Use env_logger filters

Cargo.toml

@@ -16,6 +16,7 @@ serde = "1.0.97"
 serde_derive = "1.0.97"
 serde_json = "1.0.56"
 cfg-if = "0.1.9"
+env_logger = "0.8.3"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 web-sys = { version = "0.3.25", features = ["console"] }

src/lib.rs

@@ -9,6 +9,7 @@
 //! log::info!("Listening on port 8080");
 //! ```
 
+use env_logger::filter::{Builder, Filter};
 pub use log::LevelFilter;
 
 #[cfg(not(target_arch = "wasm32"))]
@@ -36,7 +37,30 @@ mod wasm;
 /// log::info!("Listening on port 8080");
 /// ```
 pub fn start() {
-    with_level(LevelFilter::Info);
+    let filter = Builder::from_env("RUST_LOG").build();
+    with_filter(filter);
+}
+
+/// Start logging with a log filter.
+///
+/// # Examples
+/// ```
+/// let filter = env_logger::filter::Builder::from_env("RUST_LOG").build();
+/// femme::with_filter(filter);
+/// ```
+pub fn with_filter(filter: Filter) {
+    #[cfg(target_arch = "wasm32")]
+    wasm::start(filter);
+
+    #[cfg(not(target_arch = "wasm32"))]
+    {
+        // Use ndjson in release mode, pretty logging while debugging.
+        if cfg!(debug_assertions) {
+            pretty::start(filter);
+        } else {
+            ndjson::start(filter);
+        }
+    }
 }
 
 /// Start logging with a log level.
@@ -48,16 +72,18 @@ pub fn start() {
 /// femme::with_level(log::LevelFilter::Trace);
 /// ```
 pub fn with_level(level: log::LevelFilter) {
+    let filter = Builder::new().filter_level(level).build();
+
     #[cfg(target_arch = "wasm32")]
-    wasm::start(level);
+    wasm::start(filter);
 
     #[cfg(not(target_arch = "wasm32"))]
     {
         // Use ndjson in release mode, pretty logging while debugging.
         if cfg!(debug_assertions) {
-            pretty::start(level);
+            pretty::start(filter);
         } else {
-            ndjson::start(level);
+            ndjson::start(filter);
         }
     }
 }

src/ndjson.rs

@@ -1,31 +1,40 @@
 //! Print logs as ndjson.
 
-use log::{kv, LevelFilter, Log, Metadata, Record};
+use env_logger::filter::Filter;
+use log::{kv, Log, Metadata, Record};
 use std::io::{self, StdoutLock, Write};
 use std::time;
 
 /// Start logging.
-pub(crate) fn start(level: LevelFilter) {
-    let logger = Box::new(Logger {});
+pub(crate) fn start(filter: Filter) {
+    let max_level = filter.filter();
+    let logger = Box::new(Logger { filter });
     log::set_boxed_logger(logger).expect("Could not start logging");
-    log::set_max_level(level);
+    log::set_max_level(max_level);
 }
 
 #[derive(Debug)]
-pub(crate) struct Logger {}
+pub(crate) struct Logger {
+    filter: Filter,
+}
 
 impl Log for Logger {
     fn enabled(&self, metadata: &Metadata<'_>) -> bool {
-        metadata.level() <= log::max_level()
+        self.filter.enabled(metadata)
     }
 
     fn log(&self, record: &Record<'_>) {
-        if self.enabled(record.metadata()) {
+        if self.filter.matches(record) {
             let stdout = io::stdout();
             let mut handle = stdout.lock();
             let level = get_level(record.level());
             let time = time::UNIX_EPOCH.elapsed().unwrap().as_millis();
-            write!(&mut handle, "{{\"level\":{},\"time\":{},\"msg\":", level, time).unwrap();
+            write!(
+                &mut handle,
+                "{{\"level\":{},\"time\":{},\"msg\":",
+                level, time
+            )
+            .unwrap();
             serde_json::to_writer(&mut handle, record.args()).unwrap();
             format_kv_pairs(&mut handle, &record);
             writeln!(&mut handle, "}}").unwrap();

src/pretty.rs

@@ -1,6 +1,7 @@
 //! Pretty print logs.
 
-use log::{kv, Level, LevelFilter, Log, Metadata, Record};
+use env_logger::filter::Filter;
+use log::{kv, Level, Log, Metadata, Record};
 use std::io::{self, StdoutLock, Write};
 
 // ANSI term codes.
@@ -11,22 +12,25 @@ const GREEN: &'static str = "\x1b[32m";
 const YELLOW: &'static str = "\x1b[33m";
 
 /// Start logging.
-pub(crate) fn start(level: LevelFilter) {
-    let logger = Box::new(Logger {});
+pub(crate) fn start(filter: Filter) {
+    let max_level = filter.filter();
+    let logger = Box::new(Logger { filter });
     log::set_boxed_logger(logger).expect("Could not start logging");
-    log::set_max_level(level);
+    log::set_max_level(max_level);
 }
 
 #[derive(Debug)]
-pub(crate) struct Logger {}
+pub(crate) struct Logger {
+    filter: Filter,
+}
 
 impl Log for Logger {
     fn enabled(&self, metadata: &Metadata<'_>) -> bool {
-        metadata.level() <= log::max_level()
+        self.filter.enabled(metadata)
     }
 
     fn log(&self, record: &Record<'_>) {
-        if self.enabled(record.metadata()) {
+        if self.filter.matches(record) {
             let stdout = io::stdout();
             let mut handle = stdout.lock();
             format_src(&mut handle, &record);

src/wasm.rs

@@ -1,28 +1,30 @@
 //! Print logs as ndjson.
 
+use env_logger::filter::Filter;
 use js_sys::Object;
 use log::{kv, Level, LevelFilter, Log, Metadata, Record};
 use wasm_bindgen::prelude::*;
 
 use std::collections::HashMap;
 
 /// Start logging.
-pub(crate) fn start(level: LevelFilter) {
-    let logger = Box::new(Logger {});
+pub(crate) fn start(filter: Filter) {
+    let max_level = filter.filter();
+    let logger = Box::new(Logger { filter });
     log::set_boxed_logger(logger).expect("Could not start logging");
-    log::set_max_level(level);
+    log::set_max_level(max_level);
 }
 
 #[derive(Debug)]
 pub(crate) struct Logger {}
 
 impl Log for Logger {
     fn enabled(&self, metadata: &Metadata<'_>) -> bool {
-        metadata.level() <= log::max_level()
+        self.filter.enabled(metadata)
     }
 
     fn log(&self, record: &Record<'_>) {
-        if self.enabled(record.metadata()) {
+        if self.filter.matches(record) {
             let args = format!("{}", record.args()).into();
             let line = format_line(&record).into();