feat(bitswap): synchronous close

bitswap.go

@@ -9,6 +9,7 @@ import (
 
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
 	inflect "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/briantigerchow/inflect"
+	process "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/goprocess"
 
 	blocks "github.com/jbenet/go-ipfs/blocks"
 	blockstore "github.com/jbenet/go-ipfs/blocks/blockstore"
@@ -52,28 +53,47 @@ var (
 func New(parent context.Context, p peer.ID, network bsnet.BitSwapNetwork,
 	bstore blockstore.Blockstore, nice bool) 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
+	// coupled to the concerns of the IPFS daemon in this way.
+	//
+	// FIXME(btc) Now that bitswap manages itself using a process, it probably
+	// shouldn't accept a context anymore. Clients should probably use Close()
+	// exclusively. We should probably find another way to share logging data
 	ctx, cancelFunc := context.WithCancel(parent)
 
 	notif := notifications.New()
+	px := process.WithTeardown(func() error {
+		notif.Shutdown()
+		return nil
+	})
+
 	go func() {
-		<-ctx.Done()
+		<-px.Closing() // process closes first
 		cancelFunc()
-		notif.Shutdown()
+	}()
+	go func() {
+		<-ctx.Done() // parent cancelled first
+		px.Close()
 	}()
 
 	bs := &bitswap{
 		self:          p,
 		blockstore:    bstore,
-		cancelFunc:    cancelFunc,
 		notifications: notif,
-		engine:        decision.NewEngine(ctx, bstore),
+		engine:        decision.NewEngine(ctx, bstore), // TODO close the engine with Close() method
 		network:       network,
 		wantlist:      wantlist.NewThreadSafe(),
 		batchRequests: make(chan []u.Key, sizeBatchRequestChan),
+		process:       px,
 	}
 	network.SetDelegate(bs)
-	go bs.clientWorker(ctx)
-	go bs.taskWorker(ctx)
+	px.Go(func(px process.Process) {
+		bs.clientWorker(ctx)
+	})
+	px.Go(func(px process.Process) {
+		bs.taskWorker(ctx)
+	})
 
 	return bs
 }
@@ -102,8 +122,7 @@ type bitswap struct {
 
 	wantlist *wantlist.ThreadSafe
 
-	// cancelFunc signals cancellation to the bitswap event loop
-	cancelFunc func()
+	process process.Process
 }
 
 // GetBlock attempts to retrieve a particular block from peers within the
@@ -149,6 +168,11 @@ func (bs *bitswap) GetBlock(parent context.Context, k u.Key) (*blocks.Block, err
 // that lasts throughout the lifetime of the server)
 func (bs *bitswap) GetBlocks(ctx context.Context, keys []u.Key) (<-chan *blocks.Block, error) {
 
+	select {
+	case <-bs.process.Closing():
+		return nil, errors.New("bitswap is closed")
+	default:
+	}
 	promise := bs.notifications.Subscribe(ctx, keys...)
 	select {
 	case bs.batchRequests <- keys:
@@ -161,6 +185,11 @@ func (bs *bitswap) GetBlocks(ctx context.Context, keys []u.Key) (<-chan *blocks.
 // HasBlock announces the existance of a block to this bitswap service. The
 // service will potentially notify its peers.
 func (bs *bitswap) HasBlock(ctx context.Context, blk *blocks.Block) error {
+	select {
+	case <-bs.process.Closing():
+		return errors.New("bitswap is closed")
+	default:
+	}
 	if err := bs.blockstore.Put(blk); err != nil {
 		return err
 	}
@@ -235,6 +264,7 @@ func (bs *bitswap) sendWantlistToProviders(ctx context.Context, entries []wantli
 }
 
 func (bs *bitswap) taskWorker(ctx context.Context) {
+	defer log.Info("bitswap task worker shutting down...")
 	for {
 		select {
 		case <-ctx.Done():
@@ -256,6 +286,8 @@ func (bs *bitswap) taskWorker(ctx context.Context) {
 // TODO ensure only one active request per key
 func (bs *bitswap) clientWorker(parent context.Context) {
 
+	defer log.Info("bitswap client worker shutting down...")
+
 	ctx, cancel := context.WithCancel(parent)
 
 	broadcastSignal := time.After(rebroadcastDelay.Get())
@@ -384,6 +416,5 @@ func (bs *bitswap) send(ctx context.Context, p peer.ID, m bsmsg.BitSwapMessage)
 }
 
 func (bs *bitswap) Close() error {
-	bs.cancelFunc()
-	return nil // to conform to Closer interface
+	return bs.process.Close()
 }

bitswap_test.go

@@ -22,8 +22,6 @@ import (
 const kNetworkDelay = 0 * time.Millisecond
 
 func TestClose(t *testing.T) {
-	// TODO
-	t.Skip("TODO Bitswap's Close implementation is a WIP")
 	vnet := tn.VirtualNetwork(mockrouting.NewServer(), delay.Fixed(kNetworkDelay))
 	sesgen := NewTestSessionGenerator(vnet)
 	defer sesgen.Close()