Add xtask for (crudely) checking license headers

.licenserc.yaml

@@ -8,5 +8,7 @@ header:
       file, You can obtain one at https://mozilla.org/MPL/2.0/.
   paths:
     - '**/*.rs'
+  paths-ignore:
+    - 'target/**/*.rs'
 
   comment: on-failure

xtask/Cargo.toml

@@ -6,4 +6,8 @@ edition = "2021"
 [dependencies]
 anyhow.workspace = true
 clap = { workspace = true, features = ["derive"] }
+serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
+serde_yaml = { version = "0.9" }
+glob = { version = "0.3.1" }
+globset = { version = "0.4.11" }

xtask/src/main.rs

@@ -2,11 +2,12 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
-use std::process::{Command, Stdio};
-
-use anyhow::{bail, Result};
+use anyhow::Result;
 use clap::{Parser, Subcommand};
-use serde_json::{Map, Value};
+
+mod task_clippy;
+mod task_license;
+mod util;
 
 #[derive(Parser)]
 #[command(name = "cargo xtask", about = "Builder tasks for Propolis")]
@@ -23,67 +24,13 @@ enum Cmds {
         #[arg(short, long)]
         strict: bool,
     },
-}
-
-fn workspace_root() -> Result<String> {
-    let mut cmd = Command::new("cargo");
-    cmd.args(["metadata", "--format-version=1"])
-        .stdin(Stdio::null())
-        .stderr(Stdio::inherit());
-
-    let output = cmd.output()?;
-    if !output.status.success() {
-        bail!("failed to query cargo metadata");
-    }
-    let metadata: Map<String, Value> = serde_json::from_slice(&output.stdout)?;
-
-    if let Some(Value::String(root)) = metadata.get("workspace_root") {
-        Ok(root.clone())
-    } else {
-        bail!("could not location workspace root")
-    }
-}
-
-fn cmd_clippy(strict: bool) -> Result<()> {
-    let wroot = workspace_root()?;
-
-    let run_clippy = |args: &[&str]| -> Result<bool> {
-        let mut cmd = Command::new("cargo");
-        cmd.arg("clippy").arg("--no-deps").args(args).current_dir(&wroot);
-
-        if strict {
-            cmd.args(["--", "-Dwarnings"]);
-        }
-
-        let status = cmd.spawn()?.wait()?;
-        Ok(!status.success())
-    };
-
-    let mut failed = false;
-
-    // Everything in the workspace (including tests, etc)
-    failed |= run_clippy(&["--workspace", "--all-targets"])?;
-
-    // Check the server as it is built for production
-    failed |=
-        run_clippy(&["-p", "propolis-server", "--features", "omicron-build"])?;
-
-    // Check the Falcon bits
-    failed |= run_clippy(&["-p", "propolis-server", "--features", "falcon"])?;
-
-    // Check the mock server
-    failed |=
-        run_clippy(&["-p", "propolis-server", "--features", "mock-only"])?;
-
-    if failed {
-        bail!("Clippy failures detected")
-    }
-
-    Ok(())
+    /// (Crudely) Check for appropriate license headers
+    License,
 }
 
 fn main() -> Result<()> {
     match Args::parse().cmd {
-        Cmds::Clippy { strict } => cmd_clippy(strict),
+        Cmds::Clippy { strict } => task_clippy::cmd_clippy(strict),
+        Cmds::License => task_license::cmd_license(),
     }
 }

xtask/src/task_clippy.rs

@@ -0,0 +1,47 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+use std::process::Command;
+
+use anyhow::{bail, Result};
+
+use crate::util::*;
+
+pub(crate) fn cmd_clippy(strict: bool) -> Result<()> {
+    let wroot = workspace_root()?;
+
+    let run_clippy = |args: &[&str]| -> Result<bool> {
+        let mut cmd = Command::new("cargo");
+        cmd.arg("clippy").arg("--no-deps").args(args).current_dir(&wroot);
+
+        if strict {
+            cmd.args(["--", "-Dwarnings"]);
+        }
+
+        let status = cmd.spawn()?.wait()?;
+        Ok(!status.success())
+    };
+
+    let mut failed = false;
+
+    // Everything in the workspace (including tests, etc)
+    failed |= run_clippy(&["--workspace", "--all-targets"])?;
+
+    // Check the server as it is built for production
+    failed |=
+        run_clippy(&["-p", "propolis-server", "--features", "omicron-build"])?;
+
+    // Check the Falcon bits
+    failed |= run_clippy(&["-p", "propolis-server", "--features", "falcon"])?;
+
+    // Check the mock server
+    failed |=
+        run_clippy(&["-p", "propolis-server", "--features", "mock-only"])?;
+
+    if failed {
+        bail!("Clippy failures detected")
+    }
+
+    Ok(())
+}