From fc12ef4a9fa9cb93eef2dc85e6fc3fe26384a4f9 Mon Sep 17 00:00:00 2001
From: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
Date: Sun, 8 Mar 2020 22:30:54 +0000
Subject: [PATCH 1/5] Add test for alert queue Pop after multiple Push

Signed-off-by: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
---
 pkg/alert/alert_test.go | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/pkg/alert/alert_test.go b/pkg/alert/alert_test.go
index 7139dfc652..d75265866b 100644
--- a/pkg/alert/alert_test.go
+++ b/pkg/alert/alert_test.go
@@ -19,6 +19,30 @@ import (
 	"github.com/thanos-io/thanos/pkg/testutil"
 )
 
+func TestQueue_Pop_all_Pushed(t *testing.T) {
+	qcapacity := 5
+	batchsize := 1
+	pushes := 3
+
+	q := NewQueue(
+		nil, nil, qcapacity, batchsize, nil, nil,
+	)
+	for i := 0; i < pushes; i++ {
+		q.Push([]*Alert{
+			{},
+			{},
+		})
+	}
+
+	timeoutc := time.After(time.Second)
+	popped := 0
+	for p := q.Pop(timeoutc); p != nil; p = q.Pop(timeoutc) {
+		popped += len(p)
+	}
+
+	testutil.Equals(t, qcapacity, popped)
+}
+
 func TestQueue_Push_Relabelled(t *testing.T) {
 	q := NewQueue(
 		nil, nil, 10, 10,

From f87b9a188b9afcc7131d4ad2be7a3af1386a6b9c Mon Sep 17 00:00:00 2001
From: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
Date: Sun, 8 Mar 2020 22:42:46 +0000
Subject: [PATCH 2/5] Fix alert queue bug by resignal after Pop (#2204)

Signed-off-by: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
---
 pkg/alert/alert.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pkg/alert/alert.go b/pkg/alert/alert.go
index 4ad30b7c03..d527b87abe 100644
--- a/pkg/alert/alert.go
+++ b/pkg/alert/alert.go
@@ -195,6 +195,12 @@ func (q *Queue) Pop(termc <-chan struct{}) []*Alert {
 
 	q.popped.Add(float64(n))
 
+	if len(q.queue) > 0 {
+		select {
+		case q.morec <- struct{}{}:
+		default:
+		}
+	}
 	return as[:n]
 }
 

From 07285c41ec7109a728c52fb258120e5383f2fec6 Mon Sep 17 00:00:00 2001
From: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
Date: Sun, 8 Mar 2020 23:15:39 +0000
Subject: [PATCH 3/5] Fix alert queue test and simplify

Signed-off-by: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
---
 pkg/alert/alert_test.go | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/pkg/alert/alert_test.go b/pkg/alert/alert_test.go
index d75265866b..67f280280d 100644
--- a/pkg/alert/alert_test.go
+++ b/pkg/alert/alert_test.go
@@ -20,7 +20,7 @@ import (
 )
 
 func TestQueue_Pop_all_Pushed(t *testing.T) {
-	qcapacity := 5
+	qcapacity := 10
 	batchsize := 1
 	pushes := 3
 
@@ -34,13 +34,14 @@ func TestQueue_Pop_all_Pushed(t *testing.T) {
 		})
 	}
 
-	timeoutc := time.After(time.Second)
+	timeoutc := make(chan struct{}, 1)
+	time.AfterFunc(time.Second, func() { timeoutc <- struct{}{} })
 	popped := 0
 	for p := q.Pop(timeoutc); p != nil; p = q.Pop(timeoutc) {
 		popped += len(p)
 	}
 
-	testutil.Equals(t, qcapacity, popped)
+	testutil.Equals(t, pushes*2, popped)
 }
 
 func TestQueue_Push_Relabelled(t *testing.T) {

From a74567959a18c75f7478ac5ea16f0eef34ddce8f Mon Sep 17 00:00:00 2001
From: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
Date: Mon, 9 Mar 2020 11:19:00 +0000
Subject: [PATCH 4/5] Update CHANGELOG.md

Signed-off-by: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
---
 CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c33357a391..fe59e1ba92 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,10 @@ We use *breaking* word for marking changes that are not backward compatible (rel
 
 ## Unreleased
 
+### Fixed
+
+- [#TODO](https://github.com/thanos-io/thanos/pull/#TODO) Ruler: Fixed Issue #2204 bug in alert queue signalling filled up queue and alerts were dropped
+
 ## [v0.11.0](https://github.com/thanos-io/thanos/releases/tag/v0.11.0-rc.1) - 2020.03.02
 
 ### Fixed

From 3b0056c72a1dd0f6b3e27b01bb70d4a0b75b9b2e Mon Sep 17 00:00:00 2001
From: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
Date: Mon, 9 Mar 2020 13:55:54 +0000
Subject: [PATCH 5/5] Link to thanos-io/thanos PR in CHANGELOG.md

Signed-off-by: Robin Clarke-Williams <43950815+robincw-gr@users.noreply.github.com>
---
 CHANGELOG.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe59e1ba92..87b84f14d0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,7 +13,7 @@ We use *breaking* word for marking changes that are not backward compatible (rel
 
 ### Fixed
 
-- [#TODO](https://github.com/thanos-io/thanos/pull/#TODO) Ruler: Fixed Issue #2204 bug in alert queue signalling filled up queue and alerts were dropped
+- [#2238](https://github.com/thanos-io/thanos/pull/2238) Ruler: Fixed Issue #2204 bug in alert queue signalling filled up queue and alerts were dropped
 
 ## [v0.11.0](https://github.com/thanos-io/thanos/releases/tag/v0.11.0-rc.1) - 2020.03.02