Introduce functional option for enabling/disabling provide

bitswap.go

@@ -42,10 +42,6 @@ const (
 )
 
 var (
-	// ProvideEnabled is a variable that tells Bitswap whether or not
-	// to handle providing blocks (see experimental provider system)
-	ProvideEnabled = true
-
 	// HasBlockBufferSize is the buffer size of the channel for new blocks
 	// that need to be provided. They should get pulled over by the
 	// provideCollector even before they are actually provided.
@@ -58,11 +54,22 @@ var (
 	metricsBuckets = []float64{1 << 6, 1 << 10, 1 << 14, 1 << 18, 1<<18 + 15, 1 << 22}
 )
 
+// Option defines the functional option type that can be used to configure
+// bitswap instances
+type Option func(*Bitswap)
+
+// ProvideEnabled is an option for enabling/disabling provide announcements
+func ProvideEnabled(enabled bool) Option {
+	return func(bs *Bitswap) {
+		bs.provideEnabled = enabled
+	}
+}
+
 // New initializes a BitSwap instance that communicates over the provided
 // BitSwapNetwork. This function registers the returned instance as the network
 // delegate. Runs until context is cancelled or bitswap.Close is called.
 func New(parent context.Context, network bsnet.BitSwapNetwork,
-	bstore blockstore.Blockstore) exchange.Interface {
+	bstore blockstore.Blockstore, options ...Option) exchange.Interface {
 
 	// important to use provided parent context (since it may include important
 	// loggable data). It's probably not a good idea to allow bitswap to be
@@ -103,19 +110,25 @@ func New(parent context.Context, network bsnet.BitSwapNetwork,
 	}
 
 	bs := &Bitswap{
-		blockstore:    bstore,
-		engine:        decision.NewEngine(ctx, bstore), // TODO close the engine with Close() method
-		network:       network,
-		process:       px,
-		newBlocks:     make(chan cid.Cid, HasBlockBufferSize),
-		provideKeys:   make(chan cid.Cid, provideKeysBufferSize),
-		wm:            wm,
-		pqm:           pqm,
-		sm:            bssm.New(ctx, sessionFactory, sessionPeerManagerFactory, sessionRequestSplitterFactory),
-		counters:      new(counters),
-		dupMetric:     dupHist,
-		allMetric:     allHist,
-		sentHistogram: sentHistogram,
+		blockstore:     bstore,
+		engine:         decision.NewEngine(ctx, bstore), // TODO close the engine with Close() method
+		network:        network,
+		process:        px,
+		newBlocks:      make(chan cid.Cid, HasBlockBufferSize),
+		provideKeys:    make(chan cid.Cid, provideKeysBufferSize),
+		wm:             wm,
+		pqm:            pqm,
+		sm:             bssm.New(ctx, sessionFactory, sessionPeerManagerFactory, sessionRequestSplitterFactory),
+		counters:       new(counters),
+		dupMetric:      dupHist,
+		allMetric:      allHist,
+		sentHistogram:  sentHistogram,
+		provideEnabled: true,
+	}
+
+	// apply functional options before starting and running bitswap
+	for _, option := range options {
+		option(bs)
 	}
 
 	bs.wm.Startup()
@@ -174,6 +187,9 @@ type Bitswap struct {
 
 	// the sessionmanager manages tracking sessions
 	sm *bssm.SessionManager
+
+	// whether or not to make provide announcements
+	provideEnabled bool
 }
 
 type counters struct {
@@ -253,7 +269,7 @@ func (bs *Bitswap) receiveBlockFrom(blk blocks.Block, from peer.ID) error {
 
 	bs.engine.AddBlock(blk)
 
-	if ProvideEnabled {
+	if bs.provideEnabled {
 		select {
 		case bs.newBlocks <- blk.Cid():
 			// send block off to be reprovided

bitswap_test.go

@@ -102,27 +102,25 @@ func TestGetBlockFromPeerAfterPeerAnnounces(t *testing.T) {
 }
 
 func TestDoesNotProvideWhenConfiguredNotTo(t *testing.T) {
-	bitswap.ProvideEnabled = false
-	defer func() { bitswap.ProvideEnabled = true }()
-
+	bssession.SetProviderSearchDelay(10 * time.Millisecond)
 	net := tn.VirtualNetwork(mockrouting.NewServer(), delay.Fixed(kNetworkDelay))
 	block := blocks.NewBlock([]byte("block"))
-	ig := testinstance.NewTestInstanceGenerator(net)
+	ig := testinstance.NewTestInstanceGenerator(net, bitswap.ProvideEnabled(false))
 	defer ig.Close()
 
 	hasBlock := ig.Next()
 	defer hasBlock.Exchange.Close()
 
+	wantsBlock := ig.Next()
+	defer wantsBlock.Exchange.Close()
+
 	if err := hasBlock.Exchange.HasBlock(block); err != nil {
 		t.Fatal(err)
 	}
 
-	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	ctx, cancel := context.WithTimeout(context.Background(), 50*time.Millisecond)
 	defer cancel()
 
-	wantsBlock := ig.Next()
-	defer wantsBlock.Exchange.Close()
-
 	ns := wantsBlock.Exchange.NewSession(ctx).(*bssession.Session)
 	// set find providers delay to less than timeout context of this test
 	ns.SetBaseTickDelay(10 * time.Millisecond)

testinstance/testinstance.go

@@ -19,23 +19,24 @@ import (
 
 // NewTestInstanceGenerator generates a new InstanceGenerator for the given
 // testnet
-func NewTestInstanceGenerator(
-	net tn.Network) InstanceGenerator {
+func NewTestInstanceGenerator(net tn.Network, bsOptions ...bitswap.Option) InstanceGenerator {
 	ctx, cancel := context.WithCancel(context.Background())
 	return InstanceGenerator{
-		net:    net,
-		seq:    0,
-		ctx:    ctx, // TODO take ctx as param to Next, Instances
-		cancel: cancel,
+		net:       net,
+		seq:       0,
+		ctx:       ctx, // TODO take ctx as param to Next, Instances
+		cancel:    cancel,
+		bsOptions: bsOptions,
 	}
 }
 
 // InstanceGenerator generates new test instances of bitswap+dependencies
 type InstanceGenerator struct {
-	seq    int
-	net    tn.Network
-	ctx    context.Context
-	cancel context.CancelFunc
+	seq       int
+	net       tn.Network
+	ctx       context.Context
+	cancel    context.CancelFunc
+	bsOptions []bitswap.Option
 }
 
 // Close closes the clobal context, shutting down all test instances
@@ -51,7 +52,7 @@ func (g *InstanceGenerator) Next() Instance {
 	if err != nil {
 		panic("FIXME") // TODO change signature
 	}
-	return NewInstance(g.ctx, g.net, p)
+	return NewInstance(g.ctx, g.net, p, g.bsOptions...)
 }
 
 // Instances creates N test instances of bitswap + dependencies
@@ -95,7 +96,7 @@ func (i *Instance) SetBlockstoreLatency(t time.Duration) time.Duration {
 // NB: It's easy make mistakes by providing the same peer ID to two different
 // instances. To safeguard, use the InstanceGenerator to generate instances. It's
 // just a much better idea.
-func NewInstance(ctx context.Context, net tn.Network, p testutil.Identity) Instance {
+func NewInstance(ctx context.Context, net tn.Network, p testutil.Identity, options ...bitswap.Option) Instance {
 	bsdelay := delay.Fixed(0)
 
 	adapter := net.Adapter(p)
@@ -108,7 +109,7 @@ func NewInstance(ctx context.Context, net tn.Network, p testutil.Identity) Insta
 		panic(err.Error()) // FIXME perhaps change signature and return error.
 	}
 
-	bs := bitswap.New(ctx, adapter, bstore).(*bitswap.Bitswap)
+	bs := bitswap.New(ctx, adapter, bstore, options...).(*bitswap.Bitswap)
 
 	return Instance{
 		Adapter:         adapter,

workers.go

@@ -25,7 +25,7 @@ func (bs *Bitswap) startWorkers(ctx context.Context, px process.Process) {
 		})
 	}
 
-	if ProvideEnabled {
+	if bs.provideEnabled {
 		// Start up a worker to manage sending out provides messages
 		px.Go(func(px process.Process) {
 			bs.provideCollector(ctx)