From 85c4962065a19c649e8d73fd1316528f483eccb2 Mon Sep 17 00:00:00 2001
From: Martin Dale Lyness <martin.lyness@gmail.com>
Date: Mon, 6 May 2019 09:07:16 -0500
Subject: [PATCH] Use PrepForDeferral on ILoggingEvent

To avoid losing MDC context ILoggingEvent has a `prepareForDeferredProcessing` that is supposed to be used in an appender that runs asynchronously. JavaDoc: This method should be called prior to serializing an event. It should also be called when using asynchronous or deferred logging. ...
---
 .../ch/qos/logback/ext/spring/DelegatingLogbackAppender.java  | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/spring/src/main/java/ch/qos/logback/ext/spring/DelegatingLogbackAppender.java b/spring/src/main/java/ch/qos/logback/ext/spring/DelegatingLogbackAppender.java
index a9038ab..181d470 100644
--- a/spring/src/main/java/ch/qos/logback/ext/spring/DelegatingLogbackAppender.java
+++ b/spring/src/main/java/ch/qos/logback/ext/spring/DelegatingLogbackAppender.java
@@ -149,6 +149,10 @@ protected void append(ILoggingEvent event) {
                         delegate = appender;
                     } else {
                         //Otherwise, if the ApplicationContext is not ready yet, cache this event and wait
+                                                
+                        // make sure MDC and other attributes are captured before deferring
+                        event.prepareForDeferredProcessing();
+                        
                         cache.put(event);
 
                         return;