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