Golang context.Background函数代码示例

func TestClientOverMax(t *testing.T) {
	rs := NewServer()
	k := key.Key("hello")
	numProvidersForHelloKey := 100
	for i := 0; i < numProvidersForHelloKey; i++ {
		pi := testutil.RandIdentityOrFatal(t)
		err := rs.Client(pi).Provide(context.Background(), k)
		if err != nil {
			t.Fatal(err)
		}
	}

	max := 10
	pi := testutil.RandIdentityOrFatal(t)
	client := rs.Client(pi)

	providersFromClient := client.FindProvidersAsync(context.Background(), k, max)
	i := 0
	for _ = range providersFromClient {
		i++
	}
	if i != max {
		t.Fatal("Too many providers returned")
	}
}

func TestAddLink(t *testing.T) {
	ds := mdtest.Mock()
	fishnode := &dag.Node{
		Data: []byte("fishcakes!"),
	}

	fk, err := ds.Add(fishnode)
	if err != nil {
		t.Fatal(err)
	}

	nd := new(dag.Node)
	nnode, err := addLink(context.Background(), ds, nd, "fish", fishnode)
	if err != nil {
		t.Fatal(err)
	}

	fnprime, err := nnode.GetLinkedNode(context.Background(), ds, "fish")
	if err != nil {
		t.Fatal(err)
	}

	fnpkey, err := fnprime.Key()
	if err != nil {
		t.Fatal(err)
	}

	if fnpkey != fk {
		t.Fatal("wrong child node found!")
	}
}

func TestEnumerateChildren(t *testing.T) {
	bsi := bstest.Mocks(1)
	ds := NewDAGService(bsi[0])

	read := io.LimitReader(u.NewTimeSeededRand(), 1024*1024)
	root, err := imp.BuildDagFromReader(ds, chunk.NewSizeSplitter(read, 512))
	if err != nil {
		t.Fatal(err)
	}

	ks := key.NewKeySet()
	err = EnumerateChildren(context.Background(), ds, root, ks, false)
	if err != nil {
		t.Fatal(err)
	}

	var traverse func(n *Node)
	traverse = func(n *Node) {
		// traverse dag and check
		for _, lnk := range n.Links {
			k := key.Key(lnk.Hash)
			if !ks.Has(k) {
				t.Fatal("missing key in set!")
			}
			child, err := ds.Get(context.Background(), k)
			if err != nil {
				t.Fatal(err)
			}
			traverse(child)
		}
	}

	traverse(root)
}

func TestRoutingResolve(t *testing.T) {
	dstore := dssync.MutexWrap(ds.NewMapDatastore())
	serv := mockrouting.NewServer()
	id := testutil.RandIdentityOrFatal(t)
	d := serv.ClientWithDatastore(context.Background(), id, dstore)

	resolver := NewRoutingResolver(d, 0)
	publisher := NewRoutingPublisher(d, dstore)

	privk, pubk, err := testutil.RandTestKeyPair(512)
	if err != nil {
		t.Fatal(err)
	}

	h := path.FromString("/ipfs/QmZULkCELmmk5XNfCgTnCyFgAVxBRBXyDHGGMVoLFLiXEN")
	err = publisher.Publish(context.Background(), privk, h)
	if err != nil {
		t.Fatal(err)
	}

	pubkb, err := pubk.Bytes()
	if err != nil {
		t.Fatal(err)
	}

	pkhash := u.Hash(pubkb)
	res, err := resolver.Resolve(context.Background(), key.Key(pkhash).Pretty())
	if err != nil {
		t.Fatal(err)
	}

	if res != h {
		t.Fatal("Got back incorrect value.")
	}
}

func TestClientFindProviders(t *testing.T) {
	pi := testutil.RandIdentityOrFatal(t)
	rs := NewServer()
	client := rs.Client(pi)

	k := key.Key("hello")
	err := client.Provide(context.Background(), k)
	if err != nil {
		t.Fatal(err)
	}

	// This is bad... but simulating networks is hard
	time.Sleep(time.Millisecond * 300)
	max := 100

	providersFromClient := client.FindProvidersAsync(context.Background(), key.Key("hello"), max)
	isInClient := false
	for pi := range providersFromClient {
		if pi.ID == pi.ID {
			isInClient = true
		}
	}
	if !isInClient {
		t.Fatal("Despite client providing key, client didn't receive peer when finding providers")
	}
}

func TestLimitedStreams(t *testing.T) {
	mn, err := FullMeshConnected(context.Background(), 2)
	if err != nil {
		t.Fatal(err)
	}

	var wg sync.WaitGroup
	messages := 4
	messageSize := 500
	handler := func(s inet.Stream) {
		b := make([]byte, messageSize)
		for i := 0; i < messages; i++ {
			if _, err := io.ReadFull(s, b); err != nil {
				log.Fatal(err)
			}
			if !bytes.Equal(b[:4], []byte("ping")) {
				log.Fatal("bytes mismatch")
			}
			wg.Done()
		}
		s.Close()
	}

	hosts := mn.Hosts()
	for _, h := range mn.Hosts() {
		h.SetStreamHandler(protocol.TestingID, handler)
	}

	peers := mn.Peers()
	links := mn.LinksBetweenPeers(peers[0], peers[1])
	//  1000 byte per second bandwidth
	bps := float64(1000)
	opts := links[0].Options()
	opts.Bandwidth = bps
	for _, link := range links {
		link.SetOptions(opts)
	}

	ctx := context.Background()
	s, err := hosts[0].NewStream(ctx, protocol.TestingID, hosts[1].ID())
	if err != nil {
		t.Fatal(err)
	}

	filler := make([]byte, messageSize-4)
	data := append([]byte("ping"), filler...)
	before := time.Now()
	for i := 0; i < messages; i++ {
		wg.Add(1)
		if _, err := s.Write(data); err != nil {
			panic(err)
		}
	}

	wg.Wait()
	if !within(time.Since(before), time.Duration(time.Second*2), time.Second/3) {
		t.Fatal("Expected 2ish seconds but got ", time.Since(before))
	}
}

// TODO does dht ensure won't receive self as a provider? probably not.
func TestCanceledContext(t *testing.T) {
	rs := NewServer()
	k := key.Key("hello")

	// avoid leaking goroutine, without using the context to signal
	// (we want the goroutine to keep trying to publish on a
	// cancelled context until we've tested it doesnt do anything.)
	done := make(chan struct{})
	defer func() { done <- struct{}{} }()

	t.Log("async'ly announce infinite stream of providers for key")
	i := 0
	go func() { // infinite stream
		for {
			select {
			case <-done:
				t.Log("exiting async worker")
				return
			default:
			}

			pi, err := testutil.RandIdentity()
			if err != nil {
				t.Error(err)
			}
			err = rs.Client(pi).Provide(context.Background(), k)
			if err != nil {
				t.Error(err)
			}
			i++
		}
	}()

	local := testutil.RandIdentityOrFatal(t)
	client := rs.Client(local)

	t.Log("warning: max is finite so this test is non-deterministic")
	t.Log("context cancellation could simply take lower priority")
	t.Log("and result in receiving the max number of results")
	max := 1000

	t.Log("cancel the context before consuming")
	ctx, cancelFunc := context.WithCancel(context.Background())
	cancelFunc()
	providers := client.FindProvidersAsync(ctx, k, max)

	numProvidersReturned := 0
	for _ = range providers {
		numProvidersReturned++
	}
	t.Log(numProvidersReturned)

	if numProvidersReturned == max {
		t.Fatal("Context cancel had no effect")
	}
}

func TestDoubleGet(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)

	ctx1, cancel1 := context.WithCancel(context.Background())

	blkch1, err := instances[1].Exchange.GetBlocks(ctx1, []key.Key{blocks[0].Key()})
	if err != nil {
		t.Fatal(err)
	}

	ctx2, cancel2 := context.WithCancel(context.Background())
	defer cancel2()

	blkch2, err := instances[1].Exchange.GetBlocks(ctx2, []key.Key{blocks[0].Key()})
	if err != nil {
		t.Fatal(err)
	}

	// ensure both requests make it into the wantlist at the same time
	time.Sleep(time.Millisecond * 100)
	cancel1()

	_, ok := <-blkch1
	if ok {
		t.Fatal("expected channel to be closed")
	}

	err = instances[0].Exchange.HasBlock(blocks[0])
	if err != nil {
		t.Fatal(err)
	}

	blk, ok := <-blkch2
	if !ok {
		t.Fatal("expected to get the block here")
	}
	t.Log(blk)

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

func TestMultiWrite(t *testing.T) {
	dserv := getMockDagServ(t)
	_, n := getNode(t, dserv, 0)

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

	dagmod, err := NewDagModifier(ctx, n, dserv, sizeSplitterGen(512))
	if err != nil {
		t.Fatal(err)
	}

	data := make([]byte, 4000)
	u.NewTimeSeededRand().Read(data)

	for i := 0; i < len(data); i++ {
		n, err := dagmod.WriteAt(data[i:i+1], int64(i))
		if err != nil {
			t.Fatal(err)
		}
		if n != 1 {
			t.Fatal("Somehow wrote the wrong number of bytes! (n != 1)")
		}

		size, err := dagmod.Size()
		if err != nil {
			t.Fatal(err)
		}

		if size != int64(i+1) {
			t.Fatal("Size was reported incorrectly")
		}
	}
	nd, err := dagmod.GetNode()
	if err != nil {
		t.Fatal(err)
	}

	read, err := uio.NewDagReader(context.Background(), nd, dserv)
	if err != nil {
		t.Fatal(err)
	}
	rbuf, err := ioutil.ReadAll(read)
	if err != nil {
		t.Fatal(err)
	}

	err = arrComp(rbuf, data)
	if err != nil {
		t.Fatal(err)
	}
}

func testInsert(t *testing.T, e *Editor, path, data string, create bool, experr string) {
	child := &dag.Node{Data: []byte(data)}
	ck, err := e.tmp.Add(child)
	if err != nil {
		t.Fatal(err)
	}

	var c func() *dag.Node
	if create {
		c = func() *dag.Node {
			return &dag.Node{}
		}
	}

	err = e.InsertNodeAtPath(context.Background(), path, child, c)
	if experr != "" {
		var got string
		if err != nil {
			got = err.Error()
		}
		if got != experr {
			t.Fatalf("expected '%s' but got '%s'", experr, got)
		}
		return
	}

	if err != nil {
		t.Fatal(err, path, data, create, experr)
	}

	assertNodeAtPath(t, e.tmp, e.root, path, ck)
}

func RunSupernodePutRecordGetRecord(conf testutil.LatencyConfig) error {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	servers, clients, err := InitializeSupernodeNetwork(ctx, 2, 2, conf)
	if err != nil {
		return err
	}
	for _, n := range append(servers, clients...) {
		defer n.Close()
	}

	putter := clients[0]
	getter := clients[1]

	k := key.Key("key")
	note := []byte("a note from putter")

	if err := putter.Routing.PutValue(ctx, k, note); err != nil {
		return fmt.Errorf("failed to put value: %s", err)
	}

	received, err := getter.Routing.GetValue(ctx, k)
	if err != nil {
		return fmt.Errorf("failed to get value: %s", err)
	}

	if 0 != bytes.Compare(note, received) {
		return errors.New("record doesn't match")
	}
	cancel()
	return nil
}

func TestSeekingConsistency(t *testing.T) {
	nbytes := int64(128 * 1024)
	ds := mdtest.Mock()
	nd, should := getTestDag(t, ds, nbytes, 500)

	rs, err := uio.NewDagReader(context.Background(), nd, ds)
	if err != nil {
		t.Fatal(err)
	}

	out := make([]byte, nbytes)

	for coff := nbytes - 4096; coff >= 0; coff -= 4096 {
		t.Log(coff)
		n, err := rs.Seek(coff, os.SEEK_SET)
		if err != nil {
			t.Fatal(err)
		}
		if n != coff {
			t.Fatal("wasnt able to seek to the right position")
		}
		nread, err := rs.Read(out[coff : coff+4096])
		if err != nil {
			t.Fatal(err)
		}
		if nread != 4096 {
			t.Fatal("didnt read the correct number of bytes")
		}
	}

	err = arrComp(out, should)
	if err != nil {
		t.Fatal(err)
	}
}

func TestSeekToAlmostBegin(t *testing.T) {
	ds := mdtest.Mock()
	nd, should := getTestDag(t, ds, 10*1024, 500)

	rs, err := uio.NewDagReader(context.Background(), nd, ds)
	if err != nil {
		t.Fatal(err)
	}

	n, err := io.CopyN(ioutil.Discard, rs, 1024*4)
	if err != nil {
		t.Fatal(err)
	}
	if n != 4096 {
		t.Fatal("Copy didnt copy enough bytes")
	}

	seeked, err := rs.Seek(1, os.SEEK_SET)
	if err != nil {
		t.Fatal(err)
	}
	if seeked != 1 {
		t.Fatal("Failed to seek to almost beginning")
	}

	dagrArrComp(t, rs, should[1:])
}

func TestGetBlocksSequential(t *testing.T) {
	var servs = Mocks(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, cancel := context.WithTimeout(context.Background(), time.Second*50)
		defer cancel()
		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))
		}
	}
}

func TestBuilderConsistency(t *testing.T) {
	nbytes := 100000
	buf := new(bytes.Buffer)
	io.CopyN(buf, u.NewTimeSeededRand(), int64(nbytes))
	should := dup(buf.Bytes())
	dagserv := mdtest.Mock()
	nd, err := buildTestDag(dagserv, chunk.DefaultSplitter(buf))
	if err != nil {
		t.Fatal(err)
	}
	r, err := uio.NewDagReader(context.Background(), nd, dagserv)
	if err != nil {
		t.Fatal(err)
	}

	out, err := ioutil.ReadAll(r)
	if err != nil {
		t.Fatal(err)
	}

	err = arrComp(out, should)
	if err != nil {
		t.Fatal(err)
	}
}