From f1a73996704cc9420c33acf45366c25e7c9ecb28 Mon Sep 17 00:00:00 2001
From: booktrail <nebulawalker@gmail.com>
Date: Sat, 23 Apr 2022 19:48:45 -0700
Subject: [PATCH] Fix dogstatsd metric without tags in StatsDOutputWriter

---
 .../org/jmxtrans/agent/StatsDOutputWriter.java     | 10 ++++++----
 .../org/jmxtrans/agent/StatsDOutputWriterTest.java | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/main/java/org/jmxtrans/agent/StatsDOutputWriter.java b/src/main/java/org/jmxtrans/agent/StatsDOutputWriter.java
index 69f3dd36..86037a83 100644
--- a/src/main/java/org/jmxtrans/agent/StatsDOutputWriter.java
+++ b/src/main/java/org/jmxtrans/agent/StatsDOutputWriter.java
@@ -147,10 +147,12 @@ protected synchronized String buildMetricsString(String metricName, String metri
                     .append(":")
                     .append(strValue)
                     .append("|")
-                    .append(type)
-                    .append("|#")
-                    .append(StringUtils2.join(Tag.convertTagsToStrings(tags), ","))
-                    .append("\n");
+                    .append(type);
+            if (!tags.isEmpty()) {
+                sb.append("|#");
+                sb.append(StringUtils2.join(Tag.convertTagsToStrings(tags), ","));
+            }
+            sb.append("\n");
         } else if (statsType.equals(STATSD_SYSDIG)) {
             sb.append(metricNamePrefix)
                     .append(".")
diff --git a/src/test/java/org/jmxtrans/agent/StatsDOutputWriterTest.java b/src/test/java/org/jmxtrans/agent/StatsDOutputWriterTest.java
index 6e32cba6..467de935 100644
--- a/src/test/java/org/jmxtrans/agent/StatsDOutputWriterTest.java
+++ b/src/test/java/org/jmxtrans/agent/StatsDOutputWriterTest.java
@@ -87,6 +87,20 @@ public void test_write_counter_metric_dd() throws IOException {
 
     }
 
+    @Test
+    public void test_write_counter_metric_dd_without_tags() throws IOException {
+        Map<String, String> settings = new HashMap<>();
+        settings.put(StatsDOutputWriter.SETTING_ROOT_PREFIX, "foo.bar");
+        // No real connect is done. Config is here to please the postConstruct.
+        settings.put(StatsDOutputWriter.SETTING_HOST, "localhost");
+        settings.put(StatsDOutputWriter.SETTING_PORT, "8125");
+        settings.put(StatsDOutputWriter.SETTINGS_STATSD_TYPE, "dd");
+
+        writer.postConstruct(settings);
+        writer.writeQueryResult("my-metric", "gauge", 12);
+        Assert.assertThat(writer.receivedStat, equalTo("foo.bar.my-metric:12|g\n"));
+    }
+
     @Test
     public void test_write_counter_metric_sysdig() throws IOException {
         Map<String, String> settings = new HashMap<>();