syncthing/model/model.go
2014-01-20 22:22:27 +01:00

859 lines
19 KiB
Go

package model
import (
"crypto/sha1"
"errors"
"fmt"
"io"
"log"
"net"
"os"
"path"
"sync"
"time"
"github.com/calmh/syncthing/buffers"
"github.com/calmh/syncthing/protocol"
)
type Model struct {
dir string
global map[string]File // the latest version of each file as it exists in the cluster
gmut sync.RWMutex // protects global
local map[string]File // the files we currently have locally on disk
lmut sync.RWMutex // protects local
remote map[string]map[string]File
rmut sync.RWMutex // protects remote
protoConn map[string]Connection
rawConn map[string]io.Closer
pmut sync.RWMutex // protects protoConn and rawConn
// Queue for files to fetch. fq can call back into the model, so we must ensure
// to hold no locks when calling methods on fq.
fq *FileQueue
dq chan File // queue for files to delete
updatedLocal int64 // timestamp of last update to local
updateGlobal int64 // timestamp of last update to remote
lastIdxBcast time.Time
lastIdxBcastRequest time.Time
umut sync.RWMutex // provides updated* and lastIdx*
rwRunning bool
delete bool
initmut sync.Mutex // protects rwRunning and delete
trace map[string]bool
fileLastChanged map[string]time.Time
fileWasSuppressed map[string]int
fmut sync.Mutex // protects fileLastChanged and fileWasSuppressed
parallellRequests int
limitRequestRate chan struct{}
imut sync.Mutex // protects Index
}
type Connection interface {
ID() string
Index([]protocol.FileInfo)
Request(name string, offset int64, size uint32, hash []byte) ([]byte, error)
Statistics() protocol.Statistics
}
const (
idxBcastHoldtime = 15 * time.Second // Wait at least this long after the last index modification
idxBcastMaxDelay = 120 * time.Second // Unless we've already waited this long
minFileHoldTimeS = 60 // Never allow file changes more often than this
maxFileHoldTimeS = 600 // Always allow file changes at least this often
)
var (
ErrNoSuchFile = errors.New("no such file")
ErrInvalid = errors.New("file is invalid")
)
// NewModel creates and starts a new model. The model starts in read-only mode,
// where it sends index information to connected peers and responds to requests
// for file data without altering the local repository in any way.
func NewModel(dir string) *Model {
m := &Model{
dir: dir,
global: make(map[string]File),
local: make(map[string]File),
remote: make(map[string]map[string]File),
protoConn: make(map[string]Connection),
rawConn: make(map[string]io.Closer),
lastIdxBcast: time.Now(),
trace: make(map[string]bool),
fileLastChanged: make(map[string]time.Time),
fileWasSuppressed: make(map[string]int),
fq: NewFileQueue(),
dq: make(chan File),
}
go m.broadcastIndexLoop()
return m
}
func (m *Model) LimitRate(kbps int) {
m.limitRequestRate = make(chan struct{}, kbps)
n := kbps/10 + 1
go func() {
for {
time.Sleep(100 * time.Millisecond)
for i := 0; i < n; i++ {
select {
case m.limitRequestRate <- struct{}{}:
}
}
}
}()
}
// Trace enables trace logging of the given facility. This is a debugging function; grep for m.trace.
func (m *Model) Trace(t string) {
m.trace[t] = true
}
// StartRW starts read/write processing on the current model. When in
// read/write mode the model will attempt to keep in sync with the cluster by
// pulling needed files from peer nodes.
func (m *Model) StartRW(del bool, threads int) {
m.initmut.Lock()
defer m.initmut.Unlock()
if m.rwRunning {
panic("starting started model")
}
m.rwRunning = true
m.delete = del
m.parallellRequests = threads
go m.cleanTempFiles()
if del {
go m.deleteLoop()
}
}
// Generation returns an opaque integer that is guaranteed to increment on
// every change to the local repository or global model.
func (m *Model) Generation() int64 {
m.umut.RLock()
defer m.umut.RUnlock()
return m.updatedLocal + m.updateGlobal
}
func (m *Model) LocalAge() float64 {
m.umut.RLock()
defer m.umut.RUnlock()
return time.Since(time.Unix(m.updatedLocal, 0)).Seconds()
}
type ConnectionInfo struct {
protocol.Statistics
Address string
}
// ConnectionStats returns a map with connection statistics for each connected node.
func (m *Model) ConnectionStats() map[string]ConnectionInfo {
type remoteAddrer interface {
RemoteAddr() net.Addr
}
m.pmut.RLock()
var res = make(map[string]ConnectionInfo)
for node, conn := range m.protoConn {
ci := ConnectionInfo{
Statistics: conn.Statistics(),
}
if nc, ok := m.rawConn[node].(remoteAddrer); ok {
ci.Address = nc.RemoteAddr().String()
}
res[node] = ci
}
m.pmut.RUnlock()
return res
}
// LocalSize returns the number of files, deleted files and total bytes for all
// files in the global model.
func (m *Model) GlobalSize() (files, deleted, bytes int) {
m.gmut.RLock()
for _, f := range m.global {
if f.Flags&protocol.FlagDeleted == 0 {
files++
bytes += f.Size()
} else {
deleted++
}
}
m.gmut.RUnlock()
return
}
// LocalSize returns the number of files, deleted files and total bytes for all
// files in the local repository.
func (m *Model) LocalSize() (files, deleted, bytes int) {
m.lmut.RLock()
for _, f := range m.local {
if f.Flags&protocol.FlagDeleted == 0 {
files++
bytes += f.Size()
} else {
deleted++
}
}
m.lmut.RUnlock()
return
}
// InSyncSize returns the number and total byte size of the local files that
// are in sync with the global model.
func (m *Model) InSyncSize() (files, bytes int) {
m.gmut.RLock()
m.lmut.RLock()
for n, f := range m.local {
if gf, ok := m.global[n]; ok && f.Equals(gf) {
files++
bytes += f.Size()
}
}
m.lmut.RUnlock()
m.gmut.RUnlock()
return
}
// NeedFiles returns the list of currently needed files and the total size.
func (m *Model) NeedFiles() (files []File, bytes int) {
qf := m.fq.QueuedFiles()
m.gmut.RLock()
for _, n := range qf {
f := m.global[n]
files = append(files, f)
bytes += f.Size()
}
m.gmut.RUnlock()
return
}
// Index is called when a new node is connected and we receive their full index.
// Implements the protocol.Model interface.
func (m *Model) Index(nodeID string, fs []protocol.FileInfo) {
m.imut.Lock()
defer m.imut.Unlock()
if m.trace["net"] {
log.Printf("NET IDX(in): %s: %d files", nodeID, len(fs))
}
repo := make(map[string]File)
for _, f := range fs {
m.indexUpdate(repo, f)
}
m.rmut.Lock()
m.remote[nodeID] = repo
m.rmut.Unlock()
m.recomputeGlobal()
m.recomputeNeed()
}
// IndexUpdate is called for incremental updates to connected nodes' indexes.
// Implements the protocol.Model interface.
func (m *Model) IndexUpdate(nodeID string, fs []protocol.FileInfo) {
m.imut.Lock()
defer m.imut.Unlock()
if m.trace["net"] {
log.Printf("NET IDXUP(in): %s: %d files", nodeID, len(fs))
}
m.rmut.Lock()
repo, ok := m.remote[nodeID]
if !ok {
log.Printf("WARNING: Index update from node %s that does not have an index", nodeID)
m.rmut.Unlock()
return
}
for _, f := range fs {
m.indexUpdate(repo, f)
}
m.rmut.Unlock()
m.recomputeGlobal()
m.recomputeNeed()
}
func (m *Model) indexUpdate(repo map[string]File, f protocol.FileInfo) {
if m.trace["idx"] {
var flagComment string
if f.Flags&protocol.FlagDeleted != 0 {
flagComment = " (deleted)"
}
log.Printf("IDX(in): %q m=%d f=%o%s v=%d (%d blocks)", f.Name, f.Modified, f.Flags, flagComment, f.Version, len(f.Blocks))
}
if extraFlags := f.Flags &^ (protocol.FlagInvalid | protocol.FlagDeleted | 0xfff); extraFlags != 0 {
log.Printf("WARNING: IDX(in): Unknown flags 0x%x in index record %+v", extraFlags, f)
return
}
repo[f.Name] = fileFromFileInfo(f)
}
// Close removes the peer from the model and closes the underlying connection if possible.
// Implements the protocol.Model interface.
func (m *Model) Close(node string, err error) {
m.fq.RemoveAvailable(node)
m.pmut.Lock()
m.rmut.Lock()
conn, ok := m.rawConn[node]
if ok {
conn.Close()
}
delete(m.remote, node)
delete(m.protoConn, node)
delete(m.rawConn, node)
m.rmut.Unlock()
m.pmut.Unlock()
m.recomputeGlobal()
m.recomputeNeed()
}
// Request returns the specified data segment by reading it from local disk.
// Implements the protocol.Model interface.
func (m *Model) Request(nodeID, name string, offset int64, size uint32, hash []byte) ([]byte, error) {
// Verify that the requested file exists in the local and global model.
m.lmut.RLock()
lf, localOk := m.local[name]
m.lmut.RUnlock()
m.gmut.RLock()
_, globalOk := m.global[name]
m.gmut.RUnlock()
if !localOk || !globalOk {
log.Printf("SECURITY (nonexistent file) REQ(in): %s: %q o=%d s=%d h=%x", nodeID, name, offset, size, hash)
return nil, ErrNoSuchFile
}
if lf.Flags&protocol.FlagInvalid != 0 {
return nil, ErrInvalid
}
if m.trace["net"] && nodeID != "<local>" {
log.Printf("NET REQ(in): %s: %q o=%d s=%d h=%x", nodeID, name, offset, size, hash)
}
fn := path.Join(m.dir, name)
fd, err := os.Open(fn) // XXX: Inefficient, should cache fd?
if err != nil {
return nil, err
}
defer fd.Close()
buf := buffers.Get(int(size))
_, err = fd.ReadAt(buf, offset)
if err != nil {
return nil, err
}
if m.limitRequestRate != nil {
for s := 0; s < len(buf); s += 1024 {
<-m.limitRequestRate
}
}
return buf, nil
}
// ReplaceLocal replaces the local repository index with the given list of files.
// Change suppression is applied to files changing too often.
func (m *Model) ReplaceLocal(fs []File) {
var updated bool
var newLocal = make(map[string]File)
m.lmut.RLock()
for _, f := range fs {
newLocal[f.Name] = f
if ef := m.local[f.Name]; !ef.Equals(f) {
updated = true
}
}
m.lmut.RUnlock()
if m.markDeletedLocals(newLocal) {
updated = true
}
m.lmut.RLock()
if len(newLocal) != len(m.local) {
updated = true
}
m.lmut.RUnlock()
if updated {
m.lmut.Lock()
m.local = newLocal
m.lmut.Unlock()
m.recomputeGlobal()
m.recomputeNeed()
m.umut.Lock()
m.updatedLocal = time.Now().Unix()
m.lastIdxBcastRequest = time.Now()
m.umut.Unlock()
}
}
// SeedLocal replaces the local repository index with the given list of files,
// in protocol data types. Does not track deletes, should only be used to seed
// the local index from a cache file at startup.
func (m *Model) SeedLocal(fs []protocol.FileInfo) {
m.lmut.Lock()
m.local = make(map[string]File)
for _, f := range fs {
m.local[f.Name] = fileFromFileInfo(f)
}
m.lmut.Unlock()
m.recomputeGlobal()
m.recomputeNeed()
}
// ConnectedTo returns true if we are connected to the named node.
func (m *Model) ConnectedTo(nodeID string) bool {
m.pmut.RLock()
_, ok := m.protoConn[nodeID]
m.pmut.RUnlock()
return ok
}
// RepoID returns a unique ID representing the current repository location.
func (m *Model) RepoID() string {
return fmt.Sprintf("%x", sha1.Sum([]byte(m.dir)))
}
// AddConnection adds a new peer connection to the model. An initial index will
// be sent to the connected peer, thereafter index updates whenever the local
// repository changes.
func (m *Model) AddConnection(rawConn io.Closer, protoConn Connection) {
nodeID := protoConn.ID()
m.pmut.Lock()
m.protoConn[nodeID] = protoConn
m.rawConn[nodeID] = rawConn
m.pmut.Unlock()
go func() {
idx := m.ProtocolIndex()
protoConn.Index(idx)
}()
m.initmut.Lock()
rw := m.rwRunning
m.initmut.Unlock()
if !rw {
return
}
for i := 0; i < m.parallellRequests; i++ {
i := i
go func() {
if m.trace["pull"] {
log.Println("PULL: Starting", nodeID, i)
}
for {
m.pmut.RLock()
if _, ok := m.protoConn[nodeID]; !ok {
if m.trace["pull"] {
log.Println("PULL: Exiting", nodeID, i)
}
m.pmut.RUnlock()
return
}
m.pmut.RUnlock()
qb, ok := m.fq.Get(nodeID)
if ok {
if m.trace["pull"] {
log.Println("PULL: Request", nodeID, i, qb.name, qb.block.Offset)
}
data, _ := protoConn.Request(qb.name, qb.block.Offset, qb.block.Size, qb.block.Hash)
m.fq.Done(qb.name, qb.block.Offset, data)
} else {
time.Sleep(1 * time.Second)
}
}
}()
}
}
func (m *Model) shouldSuppressChange(name string) bool {
m.fmut.Lock()
sup := shouldSuppressChange(m.fileLastChanged[name], m.fileWasSuppressed[name])
if sup {
m.fileWasSuppressed[name]++
} else {
m.fileWasSuppressed[name] = 0
m.fileLastChanged[name] = time.Now()
}
m.fmut.Unlock()
return sup
}
func shouldSuppressChange(lastChange time.Time, numChanges int) bool {
sinceLast := time.Since(lastChange)
if sinceLast > maxFileHoldTimeS*time.Second {
return false
}
if sinceLast < time.Duration((numChanges+2)*minFileHoldTimeS)*time.Second {
return true
}
return false
}
// ProtocolIndex returns the current local index in protocol data types.
// Must be called with the read lock held.
func (m *Model) ProtocolIndex() []protocol.FileInfo {
var index []protocol.FileInfo
m.lmut.RLock()
for _, f := range m.local {
mf := fileInfoFromFile(f)
if m.trace["idx"] {
var flagComment string
if mf.Flags&protocol.FlagDeleted != 0 {
flagComment = " (deleted)"
}
log.Printf("IDX(out): %q m=%d f=%o%s v=%d (%d blocks)", mf.Name, mf.Modified, mf.Flags, flagComment, mf.Version, len(mf.Blocks))
}
index = append(index, mf)
}
m.lmut.RUnlock()
return index
}
func (m *Model) requestGlobal(nodeID, name string, offset int64, size uint32, hash []byte) ([]byte, error) {
m.pmut.RLock()
nc, ok := m.protoConn[nodeID]
m.pmut.RUnlock()
if !ok {
return nil, fmt.Errorf("requestGlobal: no such node: %s", nodeID)
}
if m.trace["net"] {
log.Printf("NET REQ(out): %s: %q o=%d s=%d h=%x", nodeID, name, offset, size, hash)
}
return nc.Request(name, offset, size, hash)
}
func (m *Model) broadcastIndexLoop() {
for {
m.umut.RLock()
bcastRequested := m.lastIdxBcastRequest.After(m.lastIdxBcast)
holdtimeExceeded := time.Since(m.lastIdxBcastRequest) > idxBcastHoldtime
m.umut.RUnlock()
maxDelayExceeded := time.Since(m.lastIdxBcast) > idxBcastMaxDelay
if bcastRequested && (holdtimeExceeded || maxDelayExceeded) {
idx := m.ProtocolIndex()
var indexWg sync.WaitGroup
indexWg.Add(len(m.protoConn))
m.umut.Lock()
m.lastIdxBcast = time.Now()
m.umut.Unlock()
m.pmut.RLock()
for _, node := range m.protoConn {
node := node
if m.trace["net"] {
log.Printf("NET IDX(out/loop): %s: %d files", node.ID(), len(idx))
}
go func() {
node.Index(idx)
indexWg.Done()
}()
}
m.pmut.RUnlock()
indexWg.Wait()
}
time.Sleep(idxBcastHoldtime)
}
}
// markDeletedLocals sets the deleted flag on files that have gone missing locally.
func (m *Model) markDeletedLocals(newLocal map[string]File) bool {
// For every file in the existing local table, check if they are also
// present in the new local table. If they are not, check that we already
// had the newest version available according to the global table and if so
// note the file as having been deleted.
var updated bool
m.gmut.RLock()
m.lmut.RLock()
for n, f := range m.local {
if _, ok := newLocal[n]; !ok {
if gf := m.global[n]; !gf.NewerThan(f) {
if f.Flags&protocol.FlagDeleted == 0 {
f.Flags = protocol.FlagDeleted
f.Version++
f.Blocks = nil
updated = true
}
newLocal[n] = f
}
}
}
m.lmut.RUnlock()
m.gmut.RUnlock()
return updated
}
func (m *Model) updateLocal(f File) {
var updated bool
m.lmut.Lock()
if ef, ok := m.local[f.Name]; !ok || !ef.Equals(f) {
m.local[f.Name] = f
updated = true
}
m.lmut.Unlock()
if updated {
m.recomputeGlobal()
// We don't recomputeNeed here for two reasons:
// - a need shouldn't have arisen due to having a newer local file
// - recomputeNeed might call into fq.Add but we might have been called by
// fq which would be a deadlock on fq
m.umut.Lock()
m.updatedLocal = time.Now().Unix()
m.lastIdxBcastRequest = time.Now()
m.umut.Unlock()
}
}
func (m *Model) recomputeGlobal() {
var newGlobal = make(map[string]File)
m.lmut.RLock()
for n, f := range m.local {
newGlobal[n] = f
}
m.lmut.RUnlock()
var available = make(map[string][]string)
m.rmut.RLock()
var highestMod int64
for nodeID, fs := range m.remote {
for n, nf := range fs {
if lf, ok := newGlobal[n]; !ok || nf.NewerThan(lf) {
newGlobal[n] = nf
available[n] = []string{nodeID}
if nf.Modified > highestMod {
highestMod = nf.Modified
}
} else if lf.Equals(nf) {
available[n] = append(available[n], nodeID)
}
}
}
m.rmut.RUnlock()
for f, ns := range available {
m.fq.SetAvailable(f, ns)
}
// Figure out if anything actually changed
m.gmut.RLock()
var updated bool
if highestMod > m.updateGlobal || len(newGlobal) != len(m.global) {
updated = true
} else {
for n, f0 := range newGlobal {
if f1, ok := m.global[n]; !ok || !f0.Equals(f1) {
updated = true
break
}
}
}
m.gmut.RUnlock()
if updated {
m.gmut.Lock()
m.umut.Lock()
m.global = newGlobal
m.updateGlobal = time.Now().Unix()
m.umut.Unlock()
m.gmut.Unlock()
}
}
func (m *Model) recomputeNeed() {
type addOrder struct {
n string
remote []Block
fm *fileMonitor
}
var toDelete []File
var toAdd []addOrder
m.gmut.RLock()
for n, gf := range m.global {
m.lmut.RLock()
lf, ok := m.local[n]
m.lmut.RUnlock()
if !ok || gf.NewerThan(lf) {
if gf.Flags&protocol.FlagInvalid != 0 {
// Never attempt to sync invalid files
continue
}
if gf.Flags&protocol.FlagDeleted != 0 && !m.delete {
// Don't want to delete files, so forget this need
continue
}
if gf.Flags&protocol.FlagDeleted != 0 && !ok {
// Don't have the file, so don't need to delete it
continue
}
if m.trace["need"] {
log.Printf("NEED: lf:%v gf:%v", lf, gf)
}
if gf.Flags&protocol.FlagDeleted != 0 {
toDelete = append(toDelete, gf)
} else {
local, remote := BlockDiff(lf.Blocks, gf.Blocks)
fm := fileMonitor{
name: n,
path: path.Clean(path.Join(m.dir, n)),
global: gf,
model: m,
localBlocks: local,
}
toAdd = append(toAdd, addOrder{n, remote, &fm})
}
}
}
m.gmut.RUnlock()
for _, ao := range toAdd {
if !m.fq.Queued(ao.n) {
m.fq.Add(ao.n, ao.remote, ao.fm)
}
}
for _, gf := range toDelete {
m.dq <- gf
}
}
func (m *Model) WhoHas(name string) []string {
var remote []string
m.gmut.RLock()
m.rmut.RLock()
gf := m.global[name]
for node, files := range m.remote {
if file, ok := files[name]; ok && file.Equals(gf) {
remote = append(remote, node)
}
}
m.rmut.RUnlock()
m.gmut.RUnlock()
return remote
}
func (m *Model) deleteLoop() {
for file := range m.dq {
if m.trace["file"] {
log.Println("FILE: Delete", file.Name)
}
path := path.Clean(path.Join(m.dir, file.Name))
err := os.Remove(path)
if err != nil {
log.Printf("WARNING: %s: %v", file.Name, err)
}
m.updateLocal(file)
}
}
func fileFromFileInfo(f protocol.FileInfo) File {
var blocks = make([]Block, len(f.Blocks))
var offset int64
for i, b := range f.Blocks {
blocks[i] = Block{
Offset: offset,
Size: b.Size,
Hash: b.Hash,
}
offset += int64(b.Size)
}
return File{
Name: f.Name,
Flags: f.Flags,
Modified: f.Modified,
Version: f.Version,
Blocks: blocks,
}
}
func fileInfoFromFile(f File) protocol.FileInfo {
var blocks = make([]protocol.BlockInfo, len(f.Blocks))
for i, b := range f.Blocks {
blocks[i] = protocol.BlockInfo{
Size: b.Size,
Hash: b.Hash,
}
}
return protocol.FileInfo{
Name: f.Name,
Flags: f.Flags,
Modified: f.Modified,
Version: f.Version,
Blocks: blocks,
}
}