From 7fd27bf1f6c4ea243697f00eb24b1ded857bebc6 Mon Sep 17 00:00:00 2001
From: muthu-mps <101238137+muthu-mps@users.noreply.github.com>
Date: Thu, 27 Jul 2023 14:38:57 +0000
Subject: [PATCH] [Azure Billing] Update forecast api metrics interval (#36142)

* Update forecast API metrics interval
---
 CHANGELOG.next.asciidoc                               |  1 +
 x-pack/metricbeat/module/azure/billing/billing.go     | 11 ++++++-----
 .../metricbeat/module/azure/billing/billing_test.go   |  4 ++--
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.next.asciidoc b/CHANGELOG.next.asciidoc
index 59d25cec04a..66c3113db86 100644
--- a/CHANGELOG.next.asciidoc
+++ b/CHANGELOG.next.asciidoc
@@ -231,6 +231,7 @@ automatic splitting at root level, if root level element is an array. {pull}3415
 - Improve documentation for ActiveMQ module {issue}35113[35113] {pull}35558[35558]
 - Fix EC2 host.cpu.usage {pull}35717[35717]
 - Resolve statsd module's prematurely halting of metrics parsing upon encountering an invalid packet. {pull}35075[35075]
+- Fix the gap in fetching forecast API metrics at the end of each month for Azure billing module  {pull}36142[36142]
 
 *Osquerybeat*
 
diff --git a/x-pack/metricbeat/module/azure/billing/billing.go b/x-pack/metricbeat/module/azure/billing/billing.go
index a2968d71a6d..4777df5f217 100644
--- a/x-pack/metricbeat/module/azure/billing/billing.go
+++ b/x-pack/metricbeat/module/azure/billing/billing.go
@@ -127,11 +127,12 @@ func usageIntervalFrom(reference time.Time) (time.Time, time.Time) {
 // reference time.
 //
 // For example, if the reference time is 2007-01-09 09:41:00Z, the forecast period is:
+// The forecast data is fetched from current day - 2 and for next 30 days.
 //
-//	2007-01-01T00:00:00Z -> 2007-01-31:59:59Z
+//	2007-01-07T00:00:00Z -> 2007-02-05:59:59Z
 func forecastIntervalFrom(reference time.Time) (time.Time, time.Time) {
-	referenceUTC := reference.UTC()
-	beginningOfMonth := time.Date(referenceUTC.Year(), referenceUTC.Month(), 1, 0, 0, 0, 0, time.UTC)
-	endOfMonth := beginningOfMonth.AddDate(0, 1, 0).Add(-1 * time.Second)
-	return beginningOfMonth, endOfMonth
+	referenceUTC := reference.UTC().Truncate(24 * time.Hour).Add((-48) * time.Hour)
+	forecastStartDate := time.Date(referenceUTC.Year(), referenceUTC.Month(), referenceUTC.Day(), 0, 0, 0, 0, time.UTC)
+	forecastEndDate := forecastStartDate.AddDate(0, 0, 0).Add(-1*time.Second).AddDate(0, 0, 30)
+	return forecastStartDate, forecastEndDate
 }
diff --git a/x-pack/metricbeat/module/azure/billing/billing_test.go b/x-pack/metricbeat/module/azure/billing/billing_test.go
index 65f4482cc5b..e8dc95119b4 100644
--- a/x-pack/metricbeat/module/azure/billing/billing_test.go
+++ b/x-pack/metricbeat/module/azure/billing/billing_test.go
@@ -32,9 +32,9 @@ func TestForecastPeriodFrom(t *testing.T) {
 		referenceTime, err := time.Parse("2006-01-02 15:04:05", "2007-01-09 09:41:00")
 		assert.NoError(t, err)
 
-		expectedStartTime, err := time.Parse("2006-01-02 15:04:05", "2007-01-01 00:00:00")
+		expectedStartTime, err := time.Parse("2006-01-02 15:04:05", "2007-01-07 00:00:00")
 		assert.NoError(t, err)
-		expectedEndTime, err := time.Parse("2006-01-02 15:04:05", "2007-01-31 23:59:59")
+		expectedEndTime, err := time.Parse("2006-01-02 15:04:05", "2007-02-05 23:59:59")
 		assert.NoError(t, err)
 
 		actualStartTime, actualEndTime := forecastIntervalFrom(referenceTime)