README
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go-lru-cache-stats
LRU cache with/without stats for golang
Documentation
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Overview ¶
Package cache provides a data loading mechanism with caching and de-duplication that works across a set of peer processes.
Each data Get first consults its local cache, otherwise delegates to the requested key's canonical owner, which then checks its cache or finally gets the data. In the common case, many concurrent cache misses across a set of peers for the same key result in just one cache fill.
Index ¶
- func RegisterNewGroupHook(fn func(*GroupInterface))
- type AtomicInt
- type ByteView
- func (v ByteView) At(i int) byte
- func (v ByteView) ByteSlice() []byte
- func (v ByteView) Copy(dest []byte) int
- func (v ByteView) Equal(b2 ByteView) bool
- func (v ByteView) EqualBytes(b2 []byte) bool
- func (v ByteView) EqualString(s string) bool
- func (v ByteView) Len() int
- func (v ByteView) ReadAt(p []byte, off int64) (n int, err error)
- func (v ByteView) Reader() io.ReadSeeker
- func (v ByteView) Slice(from, to int) ByteView
- func (v ByteView) SliceFrom(from int) ByteView
- func (v ByteView) String() string
- type Context
- type Getter
- type GetterFunc
- type Group
- type GroupInterface
- type GroupStats
- type GroupWithStats
- type ProtoGetter
- type Sink
- type Stats
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func RegisterNewGroupHook ¶
func RegisterNewGroupHook(fn func(*GroupInterface))
RegisterNewGroupHook registers a hook that is run each time a group is created.
Types ¶
type ByteView ¶
type ByteView struct {
// contains filtered or unexported fields
}
A ByteView holds an immutable view of bytes. Internally it wraps either a []byte or a string, but that detail is invisible to callers.
A ByteView is meant to be used as a value type, not a pointer (like a time.Time).
func (ByteView) EqualBytes ¶
EqualBytes returns whether the bytes in b are the same as the bytes in b2.
func (ByteView) EqualString ¶
EqualString returns whether the bytes in b are the same as the bytes in s.
func (ByteView) Reader ¶
func (v ByteView) Reader() io.ReadSeeker
Reader returns an io.ReadSeeker for the bytes in v.
type Context ¶
type Context interface{}
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 Getter ¶
type Getter interface {
// Get returns the value identified by key, populating dest.
//
// The returned data must be unversioned. That is, key must
// 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
}
A Getter loads data for a key.
type GetterFunc ¶
A GetterFunc implements Getter with a function.
type Group ¶
type Group struct {
// contains filtered or unexported fields
}
A Group is a cache namespace and associated data loaded spread over a group of 1 or more machines.
type GroupInterface ¶
type GroupInterface interface {
Name() string
Get(ctx Context, key string, dest Sink) error
// contains filtered or unexported methods
}
GroupInterface implements Group.
func GetGroup ¶
func GetGroup(name string) *GroupInterface
GetGroup returns the named group previously created with NewGroup, or nil if there's no such group.
func NewGroup ¶
func NewGroup(name string, cacheBytes int64, getter Getter, stats bool) *GroupInterface
NewGroup creates a coordinated group-aware Getter from a Getter.
The returned Getter tries (but does not guarantee) to run only one Get call at once for a given key across an entire set of peer processes. Concurrent callers both in the local process and in other processes receive copies of the answer once the original Get completes.
The group name must be unique for each getter.
type GroupStats ¶
GroupStats are returned by stats accessors on Group.
type GroupWithStats ¶
type GroupWithStats struct {
*Group
// Stats are statistics on the group.
Stats Stats
// contains filtered or unexported fields
}
A GroupWithStats is a cache namespace and associated data loaded spread over a group of 1 or more machines.
func (*GroupWithStats) Get ¶
func (g *GroupWithStats) Get(ctx Context, key string, dest Sink) error
Get item from cache.
func (*GroupWithStats) GroupStats ¶
func (g *GroupWithStats) GroupStats() GroupStats
GroupStats returns stats about the provided cache within the group.
type ProtoGetter ¶
type ProtoGetter interface {
Get(context Context, in *pb.GetRequest, out *pb.GetResponse) error
}
ProtoGetter is the interface that must be implemented by a peer.
type Sink ¶
type Sink interface {
// SetString sets the value to s.
SetString(s string) error
// SetBytes sets the value to the contents of v.
// The caller retains ownership of v.
SetBytes(v []byte) error
// SetProto sets the value to the encoded version of m.
// The caller retains ownership of m.
SetProto(m proto.Message) error
// contains filtered or unexported methods
}
A Sink receives data from a Get call.
Implementation of Getter must call exactly one of the Set methods on success.
func AllocatingByteSliceSink ¶
AllocatingByteSliceSink returns a Sink that allocates a byte slice to hold the received value and assigns it to *dst. The memory is not retained by groupcache.
func ByteViewSink ¶
ByteViewSink returns a Sink that populates a ByteView.
func StringSink ¶
StringSink returns a Sink that populates the provided string pointer.
func TruncatingByteSliceSink ¶
TruncatingByteSliceSink returns a Sink that writes up to len(*dst) bytes to *dst. If more bytes are available, they're silently truncated. If fewer bytes are available than len(*dst), *dst is shrunk to fit the number of bytes available.
type Stats ¶
type Stats struct {
Gets AtomicInt // any Get request, including from peers
CacheHits AtomicInt // either cache was good
Loads AtomicInt // (gets - cacheHits)
LoadsDeduped AtomicInt // after singleflight
LocalLoads AtomicInt // total good local loads
LocalLoadErrs AtomicInt // total bad local loads
}
Stats are per-group statistics.
Source Files