
+			});
+		});
+		// eslint-disable-next-line turbo/no-undeclared-env-vars
+		process.env.WRANGLER_HYPERDRIVE_LOCAL_CONNECTION_STRING_HYPERDRIVE = `postgresql://user:pass@127.0.0.1:${port}/some_db`;
+		await worker.runDevSession("", async (session) => {
+			await retry(
+				(s) => {
+					return s.status !== 200;
+				},
+				async () => {
+					const resp = await fetch(`http://127.0.0.1:${session.port}/connect`);
+					return { text: await resp.text(), status: resp.status };
+				}
+			);
+		});
+		await socketMsgPromise;
+	});
+
 	afterEach(() => {
 		if (server.listening) {
 			server.close();
 		}
+		if (
+			// eslint-disable-next-line turbo/no-undeclared-env-vars
+			process.env.WRANGLER_HYPERDRIVE_LOCAL_CONNECTION_STRING_HYPERDRIVE !==
+			undefined
+		) {
+			// eslint-disable-next-line turbo/no-undeclared-env-vars
+			delete process.env.WRANGLER_HYPERDRIVE_LOCAL_CONNECTION_STRING_HYPERDRIVE;
+		}
 	});
 });
 

packages/wrangler/src/dev.tsx

@@ -955,11 +955,28 @@ export function getBindings(
 		vectorize: configParam.vectorize,
 		constellation: configParam.constellation,
 		hyperdrive: configParam.hyperdrive.map((hyperdrive) => {
-			if (!hyperdrive.localConnectionString) {
+			const connectionStringFromEnv =
+				process.env[
+					`WRANGLER_HYPERDRIVE_LOCAL_CONNECTION_STRING_${hyperdrive.binding}`
+				];
+			if (!connectionStringFromEnv || !hyperdrive.localConnectionString) {
 				throw new UserError(
-					`In development, you should use a local postgres connection string to emulate hyperdrive functionality. Please setup postgres locally and set the value of "${hyperdrive.binding}"'s "localConnectionString" to the postgres connection string in your wrangler.toml`
+					`When developing locally, you should use a local Postgres connection string to emulate Hyperdrive functionality. Please setup Postgres locally and set the value of the 'WRANGLER_HYPERDRIVE_LOCAL_CONNECTION_STRING_${hyperdrive.binding}' variable or "${hyperdrive.binding}"'s "localConnectionString" to the Postgres connection string.`
 				);
 			}
+
+			// If there is a non-empty connection string specified in the environment,
+			// use that as our local connection stirng configuration.
+			if (
+				connectionStringFromEnv !== undefined &&
+				connectionStringFromEnv !== ""
+			) {
+				logger.log(
+					`Found a non-empty WRANGLER_HYPERDRIVE_LOCAL_CONNECTION_STRING variable for binding. Hyperdrive will connect to this database during local development.`
+				);
+				hyperdrive.localConnectionString = connectionStringFromEnv;
+			}
+
 			return hyperdrive;
 		}),
 	};

packages/wrangler/src/environment-variables/factory.ts

@@ -6,6 +6,7 @@ type VariableNames =
 	| "CLOUDFLARE_API_KEY"
 	| "CLOUDFLARE_API_TOKEN"
 	| "CLOUDFLARE_EMAIL"
+	| `WRANGLER_HYPERDRIVE_LOCAL_CONNECTION_STRING_${string}`
 	| "NO_CONSTELLATION_WARNING"
 	| "NO_HYPERDRIVE_WARNING"
 	| "WRANGLER_API_ENVIRONMENT"