server: Move server files to 'server' directory.

26  git mv mvcc wal auth etcdserver etcdmain proxy embed/ lease/ server
   36  git mv go.mod go.sum server

server/proxy/grpcproxy/cache/store.go

@@ -0,0 +1,172 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package cache exports functionality for efficiently caching and mapping
+// `RangeRequest`s to corresponding `RangeResponse`s.
+package cache
+
+import (
+	"errors"
+	"sync"
+
+	"github.com/golang/groupcache/lru"
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/pkg/v3/adt"
+)
+
+var (
+	DefaultMaxEntries = 2048
+	ErrCompacted      = rpctypes.ErrGRPCCompacted
+)
+
+type Cache interface {
+	Add(req *pb.RangeRequest, resp *pb.RangeResponse)
+	Get(req *pb.RangeRequest) (*pb.RangeResponse, error)
+	Compact(revision int64)
+	Invalidate(key []byte, endkey []byte)
+	Size() int
+	Close()
+}
+
+// keyFunc returns the key of a request, which is used to look up its caching response in the cache.
+func keyFunc(req *pb.RangeRequest) string {
+	// TODO: use marshalTo to reduce allocation
+	b, err := req.Marshal()
+	if err != nil {
+		panic(err)
+	}
+	return string(b)
+}
+
+func NewCache(maxCacheEntries int) Cache {
+	return &cache{
+		lru:          lru.New(maxCacheEntries),
+		cachedRanges: adt.NewIntervalTree(),
+		compactedRev: -1,
+	}
+}
+
+func (c *cache) Close() {}
+
+// cache implements Cache
+type cache struct {
+	mu  sync.RWMutex
+	lru *lru.Cache
+
+	// a reverse index for cache invalidation
+	cachedRanges adt.IntervalTree
+
+	compactedRev int64
+}
+
+// Add adds the response of a request to the cache if its revision is larger than the compacted revision of the cache.
+func (c *cache) Add(req *pb.RangeRequest, resp *pb.RangeResponse) {
+	key := keyFunc(req)
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if req.Revision > c.compactedRev {
+		c.lru.Add(key, resp)
+	}
+	// we do not need to invalidate a request with a revision specified.
+	// so we do not need to add it into the reverse index.
+	if req.Revision != 0 {
+		return
+	}
+
+	var (
+		iv  *adt.IntervalValue
+		ivl adt.Interval
+	)
+	if len(req.RangeEnd) != 0 {
+		ivl = adt.NewStringAffineInterval(string(req.Key), string(req.RangeEnd))
+	} else {
+		ivl = adt.NewStringAffinePoint(string(req.Key))
+	}
+
+	iv = c.cachedRanges.Find(ivl)
+
+	if iv == nil {
+		val := map[string]struct{}{key: {}}
+		c.cachedRanges.Insert(ivl, val)
+	} else {
+		val := iv.Val.(map[string]struct{})
+		val[key] = struct{}{}
+		iv.Val = val
+	}
+}
+
+// Get looks up the caching response for a given request.
+// Get is also responsible for lazy eviction when accessing compacted entries.
+func (c *cache) Get(req *pb.RangeRequest) (*pb.RangeResponse, error) {
+	key := keyFunc(req)
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if req.Revision > 0 && req.Revision < c.compactedRev {
+		c.lru.Remove(key)
+		return nil, ErrCompacted
+	}
+
+	if resp, ok := c.lru.Get(key); ok {
+		return resp.(*pb.RangeResponse), nil
+	}
+	return nil, errors.New("not exist")
+}
+
+// Invalidate invalidates the cache entries that intersecting with the given range from key to endkey.
+func (c *cache) Invalidate(key, endkey []byte) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	var (
+		ivs []*adt.IntervalValue
+		ivl adt.Interval
+	)
+	if len(endkey) == 0 {
+		ivl = adt.NewStringAffinePoint(string(key))
+	} else {
+		ivl = adt.NewStringAffineInterval(string(key), string(endkey))
+	}
+
+	ivs = c.cachedRanges.Stab(ivl)
+	for _, iv := range ivs {
+		keys := iv.Val.(map[string]struct{})
+		for key := range keys {
+			c.lru.Remove(key)
+		}
+	}
+	// delete after removing all keys since it is destructive to 'ivs'
+	c.cachedRanges.Delete(ivl)
+}
+
+// Compact invalidate all caching response before the given rev.
+// Replace with the invalidation is lazy. The actual removal happens when the entries is accessed.
+func (c *cache) Compact(revision int64) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if revision > c.compactedRev {
+		c.compactedRev = revision
+	}
+}
+
+func (c *cache) Size() int {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.lru.Len()
+}