Official Go implementation of the Ethereum protocol
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go-ethereum/swarm/storage/netstore.go

135 lines
4.3 KiB

// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package storage
import (
"path/filepath"
"sync"
"time"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
)
/*
NetStore is a cloud storage access abstaction layer for swarm
it contains the shared logic of network served chunk store/retrieval requests
both local (coming from DPA api) and remote (coming from peers via bzz protocol)
it implements the ChunkStore interface and embeds LocalStore
It is called by the bzz protocol instances via Depo (the store/retrieve request handler)
a protocol instance is running on each peer, so this is heavily parallelised.
NetStore falls back to a backend (CloudStorage interface)
implemented by bzz/network/forwarder. forwarder or IPFS or IPΞS
*/
type NetStore struct {
hashfunc Hasher
localStore *LocalStore
cloud CloudStore
lock sync.Mutex
}
// backend engine for cloud store
// It can be aggregate dispatching to several parallel implementations:
// bzz/network/forwarder. forwarder or IPFS or IPΞS
type CloudStore interface {
Store(*Chunk)
Deliver(*Chunk)
Retrieve(*Chunk)
}
type StoreParams struct {
ChunkDbPath string
DbCapacity uint64
CacheCapacity uint
Radius int
}
func NewStoreParams(path string) (self *StoreParams) {
return &StoreParams{
ChunkDbPath: filepath.Join(path, "chunks"),
DbCapacity: defaultDbCapacity,
CacheCapacity: defaultCacheCapacity,
Radius: defaultRadius,
}
}
// netstore contructor, takes path argument that is used to initialise dbStore,
// the persistent (disk) storage component of LocalStore
// the second argument is the hive, the connection/logistics manager for the node
func NewNetStore(hash Hasher, lstore *LocalStore, cloud CloudStore, params *StoreParams) *NetStore {
return &NetStore{
hashfunc: hash,
localStore: lstore,
cloud: cloud,
}
}
const (
// maximum number of peers that a retrieved message is delivered to
requesterCount = 3
)
var (
// timeout interval before retrieval is timed out
searchTimeout = 3 * time.Second
)
// store logic common to local and network chunk store requests
// ~ unsafe put in localdb no check if exists no extra copy no hash validation
// the chunk is forced to propagate (Cloud.Store) even if locally found!
// caller needs to make sure if that is wanted
func (self *NetStore) Put(entry *Chunk) {
self.localStore.Put(entry)
// handle deliveries
if entry.Req != nil {
glog.V(logger.Detail).Infof("NetStore.Put: localStore.Put %v hit existing request...delivering", entry.Key.Log())
// closing C signals to other routines (local requests)
// that the chunk is has been retrieved
close(entry.Req.C)
// deliver the chunk to requesters upstream
go self.cloud.Deliver(entry)
} else {
glog.V(logger.Detail).Infof("NetStore.Put: localStore.Put %v stored locally", entry.Key.Log())
// handle propagating store requests
// go self.cloud.Store(entry)
go self.cloud.Store(entry)
}
}
// retrieve logic common for local and network chunk retrieval requests
func (self *NetStore) Get(key Key) (*Chunk, error) {
var err error
chunk, err := self.localStore.Get(key)
if err == nil {
if chunk.Req == nil {
glog.V(logger.Detail).Infof("NetStore.Get: %v found locally", key)
} else {
glog.V(logger.Detail).Infof("NetStore.Get: %v hit on an existing request", key)
// no need to launch again
}
return chunk, err
}
// no data and no request status
glog.V(logger.Detail).Infof("NetStore.Get: %v not found locally. open new request", key)
chunk = NewChunk(key, newRequestStatus(key))
self.localStore.memStore.Put(chunk)
go self.cloud.Retrieve(chunk)
return chunk, nil
}