Add travis.yml from upstream:master

.travis.yml

@@ -0,0 +1,19 @@
+language: go
+go_import_path: github.com/golang/groupcache
+
+os: linux
+dist: trusty
+sudo: false
+
+script:
+  - go test ./...
+
+go:
+  - 1.9.x
+  - 1.10.x
+  - 1.11.x
+  - master
+
+cache:
+  directories:
+    - $GOPATH/pkg

README.md

@@ -2,8 +2,8 @@
 
 ## Summary
 
-groupcache is a caching and cache-filling library, intended as a
-replacement for memcached in many cases.
+groupcache is a distributed caching and cache-filling library, intended as a
+replacement for a pool of memcached nodes in many cases.
 
 For API docs and examples, see http://godoc.org/github.com/golang/groupcache
 
@@ -17,7 +17,8 @@ For API docs and examples, see http://godoc.org/github.com/golang/groupcache
 
  * does not require running a separate set of servers, thus massively
    reducing deployment/configuration pain.  groupcache is a client
-   library as well as a server.  It connects to its own peers.
+   library as well as a server.  It connects to its own peers, forming
+   a distributed cache.
 
  * comes with a cache filling mechanism.  Whereas memcached just says
    "Sorry, cache miss", often resulting in a thundering herd of

consistenthash/consistenthash.go

@@ -44,12 +44,12 @@ func New(replicas int, fn Hash) *Map {
 	return m
 }
 
-// Returns true if there are no items available.
+// IsEmpty returns true if there are no items available.
 func (m *Map) IsEmpty() bool {
 	return len(m.keys) == 0
 }
 
-// Adds some keys to the hash.
+// Add adds some keys to the hash.
 func (m *Map) Add(keys ...string) {
 	for _, key := range keys {
 		for i := 0; i < m.replicas; i++ {
@@ -61,7 +61,7 @@ func (m *Map) Add(keys ...string) {
 	sort.Ints(m.keys)
 }
 
-// Gets the closest item in the hash to the provided key.
+// Get gets the closest item in the hash to the provided key.
 func (m *Map) Get(key string) string {
 	if m.IsEmpty() {
 		return ""

go.mod

@@ -0,0 +1,7 @@
+module github.com/golang/groupcache
+
+go 1.20
+
+require github.com/golang/protobuf v1.5.4
+
+require google.golang.org/protobuf v1.33.0 // indirect

go.sum

@@ -0,0 +1,6 @@
+github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
+github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
+github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
+google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=

groupcache.go

@@ -25,6 +25,7 @@ limitations under the License.
 package groupcache
 
 import (
+	"context"
 	"errors"
 	"math/rand"
 	"strconv"
@@ -44,13 +45,13 @@ type Getter interface {
 	// uniquely describe the loaded data, without an implicit
 	// current time, and without relying on cache expiration
 	// mechanisms.
-	Get(ctx Context, key string, dest Sink) error
+	Get(ctx context.Context, key string, dest Sink) error
 }
 
 // A GetterFunc implements Getter with a function.
-type GetterFunc func(ctx Context, key string, dest Sink) error
+type GetterFunc func(ctx context.Context, key string, dest Sink) error
 
-func (f GetterFunc) Get(ctx Context, key string, dest Sink) error {
+func (f GetterFunc) Get(ctx context.Context, key string, dest Sink) error {
 	return f(ctx, key, dest)
 }
 
@@ -170,6 +171,10 @@ type Group struct {
 
 	// Stats are statistics on the group.
 	Stats Stats
+
+	// rand is only non-nil when testing,
+	// to get predictable results in TestPeers.
+	rand *rand.Rand
 }
 
 // flightGroup is defined as an interface which flightgroup.Group
@@ -204,7 +209,7 @@ func (g *Group) initPeers() {
 	}
 }
 
-func (g *Group) Get(ctx Context, key string, dest Sink) error {
+func (g *Group) Get(ctx context.Context, key string, dest Sink) error {
 	g.peersOnce.Do(g.initPeers)
 	g.Stats.Gets.Add(1)
 	if dest == nil {
@@ -233,7 +238,7 @@ func (g *Group) Get(ctx Context, key string, dest Sink) error {
 }
 
 // load loads key either by invoking the getter locally or by sending it to another machine.
-func (g *Group) load(ctx Context, key string, dest Sink) (value ByteView, destPopulated bool, err error) {
+func (g *Group) load(ctx context.Context, key string, dest Sink) (value ByteView, destPopulated bool, err error) {
 	g.Stats.Loads.Add(1)
 	viewi, err := g.loadGroup.Do(key, func() (interface{}, error) {
 		// Check the cache again because singleflight can only dedup calls
@@ -245,7 +250,7 @@ func (g *Group) load(ctx Context, key string, dest Sink) (value ByteView, destPo
 		// be only one entry for this key.
 		//
 		// Consider the following serialized event ordering for two
-		// goroutines in which this callback gets called twice for hte
+		// goroutines in which this callback gets called twice for the
 		// same key:
 		// 1: Get("key")
 		// 2: Get("key")
@@ -292,15 +297,15 @@ func (g *Group) load(ctx Context, key string, dest Sink) (value ByteView, destPo
 	return
 }
 
-func (g *Group) getLocally(ctx Context, key string, dest Sink) (ByteView, error) {
+func (g *Group) getLocally(ctx context.Context, key string, dest Sink) (ByteView, error) {
 	err := g.getter.Get(ctx, key, dest)
 	if err != nil {
 		return ByteView{}, err
 	}
 	return dest.view()
 }
 
-func (g *Group) getFromPeer(ctx Context, peer ProtoGetter, key string) (ByteView, error) {
+func (g *Group) getFromPeer(ctx context.Context, peer ProtoGetter, key string) (ByteView, error) {
 	req := &pb.GetRequest{
 		Group: &g.name,
 		Key:   &key,
@@ -314,7 +319,13 @@ func (g *Group) getFromPeer(ctx Context, peer ProtoGetter, key string) (ByteView
 	// TODO(bradfitz): use res.MinuteQps or something smart to
 	// conditionally populate hotCache.  For now just do it some
 	// percentage of the time.
-	if rand.Intn(10) == 0 {
+	var pop bool
+	if g.rand != nil {
+		pop = g.rand.Intn(10) == 0
+	} else {
+		pop = rand.Intn(10) == 0
+	}
+	if pop {
 		g.populateCache(key, value, &g.hotCache)
 	}
 	return value, nil

groupcache_test.go

@@ -19,6 +19,7 @@ limitations under the License.
 package groupcache
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"hash/crc32"
@@ -41,7 +42,7 @@ var (
 
 	stringc = make(chan string)
 
-	dummyCtx Context
+	dummyCtx = context.TODO()
 
 	// cacheFills is the number of times stringGroup or
 	// protoGroup's Getter have been called. Read using the
@@ -58,15 +59,15 @@ const (
 )
 
 func testSetup() {
-	stringGroup = NewGroup(stringGroupName, cacheSize, GetterFunc(func(_ Context, key string, dest Sink) error {
+	stringGroup = NewGroup(stringGroupName, cacheSize, GetterFunc(func(_ context.Context, key string, dest Sink) error {
 		if key == fromChan {
 			key = <-stringc
 		}
 		cacheFills.Add(1)
 		return dest.SetString("ECHO:" + key)
 	}))
 
-	protoGroup = NewGroup(protoGroupName, cacheSize, GetterFunc(func(_ Context, key string, dest Sink) error {
+	protoGroup = NewGroup(protoGroupName, cacheSize, GetterFunc(func(_ context.Context, key string, dest Sink) error {
 		if key == fromChan {
 			key = <-stringc
 		}
@@ -78,7 +79,7 @@ func testSetup() {
 	}))
 }
 
-// tests that a Getter's Get method is only called once with two
+// TestGetDupSuppressString tests that a Getter's Get method is only called once with two
 // outstanding callers.  This is the string variant.
 func TestGetDupSuppressString(t *testing.T) {
 	once.Do(testSetup)
@@ -120,7 +121,7 @@ func TestGetDupSuppressString(t *testing.T) {
 	}
 }
 
-// tests that a Getter's Get method is only called once with two
+// TestGetDupSuppressProto tests that a Getter's Get method is only called once with two
 // outstanding callers.  This is the proto variant.
 func TestGetDupSuppressProto(t *testing.T) {
 	once.Do(testSetup)
@@ -230,7 +231,7 @@ type fakePeer struct {
 	fail bool
 }
 
-func (p *fakePeer) Get(_ Context, in *pb.GetRequest, out *pb.GetResponse) error {
+func (p *fakePeer) Get(_ context.Context, in *pb.GetRequest, out *pb.GetResponse) error {
 	p.hits++
 	if p.fail {
 		return errors.New("simulated error from peer")
@@ -249,21 +250,21 @@ func (p fakePeers) PickPeer(key string) (peer ProtoGetter, ok bool) {
 	return p[n], p[n] != nil
 }
 
-// tests that peers (virtual, in-process) are hit, and how much.
+// TestPeers tests that peers (virtual, in-process) are hit, and how much.
 func TestPeers(t *testing.T) {
 	once.Do(testSetup)
-	rand.Seed(123)
 	peer0 := &fakePeer{}
 	peer1 := &fakePeer{}
 	peer2 := &fakePeer{}
 	peerList := fakePeers([]ProtoGetter{peer0, peer1, peer2, nil})
 	const cacheSize = 0 // disabled
 	localHits := 0
-	getter := func(_ Context, key string, dest Sink) error {
+	getter := func(_ context.Context, key string, dest Sink) error {
 		localHits++
 		return dest.SetString("got:" + key)
 	}
 	testGroup := newGroup("TestPeers-group", cacheSize, GetterFunc(getter), peerList)
+	testGroup.rand = rand.New(rand.NewSource(123))
 	run := func(name string, n int, wantSummary string) {
 		// Reset counters
 		localHits = 0
@@ -387,7 +388,7 @@ func (g *orderedFlightGroup) Do(key string, fn func() (interface{}, error)) (int
 func TestNoDedup(t *testing.T) {
 	const testkey = "testkey"
 	const testval = "testval"
-	g := newGroup("testgroup", 1024, GetterFunc(func(_ Context, key string, dest Sink) error {
+	g := newGroup("testgroup", 1024, GetterFunc(func(_ context.Context, key string, dest Sink) error {
 		return dest.SetString(testval)
 	}), nil)
 

http.go

@@ -18,6 +18,7 @@ package groupcache
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io"
 	"net/http"
@@ -38,13 +39,13 @@ const defaultReplicas = 50
 type HTTPPool struct {
 	// Context optionally specifies a context for the server to use when it
 	// receives a request.
-	// If nil, the server uses a nil Context.
-	Context func(*http.Request) Context
+	// If nil, the server uses the request's context
+	Context func(*http.Request) context.Context
 
 	// Transport optionally specifies an http.RoundTripper for the client
 	// to use when it makes a request.
 	// If nil, the client uses http.DefaultTransport.
-	Transport func(Context) http.RoundTripper
+	Transport func(context.Context) http.RoundTripper
 
 	// this peer's base URL, e.g. "https://example.net:8000"
 	self string
@@ -157,9 +158,11 @@ func (p *HTTPPool) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "no such group: "+groupName, http.StatusNotFound)
 		return
 	}
-	var ctx Context
+	var ctx context.Context
 	if p.Context != nil {
 		ctx = p.Context(r)
+	} else {
+		ctx = r.Context()
 	}
 
 	group.Stats.ServerRequests.Add(1)
@@ -181,15 +184,15 @@ func (p *HTTPPool) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }
 
 type httpGetter struct {
-	transport func(Context) http.RoundTripper
+	transport func(context.Context) http.RoundTripper
 	baseURL   string
 }
 
 var bufferPool = sync.Pool{
 	New: func() interface{} { return new(bytes.Buffer) },
 }
 
-func (h *httpGetter) Get(context Context, in *pb.GetRequest, out *pb.GetResponse) error {
+func (h *httpGetter) Get(ctx context.Context, in *pb.GetRequest, out *pb.GetResponse) error {
 	u := fmt.Sprintf(
 		"%v%v/%v",
 		h.baseURL,
@@ -200,9 +203,10 @@ func (h *httpGetter) Get(context Context, in *pb.GetRequest, out *pb.GetResponse
 	if err != nil {
 		return err
 	}
+	req = req.WithContext(ctx)
 	tr := http.DefaultTransport
 	if h.transport != nil {
-		tr = h.transport(context)
+		tr = h.transport(ctx)
 	}
 	res, err := tr.RoundTrip(req)
 	if err != nil {

http_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package groupcache
 
 import (
+	"context"
 	"errors"
 	"flag"
 	"log"
@@ -85,14 +86,14 @@ func TestHTTPPool(t *testing.T) {
 	// Dummy getter function. Gets should go to children only.
 	// The only time this process will handle a get is when the
 	// children can't be contacted for some reason.
-	getter := GetterFunc(func(ctx Context, key string, dest Sink) error {
+	getter := GetterFunc(func(ctx context.Context, key string, dest Sink) error {
 		return errors.New("parent getter called; something's wrong")
 	})
 	g := NewGroup("httpPoolTest", 1<<20, getter)
 
 	for _, key := range testKeys(nGets) {
 		var value string
-		if err := g.Get(nil, key, StringSink(&value)); err != nil {
+		if err := g.Get(context.TODO(), key, StringSink(&value)); err != nil {
 			t.Fatal(err)
 		}
 		if suffix := ":" + key; !strings.HasSuffix(value, suffix) {
@@ -116,7 +117,7 @@ func beChildForTestHTTPPool() {
 	p := NewHTTPPool("http://" + addrs[*peerIndex])
 	p.Set(addrToURL(addrs)...)
 
-	getter := GetterFunc(func(ctx Context, key string, dest Sink) error {
+	getter := GetterFunc(func(ctx context.Context, key string, dest Sink) error {
 		dest.SetString(strconv.Itoa(*peerIndex) + ":" + key)
 		return nil
 	})

lru/lru.go

@@ -25,7 +25,7 @@ type Cache struct {
 	// an item is evicted. Zero means no limit.
 	MaxEntries int
 
-	// OnEvicted optionally specificies a callback function to be
+	// OnEvicted optionally specifies a callback function to be
 	// executed when an entry is purged from the cache.
 	OnEvicted func(key Key, value interface{})
 

lru/lru_test.go

@@ -40,7 +40,7 @@ var getTests = []struct {
 	{"string_hit", "myKey", "myKey", true},
 	{"string_miss", "myKey", "nonsense", false},
 	{"simple_struct_hit", simpleStruct{1, "two"}, simpleStruct{1, "two"}, true},
-	{"simeple_struct_miss", simpleStruct{1, "two"}, simpleStruct{0, "noway"}, false},
+	{"simple_struct_miss", simpleStruct{1, "two"}, simpleStruct{0, "noway"}, false},
 	{"complex_struct_hit", complexStruct{1, simpleStruct{2, "three"}},
 		complexStruct{1, simpleStruct{2, "three"}}, true},
 }