warn instead of crashing when logging is not configured

conf/manager.conf.in

@@ -19,7 +19,7 @@ version = open Beta 1
 url = https://my.fqdn/accountmanager
 support_email = support@my.fqdn
 
-[log]
+[logger]
 file = /opt/testidp/IdPAccountManager/log/manager.log
 level = info
 

lib/AccountManager/App.pm

@@ -41,11 +41,15 @@ sub new {
         configuration => $args{configuration},
     };
 
-    Log::Any::Adapter->set(
-        'File',
-        $self->{configuration}->{log}->{file},
-        log_level => $self->{configuration}->{log}->{level}
-    );
+    if ($self->{configuration}->{logger}) {
+        Log::Any::Adapter->set(
+            'File',
+            $self->{configuration}->{log}->{file},
+            log_level => $self->{configuration}->{log}->{level}
+        );
+    } else {
+        warn "no logger defined in configuration, logging disabled\n";
+    }
 
     $self->{logger} = Log::Any->get_logger();