Fix LRU to correctly update expire on value replace (#56)

This commit is contained in:
Derrick J. Wippler 2022-12-20 11:35:12 -06:00 committed by GitHub
parent fdad20ab3a
commit bde4250129
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5 changed files with 160 additions and 29 deletions

17
go.mod
View File

@ -1,10 +1,19 @@
module github.com/mailgun/groupcache/v2
go 1.19
require (
github.com/golang/protobuf v1.3.1
github.com/golang/protobuf v1.5.2
github.com/segmentio/fasthash v1.0.3
github.com/sirupsen/logrus v1.6.0
golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a // indirect
github.com/sirupsen/logrus v1.9.0
github.com/stretchr/testify v1.8.1
)
go 1.15
require (
github.com/davecgh/go-spew v1.1.1 // indirect
github.com/pmezard/go-difflib v1.0.0 // indirect
golang.org/x/sys v0.0.0-20220919091848-fb04ddd9f9c8 // indirect
golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f // indirect
google.golang.org/protobuf v1.28.1 // indirect
gopkg.in/yaml.v3 v3.0.1 // indirect
)

43
go.sum
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@ -1,18 +1,37 @@
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg=
github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
github.com/konsorten/go-windows-terminal-sequences v1.0.3 h1:CE8S1cTafDpPvMhIxNJKvHsGVBgn1xWYf1NbHQhywc8=
github.com/konsorten/go-windows-terminal-sequences v1.0.3/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
github.com/golang/protobuf v1.5.2 h1:ROPKBNFfQgOUMifHyP+KYbvpjbdoFNs+aK7DXlji0Tw=
github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/segmentio/fasthash v1.0.3 h1:EI9+KE1EwvMLBWwjpRDc+fEM+prwxDYbslddQGtrmhM=
github.com/segmentio/fasthash v1.0.3/go.mod h1:waKX8l2N8yckOgmSsXJi7x1ZfdKZ4x7KRMzBtS3oedY=
github.com/sirupsen/logrus v1.6.0 h1:UBcNElsrwanuuMsnGSlYmtmgbb23qDR5dG+6X6Oo89I=
github.com/sirupsen/logrus v1.6.0/go.mod h1:7uNnSEd1DgxDLC74fIahvMZmmYsHGZGEOFrfsX/uA88=
github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
golang.org/x/sys v0.0.0-20190422165155-953cdadca894 h1:Cz4ceDQGXuKRnVBDTS23GTn/pU5OE2C0WrNTOYK1Uuc=
golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a h1:dGzPydgVsqGcTRVwiLJ1jVbufYwmzD3LfVPLKsKg+0k=
golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
github.com/sirupsen/logrus v1.9.0 h1:trlNQbNUG3OdDrDil03MCb1H2o9nJ1x4/5LYw7byDE0=
github.com/sirupsen/logrus v1.9.0/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220919091848-fb04ddd9f9c8 h1:h+EGohizhe9XlX18rfpa8k8RAc5XyaeamM+0VHRd4lc=
golang.org/x/sys v0.0.0-20220919091848-fb04ddd9f9c8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f h1:uF6paiQQebLeSXkrTqHqz0MXhXXS1KgF41eUdBNvxK0=
golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
google.golang.org/protobuf v1.28.1 h1:d0NfwRgPtno5B1Wa6L2DAG+KivqkdutMf1UhdNx175w=
google.golang.org/protobuf v1.28.1/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

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@ -582,6 +582,11 @@ func (g *Group) CacheStats(which CacheType) CacheStats {
}
}
// NowFunc returns the current time which is used by the LRU to
// determine if the value has expired. This can be overridden by
// tests to ensure items are evicted when expired.
var NowFunc lru.NowFunc = time.Now
// cache is a wrapper around an *lru.Cache that adds synchronization,
// makes values always be ByteView, and counts the size of all keys and
// values.
@ -610,6 +615,7 @@ func (c *cache) add(key string, value ByteView) {
defer c.mu.Unlock()
if c.lru == nil {
c.lru = &lru.Cache{
Now: NowFunc,
OnEvicted: func(key lru.Key, value interface{}) {
val := value.(ByteView)
c.nbytes -= int64(len(key.(string))) + int64(val.Len())

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@ -30,9 +30,9 @@ import (
"unsafe"
"github.com/golang/protobuf/proto"
pb "github.com/mailgun/groupcache/v2/groupcachepb"
"github.com/mailgun/groupcache/v2/testpb"
"github.com/stretchr/testify/assert"
)
var (
@ -536,17 +536,105 @@ func TestContextDeadlineOnPeer(t *testing.T) {
}
}
func TestCacheRemovesBytesOfReplacedValues(t *testing.T) {
c := cache{}
func TestEnsureSizeReportedCorrectly(t *testing.T) {
c := &cache{}
const key = "test"
keyLen := len(key)
// Add the first value
bv1 := ByteView{s: "first", e: time.Now().Add(100 * time.Second)}
c.add("key1", bv1)
v, ok := c.get("key1")
for _, bytes := range []int{100, 1000, 2000} {
c.add(key, ByteView{b: make([]byte, bytes)})
expected := int64(bytes + keyLen)
if c.nbytes != expected {
t.Fatalf("%s: expected %d was %d", t.Name(), expected, c.nbytes)
}
}
// Should be len("key1" + "first") == 9
assert.True(t, ok)
assert.True(t, v.Equal(bv1))
assert.Equal(t, int64(9), c.bytes())
// Add a second value
bv2 := ByteView{s: "second", e: time.Now().Add(200 * time.Second)}
c.add("key2", bv2)
v, ok = c.get("key2")
// Should be len("key2" + "second") == (10 + 9) == 19
assert.True(t, ok)
assert.True(t, v.Equal(bv2))
assert.Equal(t, int64(19), c.bytes())
// Replace the first value with a shorter value
bv3 := ByteView{s: "3", e: time.Now().Add(200 * time.Second)}
c.add("key1", bv3)
v, ok = c.get("key1")
// len("key1" + "3") == 5
// len("key2" + "second") == 10
assert.True(t, ok)
assert.True(t, v.Equal(bv3))
assert.Equal(t, int64(15), c.bytes())
// Replace the second value with a longer value
bv4 := ByteView{s: "this-string-is-28-chars-long", e: time.Now().Add(200 * time.Second)}
c.add("key2", bv4)
v, ok = c.get("key2")
// len("key1" + "3") == 5
// len("key2" + "this-string-is-28-chars-long") == 32
assert.True(t, ok)
assert.True(t, v.Equal(bv4))
assert.Equal(t, int64(37), c.bytes())
}
func TestEnsureUpdateExpiredValue(t *testing.T) {
c := &cache{}
curTime := time.Now()
// Override the now function so we control time
NowFunc = func() time.Time {
return curTime
}
// Expires in 1 second
c.add("key1", ByteView{s: "value1", e: curTime.Add(time.Second)})
_, ok := c.get("key1")
assert.True(t, ok)
// Advance 1.1 seconds into the future
curTime = curTime.Add(time.Millisecond * 1100)
// Value should have expired
_, ok = c.get("key1")
assert.False(t, ok)
// Add a new key that expires in 1 second
c.add("key2", ByteView{s: "value2", e: curTime.Add(time.Second)})
_, ok = c.get("key2")
assert.True(t, ok)
// Advance 0.5 seconds into the future
curTime = curTime.Add(time.Millisecond * 500)
// Value should still exist
_, ok = c.get("key2")
assert.True(t, ok)
// Replace the existing key, this should update the expired time
c.add("key2", ByteView{s: "updated value2", e: curTime.Add(time.Second)})
_, ok = c.get("key2")
assert.True(t, ok)
// Advance 0.6 seconds into the future, which puts us past the initial
// expired time for key2.
curTime = curTime.Add(time.Millisecond * 600)
// Should still exist
_, ok = c.get("key2")
assert.True(t, ok)
// Advance 1.1 seconds into the future
curTime = curTime.Add(time.Millisecond * 1100)
// Should not exist
_, ok = c.get("key2")
assert.False(t, ok)
}

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@ -22,6 +22,8 @@ import (
"time"
)
type NowFunc func() time.Time
// Cache is an LRU cache. It is not safe for concurrent access.
type Cache struct {
// MaxEntries is the maximum number of cache entries before
@ -32,6 +34,11 @@ type Cache struct {
// executed when an entry is purged from the cache.
OnEvicted func(key Key, value interface{})
// Now is the Now() function the cache will use to determine
// the current time which is used to calculate expired values
// Defaults to time.Now()
Now NowFunc
ll *list.List
cache map[interface{}]*list.Element
}
@ -53,6 +60,7 @@ func New(maxEntries int) *Cache {
MaxEntries: maxEntries,
ll: list.New(),
cache: make(map[interface{}]*list.Element),
Now: time.Now,
}
}
@ -68,6 +76,7 @@ func (c *Cache) Add(key Key, value interface{}, expire time.Time) {
c.OnEvicted(key, eee.value)
}
c.ll.MoveToFront(ee)
eee.expire = expire
eee.value = value
return
}
@ -86,7 +95,7 @@ func (c *Cache) Get(key Key) (value interface{}, ok bool) {
if ele, hit := c.cache[key]; hit {
entry := ele.Value.(*entry)
// If the entry has expired, remove it from the cache
if !entry.expire.IsZero() && entry.expire.Before(time.Now()) {
if !entry.expire.IsZero() && entry.expire.Before(c.Now()) {
c.removeElement(ele)
return nil, false
}