Slightly improve logging (#2734)

* Add crate name to cache hit and cache error logging message

* Log ProcessError output

Not the best formatting, but more useful than nothing at all.

Author: glandium

src/compiler/compiler.rs

@@ -557,7 +557,10 @@ where
         let (key, compilation, weak_toolchain_key) = match result {
             Err(e) => {
                 return match e.downcast::<ProcessError>() {
-                    Ok(ProcessError(output)) => Ok((CompileResult::Error, output)),
+                    Ok(ProcessError(output)) => {
+                        debug!("[{}]: process error: {:?}", out_pretty, output);
+                        Ok((CompileResult::Error, output))
+                    }
                     Err(e) => Err(e),
                 };
             }

src/server.rs

@@ -1383,12 +1383,12 @@ where
 
                         match compiled {
                             CompileResult::Error => {
-                                debug!("compile result: cache error");
+                                debug!("[{}]: compile result: cache error", out_pretty);
 
                                 stats.cache_errors.increment(&kind, &lang);
                             }
                             CompileResult::CacheHit(duration) => {
-                                debug!("compile result: cache hit");
+                                debug!("[{}]: compile result: cache hit", out_pretty);
 
                                 stats.cache_hits.increment(&kind, &lang);
                                 stats.cache_read_hit_duration += duration;