path: root/swarm/storage/localstore.go

// 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 (
    "encoding/binary"
    "fmt"
    "path/filepath"
    "sync"

    "github.com/ethereum/go-ethereum/metrics"
    "github.com/ethereum/go-ethereum/swarm/log"
    "github.com/ethereum/go-ethereum/swarm/storage/mock"
)

type LocalStoreParams struct {
    *StoreParams
    ChunkDbPath string
    Validators  []ChunkValidator `toml:"-"`
}

func NewDefaultLocalStoreParams() *LocalStoreParams {
    return &LocalStoreParams{
        StoreParams: NewDefaultStoreParams(),
    }
}

//this can only finally be set after all config options (file, cmd line, env vars)
//have been evaluated
func (p *LocalStoreParams) Init(path string) {
    if p.ChunkDbPath == "" {
        p.ChunkDbPath = filepath.Join(path, "chunks")
    }
}

// LocalStore is a combination of inmemory db over a disk persisted db
// implements a Get/Put with fallback (caching) logic using any 2 ChunkStores
type LocalStore struct {
    Validators []ChunkValidator
    memStore   *MemStore
    DbStore    *LDBStore
    mu         sync.Mutex
}

// This constructor uses MemStore and DbStore as components
func NewLocalStore(params *LocalStoreParams, mockStore *mock.NodeStore) (*LocalStore, error) {
    ldbparams := NewLDBStoreParams(params.StoreParams, params.ChunkDbPath)
    dbStore, err := NewMockDbStore(ldbparams, mockStore)
    if err != nil {
        return nil, err
    }
    return &LocalStore{
        memStore:   NewMemStore(params.StoreParams, dbStore),
        DbStore:    dbStore,
        Validators: params.Validators,
    }, nil
}

func NewTestLocalStoreForAddr(params *LocalStoreParams) (*LocalStore, error) {
    ldbparams := NewLDBStoreParams(params.StoreParams, params.ChunkDbPath)
    dbStore, err := NewLDBStore(ldbparams)
    if err != nil {
        return nil, err
    }
    localStore := &LocalStore{
        memStore:   NewMemStore(params.StoreParams, dbStore),
        DbStore:    dbStore,
        Validators: params.Validators,
    }
    return localStore, nil
}

// Put is responsible for doing validation and storage of the chunk
// by using configured ChunkValidators, MemStore and LDBStore.
// If the chunk is not valid, its GetErrored function will
// return ErrChunkInvalid.
// This method will check if the chunk is already in the MemStore
// and it will return it if it is. If there is an error from
// the MemStore.Get, it will be returned by calling GetErrored
// on the chunk.
// This method is responsible for closing Chunk.ReqC channel
// when the chunk is stored in memstore.
// After the LDBStore.Put, it is ensured that the MemStore
// contains the chunk with the same data, but nil ReqC channel.
func (ls *LocalStore) Put(chunk *Chunk) {
    if l := len(chunk.SData); l < 9 {
        log.Debug("incomplete chunk data", "addr", chunk.Addr, "length", l)
        chunk.SetErrored(ErrChunkInvalid)
        chunk.markAsStored()
        return
    }
    valid := true
    for _, v := range ls.Validators {
        if valid = v.Validate(chunk.Addr, chunk.SData); valid {
            break
        }
    }
    if !valid {
        log.Trace("invalid content address", "addr", chunk.Addr)
        chunk.SetErrored(ErrChunkInvalid)
        chunk.markAsStored()
        return
    }

    log.Trace("localstore.put", "addr", chunk.Addr)

    ls.mu.Lock()
    defer ls.mu.Unlock()

    chunk.Size = int64(binary.LittleEndian.Uint64(chunk.SData[0:8]))

    memChunk, err := ls.memStore.Get(chunk.Addr)
    switch err {
    case nil:
        if memChunk.ReqC == nil {
            chunk.markAsStored()
            return
        }
    case ErrChunkNotFound:
    default:
        chunk.SetErrored(err)
        return
    }

    ls.DbStore.Put(chunk)

    // chunk is no longer a request, but a chunk with data, so replace it in memStore
    newc := NewChunk(chunk.Addr, nil)
    newc.SData = chunk.SData
    newc.Size = chunk.Size
    newc.dbStoredC = chunk.dbStoredC

    ls.memStore.Put(newc)

    if memChunk != nil && memChunk.ReqC != nil {
        close(memChunk.ReqC)
    }
}

// Get(chunk *Chunk) looks up a chunk in the local stores
// This method is blocking until the chunk is retrieved
// so additional timeout may be needed to wrap this call if
// ChunkStores are remote and can have long latency
func (ls *LocalStore) Get(addr Address) (chunk *Chunk, err error) {
    ls.mu.Lock()
    defer ls.mu.Unlock()

    return ls.get(addr)
}

func (ls *LocalStore) get(addr Address) (chunk *Chunk, err error) {
    chunk, err = ls.memStore.Get(addr)
    if err == nil {
        if chunk.ReqC != nil {
            select {
            case <-chunk.ReqC:
            default:
                metrics.GetOrRegisterCounter("localstore.get.errfetching", nil).Inc(1)
                return chunk, ErrFetching
            }
        }
        metrics.GetOrRegisterCounter("localstore.get.cachehit", nil).Inc(1)
        return
    }
    metrics.GetOrRegisterCounter("localstore.get.cachemiss", nil).Inc(1)
    chunk, err = ls.DbStore.Get(addr)
    if err != nil {
        metrics.GetOrRegisterCounter("localstore.get.error", nil).Inc(1)
        return
    }
    chunk.Size = int64(binary.LittleEndian.Uint64(chunk.SData[0:8]))
    ls.memStore.Put(chunk)
    return
}

// retrieve logic common for local and network chunk retrieval requests
func (ls *LocalStore) GetOrCreateRequest(addr Address) (chunk *Chunk, created bool) {
    metrics.GetOrRegisterCounter("localstore.getorcreaterequest", nil).Inc(1)

    ls.mu.Lock()
    defer ls.mu.Unlock()

    var err error
    chunk, err = ls.get(addr)
    if err == nil && chunk.GetErrored() == nil {
        metrics.GetOrRegisterCounter("localstore.getorcreaterequest.hit", nil).Inc(1)
        log.Trace(fmt.Sprintf("LocalStore.GetOrRetrieve: %v found locally", addr))
        return chunk, false
    }
    if err == ErrFetching && chunk.GetErrored() == nil {
        metrics.GetOrRegisterCounter("localstore.getorcreaterequest.errfetching", nil).Inc(1)
        log.Trace(fmt.Sprintf("LocalStore.GetOrRetrieve: %v hit on an existing request %v", addr, chunk.ReqC))
        return chunk, false
    }
    // no data and no request status
    metrics.GetOrRegisterCounter("localstore.getorcreaterequest.miss", nil).Inc(1)
    log.Trace(fmt.Sprintf("LocalStore.GetOrRetrieve: %v not found locally. open new request", addr))
    chunk = NewChunk(addr, make(chan bool))
    ls.memStore.Put(chunk)
    return chunk, true
}

// RequestsCacheLen returns the current number of outgoing requests stored in the cache
func (ls *LocalStore) RequestsCacheLen() int {
    return ls.memStore.requests.Len()
}

// Close the local store
func (ls *LocalStore) Close() {
    ls.DbStore.Close()
}