From e5a0392994b66ecf23eea42061b5d41f6c1f4f67 Mon Sep 17 00:00:00 2001
From: shikhman <shikhman@google.com>
Date: Tue, 6 Sep 2016 14:01:43 -0700
Subject: [PATCH] Make StackdriverWriter#flush() return early when attempting
 to flush empty timeseries

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=132359115
---
 .../registry/monitoring/metrics/StackdriverWriter.java      | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/java/google/registry/monitoring/metrics/StackdriverWriter.java b/java/google/registry/monitoring/metrics/StackdriverWriter.java
index d77cb3baa..0b3e72fbd 100644
--- a/java/google/registry/monitoring/metrics/StackdriverWriter.java
+++ b/java/google/registry/monitoring/metrics/StackdriverWriter.java
@@ -193,6 +193,12 @@ public class StackdriverWriter implements MetricWriter {
   public void flush() throws IOException {
     checkState(timeSeriesBuffer.size() <= 200, FLUSH_OVERFLOW_ERROR);
 
+    // Return early; Stackdriver throws errors if we attempt to send empty requests.
+    if (timeSeriesBuffer.isEmpty()) {
+      logger.fine("Attempted to flush with no pending points, doing nothing");
+      return;
+    }
+
     ImmutableList<TimeSeries> timeSeriesList = ImmutableList.copyOf(timeSeriesBuffer);
     timeSeriesBuffer.clear();