Fix a couple of bugs in the logic for how AWS metric periods are calc…

…ulated (#32724)

* Fix a couple of bugs in the logic for how AWS metric periods are calcuated.

Firstly, we clarify that periods are always whole-minute durations.
Any period that is less than or in between minutes is rounded up to the
next whole-minute.

Secondly, we ensure that the resulting time period is always in the past.
This stops us getting empty metrics for the current-minute period.

Thirdly, we follow the AWS guidelines of aligning periods to whole
multiples within the hour e.g. 10:25->10:30 instead of 10:27->10:32
for a 5 minute period.

* add test that validates intervals are continuous for given periods

* update changelog

* fix merge error

CHANGELOG.next.asciidoc

@@ -78,6 +78,7 @@ https://github.com/elastic/beats/compare/v8.2.0\...main[Check the HEAD diff]
 
 *Metricbeat*
 
+- Fix and improve AWS metric period calculation to avoid zero-length intervals {pull}32724[32724]
 
 *Packetbeat*
 

x-pack/metricbeat/module/aws/billing/billing.go

@@ -124,7 +124,7 @@ func (m *MetricSet) Fetch(report mb.ReporterV2) error {
  startDate, endDate := getStartDateEndDate(m.Period)
 
  // Get startTime and endTime
- startTime, endTime := aws.GetStartTimeEndTime(m.Period, m.Latency)
+ startTime, endTime := aws.GetStartTimeEndTime(time.Now(), m.Period, m.Latency)
 
  // get cost metrics from cost explorer
  awsBeatsConfig := m.MetricSet.AwsConfig.Copy()

x-pack/metricbeat/module/aws/cloudwatch/cloudwatch.go

@@ -126,7 +126,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 // of an error set the Error field of mb.Event or simply call report.Error().
 func (m *MetricSet) Fetch(report mb.ReporterV2) error {
  // Get startTime and endTime
- startTime, endTime := aws.GetStartTimeEndTime(m.Period, m.Latency)
+ startTime, endTime := aws.GetStartTimeEndTime(time.Now(), m.Period, m.Latency)
  m.Logger().Debugf("startTime = %s, endTime = %s", startTime, endTime)
 
  // Check statistic method in config

x-pack/metricbeat/module/aws/cloudwatch/cloudwatch_test.go

@@ -1392,7 +1392,7 @@ func TestCreateEventsWithIdentifier(t *testing.T) {
  Value: "test-ec2",
  },
  }
- startTime, endTime := aws.GetStartTimeEndTime(m.MetricSet.Period, m.MetricSet.Latency)
+ startTime, endTime := aws.GetStartTimeEndTime(time.Now(), m.MetricSet.Period, m.MetricSet.Latency)
 
  events, err := m.createEvents(mockCloudwatchSvc, mockTaggingSvc, listMetricWithStatsTotal, resourceTypeTagFilters, regionName, startTime, endTime)
  assert.NoError(t, err)
@@ -1432,7 +1432,7 @@ func TestCreateEventsWithoutIdentifier(t *testing.T) {
  }
 
  resourceTypeTagFilters := map[string][]aws.Tag{}
- startTime, endTime := aws.GetStartTimeEndTime(m.MetricSet.Period, m.MetricSet.Latency)
+ startTime, endTime := aws.GetStartTimeEndTime(time.Now(), m.MetricSet.Period, m.MetricSet.Latency)
 
  events, err := m.createEvents(mockCloudwatchSvc, mockTaggingSvc, listMetricWithStatsTotal, resourceTypeTagFilters, regionName, startTime, endTime)
  assert.NoError(t, err)
@@ -1478,7 +1478,7 @@ func TestCreateEventsWithTagsFilter(t *testing.T) {
  },
  }
 
- startTime, endTime := aws.GetStartTimeEndTime(m.MetricSet.Period, m.MetricSet.Latency)
+ startTime, endTime := aws.GetStartTimeEndTime(time.Now(), m.MetricSet.Period, m.MetricSet.Latency)
  events, err := m.createEvents(mockCloudwatchSvc, mockTaggingSvc, listMetricWithStatsTotal, resourceTypeTagFilters, regionName, startTime, endTime)
  assert.NoError(t, err)
  assert.Equal(t, 1, len(events))
@@ -1630,7 +1630,7 @@ func TestCreateEventsTimestamp(t *testing.T) {
  }
 
  resourceTypeTagFilters := map[string][]aws.Tag{}
- startTime, endTime := aws.GetStartTimeEndTime(m.MetricSet.Period, m.MetricSet.Latency)
+ startTime, endTime := aws.GetStartTimeEndTime(time.Now(), m.MetricSet.Period, m.MetricSet.Latency)
 
  cloudwatchMock := &MockCloudWatchClientWithoutDim{}
  resGroupTaggingClientMock := &MockResourceGroupsTaggingClient{}
@@ -1644,6 +1644,6 @@ func TestGetStartTimeEndTime(t *testing.T) {
  m.CloudwatchConfigs = []Config{{Statistic: []string{"Average"}}}
  m.MetricSet = &aws.MetricSet{Period: 5 * time.Minute}
  m.logger = logp.NewLogger("test")
- startTime, endTime := aws.GetStartTimeEndTime(m.MetricSet.Period, m.MetricSet.Latency)
+ startTime, endTime := aws.GetStartTimeEndTime(time.Now(), m.MetricSet.Period, m.MetricSet.Latency)
  assert.Equal(t, 5*time.Minute, endTime.Sub(startTime))
 }

x-pack/metricbeat/module/aws/utils.go

@@ -18,22 +18,22 @@ import (
  resourcegroupstaggingapitypes "github.com/aws/aws-sdk-go-v2/service/resourcegroupstaggingapi/types"
 )
 
-// GetStartTimeEndTime function uses durationString to create startTime and endTime for queries.
-func GetStartTimeEndTime(period time.Duration, latency time.Duration) (time.Time, time.Time) {
- endTime := time.Now()
- if latency != 0 {
- // add latency if config is not 0
- endTime = endTime.Add(latency * -1)
- }
-
- // Set startTime to be one period earlier than the endTime. If metrics are
- // not being collected, use latency config parameter to offset the startTime
- // and endTime.
- startTime := endTime.Add(period * -1)
- // Defining duration
- d := 60 * time.Second
- // Calling Round() method
- return startTime.Round(d), endTime.Round(d)
+// GetStartTimeEndTime calculates start and end times for queries based on the current time and a duration.
+//
+// Whilst the inputs to this function are continuous, the maximum period granularity we can consistently use
+// is 1 minute. The resulting interval should also be aligned to the period for best performance. This means
+// if a period of 3 minutes is requested at 12:05, for example, the calculated times are 12:00->12:03. See
+// https://github.com/aws/aws-sdk-go-v2/blob/fdbd882cdf5c63a578caed14688cf9a456c75f2b/service/cloudwatch/api_op_GetMetricData.go#L88
+// for more information about granularity and period alignment.
+//
+// If durations are configured in non-whole minute periods, they are rounded up to the next minute e.g. 90s becomes 120s.
+//
+// If `latency` is configured, the period is shifted back in time by specified duration (before period alignment).
+func GetStartTimeEndTime(now time.Time, period time.Duration, latency time.Duration) (time.Time, time.Time) {
+ periodInMinutes := (period + time.Second*29).Round(time.Second * 60)
+ endTime := now.Add(latency * -1).Truncate(periodInMinutes)
+ startTime := endTime.Add(periodInMinutes * -1)
+ return startTime, endTime
 }
 
 // GetListMetricsOutput function gets listMetrics results from cloudwatch ~~per namespace~~ for each region.

x-pack/metricbeat/module/aws/utils_test.go

@@ -160,7 +160,7 @@ func TestGetListMetricsOutputWithWildcard(t *testing.T) {
 }
 
 func TestGetMetricDataPerRegion(t *testing.T) {
- startTime, endTime := GetStartTimeEndTime(10*time.Minute, 0)
+ startTime, endTime := GetStartTimeEndTime(time.Now(), 10*time.Minute, 0)
 
  mockSvc := &MockCloudWatchClient{}
  var metricDataQueries []cloudwatchtypes.MetricDataQuery
@@ -194,7 +194,7 @@ func TestGetMetricDataPerRegion(t *testing.T) {
 }
 
 func TestGetMetricDataResults(t *testing.T) {
- startTime, endTime := GetStartTimeEndTime(10*time.Minute, 0)
+ startTime, endTime := GetStartTimeEndTime(time.Now(), 10*time.Minute, 0)
 
  mockSvc := &MockCloudWatchClient{}
  metricInfo := cloudwatchtypes.Metric{
@@ -434,3 +434,135 @@ func TestGetResourcesTags(t *testing.T) {
  }
  assert.Equal(t, expectedResourceTagMap, resourceTagMap)
 }
+
+func parseTime(t *testing.T, in string) time.Time {
+ time, err := time.Parse(time.RFC3339, in)
+ if err != nil {
+ t.Errorf("test setup failed - could not parse time with time.RFC3339: %s", in)
+ }
+ return time
+}
+
+func TestGetStartTimeEndTime(t *testing.T) {
+ var cases = []struct {
+ title string
+ start string
+ period time.Duration
+ latency time.Duration
+ expectedStart string
+ expectedEnd string
+ }{
+ // window should align with period e.g. requesting a 5 minute period at 10:27 gives 10:20->10:25
+ {"1 minute", "2022-08-15T13:38:45Z", time.Second * 60, 0, "2022-08-15T13:37:00Z", "2022-08-15T13:38:00Z"},
+ {"2 minutes", "2022-08-15T13:38:45Z", time.Second * 60 * 2, 0, "2022-08-15T13:36:00Z", "2022-08-15T13:38:00Z"},
+ {"3 minutes", "2022-08-15T13:38:45Z", time.Second * 60 * 3, 0, "2022-08-15T13:33:00Z", "2022-08-15T13:36:00Z"},
+ {"5 minutes", "2022-08-15T13:38:45Z", time.Second * 60 * 5, 0, "2022-08-15T13:30:00Z", "2022-08-15T13:35:00Z"},
+ {"30 minutes", "2022-08-15T13:38:45Z", time.Second * 60 * 30, 0, "2022-08-15T13:00:00Z", "2022-08-15T13:30:00Z"},
+
+ // latency should shift the time *before* period alignment
+ // e.g. requesting a 5 minute period at 10:27 with 1 minutes latency still gives 10:20->10:25,
+ // but with 3 minutes latency gives 10:15->10:20
+ {"1 minute, 10 minutes latency", "2022-08-15T13:38:45Z", time.Second * 60, time.Second * 60 * 10, "2022-08-15T13:27:00Z", "2022-08-15T13:28:00Z"},
+ {"2 minutes, 1 minute latency", "2022-08-15T13:38:45Z", time.Second * 60 * 2, time.Second * 60, "2022-08-15T13:34:00Z", "2022-08-15T13:36:00Z"},
+ {"5 minutes, 4 minutes latency", "2022-08-15T13:38:45Z", time.Second * 60 * 5, time.Second * 60 * 4, "2022-08-15T13:25:00Z", "2022-08-15T13:30:00Z"},
+ {"30 minutes, 30 minutes latency", "2022-08-15T13:38:45Z", time.Second * 60 * 30, time.Second * 60 * 30, "2022-08-15T12:30:00Z", "2022-08-15T13:00:00Z"},
+
+ // non-whole-minute periods should be rounded up to the nearest minute; latency is applied as-is before period adjustment
+ {"20 seconds, 45 second latency", "2022-08-15T13:38:45Z", time.Second * 20, time.Second * 45, "2022-08-15T13:37:00Z", "2022-08-15T13:38:00Z"},
+ {"1.5 minutes, 60 second latency", "2022-08-15T13:38:45Z", time.Second * 90, time.Second * 60, "2022-08-15T13:34:00Z", "2022-08-15T13:36:00Z"},
+ {"just less than 5 minutes, 3 minute latency", "2022-08-15T13:38:45Z", time.Second * 59 * 5, time.Second * 90, "2022-08-15T13:30:00Z", "2022-08-15T13:35:00Z"},
+ }
+
+ for _, tt := range cases {
+ t.Run(tt.title, func(t *testing.T) {
+ startTime, expectedStartTime, expectedEndTime := parseTime(t, tt.start), parseTime(t, tt.expectedStart), parseTime(t, tt.expectedEnd)
+
+ start, end := GetStartTimeEndTime(startTime, tt.period, tt.latency)
+
+ if expectedStartTime != start || expectedEndTime != end {
+ t.Errorf("got (%s, %s), want (%s, %s)", start, end, tt.expectedStart, tt.expectedEnd)
+ }
+ })
+ }
+}
+
+func TestGetStartTimeEndTime_AlwaysCreatesContinuousIntervals(t *testing.T) {
+ type interval struct {
+ start, end string
+ }
+
+ startTime := parseTime(t, "2022-08-24T11:01:00Z")
+ numCalls := 5
+
+ var cases = []struct {
+ title string
+ period time.Duration
+ latency time.Duration
+ expectedIntervals []interval
+ }{
+ // with no latency
+ {"1 minute", time.Second * 60, 0, []interval{
+ {"2022-08-24T11:00:00Z", "2022-08-24T11:01:00Z"},
+ {"2022-08-24T11:01:00Z", "2022-08-24T11:02:00Z"},
+ {"2022-08-24T11:02:00Z", "2022-08-24T11:03:00Z"},
+ {"2022-08-24T11:03:00Z", "2022-08-24T11:04:00Z"},
+ {"2022-08-24T11:04:00Z", "2022-08-24T11:05:00Z"},
+ }},
+ {"2 minutes", time.Second * 60 * 2, 0, []interval{
+ {"2022-08-24T10:58:00Z", "2022-08-24T11:00:00Z"},
+ {"2022-08-24T11:00:00Z", "2022-08-24T11:02:00Z"},
+ {"2022-08-24T11:02:00Z", "2022-08-24T11:04:00Z"},
+ {"2022-08-24T11:04:00Z", "2022-08-24T11:06:00Z"},
+ {"2022-08-24T11:06:00Z", "2022-08-24T11:08:00Z"},
+ }},
+ {"3 minutes", time.Second * 60 * 3, 0, []interval{
+ {"2022-08-24T10:57:00Z", "2022-08-24T11:00:00Z"},
+ {"2022-08-24T11:00:00Z", "2022-08-24T11:03:00Z"},
+ {"2022-08-24T11:03:00Z", "2022-08-24T11:06:00Z"},
+ {"2022-08-24T11:06:00Z", "2022-08-24T11:09:00Z"},
+ {"2022-08-24T11:09:00Z", "2022-08-24T11:12:00Z"},
+ }},
+ {"5 minutes", time.Second * 60 * 5, 0, []interval{
+ {"2022-08-24T10:55:00Z", "2022-08-24T11:00:00Z"},
+ {"2022-08-24T11:00:00Z", "2022-08-24T11:05:00Z"},
+ {"2022-08-24T11:05:00Z", "2022-08-24T11:10:00Z"},
+ {"2022-08-24T11:10:00Z", "2022-08-24T11:15:00Z"},
+ {"2022-08-24T11:15:00Z", "2022-08-24T11:20:00Z"},
+ }},
+ {"30 minutes", time.Second * 60 * 30, 0, []interval{
+ {"2022-08-24T10:30:00Z", "2022-08-24T11:00:00Z"},
+ {"2022-08-24T11:00:00Z", "2022-08-24T11:30:00Z"},
+ {"2022-08-24T11:30:00Z", "2022-08-24T12:00:00Z"},
+ {"2022-08-24T12:00:00Z", "2022-08-24T12:30:00Z"},
+ {"2022-08-24T12:30:00Z", "2022-08-24T13:00:00Z"},
+ }},
+
+ // with 90s latency (sanity check)
+ {"1 minute with 2 minute latency", time.Second * 60, time.Second * 90, []interval{
+ {"2022-08-24T10:58:00Z", "2022-08-24T10:59:00Z"},
+ {"2022-08-24T10:59:00Z", "2022-08-24T11:00:00Z"},
+ {"2022-08-24T11:00:00Z", "2022-08-24T11:01:00Z"},
+ {"2022-08-24T11:01:00Z", "2022-08-24T11:02:00Z"},
+ {"2022-08-24T11:02:00Z", "2022-08-24T11:03:00Z"},
+ }},
+ }
+
+ for _, tt := range cases {
+ t.Run(tt.title, func(t *testing.T) {
+ // get a few repeated intervals
+ intervals := make([]interval, numCalls)
+ for i := range intervals {
+ adjustedStartTime := startTime.Add(tt.period * time.Duration(i))
+ start, end := GetStartTimeEndTime(adjustedStartTime, tt.period, tt.latency)
+ intervals[i] = interval{start.Format(time.RFC3339), end.Format(time.RFC3339)}
+ }
+
+ for i, val := range intervals {
+ if val != tt.expectedIntervals[i] {
+ t.Errorf("got %v, want %v", intervals, tt.expectedIntervals)
+ break
+ }
+ }
+ })
+ }
+}