path: root/swarm/network/fetcher_test.go

// Copyright 2018 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 network

import (
    "context"
    "sync"
    "testing"
    "time"

    "github.com/ethereum/go-ethereum/p2p/enode"
)

var requestedPeerID = enode.HexID("3431c3939e1ee2a6345e976a8234f9870152d64879f30bc272a074f6859e75e8")
var sourcePeerID = enode.HexID("99d8594b52298567d2ca3f4c441a5ba0140ee9245e26460d01102a52773c73b9")

// mockRequester pushes every request to the requestC channel when its doRequest function is called
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)
    count     int             //counts the number of requests
    quitC     chan struct{}
}

func newMockRequester(waitTimes ...time.Duration) *mockRequester {
    return &mockRequester{
        requestC:  make(chan *Request),
        waitTimes: waitTimes,
        quitC:     make(chan struct{}),
    }
}

func (m *mockRequester) doRequest(ctx context.Context, request *Request) (*enode.ID, chan struct{}, error) {
    waitTime := time.Duration(0)
    if m.count < len(m.waitTimes) {
        waitTime = m.waitTimes[m.count]
        m.count++
    }
    time.Sleep(waitTime)
    m.requestC <- request

    // if there is a Source in the request use that, if not use the global requestedPeerId
    source := request.Source
    if source == nil {
        source = &requestedPeerID
    }
    return source, m.quitC, nil
}

// TestFetcherSingleRequest creates a Fetcher using mockRequester, and run it with a sample set of peers to skip.
// mockRequester pushes a Request on a channel every time the request function is called. Using
// this channel we test if calling Fetcher.Request calls the request function, and whether it uses
// the correct peers to skip which we provided for the fetcher.run function.
func TestFetcherSingleRequest(t *testing.T) {
    requester := newMockRequester()
    addr := make([]byte, 32)

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()

    fetcher := NewFetcher(ctx, addr, requester.doRequest, true)

    peers := []string{"a", "b", "c", "d"}
    peersToSkip := &sync.Map{}
    for _, p := range peers {
        peersToSkip.Store(p, time.Now())
    }

    go fetcher.run(peersToSkip)

    fetcher.Request(0)

    select {
    case request := <-requester.requestC:
        // request should contain all peers from peersToSkip provided to the fetcher
        for _, p := range peers {
            if _, ok := request.peersToSkip.Load(p); !ok {
                t.Fatalf("request.peersToSkip misses peer")
            }
        }

        // source peer should be also added to peersToSkip eventually
        time.Sleep(100 * time.Millisecond)
        if _, ok := request.peersToSkip.Load(requestedPeerID.String()); !ok {
            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")
    }
}

// TestCancelStopsFetcher tests that a cancelled fetcher does not initiate further requests even if its fetch function is called
func TestFetcherCancelStopsFetcher(t *testing.T) {
    requester := newMockRequester()
    addr := make([]byte, 32)

    ctx, cancel := context.WithCancel(context.Background())

    fetcher := NewFetcher(ctx, addr, requester.doRequest, true)

    peersToSkip := &sync.Map{}

    // we start the fetcher, and then we immediately cancel the context
    go fetcher.run(peersToSkip)
    cancel()

    // we call Request with an active context
    fetcher.Request(0)

    // fetcher should not initiate request, we can only check by waiting a bit and making sure no request is happening
    select {
    case <-requester.requestC:
        t.Fatalf("cancelled fetcher initiated request")
    case <-time.After(200 * time.Millisecond):
    }
}

// TestFetchCancelStopsRequest tests that calling a Request function with a cancelled context does not initiate a request
func TestFetcherCancelStopsRequest(t *testing.T) {
    t.Skip("since context is now per fetcher, this test is likely redundant")

    requester := newMockRequester(100 * time.Millisecond)
    addr := make([]byte, 32)

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()

    fetcher := NewFetcher(ctx, addr, requester.doRequest, true)

    peersToSkip := &sync.Map{}

    // we start the fetcher with an active context
    go fetcher.run(peersToSkip)

    // we call Request with a cancelled context
    fetcher.Request(0)

    // fetcher should not initiate request, we can only check by waiting a bit and making sure no request is happening
    select {
    case <-requester.requestC:
        t.Fatalf("cancelled fetch function initiated request")
    case <-time.After(200 * time.Millisecond):
    }

    // if there is another Request with active context, there should be a request, because the fetcher itself is not cancelled
    fetcher.Request(0)

    select {
    case <-requester.requestC:
    case <-time.After(200 * time.Millisecond):
        t.Fatalf("expected request")
    }
}

// TestOfferUsesSource tests Fetcher Offer behavior.
// In this case there should be 1 (and only one) request initiated from the source peer, and the
// source nodeid should appear in the peersToSkip map.
func TestFetcherOfferUsesSource(t *testing.T) {
    requester := newMockRequester(100 * time.Millisecond)
    addr := make([]byte, 32)

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()

    fetcher := NewFetcher(ctx, addr, requester.doRequest, true)

    peersToSkip := &sync.Map{}

    // start the fetcher
    go fetcher.run(peersToSkip)

    // call the Offer function with the source peer
    fetcher.Offer(&sourcePeerID)

    // fetcher should not initiate request
    select {
    case <-requester.requestC:
        t.Fatalf("fetcher initiated request")
    case <-time.After(200 * time.Millisecond):
    }

    // call Request after the Offer
    fetcher.Request(0)

    // there should be exactly 1 request coming from fetcher
    var request *Request
    select {
    case request = <-requester.requestC:
        if *request.Source != sourcePeerID {
            t.Fatalf("Expected source id %v got %v", sourcePeerID, request.Source)
        }
    case <-time.After(200 * time.Millisecond):
        t.Fatalf("fetcher did not initiate request")
    }

    select {
    case <-requester.requestC:
        t.Fatalf("Fetcher number of requests expected 1 got 2")
    case <-time.After(200 * time.Millisecond):
    }

    // source peer should be added to peersToSkip eventually
    time.Sleep(100 * time.Millisecond)
    if _, ok := request.peersToSkip.Load(sourcePeerID.String()); !ok {
        t.Fatalf("SourcePeerId not added to peersToSkip")
    }
}

func TestFetcherOfferAfterRequestUsesSourceFromContext(t *testing.T) {
    requester := newMockRequester(100 * time.Millisecond)
    addr := make([]byte, 32)

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()

    fetcher := NewFetcher(ctx, addr, requester.doRequest, true)

    peersToSkip := &sync.Map{}

    // start the fetcher
    go fetcher.run(peersToSkip)

    // call Request first
    fetcher.Request(0)

    // there should be a request coming from fetcher
    var request *Request
    select {
    case request = <-requester.requestC:
        if request.Source != nil {
            t.Fatalf("Incorrect source peer id, expected nil got %v", request.Source)
        }
    case <-time.After(200 * time.Millisecond):
        t.Fatalf("fetcher did not initiate request")
    }

    // after the Request call Offer
    fetcher.Offer(&sourcePeerID)

    // there should be a request coming from fetcher
    select {
    case request = <-requester.requestC:
        if *request.Source != sourcePeerID {
            t.Fatalf("Incorrect source peer id, expected %v got %v", sourcePeerID, request.Source)
        }
    case <-time.After(200 * time.Millisecond):
        t.Fatalf("fetcher did not initiate request")
    }

    // source peer should be added to peersToSkip eventually
    time.Sleep(100 * time.Millisecond)
    if _, ok := request.peersToSkip.Load(sourcePeerID.String()); !ok {
        t.Fatalf("SourcePeerId not added to peersToSkip")
    }
}

// TestFetcherRetryOnTimeout tests that fetch retries after searchTimeOut has passed
func TestFetcherRetryOnTimeout(t *testing.T) {
    requester := newMockRequester()
    addr := make([]byte, 32)

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()

    fetcher := NewFetcher(ctx, addr, requester.doRequest, true)
    // set searchTimeOut to low value so the test is quicker
    fetcher.searchTimeout = 250 * time.Millisecond

    peersToSkip := &sync.Map{}

    // start the fetcher
    go fetcher.run(peersToSkip)

    // call the fetch function with an active context
    fetcher.Request(0)

    // after 100ms the first request should be initiated
    time.Sleep(100 * time.Millisecond)

    select {
    case <-requester.requestC:
    default:
        t.Fatalf("fetch did not initiate request")
    }

    // after another 100ms no new request should be initiated, because search timeout is 250ms
    time.Sleep(100 * time.Millisecond)

    select {
    case <-requester.requestC:
        t.Fatalf("unexpected request from fetcher")
    default:
    }

    // after another 300ms search timeout is over, there should be a new request
    time.Sleep(300 * time.Millisecond)

    select {
    case <-requester.requestC:
    default:
        t.Fatalf("fetch did not retry request")
    }
}

// TestFetcherFactory creates a FetcherFactory and checks if the factory really creates and starts
// a Fetcher when it return a fetch function. We test the fetching functionality just by checking if
// a request is initiated when the fetch function is called
func TestFetcherFactory(t *testing.T) {
    requester := newMockRequester(100 * time.Millisecond)
    addr := make([]byte, 32)
    fetcherFactory := NewFetcherFactory(requester.doRequest, false)

    peersToSkip := &sync.Map{}

    fetcher := fetcherFactory.New(context.Background(), addr, peersToSkip)

    fetcher.Request(0)

    // check if the created fetchFunction really starts a fetcher and initiates a request
    select {
    case <-requester.requestC:
    case <-time.After(200 * time.Millisecond):
        t.Fatalf("fetch timeout")
    }

}

func TestFetcherRequestQuitRetriesRequest(t *testing.T) {
    requester := newMockRequester()
    addr := make([]byte, 32)

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()

    fetcher := NewFetcher(ctx, addr, requester.doRequest, true)

    // make sure the searchTimeout is long so it is sure the request is not
    // retried because of timeout
    fetcher.searchTimeout = 10 * time.Second

    peersToSkip := &sync.Map{}

    go fetcher.run(peersToSkip)

    fetcher.Request(0)

    select {
    case <-requester.requestC:
    case <-time.After(200 * time.Millisecond):
        t.Fatalf("request is not initiated")
    }

    close(requester.quitC)

    select {
    case <-requester.requestC:
    case <-time.After(200 * time.Millisecond):
        t.Fatalf("request is not initiated after failed request")
    }
}

// TestRequestSkipPeer checks if PeerSkip function will skip provided peer
// and not skip unknown one.
func TestRequestSkipPeer(t *testing.T) {
    addr := make([]byte, 32)
    peers := []enode.ID{
        enode.HexID("3431c3939e1ee2a6345e976a8234f9870152d64879f30bc272a074f6859e75e8"),
        enode.HexID("99d8594b52298567d2ca3f4c441a5ba0140ee9245e26460d01102a52773c73b9"),
    }

    peersToSkip := new(sync.Map)
    peersToSkip.Store(peers[0].String(), time.Now())
    r := NewRequest(addr, false, peersToSkip)

    if !r.SkipPeer(peers[0].String()) {
        t.Errorf("peer not skipped")
    }

    if r.SkipPeer(peers[1].String()) {
        t.Errorf("peer skipped")
    }
}

// TestRequestSkipPeerExpired checks if a peer to skip is not skipped
// after RequestTimeout has passed.
func TestRequestSkipPeerExpired(t *testing.T) {
    addr := make([]byte, 32)
    peer := enode.HexID("3431c3939e1ee2a6345e976a8234f9870152d64879f30bc272a074f6859e75e8")

    // set RequestTimeout to a low value and reset it after the test
    defer func(t time.Duration) { RequestTimeout = t }(RequestTimeout)
    RequestTimeout = 250 * time.Millisecond

    peersToSkip := new(sync.Map)
    peersToSkip.Store(peer.String(), time.Now())
    r := NewRequest(addr, false, peersToSkip)

    if !r.SkipPeer(peer.String()) {
        t.Errorf("peer not skipped")
    }

    time.Sleep(500 * time.Millisecond)

    if r.SkipPeer(peer.String()) {
        t.Errorf("peer skipped")
    }
}

// TestRequestSkipPeerPermanent checks if a peer to skip is not skipped
// after RequestTimeout is not skipped if it is set for a permanent skipping
// by value to peersToSkip map is not time.Duration.
func TestRequestSkipPeerPermanent(t *testing.T) {
    addr := make([]byte, 32)
    peer := enode.HexID("3431c3939e1ee2a6345e976a8234f9870152d64879f30bc272a074f6859e75e8")

    // set RequestTimeout to a low value and reset it after the test
    defer func(t time.Duration) { RequestTimeout = t }(RequestTimeout)
    RequestTimeout = 250 * time.Millisecond

    peersToSkip := new(sync.Map)
    peersToSkip.Store(peer.String(), true)
    r := NewRequest(addr, false, peersToSkip)

    if !r.SkipPeer(peer.String()) {
        t.Errorf("peer not skipped")
    }

    time.Sleep(500 * time.Millisecond)

    if !r.SkipPeer(peer.String()) {
        t.Errorf("peer not skipped")
    }
}

func TestFetcherMaxHopCount(t *testing.T) {
    requester := newMockRequester()
    addr := make([]byte, 32)

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()

    fetcher := NewFetcher(ctx, addr, requester.doRequest, true)

    peersToSkip := &sync.Map{}

    go fetcher.run(peersToSkip)

    // 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):
    }
}