feat: add extended exception context to EXN_STACKTRACE

Adds the cause exception stacktrace (if exists) of the logged exception to the `EXN_STACKTRACE` along with the original exceptions stacktrace.
dogukancagatay · Nov 1, 2024 · 6c123ed · 6c123ed
1 parent 2ed5ab4
commit 6c123ed
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diff --git a/src/main/java/com/dgkncgty/logback/SystemdJournalAppender.java b/src/main/java/com/dgkncgty/logback/SystemdJournalAppender.java
@@ -17,6 +17,7 @@
 
 import ch.qos.logback.classic.Level;
 import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.classic.spi.IThrowableProxy;
 import ch.qos.logback.classic.spi.StackTraceElementProxy;
 import ch.qos.logback.core.AppenderBase;
 import ch.qos.logback.core.encoder.Encoder;
@@ -25,6 +26,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * An appender that send the events to systemd journal
@@ -96,11 +98,29 @@ protected void append(ILoggingEvent event) {
                     // if one wants to log the exception stack trace, just do it
                     if (logStackTrace) {
                         messages.add("EXN_STACKTRACE=%s");
+
+                        // The main exception
                         StringWriter stacktrace = new StringWriter();
                         for (StackTraceElementProxy st : stack) {
                             stacktrace.write(st.getSTEAsString());
                             stacktrace.write('\n');
                         }
+
+                        // Go down the caused by chain
+                        IThrowableProxy cause = event.getThrowableProxy().getCause();
+                        while (cause != null) {
+                            stacktrace.write("Caused by: ");
+                            stacktrace.write(cause.getClassName());
+                            stacktrace.write(": ");
+                            stacktrace.write(Objects.toString(cause.getMessage(), ""));
+                            stacktrace.write("\n");
+                            for (StackTraceElementProxy st : cause.getStackTraceElementProxyArray()) {
+                                stacktrace.write(st.getSTEAsString());
+                                stacktrace.write('\n');
+                            }
+                            cause = cause.getCause();
+                        }
+
                         messages.add(stacktrace.toString());
                     }
                 }

diff --git a/src/test/java/com/dgkncgty/logback/SystemdJournalAppenderTest.java b/src/test/java/com/dgkncgty/logback/SystemdJournalAppenderTest.java
@@ -71,5 +71,13 @@ public void testLogWithSourceAndException() throws Exception {
         logWithSource.error("some exception", exception);
     }
 
+    @Test
+    public void testLogWithSourceAndNestedException() {
+        Exception exception = new RuntimeException("some exception");
+        Exception exception1 = new Exception("nested exception 1", exception);
+        Exception exception2 = new Exception("nested exception 2", exception1);
+        Exception exception3 = new Exception("nested exception 3", exception2);
+        logWithSource.error("an exception occurred ", exception3);
+    }
 
 }