Golang context.WithTimeout函数代码示例

func (mq *msgQueue) doWork(ctx context.Context) {
	// allow ten minutes for connections
	// this includes looking them up in the dht
	// dialing them, and handshaking
	conctx, cancel := context.WithTimeout(ctx, time.Minute*10)
	defer cancel()

	err := mq.network.ConnectTo(conctx, mq.p)
	if err != nil {
		log.Infof("cant connect to peer %s: %s", mq.p, err)
		// TODO: cant connect, what now?
		return
	}

	// grab outgoing message
	mq.outlk.Lock()
	wlm := mq.out
	if wlm == nil || wlm.Empty() {
		mq.outlk.Unlock()
		return
	}
	mq.out = nil
	mq.outlk.Unlock()

	sendctx, cancel := context.WithTimeout(ctx, time.Minute*5)
	defer cancel()

	// send wantlist updates
	err = mq.network.SendMessage(sendctx, mq.p, wlm)
	if err != nil {
		log.Infof("bitswap send error: %s", err)
		// TODO: what do we do if this fails?
		return
	}
}

func getFileCmd(nodes []int, file string) error {
	file = normalizePath(file)
	blocks, ok := files[file]
	if !ok {
		return fmt.Errorf("Tried to get file, '%s', which has not been added.\n", file)
	}
	var wg sync.WaitGroup
	//  Get blocks and then Has them
	for _, node := range nodes {
		//  remove blocks peer already has or nah?
		//  I'm assuming that peers with the first block of the file have the whole file,
		//  which i think is ok for the simulation, but i might have to change this later
		alreadyhas, err := peers[node].Blockstore().Has(files[file][0])
		check(err)

		if alreadyhas {
			continue
		}
		wg.Add(1)
		go func(i int) {
			timer := recorder.NewTimer()
			ctx, cancel := context.WithTimeout(context.Background(), deadline)
			defer cancel()
			received, _ := peers[i].Exchange.GetBlocks(ctx, blocks)

			for j := 0; j < len(blocks); j++ {
				blockTimer := recorder.NewTimer()
				x := <-received
				if x == nil {
					wg.Done()
					return
				}
				recorder.EndBlockTime(blockTimer, peers[i].Peer.Pretty())
				fmt.Println(i, x, j)
				ctx, cancel := context.WithTimeout(context.Background(), time.Second)
				err := peers[i].Exchange.HasBlock(ctx, x)
				if err != nil {
					fmt.Println("error when adding block", i, err)
				}
				cancel()
			}
			recorder.EndFileTime(timer, peers[i].Peer.Pretty(), file)

			//	peers[i].Exchange.Close()
			wg.Done()
		}(node)
	}

	wg.Wait()
	testGet(nodes, file)
	return nil
}

// TODO simplify this test. get to the _essence_!
func TestSendToWantingPeer(t *testing.T) {
	if testing.Short() {
		t.SkipNow()
	}

	net := tn.VirtualNetwork(mockrouting.NewServer(), delay.Fixed(kNetworkDelay))
	sg := NewTestSessionGenerator(net)
	defer sg.Close()
	bg := blocksutil.NewBlockGenerator()

	prev := rebroadcastDelay.Set(time.Second / 2)
	defer func() { rebroadcastDelay.Set(prev) }()

	peers := sg.Instances(2)
	peerA := peers[0]
	peerB := peers[1]

	t.Logf("Session %v\n", peerA.Peer)
	t.Logf("Session %v\n", peerB.Peer)

	timeout := time.Second
	waitTime := time.Second * 5

	alpha := bg.Next()
	// peerA requests and waits for block alpha
	ctx, _ := context.WithTimeout(context.TODO(), waitTime)
	alphaPromise, err := peerA.Exchange.GetBlocks(ctx, []key.Key{alpha.Key()})
	if err != nil {
		t.Fatal(err)
	}

	// peerB announces to the network that he has block alpha
	ctx, _ = context.WithTimeout(context.TODO(), timeout)
	err = peerB.Exchange.HasBlock(ctx, alpha)
	if err != nil {
		t.Fatal(err)
	}

	// At some point, peerA should get alpha (or timeout)
	blkrecvd, ok := <-alphaPromise
	if !ok {
		t.Fatal("context timed out and broke promise channel!")
	}

	if blkrecvd.Key() != alpha.Key() {
		t.Fatal("Wrong block!")
	}

}

func TestDeadlineFractionCancel(t *testing.T) {

	ctx1, cancel1 := context.WithTimeout(context.Background(), 10*time.Millisecond)
	ctx2, cancel2 := WithDeadlineFraction(ctx1, 0.5)

	select {
	case <-ctx1.Done():
		t.Fatal("ctx1 ended too early")
	case <-ctx2.Done():
		t.Fatal("ctx2 ended too early")
	default:
	}

	cancel2()

	select {
	case <-ctx1.Done():
		t.Fatal("ctx1 should NOT be cancelled")
	case <-ctx2.Done():
	default:
		t.Fatal("ctx2 should be cancelled")
	}

	cancel1()

	select {
	case <-ctx1.Done():
	case <-ctx2.Done():
	default:
		t.Fatal("ctx1 should be cancelled")
	}

}

// connects to providers for the given keys
func (bs *Bitswap) providerConnector(parent context.Context) {
	defer log.Info("bitswap client worker shutting down...")

	for {
		log.Event(parent, "Bitswap.ProviderConnector.Loop")
		select {
		case req := <-bs.findKeys:
			keys := req.keys
			if len(keys) == 0 {
				log.Warning("Received batch request for zero blocks")
				continue
			}
			log.Event(parent, "Bitswap.ProviderConnector.Work", eventlog.LoggableMap{"Keys": keys})

			// NB: Optimization. Assumes that providers of key[0] are likely to
			// be able to provide for all keys. This currently holds true in most
			// every situation. Later, this assumption may not hold as true.
			child, cancel := context.WithTimeout(req.ctx, providerRequestTimeout)
			providers := bs.network.FindProvidersAsync(child, keys[0], maxProvidersPerRequest)
			for p := range providers {
				go bs.network.ConnectTo(req.ctx, p)
			}
			cancel()

		case <-parent.Done():
			return
		}
	}
}

func TestFindPeer(t *testing.T) {
	// t.Skip("skipping test to debug another")
	if testing.Short() {
		t.SkipNow()
	}

	ctx := context.Background()

	_, peers, dhts := setupDHTS(ctx, 4, t)
	defer func() {
		for i := 0; i < 4; i++ {
			dhts[i].Close()
			dhts[i].host.Close()
		}
	}()

	connect(t, ctx, dhts[0], dhts[1])
	connect(t, ctx, dhts[1], dhts[2])
	connect(t, ctx, dhts[1], dhts[3])

	ctxT, _ := context.WithTimeout(ctx, time.Second)
	p, err := dhts[0].FindPeer(ctxT, peers[2])
	if err != nil {
		t.Fatal(err)
	}

	if p.ID == "" {
		t.Fatal("Failed to find peer.")
	}

	if p.ID != peers[2] {
		t.Fatal("Didnt find expected peer.")
	}
}

func TestGetBlocksSequential(t *testing.T) {
	var servs = Mocks(t, 4)
	for _, s := range servs {
		defer s.Close()
	}
	bg := blocksutil.NewBlockGenerator()
	blks := bg.Blocks(50)

	var keys []key.Key
	for _, blk := range blks {
		keys = append(keys, blk.Key())
		servs[0].AddBlock(blk)
	}

	t.Log("one instance at a time, get blocks concurrently")

	for i := 1; i < len(servs); i++ {
		ctx, _ := context.WithTimeout(context.TODO(), time.Second*50)
		out := servs[i].GetBlocks(ctx, keys)
		gotten := make(map[key.Key]*blocks.Block)
		for blk := range out {
			if _, ok := gotten[blk.Key()]; ok {
				t.Fatal("Got duplicate block!")
			}
			gotten[blk.Key()] = blk
		}
		if len(gotten) != len(blks) {
			t.Fatalf("Didnt get enough blocks back: %d/%d", len(gotten), len(blks))
		}
	}
}

// getNode returns the node for link. If it return an error,
// stop processing. if it returns a nil node, just skip it.
//
// the error handling is a little complicated.
func (t *traversal) getNode(link *mdag.Link) (*mdag.Node, error) {

	getNode := func(l *mdag.Link) (*mdag.Node, error) {
		ctx, cancel := context.WithTimeout(context.TODO(), time.Minute)
		defer cancel()

		next, err := l.GetNode(ctx, t.opts.DAG)
		if err != nil {
			return nil, err
		}

		skip, err := t.shouldSkip(next)
		if skip {
			next = nil
		}
		return next, err
	}

	next, err := getNode(link)
	if err != nil && t.opts.ErrFunc != nil { // attempt recovery.
		err = t.opts.ErrFunc(err)
		next = nil // skip regardless
	}
	return next, err
}

func TestBasicBitswap(t *testing.T) {
	net := tn.VirtualNetwork(mockrouting.NewServer(), delay.Fixed(kNetworkDelay))
	sg := NewTestSessionGenerator(net)
	defer sg.Close()
	bg := blocksutil.NewBlockGenerator()

	t.Log("Test a one node trying to get one block from another")

	instances := sg.Instances(2)
	blocks := bg.Blocks(1)
	err := instances[0].Exchange.HasBlock(context.TODO(), blocks[0])
	if err != nil {
		t.Fatal(err)
	}

	ctx, _ := context.WithTimeout(context.TODO(), time.Second*5)
	blk, err := instances[1].Exchange.GetBlock(ctx, blocks[0].Key())
	if err != nil {
		t.Fatal(err)
	}

	t.Log(blk)
	for _, inst := range instances {
		err := inst.Exchange.Close()
		if err != nil {
			t.Fatal(err)
		}
	}
}

func (bs *Bitswap) connectToProviders(ctx context.Context, entries []wantlist.Entry) {

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

	// Get providers for all entries in wantlist (could take a while)
	wg := sync.WaitGroup{}
	for _, e := range entries {
		wg.Add(1)
		go func(k key.Key) {
			defer wg.Done()

			child, cancel := context.WithTimeout(ctx, providerRequestTimeout)
			defer cancel()
			providers := bs.network.FindProvidersAsync(child, k, maxProvidersPerRequest)
			for prov := range providers {
				go func(p peer.ID) {
					bs.network.ConnectTo(ctx, p)
				}(prov)
			}
		}(e.Key)
	}

	wg.Wait() // make sure all our children do finish.
}

func TestGetBlockFromPeerAfterPeerAnnounces(t *testing.T) {

	net := tn.VirtualNetwork(mockrouting.NewServer(), delay.Fixed(kNetworkDelay))
	block := blocks.NewBlock([]byte("block"))
	g := NewTestSessionGenerator(net)
	defer g.Close()

	peers := g.Instances(2)
	hasBlock := peers[0]
	defer hasBlock.Exchange.Close()

	if err := hasBlock.Exchange.HasBlock(context.Background(), block); err != nil {
		t.Fatal(err)
	}

	wantsBlock := peers[1]
	defer wantsBlock.Exchange.Close()

	ctx, _ := context.WithTimeout(context.Background(), time.Second)
	received, err := wantsBlock.Exchange.GetBlock(ctx, block.Key())
	if err != nil {
		t.Log(err)
		t.Fatal("Expected to succeed")
	}

	if !bytes.Equal(block.Data, received.Data) {
		t.Fatal("Data doesn't match")
	}
}

func TestValueGetSet(t *testing.T) {
	// t.Skip("skipping test to debug another")

	ctx := context.Background()

	dhtA := setupDHT(ctx, t)
	dhtB := setupDHT(ctx, t)

	defer dhtA.Close()
	defer dhtB.Close()
	defer dhtA.host.Close()
	defer dhtB.host.Close()

	vf := &record.ValidChecker{
		Func: func(key.Key, []byte) error {
			return nil
		},
		Sign: false,
	}
	dhtA.Validator["v"] = vf
	dhtB.Validator["v"] = vf

	connect(t, ctx, dhtA, dhtB)

	ctxT, _ := context.WithTimeout(ctx, time.Second)
	dhtA.PutValue(ctxT, "/v/hello", []byte("world"))

	ctxT, _ = context.WithTimeout(ctx, time.Second*2)
	val, err := dhtA.GetValue(ctxT, "/v/hello")
	if err != nil {
		t.Fatal(err)
	}

	if string(val) != "world" {
		t.Fatalf("Expected 'world' got '%s'", string(val))
	}

	ctxT, _ = context.WithTimeout(ctx, time.Second*2)
	val, err = dhtB.GetValue(ctxT, "/v/hello")
	if err != nil {
		t.Fatal(err)
	}

	if string(val) != "world" {
		t.Fatalf("Expected 'world' got '%s'", string(val))
	}
}

// gatedDialAttempt is an attempt to dial a node. It is gated by the swarm's
// dial synchronization systems: dialsync and dialbackoff.
func (s *Swarm) gatedDialAttempt(ctx context.Context, p peer.ID) (*Conn, error) {
	var logdial = lgbl.Dial("swarm", s.LocalPeer(), p, nil, nil)
	defer log.EventBegin(ctx, "swarmDialAttemptSync", logdial).Done()

	// check if we already have an open connection first
	conn := s.bestConnectionToPeer(p)
	if conn != nil {
		return conn, nil
	}

	// check if there's an ongoing dial to this peer
	if ok, wait := s.dsync.Lock(p); ok {
		// ok, we have been charged to dial! let's do it.
		// if it succeeds, dial will add the conn to the swarm itself.

		defer log.EventBegin(ctx, "swarmDialAttemptStart", logdial).Done()
		ctxT, cancel := context.WithTimeout(ctx, s.dialT)
		conn, err := s.dial(ctxT, p)
		cancel()
		s.dsync.Unlock(p)
		log.Debugf("dial end %s", conn)
		if err != nil {
			log.Event(ctx, "swarmDialBackoffAdd", logdial)
			s.backf.AddBackoff(p) // let others know to backoff

			// ok, we failed. try again. (if loop is done, our error is output)
			return nil, fmt.Errorf("dial attempt failed: %s", err)
		}
		log.Event(ctx, "swarmDialBackoffClear", logdial)
		s.backf.Clear(p) // okay, no longer need to backoff
		return conn, nil

	} else {
		// we did not dial. we must wait for someone else to dial.

		// check whether we should backoff first...
		if s.backf.Backoff(p) {
			log.Event(ctx, "swarmDialBackoff", logdial)
			return nil, ErrDialBackoff
		}

		defer log.EventBegin(ctx, "swarmDialWait", logdial).Done()
		select {
		case <-wait: // wait for that other dial to finish.

			// see if it worked, OR we got an incoming dial in the meantime...
			conn := s.bestConnectionToPeer(p)
			if conn != nil {
				return conn, nil
			}
			return nil, ErrDialFailed
		case <-ctx.Done(): // or we may have to bail...
			return nil, ctx.Err()
		}
	}
}

func TestCarryOnWhenDeadlineExpires(t *testing.T) {

	impossibleDeadline := time.Nanosecond
	fastExpiringCtx, _ := context.WithTimeout(context.Background(), impossibleDeadline)

	n := New()
	defer n.Shutdown()
	block := blocks.NewBlock([]byte("A Missed Connection"))
	blockChannel := n.Subscribe(fastExpiringCtx, block.Key())

	assertBlockChannelNil(t, blockChannel)
}

func TestFindPeersConnectedToPeer(t *testing.T) {
	t.Skip("not quite correct (see note)")

	if testing.Short() {
		t.SkipNow()
	}

	ctx := context.Background()

	_, peers, dhts := setupDHTS(ctx, 4, t)
	defer func() {
		for i := 0; i < 4; i++ {
			dhts[i].Close()
			dhts[i].host.Close()
		}
	}()

	// topology:
	// 0-1, 1-2, 1-3, 2-3
	connect(t, ctx, dhts[0], dhts[1])
	connect(t, ctx, dhts[1], dhts[2])
	connect(t, ctx, dhts[1], dhts[3])
	connect(t, ctx, dhts[2], dhts[3])

	// fmt.Println("0 is", peers[0])
	// fmt.Println("1 is", peers[1])
	// fmt.Println("2 is", peers[2])
	// fmt.Println("3 is", peers[3])

	ctxT, _ := context.WithTimeout(ctx, time.Second)
	pchan, err := dhts[0].FindPeersConnectedToPeer(ctxT, peers[2])
	if err != nil {
		t.Fatal(err)
	}

	// shouldFind := []peer.ID{peers[1], peers[3]}
	found := []peer.PeerInfo{}
	for nextp := range pchan {
		found = append(found, nextp)
	}

	// fmt.Printf("querying 0 (%s) FindPeersConnectedToPeer 2 (%s)\n", peers[0], peers[2])
	// fmt.Println("should find 1, 3", shouldFind)
	// fmt.Println("found", found)

	// testPeerListsMatch(t, shouldFind, found)

	log.Warning("TestFindPeersConnectedToPeer is not quite correct")
	if len(found) == 0 {
		t.Fatal("didn't find any peers.")
	}
}