From 1a3752b81f939b80a6429e170b9acad4e06db92e Mon Sep 17 00:00:00 2001
From: Juan Batiz-Benet <juan@benet.ai>
Date: Fri, 30 Jan 2015 20:25:48 -0800
Subject: [PATCH] core: setup peerhost + listen separate steps

We had a problem: we were starting all the services with the network
live, and so would miss early messages. We were noticing bitswap
messages not handled (not in muxer). Many of the subsystems expect
the network to _exist_ when they start up, so we split construction
and starting to listen into two separate steps.
---
 core/core.go | 75 +++++++++++++++++++++++++++++++++-------------------
 1 file changed, 48 insertions(+), 27 deletions(-)

diff --git a/core/core.go b/core/core.go
index af95cac98..058a68b39 100644
--- a/core/core.go
+++ b/core/core.go
@@ -214,30 +214,39 @@ func (n *IpfsNode) StartOnlineServices(ctx context.Context) error {
 		return err
 	}
 
-	peerhost, err := constructPeerHost(ctx, n.Repo.Config(), n.Identity, n.Peerstore)
+	peerhost, err := constructPeerHost(ctx, n.Identity, n.Peerstore)
 	if err != nil {
 		return debugerror.Wrap(err)
 	}
 	n.PeerHost = peerhost
 
-	// setup diagnostics service
-	n.Diagnostics = diag.NewDiagnostics(n.Identity, n.PeerHost)
+	// this block is the set of services which need to be initialized with the host
+	// and _before_ we start listening.
+	{
+		// setup diagnostics service
+		n.Diagnostics = diag.NewDiagnostics(n.Identity, n.PeerHost)
 
-	// setup routing service
-	dhtRouting, err := constructDHTRouting(ctx, n.PeerHost, n.Repo.Datastore())
-	if err != nil {
+		// setup routing service
+		dhtRouting, err := constructDHTRouting(ctx, n.PeerHost, n.Repo.Datastore())
+		if err != nil {
+			return debugerror.Wrap(err)
+		}
+		n.Routing = dhtRouting
+
+		// setup exchange service
+		const alwaysSendToPeer = true // use YesManStrategy
+		bitswapNetwork := bsnet.NewFromIpfsHost(n.PeerHost, n.Routing)
+		n.Exchange = bitswap.New(ctx, n.Identity, bitswapNetwork, n.Blockstore, alwaysSendToPeer)
+
+		// setup name system
+		// TODO implement an offline namesys that serves only local names.
+		n.Namesys = namesys.NewNameSystem(n.Routing)
+	}
+
+	// Ok, now we're ready to listen.
+	if err := startListening(ctx, n.PeerHost, n.Repo.Config()); err != nil {
 		return debugerror.Wrap(err)
 	}
-	n.Routing = dhtRouting
-
-	// setup exchange service
-	const alwaysSendToPeer = true // use YesManStrategy
-	bitswapNetwork := bsnet.NewFromIpfsHost(n.PeerHost, n.Routing)
-	n.Exchange = bitswap.New(ctx, n.Identity, bitswapNetwork, n.Blockstore, alwaysSendToPeer)
-
-	// setup name system
-	// TODO implement an offline namesys that serves only local names.
-	n.Namesys = namesys.NewNameSystem(n.Routing)
 
 	n.Reprovider = rp.NewReprovider(n.Routing, n.Blockstore)
 	go n.Reprovider.ProvideEvery(ctx, kReprovideFrequency)
@@ -405,37 +414,49 @@ func listenAddresses(cfg *config.Config) ([]ma.Multiaddr, error) {
 }
 
 // isolates the complex initialization steps
-func constructPeerHost(ctx context.Context, cfg *config.Config, id peer.ID, ps peer.Peerstore) (p2phost.Host, error) {
-	listenAddrs, err := listenAddresses(cfg)
+func constructPeerHost(ctx context.Context, id peer.ID, ps peer.Peerstore) (p2phost.Host, error) {
+
+	// no addresses to begin with. we'll start later.
+	network, err := swarm.NewNetwork(ctx, nil, id, ps)
 	if err != nil {
 		return nil, debugerror.Wrap(err)
 	}
 
+	host := p2pbhost.New(network, p2pbhost.NATPortMap)
+	return host, nil
+}
+
+// startListening on the network addresses
+func startListening(ctx context.Context, host p2phost.Host, cfg *config.Config) error {
+	listenAddrs, err := listenAddresses(cfg)
+	if err != nil {
+		return debugerror.Wrap(err)
+	}
+
 	// make sure we error out if our config does not have addresses we can use
 	log.Debugf("Config.Addresses.Swarm:%s", listenAddrs)
 	filteredAddrs := addrutil.FilterUsableAddrs(listenAddrs)
 	log.Debugf("Config.Addresses.Swarm:%s (filtered)", filteredAddrs)
 	if len(filteredAddrs) < 1 {
-		return nil, debugerror.Errorf("addresses in config not usable: %s", listenAddrs)
+		return debugerror.Errorf("addresses in config not usable: %s", listenAddrs)
 	}
 
-	network, err := swarm.NewNetwork(ctx, filteredAddrs, id, ps)
-	if err != nil {
-		return nil, debugerror.Wrap(err)
+	// Actually start listening:
+	if err := host.Network().Listen(filteredAddrs...); err != nil {
+		return err
 	}
 
-	peerhost := p2pbhost.New(network, p2pbhost.NATPortMap)
 	// explicitly set these as our listen addrs.
 	// (why not do it inside inet.NewNetwork? because this way we can
 	// listen on addresses without necessarily advertising those publicly.)
-	addrs, err := peerhost.Network().InterfaceListenAddresses()
+	addrs, err := host.Network().InterfaceListenAddresses()
 	if err != nil {
-		return nil, debugerror.Wrap(err)
+		return debugerror.Wrap(err)
 	}
 	log.Infof("Swarm listening at: %s", addrs)
 
-	ps.AddAddresses(id, addrs)
-	return peerhost, nil
+	host.Peerstore().AddAddresses(host.ID(), addrs)
+	return nil
 }
 
 func constructDHTRouting(ctx context.Context, host p2phost.Host, ds datastore.ThreadSafeDatastore) (*dht.IpfsDHT, error) {