Add support for env_logger

When RUST_LOG environment variable is set, uses env_logger instead of
our custom logger. This is desirable for debugging purposes.

2 files changed, 11 insertions, 5 deletions

diff --git a/src/lib.rs b/src/lib.rs
index d48ab93b..255215c7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -33,6 +33,7 @@ extern crate arraydeque;
 extern crate cgmath;
 extern crate copypasta;
 extern crate errno;
+extern crate env_logger;
 extern crate fnv;
 extern crate font;
 extern crate glutin;
diff --git a/src/logging.rs b/src/logging.rs
index 6b7a7968..4584b5f6 100644
--- a/src/logging.rs
+++ b/src/logging.rs
@@ -36,7 +36,6 @@ impl<T: Send + io::Write> Logger<T> {
     }
 }
 
-
 impl<T: Send + io::Write> log::Log for Logger<T> {
     fn enabled(&self, metadata: &log::LogMetadata) -> bool {
         metadata.level() <= self.level
@@ -52,8 +51,14 @@ impl<T: Send + io::Write> log::Log for Logger<T> {
 }
 
 pub fn initialize(options: &cli::Options) -> Result<(), log::SetLoggerError> {
-    log::set_logger(|max_log_level| {
-        max_log_level.set(options.log_level);
-        Box::new(Logger::new(io::stdout(), options.log_level))
-    })
+    // Use env_logger if RUST_LOG environment variable is defined. Otherwise,
+    // use the alacritty-only logger.
+    if ::std::env::var("RUST_LOG").is_ok() {
+        ::env_logger::init()
+    } else {
+        log::set_logger(|max_log_level| {
+            max_log_level.set(options.log_level);
+            Box::new(Logger::new(io::stdout(), options.log_level))
+        })
+    }
 }