From ab99385edac3d54b1aeedcd41c817cd48fdfd470 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gr=C3=A9goire=20D=C3=A9trez?= <gregoire@mullvad.net>
Date: Tue, 30 Aug 2022 11:11:42 +0200
Subject: [PATCH 1/2] Fix log server not exiting properly on SIGINT

Make the tree garbage collection coroutine exit immediately when the
context is cancelled.
---
 CHANGELOG.md                 |  3 +++
 server/admin/tree_gc.go      | 16 ++++++++--------
 server/admin/tree_gc_test.go | 16 +++++++++++-----
 3 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4d2448d00a..4a0f400ce3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ## HEAD
 
+### Misc
+* Fix log server not exiting properly on SIGINT
+
 ## v.1.5.0
 
 ### Storage
diff --git a/server/admin/tree_gc.go b/server/admin/tree_gc.go
index 9b1eacf0c1..ab55ce5f87 100644
--- a/server/admin/tree_gc.go
+++ b/server/admin/tree_gc.go
@@ -35,7 +35,7 @@ const (
 
 var (
 	timeNow   = time.Now
-	timeSleep = time.Sleep
+	timeAfter = time.After
 
 	hardDeleteCounter monitoring.Counter
 	metricsOnce       sync.Once
@@ -85,12 +85,6 @@ func NewDeletedTreeGC(admin storage.AdminStorage, threshold, minRunInterval time
 // Run starts the tree garbage collection process. It runs until ctx is cancelled.
 func (gc *DeletedTreeGC) Run(ctx context.Context) {
 	for {
-		select {
-		case <-ctx.Done():
-			return
-		default:
-		}
-
 		count, err := gc.RunOnce(ctx)
 		if err != nil {
 			klog.Errorf("DeletedTreeGC.Run: %v", err)
@@ -100,7 +94,13 @@ func (gc *DeletedTreeGC) Run(ctx context.Context) {
 		}
 
 		d := gc.minRunInterval + time.Duration(rand.Int63n(gc.minRunInterval.Nanoseconds()))
-		timeSleep(d)
+		select {
+		case <-ctx.Done():
+			return
+		case <-timeAfter(d):
+		default:
+		}
+
 	}
 }
 
diff --git a/server/admin/tree_gc_test.go b/server/admin/tree_gc_test.go
index 65f2916211..097de19193 100644
--- a/server/admin/tree_gc_test.go
+++ b/server/admin/tree_gc_test.go
@@ -40,7 +40,7 @@ func TestDeletedTreeGC_Run(t *testing.T) {
 	// * Sleep (ctx cancelled)
 	//
 	// DeletedTreeGC.Run() until ctx in cancelled. Since it always sleeps between iterations, we
-	// make "timeSleep" cancel ctx the second time around to break the loop.
+	// make "timeAfter" cancel ctx the second time around to break the loop.
 
 	tree1 := proto.Clone(testonly.LogTree).(*trillian.Tree)
 	tree1.TreeId = 1
@@ -74,10 +74,10 @@ func TestDeletedTreeGC_Run(t *testing.T) {
 	listTX2.EXPECT().Close().Return(nil)
 	listTX2.EXPECT().Commit().Return(nil)
 
-	defer func(now func() time.Time, sleep func(time.Duration)) {
+	defer func(now func() time.Time, after func(time.Duration) <-chan time.Time) {
 		timeNow = now
-		timeSleep = sleep
-	}(timeNow, timeSleep)
+		timeAfter = after
+	}(timeNow, timeAfter)
 
 	const deleteThreshold = 1 * time.Hour
 	const runInterval = 3 * time.Second
@@ -87,14 +87,20 @@ func TestDeletedTreeGC_Run(t *testing.T) {
 	timeNow = func() time.Time { return now }
 
 	calls := 0
-	timeSleep = func(d time.Duration) {
+	timeAfter = func(d time.Duration) <-chan time.Time {
 		calls++
 		if d < runInterval || d >= 2*runInterval {
 			t.Errorf("Called time.Sleep(%v), want %v", d, runInterval)
 		}
 		if calls >= 2 {
 			cancel()
+			// Block to make sure we're exiting because of the cancelled context and
+			// not because the timer elapsed.
+			return make(chan time.Time)
 		}
+		ch := make(chan time.Time, 1)
+		ch <- now
+		return ch
 	}
 
 	NewDeletedTreeGC(as, deleteThreshold, runInterval, nil /* mf */).Run(ctx)

From 8a457e0172abe670f8964ee2c1808ed0fd3b9d41 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gr=C3=A9goire=20D=C3=A9trez?= <gregoire@mullvad.net>
Date: Mon, 5 Sep 2022 16:53:42 +0200
Subject: [PATCH 2/2] Remove erroneous default case

---
 server/admin/tree_gc.go | 1 -
 1 file changed, 1 deletion(-)

diff --git a/server/admin/tree_gc.go b/server/admin/tree_gc.go
index ab55ce5f87..47af78a21c 100644
--- a/server/admin/tree_gc.go
+++ b/server/admin/tree_gc.go
@@ -98,7 +98,6 @@ func (gc *DeletedTreeGC) Run(ctx context.Context) {
 		case <-ctx.Done():
 			return
 		case <-timeAfter(d):
-		default:
 		}
 
 	}