From 893463efca488f67813e53f69882ca56a66eccd6 Mon Sep 17 00:00:00 2001
From: Olivier Vielpeau <olivier.vielpeau@datadoghq.com>
Date: Thu, 27 Jul 2017 17:32:10 -0400
Subject: [PATCH] [dogstatsd] Parse distribution metrics and ignore them

Instead of failing on known but unsupported metric types, ignore these
metrics and continue parsing the rest of the packet.

Without this, sending a new "distribution" type metric in a datagram
makes dogstatsd drop the whole datagram.

This change has virtually no impact on the performance of the dogstatsd
parser.
---
 aggregator.py                 |  4 ++++
 tests/core/test_aggregator.py | 12 ++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/aggregator.py b/aggregator.py
index 9bbbefd5aa..247652e60a 100644
--- a/aggregator.py
+++ b/aggregator.py
@@ -399,6 +399,8 @@ class Aggregator(object):
     """
     # Types of metrics that allow strings
     ALLOW_STRINGS = ['s', ]
+    # Types that are not implemented and ignored
+    IGNORE_TYPES = ['d', ]
 
     def __init__(self, hostname, interval=1.0, expiry_seconds=300,
             formatter=None, recent_point_threshold=None,
@@ -472,6 +474,8 @@ def parse_metric_packet(self, packet):
 
             if metric_type in self.ALLOW_STRINGS:
                 value = raw_value
+            elif metric_type in self.IGNORE_TYPES:
+                continue
             else:
                 # Try to cast as an int first to avoid precision issues, then as a
                 # float.
diff --git a/tests/core/test_aggregator.py b/tests/core/test_aggregator.py
index b2d58d9808..8b95205b49 100644
--- a/tests/core/test_aggregator.py
+++ b/tests/core/test_aggregator.py
@@ -288,6 +288,18 @@ def test_string_sets(self):
         # Assert there are no more sets
         assert not stats.flush()
 
+    def test_ignore_distribution(self):
+        stats = MetricsAggregator('myhost')
+        stats.submit_packets('my.dist:5.0|d')
+        stats.submit_packets('my.gauge:1|g')
+
+        # Assert that it's treated normally, and that the distribution is ignored
+        metrics = stats.flush()
+        nt.assert_equal(len(metrics), 1)
+        m = metrics[0]
+        nt.assert_equal(m['metric'], 'my.gauge')
+        nt.assert_equal(m['points'][0][1], 1)
+
     @attr(requires='core_integration')
     def test_rate(self):
         stats = MetricsAggregator('myhost')