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swarm: prevent forever running retrieve request loops

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This commit is contained in:
Balint Gabor 2018-09-25 17:35:54 +02:00 committed by Janos Guljas
parent d3441ebb56
commit 3f7acbbeb9
7 changed files with 79 additions and 27 deletions
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24
swarm/network/fetcher.go
View File

@ -32,6 +32,8 @@ var searchTimeout = 1 * time.Second
// Also used in stream delivery.
var RequestTimeout = 10 * time.Second
var maxHopCount uint8 = 20 // maximum number of forwarded requests (hops), to make sure requests are not forwarded forever in peer loops
type RequestFunc func(context.Context, *Request) (*enode.ID, chan struct{}, error)
// Fetcher is created when a chunk is not found locally. It starts a request handler loop once and
@ -44,7 +46,7 @@ type Fetcher struct {
protoRequestFunc RequestFunc // request function fetcher calls to issue retrieve request for a chunk
addr storage.Address // the address of the chunk to be fetched
offerC chan *enode.ID // channel of sources (peer node id strings)
requestC chan struct{}
requestC chan uint8 // channel for incoming requests (with the hopCount value in it)
skipCheck bool
}
@ -53,6 +55,7 @@ type Request struct {
Source *enode.ID // nodeID of peer to request from (can be nil)
SkipCheck bool // whether to offer the chunk first or deliver directly
peersToSkip *sync.Map // peers not to request chunk from (only makes sense if source is nil)
HopCount uint8 // number of forwarded requests (hops)
}
// NewRequest returns a new instance of Request based on chunk address skip check and
@ -113,7 +116,7 @@ func NewFetcher(addr storage.Address, rf RequestFunc, skipCheck bool) *Fetcher {
addr: addr,
protoRequestFunc: rf,
offerC: make(chan *enode.ID),
requestC: make(chan struct{}),
requestC: make(chan uint8),
skipCheck: skipCheck,
}
}
@ -136,7 +139,7 @@ func (f *Fetcher) Offer(ctx context.Context, source *enode.ID) {
}
// Request is called when an upstream peer request the chunk as part of `RetrieveRequestMsg`, or from a local request through FileStore, and the node does not have the chunk locally.
func (f *Fetcher) Request(ctx context.Context) {
func (f *Fetcher) Request(ctx context.Context, hopCount uint8) {
// First we need to have this select to make sure that we return if context is done
select {
case <-ctx.Done():
@ -144,10 +147,15 @@ func (f *Fetcher) Request(ctx context.Context) {
default:
}
if hopCount >= maxHopCount {
log.Debug("fetcher request hop count limit reached", "hops", hopCount)
return
}
// This select alone would not guarantee that we return of context is done, it could potentially
// push to offerC instead if offerC is available (see number 2 in https://golang.org/ref/spec#Select_statements)
select {
case f.requestC <- struct{}{}:
case f.requestC <- hopCount + 1:
case <-ctx.Done():
}
}
@ -161,6 +169,7 @@ func (f *Fetcher) run(ctx context.Context, peers *sync.Map) {
waitC <-chan time.Time // timer channel
sources []*enode.ID // known sources, ie. peers that offered the chunk
requested bool // true if the chunk was actually requested
hopCount uint8
)
gone := make(chan *enode.ID) // channel to signal that a peer we requested from disconnected
@ -183,7 +192,7 @@ func (f *Fetcher) run(ctx context.Context, peers *sync.Map) {
doRequest = requested
// incoming request
case <-f.requestC:
case hopCount = <-f.requestC:
log.Trace("new request", "request addr", f.addr)
// 2) chunk is requested, set requested flag
// launch a request iff none been launched yet
@ -213,7 +222,7 @@ func (f *Fetcher) run(ctx context.Context, peers *sync.Map) {
// need to issue a new request
if doRequest {
var err error
sources, err = f.doRequest(ctx, gone, peers, sources)
sources, err = f.doRequest(ctx, gone, peers, sources, hopCount)
if err != nil {
log.Info("unable to request", "request addr", f.addr, "err", err)
}
@ -251,7 +260,7 @@ func (f *Fetcher) run(ctx context.Context, peers *sync.Map) {
// * the peer's address is added to the set of peers to skip
// * the peer's address is removed from prospective sources, and
// * a go routine is started that reports on the gone channel if the peer is disconnected (or terminated their streamer)
func (f *Fetcher) doRequest(ctx context.Context, gone chan *enode.ID, peersToSkip *sync.Map, sources []*enode.ID) ([]*enode.ID, error) {
func (f *Fetcher) doRequest(ctx context.Context, gone chan *enode.ID, peersToSkip *sync.Map, sources []*enode.ID, hopCount uint8) ([]*enode.ID, error) {
var i int
var sourceID *enode.ID
var quit chan struct{}
@ -260,6 +269,7 @@ func (f *Fetcher) doRequest(ctx context.Context, gone chan *enode.ID, peersToSki
Addr: f.addr,
SkipCheck: f.skipCheck,
peersToSkip: peersToSkip,
HopCount: hopCount,
}
foundSource := false

54
swarm/network/fetcher_test.go
View File

@ -33,7 +33,7 @@ type mockRequester struct {
// requests []Request
requestC chan *Request // when a request is coming it is pushed to requestC
waitTimes []time.Duration // with waitTimes[i] you can define how much to wait on the ith request (optional)
ctr int //counts the number of requests
count int //counts the number of requests
quitC chan struct{}
}
@ -47,9 +47,9 @@ func newMockRequester(waitTimes ...time.Duration) *mockRequester {
func (m *mockRequester) doRequest(ctx context.Context, request *Request) (*enode.ID, chan struct{}, error) {
waitTime := time.Duration(0)
if m.ctr < len(m.waitTimes) {
waitTime = m.waitTimes[m.ctr]
m.ctr++
if m.count < len(m.waitTimes) {
waitTime = m.waitTimes[m.count]
m.count++
}
time.Sleep(waitTime)
m.requestC <- request
@ -83,7 +83,7 @@ func TestFetcherSingleRequest(t *testing.T) {
go fetcher.run(ctx, peersToSkip)
rctx := context.Background()
fetcher.Request(rctx)
fetcher.Request(rctx, 0)
select {
case request := <-requester.requestC:
@ -100,6 +100,11 @@ func TestFetcherSingleRequest(t *testing.T) {
t.Fatalf("request.peersToSkip does not contain peer returned by the request function")
}
// hopCount in the forwarded request should be incremented
if request.HopCount != 1 {
t.Fatalf("Expected request.HopCount 1 got %v", request.HopCount)
}
// fetch should trigger a request, if it doesn't happen in time, test should fail
case <-time.After(200 * time.Millisecond):
t.Fatalf("fetch timeout")
@ -123,7 +128,7 @@ func TestFetcherCancelStopsFetcher(t *testing.T) {
rctx, rcancel := context.WithTimeout(ctx, 100*time.Millisecond)
defer rcancel()
// we call Request with an active context
fetcher.Request(rctx)
fetcher.Request(rctx, 0)
// fetcher should not initiate request, we can only check by waiting a bit and making sure no request is happening
select {
@ -151,7 +156,7 @@ func TestFetcherCancelStopsRequest(t *testing.T) {
rcancel()
// we call Request with a cancelled context
fetcher.Request(rctx)
fetcher.Request(rctx, 0)
// fetcher should not initiate request, we can only check by waiting a bit and making sure no request is happening
select {
@ -162,7 +167,7 @@ func TestFetcherCancelStopsRequest(t *testing.T) {
// if there is another Request with active context, there should be a request, because the fetcher itself is not cancelled
rctx = context.Background()
fetcher.Request(rctx)
fetcher.Request(rctx, 0)
select {
case <-requester.requestC:
@ -200,7 +205,7 @@ func TestFetcherOfferUsesSource(t *testing.T) {
// call Request after the Offer
rctx = context.Background()
fetcher.Request(rctx)
fetcher.Request(rctx, 0)
// there should be exactly 1 request coming from fetcher
var request *Request
@ -241,7 +246,7 @@ func TestFetcherOfferAfterRequestUsesSourceFromContext(t *testing.T) {
// call Request first
rctx := context.Background()
fetcher.Request(rctx)
fetcher.Request(rctx, 0)
// there should be a request coming from fetcher
var request *Request
@ -296,7 +301,7 @@ func TestFetcherRetryOnTimeout(t *testing.T) {
// call the fetch function with an active context
rctx := context.Background()
fetcher.Request(rctx)
fetcher.Request(rctx, 0)
// after 100ms the first request should be initiated
time.Sleep(100 * time.Millisecond)
@ -338,7 +343,7 @@ func TestFetcherFactory(t *testing.T) {
fetcher := fetcherFactory.New(context.Background(), addr, peersToSkip)
fetcher.Request(context.Background())
fetcher.Request(context.Background(), 0)
// check if the created fetchFunction really starts a fetcher and initiates a request
select {
@ -368,7 +373,7 @@ func TestFetcherRequestQuitRetriesRequest(t *testing.T) {
go fetcher.run(ctx, peersToSkip)
rctx := context.Background()
fetcher.Request(rctx)
fetcher.Request(rctx, 0)
select {
case <-requester.requestC:
@ -457,3 +462,26 @@ func TestRequestSkipPeerPermanent(t *testing.T) {
t.Errorf("peer not skipped")
}
}
func TestFetcherMaxHopCount(t *testing.T) {
requester := newMockRequester()
addr := make([]byte, 32)
fetcher := NewFetcher(addr, requester.doRequest, true)
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
peersToSkip := &sync.Map{}
go fetcher.run(ctx, peersToSkip)
rctx := context.Background()
fetcher.Request(rctx, maxHopCount)
// if hopCount is already at max no request should be initiated
select {
case <-requester.requestC:
t.Fatalf("cancelled fetcher initiated request")
case <-time.After(200 * time.Millisecond):
}
}

6
swarm/network/stream/delivery.go
View File

@ -128,6 +128,7 @@ func (s *SwarmChunkServer) GetData(ctx context.Context, key []byte) ([]byte, err
type RetrieveRequestMsg struct {
Addr storage.Address
SkipCheck bool
HopCount uint8
}
func (d *Delivery) handleRetrieveRequestMsg(ctx context.Context, sp *Peer, req *RetrieveRequestMsg) error {
@ -148,7 +149,9 @@ func (d *Delivery) handleRetrieveRequestMsg(ctx context.Context, sp *Peer, req *
var cancel func()
// TODO: do something with this hardcoded timeout, maybe use TTL in the future
ctx, cancel = context.WithTimeout(context.WithValue(ctx, "peer", sp.ID().String()), network.RequestTimeout)
ctx = context.WithValue(ctx, "peer", sp.ID().String())
ctx = context.WithValue(ctx, "hopcount", req.HopCount)
ctx, cancel = context.WithTimeout(ctx, network.RequestTimeout)
go func() {
select {
@ -247,6 +250,7 @@ func (d *Delivery) RequestFromPeers(ctx context.Context, req *network.Request) (
err := sp.SendPriority(ctx, &RetrieveRequestMsg{
Addr: req.Addr,
SkipCheck: req.SkipCheck,
HopCount: req.HopCount,
}, Top)
if err != nil {
return nil, nil, err

2
swarm/network/stream/stream.go
View File

@ -639,7 +639,7 @@ func (c *clientParams) clientCreated() {
// Spec is the spec of the streamer protocol
var Spec = &protocols.Spec{
Name: "stream",
Version: 6,
Version: 7,
MaxMsgSize: 10 * 1024 * 1024,
Messages: []interface{}{
UnsubscribeMsg{},

2
swarm/storage/mru/testutil.go
View File

@ -40,7 +40,7 @@ func (t *TestHandler) Close() {
type mockNetFetcher struct{}
func (m *mockNetFetcher) Request(ctx context.Context) {
func (m *mockNetFetcher) Request(ctx context.Context, hopCount uint8) {
}
func (m *mockNetFetcher) Offer(ctx context.Context, source *enode.ID) {
}

7
swarm/storage/netstore.go
View File

@ -34,7 +34,7 @@ type (
)
type NetFetcher interface {
Request(ctx context.Context)
Request(ctx context.Context, hopCount uint8)
Offer(ctx context.Context, source *enode.ID)
}
@ -263,6 +263,9 @@ func (f *fetcher) Fetch(rctx context.Context) (Chunk, error) {
// If there is a source in the context then it is an offer, otherwise a request
sourceIF := rctx.Value("source")
hopCount, _ := rctx.Value("hopcount").(uint8)
if sourceIF != nil {
var source enode.ID
if err := source.UnmarshalText([]byte(sourceIF.(string))); err != nil {
@ -270,7 +273,7 @@ func (f *fetcher) Fetch(rctx context.Context) (Chunk, error) {
}
f.netFetcher.Offer(rctx, &source)
} else {
f.netFetcher.Request(rctx)
f.netFetcher.Request(rctx, hopCount)
}
// wait until either the chunk is delivered or the context is done

11
swarm/storage/netstore_test.go
View File

@ -40,6 +40,7 @@ type mockNetFetcher struct {
offerCalled bool
quit <-chan struct{}
ctx context.Context
hopCounts []uint8
}
func (m *mockNetFetcher) Offer(ctx context.Context, source *enode.ID) {
@ -47,7 +48,7 @@ func (m *mockNetFetcher) Offer(ctx context.Context, source *enode.ID) {
m.sources = append(m.sources, source)
}
func (m *mockNetFetcher) Request(ctx context.Context) {
func (m *mockNetFetcher) Request(ctx context.Context, hopCount uint8) {
m.requestCalled = true
var peers []Address
m.peers.Range(func(key interface{}, _ interface{}) bool {
@ -55,6 +56,7 @@ func (m *mockNetFetcher) Request(ctx context.Context) {
return true
})
m.peersPerRequest = append(m.peersPerRequest, peers)
m.hopCounts = append(m.hopCounts, hopCount)
}
type mockNetFetchFuncFactory struct {
@ -412,7 +414,8 @@ func TestNetStoreGetCallsRequest(t *testing.T) {
chunk := GenerateRandomChunk(ch.DefaultSize)
ctx, cancel := context.WithTimeout(context.Background(), 200*time.Millisecond)
ctx := context.WithValue(context.Background(), "hopcount", uint8(5))
ctx, cancel := context.WithTimeout(ctx, 200*time.Millisecond)
defer cancel()
// We call get for a not available chunk, it will timeout because the chunk is not delivered
@ -426,6 +429,10 @@ func TestNetStoreGetCallsRequest(t *testing.T) {
if !fetcher.requestCalled {
t.Fatal("Expected NetFetcher.Request to be called")
}
if fetcher.hopCounts[0] != 5 {
t.Fatalf("Expected NetFetcher.Request be called with hopCount 5, got %v", fetcher.hopCounts[0])
}
}
// TestNetStoreGetCallsOffer tests if Get created a request on the NetFetcher for an unavailable chunk