log configured values as integer

src/main/java/de/siegmar/logbackgelf/GelfEncoder.java

@@ -103,6 +103,8 @@ public class GelfEncoder extends EncoderBase<ILoggingEvent> {
      */
     private PatternLayout fullPatternLayout;
 
+    private boolean numbersAsString = true;
+
     /**
      * Additional, static fields to send to graylog. Defaults: none.
      */
@@ -172,6 +174,14 @@ public void setAppendNewline(final boolean appendNewline) {
         this.appendNewline = appendNewline;
     }
 
+    public boolean isNumbersAsString() {
+        return numbersAsString;
+    }
+
+    public void setNumbersAsString(final boolean numbersAsString) {
+        this.numbersAsString = numbersAsString;
+    }
+
     public PatternLayout getShortPatternLayout() {
         return shortPatternLayout;
     }
@@ -216,8 +226,22 @@ private void addField(final Map<String, Object> dst, final String key, final Str
             addWarn("staticField key '" + key + "' is illegal. "
                 + "Keys must apply to regex ^[\\w.-]*$");
         } else {
-            dst.put(key, value);
+            final Object processedValue = processValue(key, value);
+            if (processedValue != null) {
+                dst.put(key, processedValue);
+            }
+        }
+    }
+
+    private Object processValue(final String key, final String value) {
+        if (!numbersAsString) {
+            try {
+                return Double.valueOf(value);
+            } catch (final NumberFormatException e) {
+                return value;
+            }
         }
+        return value;
     }
 
     @Override

src/test/java/de/siegmar/logbackgelf/GelfEncoderTest.java

@@ -267,6 +267,50 @@ public void rootExceptionWithCause() throws IOException {
             jsonNode.get("_root_cause_message").textValue());
     }
 
+    @Test
+    public void numericValueAsNumber() throws IOException {
+        encoder.setNumbersAsString(false);
+        encoder.start();
+
+        final LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
+        final Logger logger = lc.getLogger(LOGGER_NAME);
+
+        final LoggingEvent event = simpleLoggingEvent(logger, null);
+
+        event.setMDCPropertyMap(ImmutableMap.of("http_status", "200"));
+
+        final String logMsg = encodeToStr(event);
+
+        final ObjectMapper om = new ObjectMapper();
+        final JsonNode jsonNode = om.readTree(logMsg);
+        basicValidation(jsonNode);
+        final JsonNode httpStatus = jsonNode.get("_http_status");
+        assertEquals(200, httpStatus.asDouble(), 0);
+        assertTrue(httpStatus.isNumber());
+    }
+
+    @Test
+    public void numericValueAsString() throws IOException {
+        encoder.setNumbersAsString(true);
+        encoder.start();
+
+        final LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
+        final Logger logger = lc.getLogger(LOGGER_NAME);
+
+        final LoggingEvent event = simpleLoggingEvent(logger, null);
+
+        event.setMDCPropertyMap(ImmutableMap.of("http_status", "200"));
+
+        final String logMsg = encodeToStr(event);
+
+        final ObjectMapper om = new ObjectMapper();
+        final JsonNode jsonNode = om.readTree(logMsg);
+        basicValidation(jsonNode);
+        final JsonNode httpStatus = jsonNode.get("_http_status");
+        assertEquals("200", httpStatus.asText());
+        assertFalse(httpStatus.isNumber());
+    }
+
     private String encodeToStr(final LoggingEvent event) {
         return new String(encoder.encode(event), StandardCharsets.UTF_8);
     }