Add flag to measure recipe execution time

src/arguments.rs

@@ -283,6 +283,8 @@ pub struct Arguments {
     value_name = "TEMPDIR"
   )]
   pub(crate) tempdir: Option<PathBuf>,
+  #[arg(env = "JUST_TIME", help = "Print recipe execution time", long)]
+  pub(crate) time: bool,
   #[arg(env = "JUST_TIMESTAMP", help = "Print recipe command timestamps", long)]
   pub(crate) timestamp: bool,
   #[arg(

src/config.rs

@@ -32,6 +32,7 @@ pub(crate) struct Config {
   pub(crate) shell_command: bool,
   pub(crate) subcommand: Subcommand,
   pub(crate) tempdir: Option<PathBuf>,
+  pub(crate) time: bool,
   pub(crate) timestamp: bool,
   pub(crate) timestamp_format: String,
   pub(crate) unsorted: bool,
@@ -281,6 +282,7 @@ impl Config {
       shell_command: arguments.shell_command,
       subcommand,
       tempdir: arguments.tempdir,
+      time: arguments.time,
       timestamp: arguments.timestamp,
       timestamp_format: arguments.timestamp_format,
       unsorted: arguments.unsorted,

src/lib.rs

@@ -147,7 +147,9 @@ pub(crate) use {
     slice,
     str::{self, Chars, FromStr},
     sync::{Arc, LazyLock, Mutex, MutexGuard},
-    thread, vec,
+    thread,
+    time::Instant,
+    vec,
   },
   strum::{Display, EnumDiscriminants, EnumIter, EnumString, IntoStaticStr},
   tempfile::TempDir,

src/recipe.rs

@@ -221,11 +221,33 @@ impl<'src> Recipe<'src> {
 
     let evaluator = Evaluator::new(context, BTreeMap::new(), is_dependency, scope);
 
-    if self.is_script() {
+    let start = Instant::now();
+    let result = if self.is_script() {
       self.run_script(context, scope, positional, evaluator)
     } else {
       self.run_linewise(context, scope, positional, evaluator)
+    };
+    let elapsed = start.elapsed();
+
+    if context.config.time {
+      let color = if context.config.highlight {
+        context.config.color.command(context.config.command_color)
+      } else {
+        context.config.color
+      }
+      .stderr();
+
+      let prefix = color.prefix();
+      let suffix = color.suffix();
+      let recipe_name = self.name.lexeme();
+
+      eprintln!(
+        "{prefix}---> {recipe_name} completed in {:.3}s{suffix}",
+        elapsed.as_secs_f64(),
+      );
     }
+
+    result
   }
 
   fn run_linewise<'run>(

tests/run.rs

@@ -41,3 +41,18 @@ fn one_flag_only_allows_one_invocation() {
     .stderr("error: Expected 1 command-line recipe invocation but found 2.\n")
     .failure();
 }
+
+#[test]
+fn time_reports_time_when_specified() {
+  Test::new()
+    .justfile(
+      "
+        foo:
+          @echo FOO
+      ",
+    )
+    .arg("--time")
+    .stdout("FOO\n")
+    .stderr_regex(r"---> foo completed in \d+\.\d+s\n")
+    .success();
+}