Add output about logger settings in logging setup

This way we can get trace-level information about the logger itself when
it is generated. Because from time to time we might want to have a look
at that.

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

lib/core/libimagrt/src/logger.rs

@@ -41,6 +41,7 @@ use libimagerror::errors::ErrorMsg as EM;
 
 type ModuleName = String;
 
+#[derive(Debug)]
 enum LogDestination {
     Stderr,
     File(Arc<Mutex<::std::fs::File>>),
@@ -52,6 +53,7 @@ impl Default for LogDestination {
     }
 }
 
+#[derive(Debug)]
 struct ModuleSettings {
     enabled:        bool,
     level:          Option<Level>,
@@ -61,6 +63,7 @@ struct ModuleSettings {
 }
 
 /// Logger implementation for `log` crate.
+#[derive(Debug)]
 pub struct ImagLogger {
     global_loglevel     : Level,
 

lib/core/libimagrt/src/runtime.rs

@@ -367,11 +367,15 @@ impl<'a> Runtime<'a> {
 
             set_max_level(logger.global_loglevel().to_level_filter());
 
-            debug!("Init logger with {}", logger.global_loglevel());
+            // safe debug output for later, after the instance itself
+            // is moved away
+            let logger_expl = format!("{:?}", logger);
 
             set_boxed_logger(Box::new(logger))
                 .map_err(|e| panic!("Could not setup logger: {:?}", e))
                 .ok();
+
+            trace!("Imag Logger = {}", logger_expl);
         }
     }