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Now using context.Context instead of groupcache.Context

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This commit is contained in:
Derrick J. Wippler 2019-05-30 17:03:06 -05:00
parent a5eee224aa
commit f352930de5
5 changed files with 34 additions and 37 deletions
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19
groupcache.go
View File

@ -25,6 +25,7 @@ limitations under the License.
package groupcache package groupcache
import ( import (
"context"
"errors" "errors"
"math/rand" "math/rand"
"strconv" "strconv"
@ -45,13 +46,13 @@ type Getter interface {
// uniquely describe the loaded data, without an implicit // uniquely describe the loaded data, without an implicit
// current time, and without relying on cache expiration // current time, and without relying on cache expiration
// mechanisms. // 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. // 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) return f(ctx, key, dest)
} }
@ -210,7 +211,7 @@ 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.peersOnce.Do(g.initPeers)
g.Stats.Gets.Add(1) g.Stats.Gets.Add(1)
if dest == nil { if dest == nil {
@ -240,7 +241,7 @@ func (g *Group) Get(ctx Context, key string, dest Sink) error {
// Remove clears the key from our cache then forwards the remove // Remove clears the key from our cache then forwards the remove
// request to all peers. // request to all peers.
func (g *Group) Remove(ctx Context, key string) error { func (g *Group) Remove(ctx context.Context, key string) error {
g.peersOnce.Do(g.initPeers) g.peersOnce.Do(g.initPeers)
_, err := g.removeGroup.Do(key, func() (interface{}, error) { _, err := g.removeGroup.Do(key, func() (interface{}, error) {
@ -288,7 +289,7 @@ func (g *Group) Remove(ctx Context, key string) error {
} }
// load loads key either by invoking the getter locally or by sending it to another machine. // 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) g.Stats.Loads.Add(1)
viewi, err := g.loadGroup.Do(key, func() (interface{}, error) { viewi, err := g.loadGroup.Do(key, func() (interface{}, error) {
// Check the cache again because singleflight can only dedup calls // Check the cache again because singleflight can only dedup calls
@ -347,7 +348,7 @@ func (g *Group) load(ctx Context, key string, dest Sink) (value ByteView, destPo
return 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) err := g.getter.Get(ctx, key, dest)
if err != nil { if err != nil {
return ByteView{}, err return ByteView{}, err
@ -355,7 +356,7 @@ func (g *Group) getLocally(ctx Context, key string, dest Sink) (ByteView, error)
return dest.view() 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{ req := &pb.GetRequest{
Group: &g.name, Group: &g.name,
Key: &key, Key: &key,
@ -384,7 +385,7 @@ func (g *Group) getFromPeer(ctx Context, peer ProtoGetter, key string) (ByteView
return value, nil return value, nil
} }
func (g *Group) removeFromPeer(ctx Context, peer ProtoGetter, key string) error { func (g *Group) removeFromPeer(ctx context.Context, peer ProtoGetter, key string) error {
req := &pb.GetRequest{ req := &pb.GetRequest{
Group: &g.name, Group: &g.name,
Key: &key, Key: &key,

17
groupcache_test.go
View File

@ -19,6 +19,7 @@ limitations under the License.
package groupcache package groupcache
import ( import (
"context"
"errors" "errors"
"fmt" "fmt"
"hash/crc32" "hash/crc32"
@ -41,7 +42,7 @@ var (
stringc = make(chan string) stringc = make(chan string)
dummyCtx Context dummyCtx context.Context
// cacheFills is the number of times stringGroup or // cacheFills is the number of times stringGroup or
// protoGroup's Getter have been called. Read using the // protoGroup's Getter have been called. Read using the
@ -59,7 +60,7 @@ const (
) )
func testSetup() { 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 { if key == fromChan {
key = <-stringc key = <-stringc
} }
@ -67,7 +68,7 @@ func testSetup() {
return dest.SetString("ECHO:"+key, time.Time{}) return dest.SetString("ECHO:"+key, time.Time{})
})) }))
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 { if key == fromChan {
key = <-stringc key = <-stringc
} }
@ -78,7 +79,7 @@ func testSetup() {
}, time.Time{}) }, time.Time{})
})) }))
expireGroup = NewGroup(expireGroupName, cacheSize, GetterFunc(func(_ Context, key string, dest Sink) error { expireGroup = NewGroup(expireGroupName, cacheSize, GetterFunc(func(_ context.Context, key string, dest Sink) error {
cacheFills.Add(1) cacheFills.Add(1)
return dest.SetString("ECHO:"+key, time.Now().Add(time.Millisecond*100)) return dest.SetString("ECHO:"+key, time.Now().Add(time.Millisecond*100))
})) }))
@ -254,7 +255,7 @@ type fakePeer struct {
fail bool 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++ p.hits++
if p.fail { if p.fail {
return errors.New("simulated error from peer") return errors.New("simulated error from peer")
@ -263,7 +264,7 @@ func (p *fakePeer) Get(_ Context, in *pb.GetRequest, out *pb.GetResponse) error
return nil return nil
} }
func (p *fakePeer) Remove(_ Context, in *pb.GetRequest) error { func (p *fakePeer) Remove(_ context.Context, in *pb.GetRequest) error {
p.hits++ p.hits++
if p.fail { if p.fail {
return errors.New("simulated error from peer") return errors.New("simulated error from peer")
@ -295,7 +296,7 @@ func TestPeers(t *testing.T) {
peerList := fakePeers([]ProtoGetter{peer0, peer1, peer2, nil}) peerList := fakePeers([]ProtoGetter{peer0, peer1, peer2, nil})
const cacheSize = 0 // disabled const cacheSize = 0 // disabled
localHits := 0 localHits := 0
getter := func(_ Context, key string, dest Sink) error { getter := func(_ context.Context, key string, dest Sink) error {
localHits++ localHits++
return dest.SetString("got:"+key, time.Time{}) return dest.SetString("got:"+key, time.Time{})
} }
@ -427,7 +428,7 @@ func (g *orderedFlightGroup) Lock(fn func()) {
func TestNoDedup(t *testing.T) { func TestNoDedup(t *testing.T) {
const testkey = "testkey" const testkey = "testkey"
const testval = "testval" 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, time.Time{}) return dest.SetString(testval, time.Time{})
}), nil) }), nil)

20
http.go
View File

@ -41,12 +41,12 @@ type HTTPPool struct {
// Context optionally specifies a context for the server to use when it // Context optionally specifies a context for the server to use when it
// receives a request. // receives a request.
// If nil, the server uses a nil Context. // If nil, the server uses a nil Context.
Context func(*http.Request) Context Context func(*http.Request) context.Context
// Transport optionally specifies an http.RoundTripper for the client // Transport optionally specifies an http.RoundTripper for the client
// to use when it makes a request. // to use when it makes a request.
// If nil, the client uses http.DefaultTransport. // 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" // this peer's base URL, e.g. "https://example.net:8000"
self string self string
@ -173,7 +173,7 @@ func (p *HTTPPool) ServeHTTP(w http.ResponseWriter, r *http.Request) {
http.Error(w, "no such group: "+groupName, http.StatusNotFound) http.Error(w, "no such group: "+groupName, http.StatusNotFound)
return return
} }
var ctx Context var ctx context.Context
if p.Context != nil { if p.Context != nil {
ctx = p.Context(r) ctx = p.Context(r)
} }
@ -216,7 +216,7 @@ func (p *HTTPPool) ServeHTTP(w http.ResponseWriter, r *http.Request) {
} }
type httpGetter struct { type httpGetter struct {
transport func(Context) http.RoundTripper transport func(context.Context) http.RoundTripper
baseURL string baseURL string
} }
@ -224,7 +224,7 @@ var bufferPool = sync.Pool{
New: func() interface{} { return new(bytes.Buffer) }, New: func() interface{} { return new(bytes.Buffer) },
} }
func (h *httpGetter) makeRequest(ctx Context, method string, in *pb.GetRequest, out *http.Response) error { func (h *httpGetter) makeRequest(ctx context.Context, method string, in *pb.GetRequest, out *http.Response) error {
u := fmt.Sprintf( u := fmt.Sprintf(
"%v%v/%v", "%v%v/%v",
h.baseURL, h.baseURL,
@ -236,10 +236,8 @@ func (h *httpGetter) makeRequest(ctx Context, method string, in *pb.GetRequest,
return err return err
} }
// If user passed a standard context object, use it in the request. // Pass along the context to the RoundTripper
if stdCtx, ok := ctx.(context.Context); ok { req = req.WithContext(ctx)
req = req.WithContext(stdCtx)
}
tr := http.DefaultTransport tr := http.DefaultTransport
if h.transport != nil { if h.transport != nil {
@ -253,7 +251,7 @@ func (h *httpGetter) makeRequest(ctx Context, method string, in *pb.GetRequest,
return nil return nil
} }
func (h *httpGetter) Get(ctx Context, in *pb.GetRequest, out *pb.GetResponse) error { func (h *httpGetter) Get(ctx context.Context, in *pb.GetRequest, out *pb.GetResponse) error {
var res http.Response var res http.Response
if err := h.makeRequest(ctx, http.MethodGet, in, &res); err != nil { if err := h.makeRequest(ctx, http.MethodGet, in, &res); err != nil {
return err return err
@ -276,7 +274,7 @@ func (h *httpGetter) Get(ctx Context, in *pb.GetRequest, out *pb.GetResponse) er
return nil return nil
} }
func (h *httpGetter) Remove(ctx Context, in *pb.GetRequest) error { func (h *httpGetter) Remove(ctx context.Context, in *pb.GetRequest) error {
var res http.Response var res http.Response
if err := h.makeRequest(ctx, http.MethodDelete, in, &res); err != nil { if err := h.makeRequest(ctx, http.MethodDelete, in, &res); err != nil {
return err return err

5
http_test.go
View File

@ -17,6 +17,7 @@ limitations under the License.
package groupcache package groupcache
import ( import (
"context"
"errors" "errors"
"flag" "flag"
"fmt" "fmt"
@ -96,7 +97,7 @@ func TestHTTPPool(t *testing.T) {
// Dummy getter function. Gets should go to children only. // Dummy getter function. Gets should go to children only.
// The only time this process will handle a get is when the // The only time this process will handle a get is when the
// children can't be contacted for some reason. // 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") return errors.New("parent getter called; something's wrong")
}) })
g := NewGroup("httpPoolTest", 1<<20, getter) g := NewGroup("httpPoolTest", 1<<20, getter)
@ -162,7 +163,7 @@ func beChildForTestHTTPPool(t *testing.T) {
p := NewHTTPPool("http://" + addrs[*peerIndex]) p := NewHTTPPool("http://" + addrs[*peerIndex])
p.Set(addrToURL(addrs)...) 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 {
if _, err := http.Get(*serverAddr); err != nil { if _, err := http.Get(*serverAddr); err != nil {
t.Logf("HTTP request from getter failed with '%s'", err) t.Logf("HTTP request from getter failed with '%s'", err)
} }

10
peers.go
View File

@ -19,18 +19,14 @@ limitations under the License.
package groupcache package groupcache
import ( import (
"context"
pb "github.com/mailgun/groupcache/groupcachepb" pb "github.com/mailgun/groupcache/groupcachepb"
) )
// Context is an opaque value passed through calls to the
// ProtoGetter. It may be nil if your ProtoGetter implementation does
// not require a context.
type Context interface{}
// ProtoGetter is the interface that must be implemented by a peer. // ProtoGetter is the interface that must be implemented by a peer.
type ProtoGetter interface { type ProtoGetter interface {
Get(context Context, in *pb.GetRequest, out *pb.GetResponse) error Get(context context.Context, in *pb.GetRequest, out *pb.GetResponse) error
Remove(context Context, in *pb.GetRequest) error Remove(context context.Context, in *pb.GetRequest) error
} }
// PeerPicker is the interface that must be implemented to locate // PeerPicker is the interface that must be implemented to locate