Add severity

Author: ecerulm

logback-classic/src/main/java/ch/qos/logback/classic/encoder/StructuredLoggingJsonEncoder.java

@@ -80,6 +80,11 @@ protected void appenderExtra(StringBuilder sb, ILoggingEvent event) {
             sb.append(VALUE_SEPARATOR);
             appenderMember(sb, "time", java.time.format.DateTimeFormatter.ISO_INSTANT.format(timestamp));
         }
+        if (withSeverity) {
+            sb.append(VALUE_SEPARATOR);
+            String levelStr = event.getLevel() != null ? event.getLevel().levelStr : NULL_STR;
+            appenderMember(sb, "severity",levelStr);
+        }
     }
 
     @Override

logback-classic/src/test/java/ch/qos/logback/classic/encoder/StructuredLoggingJsonEncoderTest.java

@@ -114,6 +114,7 @@ void smoke() throws JsonProcessingException {
         assertNull(json.get("time"));
         assertNull(json.get("arguments"));
         assertNull(json.get("level"));
+        assertEquals("WARN", json.get("severity").asText());