Create an xtask crate for workspace task automation

Initially covering:

* Building docs
* Nightly CI jobs

.cargo/config.toml

@@ -1,2 +1,5 @@
+[alias]
+xtask = "run --package xtask --"
+
 [doc.extern-map.registries]
 crates-io = "https://docs.rs/"

.github/workflows/ci.yml

@@ -67,14 +67,8 @@ jobs:
     - name: Clippy
       uses: actions-rs/cargo@v1
       with:
-        command: clippy
-        args: --all-targets -- -D warnings
-
-    - name: Clippy without default features
-      uses: actions-rs/cargo@v1
-      with:
-        command: clippy
-        args: --all-targets --no-default-features --features native-tls,warp -- -D warnings
+        command: run
+        args: -p xtask -- ci clippy
 
   check-wasm:
     name: checking WASM builds

.github/workflows/docs.yml

@@ -24,6 +24,7 @@ jobs:
       - name: Load cache
         uses: Swatinem/rust-cache@v1
 
+      # Keep in sync with xtask docs
       - name: Build docs
         uses: actions-rs/cargo@v1
         env:

Cargo.toml

@@ -1,2 +1,4 @@
 [workspace]
-members = ["crates/*"]
+members = ["crates/*", "xtask"]
+# xtask should only be compiled when invoked explicitly
+default-members = ["crates/*"]

xtask/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "xtask"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]
+clap = { version = "3.1.3", features = ["derive"] }
+serde = { version = "1.0.136", features = ["derive"] }
+serde_json = "1.0.79"
+xshell = "0.1.17"

xtask/src/ci.rs

@@ -0,0 +1,86 @@
+use std::{env, path::PathBuf};
+
+use clap::{Args, Subcommand};
+use serde::Deserialize;
+use xshell::{cmd, pushd};
+
+use crate::{build_docs, DenyWarnings, Result};
+
+#[derive(Args)]
+pub struct CiArgs {
+    #[clap(subcommand)]
+    cmd: Option<CiCommand>,
+}
+
+#[derive(Subcommand)]
+enum CiCommand {
+    /// Check style
+    Style,
+    /// Check for typos
+    Typos,
+    /// Check clippy lints
+    Clippy,
+    /// Check documentation
+    Docs,
+}
+
+impl CiArgs {
+    pub fn run(self) -> Result<()> {
+        let _p = pushd(&workspace_root()?)?;
+
+        match self.cmd {
+            Some(cmd) => match cmd {
+                CiCommand::Style => check_style(),
+                CiCommand::Typos => check_typos(),
+                CiCommand::Clippy => check_clippy(),
+                CiCommand::Docs => check_docs(),
+            },
+            None => {
+                check_style()?;
+                check_clippy()?;
+                check_typos()?;
+                check_docs()?;
+
+                Ok(())
+            }
+        }
+    }
+}
+
+fn check_style() -> Result<()> {
+    cmd!("rustup run nightly cargo fmt -- --check").run()?;
+    Ok(())
+}
+
+fn check_typos() -> Result<()> {
+    // FIXME: Print install instructions if command-not-found (needs an xshell
+    //        change: https://github.com/matklad/xshell/issues/46)
+    cmd!("typos").run()?;
+    Ok(())
+}
+
+fn check_clippy() -> Result<()> {
+    cmd!("rustup run nightly cargo clippy --all-targets -- -D warnings").run()?;
+    cmd!(
+        "rustup run nightly cargo clippy --all-targets
+            --no-default-features --features native-tls,warp
+            -- -D warnings"
+    )
+    .run()?;
+    Ok(())
+}
+
+fn check_docs() -> Result<()> {
+    build_docs([], DenyWarnings::Yes)
+}
+
+fn workspace_root() -> Result<PathBuf> {
+    #[derive(Deserialize)]
+    struct Metadata {
+        workspace_root: PathBuf,
+    }
+
+    let cargo = env::var("CARGO").unwrap_or_else(|_| "cargo".to_owned());
+    let metadata_json = cmd!("{cargo} metadata --no-deps --format-version 1").read()?;
+    Ok(serde_json::from_str::<Metadata>(&metadata_json)?.workspace_root)
+}

xtask/src/main.rs

@@ -0,0 +1,55 @@
+mod ci;
+
+use ci::CiArgs;
+use clap::{Parser, Subcommand};
+use xshell::cmd;
+
+type Result<T, E = Box<dyn std::error::Error>> = std::result::Result<T, E>;
+
+#[derive(Parser)]
+struct Xtask {
+    #[clap(subcommand)]
+    cmd: Command,
+}
+
+#[derive(Subcommand)]
+enum Command {
+    /// Run continuous integration checks
+    Ci(CiArgs),
+    /// Build the SDKs documentation
+    Doc {
+        /// Opens the docs in a browser after the operation
+        #[clap(long)]
+        open: bool,
+    },
+}
+
+fn main() -> Result<()> {
+    match Xtask::parse().cmd {
+        Command::Ci(ci) => ci.run(),
+        Command::Doc { open } => build_docs(open.then(|| "--open"), DenyWarnings::No),
+    }
+}
+
+enum DenyWarnings {
+    Yes,
+    No,
+}
+
+fn build_docs(
+    extra_args: impl IntoIterator<Item = &'static str>,
+    deny_warnings: DenyWarnings,
+) -> Result<()> {
+    let mut rustdocflags = "--enable-index-page -Zunstable-options --cfg docsrs".to_owned();
+    if let DenyWarnings::Yes = deny_warnings {
+        rustdocflags += " -Dwarnings";
+    }
+
+    // Keep in sync with .github/workflows/docs.yml
+    cmd!("rustup run nightly cargo doc --no-deps --workspace --features docsrs -Zrustdoc-map")
+        .env("RUSTDOCFLAGS", rustdocflags)
+        .args(extra_args)
+        .run()?;
+
+    Ok(())
+}