xtask: Add util::run_cmd_capture_stdout

Author: nicholasbishop

xtask/src/util.rs

@@ -1,4 +1,4 @@
-use anyhow::{bail, Result};
+use anyhow::{bail, Context, Result};
 use std::process::Command;
 
 /// Format a `Command` as a `String.
@@ -44,6 +44,19 @@ pub fn run_cmd(mut cmd: Command) -> Result<()> {
     }
 }
 
+/// Print a `Command` and run it, then check that it completes
+/// successfully. Return the command's stdout as a `String`.
+pub fn run_cmd_get_stdout(mut cmd: Command) -> Result<String> {
+    println!("run_cmd: '{}'", command_to_string(&cmd));
+
+    let output = cmd.output()?;
+    if output.status.success() {
+        String::from_utf8(output.stdout).context("command output is not utf-8")
+    } else {
+        bail!("command failed: {}", output.status);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;