Use tracing in ruff_cli

Cargo.lock

@@ -783,15 +783,6 @@ version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6999dc1837253364c2ebb0704ba97994bd874e8f195d665c50b7548f6ea92764"
 
-[[package]]
-name = "fern"
-version = "0.6.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9f0c14694cbd524c8720dd69b0e3179344f04ebb5f90f2e4a440c6ea3b2f1ee"
-dependencies = [
- "log",
-]
-
 [[package]]
 name = "filetime"
 version = "0.2.22"
@@ -2030,7 +2021,6 @@ dependencies = [
  "chrono",
  "clap",
  "colored",
- "fern",
  "glob",
  "globset",
  "imperative",
@@ -2080,6 +2070,8 @@ dependencies = [
  "test-case",
  "thiserror",
  "toml",
+ "tracing",
+ "tracing-subscriber",
  "typed-arena",
  "unicode-width",
  "unicode_names2",

crates/ruff/Cargo.toml

@@ -37,7 +37,6 @@ bitflags = { workspace = true }
 chrono = { workspace = true }
 clap = { workspace = true, features = ["derive", "string"], optional = true }
 colored = { workspace = true }
-fern = { version = "0.6.1" }
 glob = { workspace = true }
 globset = { workspace = true }
 imperative = { version = "1.0.4" }
@@ -71,6 +70,8 @@ strum = { workspace = true }
 strum_macros = { workspace = true }
 thiserror = { workspace = true }
 toml = { workspace = true }
+tracing = { workspace = true }
+tracing-subscriber = { workspace = true }
 typed-arena = { version = "2.0.2" }
 unicode-width = { workspace = true }
 unicode_names2 = { version = "0.6.0", git = "https://github.com/youknowone/unicode_names2.git", rev = "4ce16aa85cbcdd9cc830410f1a72ef9a235f2fde" }

crates/ruff/src/logging.rs

@@ -4,16 +4,17 @@ use std::sync::Mutex;
 
 use anyhow::Result;
 use colored::Colorize;
-use fern;
-use log::Level;
 use once_cell::sync::Lazy;
-use ruff_python_parser::{ParseError, ParseErrorType};
+use tracing_subscriber::layer::SubscriberExt;
+use tracing_subscriber::util::SubscriberInitExt;
+use tracing_subscriber::EnvFilter;
 
+use ruff_notebook::Notebook;
+use ruff_python_parser::{ParseError, ParseErrorType};
 use ruff_source_file::{OneIndexed, SourceCode, SourceLocation};
 
 use crate::fs;
 use crate::source_kind::SourceKind;
-use ruff_notebook::Notebook;
 
 pub static WARNINGS: Lazy<Mutex<Vec<&'static str>>> = Lazy::new(Mutex::default);
 
@@ -90,49 +91,27 @@ pub enum LogLevel {
 
 impl LogLevel {
     #[allow(clippy::trivially_copy_pass_by_ref)]
-    const fn level_filter(&self) -> log::LevelFilter {
+    const fn tracing_level(&self) -> tracing::Level {
         match self {
-            LogLevel::Default => log::LevelFilter::Info,
-            LogLevel::Verbose => log::LevelFilter::Debug,
-            LogLevel::Quiet => log::LevelFilter::Off,
-            LogLevel::Silent => log::LevelFilter::Off,
+            LogLevel::Default => tracing::Level::INFO,
+            LogLevel::Verbose => tracing::Level::DEBUG,
+            LogLevel::Quiet => tracing::Level::WARN,
+            LogLevel::Silent => tracing::Level::ERROR,
         }
     }
 }
 
+/// Log level priorities: 1. `RUST_LOG=`, 2. explicit CLI log level, 3. default to info
 pub fn set_up_logging(level: &LogLevel) -> Result<()> {
-    fern::Dispatch::new()
-        .format(|out, message, record| match record.level() {
-            Level::Error => {
-                out.finish(format_args!(
-                    "{}{} {}",
-                    "error".red().bold(),
-                    ":".bold(),
-                    message
-                ));
-            }
-            Level::Warn => {
-                out.finish(format_args!(
-                    "{}{} {}",
-                    "warning".yellow().bold(),
-                    ":".bold(),
-                    message
-                ));
-            }
-            Level::Info | Level::Debug | Level::Trace => {
-                out.finish(format_args!(
-                    "{}[{}][{}] {}",
-                    chrono::Local::now().format("[%Y-%m-%d][%H:%M:%S]"),
-                    record.target(),
-                    record.level(),
-                    message
-                ));
-            }
-        })
-        .level(level.level_filter())
-        .level_for("globset", log::LevelFilter::Warn)
-        .chain(std::io::stderr())
-        .apply()?;
+    let filter_layer = EnvFilter::try_from_default_env().unwrap_or_else(|_| {
+        EnvFilter::builder()
+            .with_default_directive(level.tracing_level().into())
+            .parse_lossy("")
+    });
+    tracing_subscriber::registry()
+        .with(filter_layer)
+        .with(tracing_subscriber::fmt::layer())
+        .init();
     Ok(())
 }
 

crates/ruff_cli/Cargo.toml

@@ -64,7 +64,7 @@ shellexpand = { workspace = true }
 similar = { workspace = true }
 strum = { workspace = true, features = [] }
 thiserror = { workspace = true }
-tracing = { workspace = true, features = ["log"] }
+tracing = { workspace = true }
 walkdir = { version = "2.3.2" }
 wild = { version = "2" }