Fix panic when pruning shard groups

* Fix #7812 - Panic when pruning shard groups

* Update CHANGELOG.md

CHANGELOG.md

@@ -42,6 +42,7 @@ The stress tool `influx_stress` will be removed in a subsequent release. We reco
 - [#7740](https://github.com/influxdata/influxdb/issues/7740): Fix parse key panic when missing tag value @oiooj
 - [#7563](https://github.com/influxdata/influxdb/issues/7563): RP should not allow `INF` or `0` as a shard duration.
 - [#7585](https://github.com/influxdata/influxdb/pull/7585): Return Error instead of panic when decoding point values.
+- [#7812](https://github.com/influxdata/influxdb/issues/7812): Fix slice out of bounds panic when pruning shard groups. Thanks @vladlopes
 
 ## v1.1.1 [2016-12-06]
 

services/meta/client.go

@@ -676,15 +676,15 @@ func (c *Client) PruneShardGroups() error {
 	data := c.cacheData.Clone()
 	for i, d := range data.Databases {
 		for j, rp := range d.RetentionPolicies {
+			var remainingShardGroups []ShardGroupInfo
 			for _, sgi := range rp.ShardGroups {
 				if sgi.DeletedAt.IsZero() || !expiration.After(sgi.DeletedAt) {
+					remainingShardGroups = append(remainingShardGroups, sgi)
 					continue
 				}
-				// we are safe to delete the shard group as it's been marked deleted for the required expiration
-				s := append(rp.ShardGroups[:i], rp.ShardGroups[i+1:]...)
-				data.Databases[i].RetentionPolicies[j].ShardGroups = s
 				changed = true
 			}
+			data.Databases[i].RetentionPolicies[j].ShardGroups = remainingShardGroups
 		}
 	}
 	if changed {

services/meta/client_test.go

@@ -972,10 +972,14 @@ func TestMetaClient_PruneShardGroups(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	if _, err := c.CreateDatabase("db1"); err != nil {
+		t.Fatal(err)
+	}
+
 	duration := 1 * time.Hour
 	replicaN := 1
 
-	if _, err := c.CreateRetentionPolicy("db0", &meta.RetentionPolicySpec{
+	if _, err := c.CreateRetentionPolicy("db1", &meta.RetentionPolicySpec{
 		Name:     "rp0",
 		Duration: &duration,
 		ReplicaN: &replicaN,
@@ -983,14 +987,21 @@ func TestMetaClient_PruneShardGroups(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	sg, err := c.CreateShardGroup("db0", "autogen", time.Now())
+	sg, err := c.CreateShardGroup("db1", "autogen", time.Now())
 	if err != nil {
 		t.Fatal(err)
 	} else if sg == nil {
 		t.Fatalf("expected ShardGroup")
 	}
 
-	sg, err = c.CreateShardGroup("db0", "rp0", time.Now())
+	sg, err = c.CreateShardGroup("db1", "autogen", time.Now().Add(15*24*time.Hour))
+	if err != nil {
+		t.Fatal(err)
+	} else if sg == nil {
+		t.Fatalf("expected ShardGroup")
+	}
+
+	sg, err = c.CreateShardGroup("db1", "rp0", time.Now())
 	if err != nil {
 		t.Fatal(err)
 	} else if sg == nil {
@@ -1000,7 +1011,8 @@ func TestMetaClient_PruneShardGroups(t *testing.T) {
 	expiration := time.Now().Add(-2 * 7 * 24 * time.Hour).Add(-1 * time.Hour)
 
 	data := c.Data()
-	data.Databases[0].RetentionPolicies[0].ShardGroups[0].DeletedAt = expiration
+	data.Databases[1].RetentionPolicies[0].ShardGroups[0].DeletedAt = expiration
+	data.Databases[1].RetentionPolicies[0].ShardGroups[1].DeletedAt = expiration
 
 	if err := c.SetData(&data); err != nil {
 		t.Fatal(err)
@@ -1011,7 +1023,7 @@ func TestMetaClient_PruneShardGroups(t *testing.T) {
 	}
 
 	data = c.Data()
-	rp, err := data.RetentionPolicy("db0", "autogen")
+	rp, err := data.RetentionPolicy("db1", "autogen")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1019,7 +1031,7 @@ func TestMetaClient_PruneShardGroups(t *testing.T) {
 		t.Fatalf("failed to prune shard group. got: %d, exp: %d", got, exp)
 	}
 
-	rp, err = data.RetentionPolicy("db0", "rp0")
+	rp, err = data.RetentionPolicy("db1", "rp0")
 	if err != nil {
 		t.Fatal(err)
 	}