From 601dc99606359a47c1b1519bf4e3be59a6f5f364 Mon Sep 17 00:00:00 2001
From: Piotr Popieluch <piotr1212@gmail.com>
Date: Fri, 19 Jan 2018 02:37:53 +0100
Subject: [PATCH] Align aggregator period with internal ticker to avoid
 skipping metrics (#3693)

By the time the aggregator.run() was called about 600ms already passed since setting now which was skewing up the aggregation intervals and skipping metrics.
---
 agent/agent.go                             | 4 +---
 internal/models/running_aggregator.go      | 2 +-
 internal/models/running_aggregator_test.go | 6 +++---
 3 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/agent/agent.go b/agent/agent.go
index af96718cd..8739f941d 100644
--- a/agent/agent.go
+++ b/agent/agent.go
@@ -364,8 +364,6 @@ func (a *Agent) Run(shutdown chan struct{}) error {
 	metricC := make(chan telegraf.Metric, 100)
 	aggC := make(chan telegraf.Metric, 100)
 
-	now := time.Now()
-
 	// Start all ServicePlugins
 	for _, input := range a.Config.Inputs {
 		input.SetDefaultTags(a.Config.Tags)
@@ -406,7 +404,7 @@ func (a *Agent) Run(shutdown chan struct{}) error {
 			acc := NewAccumulator(agg, aggC)
 			acc.SetPrecision(a.Config.Agent.Precision.Duration,
 				a.Config.Agent.Interval.Duration)
-			agg.Run(acc, now, shutdown)
+			agg.Run(acc, shutdown)
 		}(aggregator)
 	}
 
diff --git a/internal/models/running_aggregator.go b/internal/models/running_aggregator.go
index 91e5334e8..8189a6667 100644
--- a/internal/models/running_aggregator.go
+++ b/internal/models/running_aggregator.go
@@ -114,7 +114,6 @@ func (r *RunningAggregator) reset() {
 // for period ticks to tell it when to push and reset the aggregator.
 func (r *RunningAggregator) Run(
 	acc telegraf.Accumulator,
-	now time.Time,
 	shutdown chan struct{},
 ) {
 	// The start of the period is truncated to the nearest second.
@@ -133,6 +132,7 @@ func (r *RunningAggregator) Run(
 	// 2nd interval: 00:10 - 00:20.5
 	// etc.
 	//
+	now := time.Now()
 	r.periodStart = now.Truncate(time.Second)
 	truncation := now.Sub(r.periodStart)
 	r.periodEnd = r.periodStart.Add(r.Config.Period)
diff --git a/internal/models/running_aggregator_test.go b/internal/models/running_aggregator_test.go
index cb56dc4ef..30279f0ee 100644
--- a/internal/models/running_aggregator_test.go
+++ b/internal/models/running_aggregator_test.go
@@ -24,7 +24,7 @@ func TestAdd(t *testing.T) {
 	})
 	assert.NoError(t, ra.Config.Filter.Compile())
 	acc := testutil.Accumulator{}
-	go ra.Run(&acc, time.Now(), make(chan struct{}))
+	go ra.Run(&acc, make(chan struct{}))
 
 	m := ra.MakeMetric(
 		"RITest",
@@ -55,7 +55,7 @@ func TestAddMetricsOutsideCurrentPeriod(t *testing.T) {
 	})
 	assert.NoError(t, ra.Config.Filter.Compile())
 	acc := testutil.Accumulator{}
-	go ra.Run(&acc, time.Now(), make(chan struct{}))
+	go ra.Run(&acc, make(chan struct{}))
 
 	// metric before current period
 	m := ra.MakeMetric(
@@ -113,7 +113,7 @@ func TestAddAndPushOnePeriod(t *testing.T) {
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
-		ra.Run(&acc, time.Now(), shutdown)
+		ra.Run(&acc, shutdown)
 	}()
 
 	m := ra.MakeMetric(