feat: add tests and docs for configurable toolchain overrides (#89)

* `4.0.0.beta.3`

* clean up readme and `.gitignore`

* fix center align

* update readme

* add docs and clean up logic for toolchain override

* mv root toolchain file

Author: ecklf

.gitignore

@@ -10,5 +10,3 @@ target/
 dist/
 node_modules/
 .vercel/
-
-fixtures/**/vercel.json

Cargo.toml

@@ -12,5 +12,6 @@ exclude = [
     "test/fixtures/02-with-utility",
     "test/fixtures/03-with-function",
     "test/fixtures/04-with-parameter",
-    "test/fixtures/05-with-similar-entrypaths"
+    "test/fixtures/05-with-similar-entrypaths",
+    "test/fixtures/06-with-toolchain-override"
 ]

README.md

@@ -1,13 +1,21 @@
 <p align="center">
-  <a href="https://vercel.com">
+  <a align="center" href="https://vercel.com">
     <img src="https://assets.vercel.com/image/upload/v1588805858/repositories/vercel/logo.png" height="96">
     <h3 align="center">Rust</h3>
   </a>
-  <p align="center">Rust runtime for Vercel Functions.</p>
+  <p align="center">Rust Runtime for Vercel Functions.</p>
 </p>
 
+<div align="center">
+
+<a href="https://www.npmjs.com/package/vercel-rust">![npm version](https://img.shields.io/npm/v/vercel-rust.svg)</a>
+<a href="https://www.npmjs.com/package/vercel-rust">![npm downloads](https://img.shields.io/npm/dm/vercel-rust.svg?label=npm%20downloads)</a>
+<a href="https://crates.io/crates/vercel_runtime">![crates.io downloads](https://img.shields.io/crates/d/vercel_runtime?color=yellow&label=crates.io)</a>
+
 Community-maintained package to support using [Rust](https://www.rust-lang.org/) inside [Vercel Functions](https://vercel.com/docs/serverless-functions/introduction) as a [Runtime](https://vercel.com/docs/runtimes).
 
+</div>
+
 ## Legacy Runtime
 
 The below documentation is for the `vercel_runtime` crate (in beta). If you are looking for the legacy runtime instructions using `vercel_lambda` see [tree/a9495a0](https://github.com/vercel-community/rust/tree/a9495a0f0d882a36ea165f1629fcc79c30bc3108).
@@ -59,7 +67,8 @@ Finally we need a `Cargo.toml` file at the root of your repository.
 # --snip--
 
 [dependencies]
-# --snip--
+tokio = { version = "1", features = ["macros"] }
+serde_json = { version = "1", features = ["raw_value"] }
 # Documentation: https://docs.rs/vercel_runtime/latest/vercel_runtime
 vercel_runtime = { version = "0.2.1" }
 
@@ -72,7 +81,7 @@ vercel_runtime = { version = "0.2.1" }
 name = "handler"
 path = "api/handler.rs"
 
-# Note that you need to provide unique names for dynamic paths
+# Note that you need to provide unique names for each binary
 [[bin]]
 name = "user-id"
 path = "api/user/[id].rs"
@@ -81,7 +90,6 @@ path = "api/user/[id].rs"
 name = "group-id"
 path = "api/group/[id].rs"
 
-
 # --snip--
 ```
 
@@ -99,13 +107,12 @@ During local development with `vercel dev`, ensure `rust` and `cargo` are alread
 
 ## Contributing
 
-Since this project contains both Rust and Node.js code, you need to install the relevant dependencies. If you're only working on the JavaScript side, you only need to install those dependencies (and vice-versa).
+Since this project contains both Rust and Node.js code, you need to install the relevant dependencies. If you're only working on the TypeScript side, you only need to install those dependencies (and vice-versa).
 
 ```shell
 # install node dependencies
 pnpm install
 
-
 # install cargo dependencies
 cargo fetch
 ```
@@ -121,6 +128,13 @@ graph TD
 
 ## FAQ
 
+<details>
+  <summary>How to specify toolchain overrides</summary>
+
+An example on how this can be achieved is using a `rust-toolchain` file adjacent to your `Cargo.toml`. Please refer to [Rust Documentation](https://rust-lang.github.io/rustup/overrides.html#the-toolchain-file) for more details.
+
+</details>
+
 <details>
   <summary>Can I use musl/static linking?</summary>
 

rust-toolchain.toml

@@ -0,0 +1,2 @@
+[toolchain]
+channel = "nightly"

src/lib/rust-toolchain.ts

@@ -1,14 +1,10 @@
 import { debug } from '@vercel/build-utils';
 import execa from 'execa';
 
-async function downloadRustToolchain({
-  version = 'stable',
-}: {
-  version?: string;
-}): Promise<void> {
+async function downloadRustToolchain(): Promise<void> {
   try {
     await execa(
-      `curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain ${version}`,
+      `curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y`,
       [],
       { shell: true, stdio: 'inherit' },
     );
@@ -21,11 +17,11 @@ async function downloadRustToolchain({
   }
 }
 
-export const installRustToolchain = async (version?: string): Promise<void> => {
+export const installRustToolchain = async (): Promise<void> => {
   try {
     await execa(`rustup -V`, [], { shell: true, stdio: 'ignore' });
     debug('Rust Toolchain is already installed, skipping download');
   } catch (err) {
-    await downloadRustToolchain({ version });
+    await downloadRustToolchain();
   }
 };

test/fixtures.test.ts

@@ -1,21 +1,12 @@
 import { join } from 'node:path';
 import ms from 'ms';
 import execa from 'execa';
-import { writeJSON } from 'fs-extra';
 import fetch from 'node-fetch';
 
-const vercelFileName = 'test.vercel.json';
-const pkgRootFile = `file:${process.cwd()}`;
 const readyRegex = /Ready!\s+Available at (?<url>https?:\/\/\w+:\d+)/;
 
 jest.setTimeout(ms('50m'));
 
-interface Config {
-  builds: {
-    use: string;
-  }[];
-}
-
 interface Probe {
   path: string;
   status?: number;
@@ -30,19 +21,6 @@ async function importJSON<T>(path: string): Promise<T> {
   return (await import(path)) as unknown as Promise<T>;
 }
 
-async function injectConf(confPath: string): Promise<Config> {
-  const conf = await importJSON<Config>(join(confPath, vercelFileName));
-
-  conf.builds[0].use = pkgRootFile;
-
-  await writeJSON(join(confPath, 'vercel.json'), conf, {
-    spaces: 2,
-    EOL: '\n',
-  });
-
-  return conf;
-}
-
 async function checkProbes(baseUrl: string, probes: Probe[]): Promise<void> {
   for (const probe of probes) {
     // eslint-disable-next-line no-await-in-loop
@@ -121,4 +99,7 @@ describe('vercel-rust', () => {
   it('deploy 05-with-similar-entrypaths', async () => {
     await expect(testFixture('05-with-similar-entrypaths')).resolves.toBe('ok');
   });
+  it('deploy 06-with-toolchain-override', async () => {
+    await expect(testFixture('06-with-toolchain-override')).resolves.toBe('ok');
+  });
 });

test/fixtures/06-with-toolchain-override/.gitignore

@@ -0,0 +1 @@
+.vercel

test/fixtures/06-with-toolchain-override/.vercelignore

@@ -0,0 +1 @@
+target/