better user-agent handling

.travis.yml

@@ -4,7 +4,7 @@ os:
 language: go
 
 go:
-  - 1.11.x
+  - 1.12.x
 
 env:
   global:

README.md

@@ -58,9 +58,9 @@ libp2p is the product of a long, and arduous quest of understanding -- a deep di
 
 ## Usage
 
-This repository (`go-libp2p`) serves as the entrypoint to the universe of modules that compose the Go implementation of the libp2p stack.
+This repository (`go-libp2p`) serves as the entrypoint to the universe of modules that compose the Go implementation of the libp2p stack. Libp2p requires go 1.12+.
 
-We mainly use [Go modules](https://github.com/golang/go/wiki/Modules) for our dependency and release management (and thus require go >= 1.11). In order to get the best developer experience, we recommend you do too. Otherwise, you may ocassionally encounter a breaking build as you'll be running off master (which, by definition, is not guaranteed to be stable).
+We mainly use [Go modules](https://github.com/golang/go/wiki/Modules) for our dependency and release management (and thus require go >= 1.12+). In order to get the best developer experience, we recommend you do too. Otherwise, you may ocassionally encounter a breaking build as you'll be running off master (which, by definition, is not guaranteed to be stable).
 
 You can start using go-libp2p in your Go application simply by adding imports from our repos, e.g.:
 

config/config.go

@@ -44,6 +44,12 @@ type RoutingC func(host.Host) (routing.PeerRouting, error)
 // This is *not* a stable interface. Use the options defined in the root
 // package.
 type Config struct {
+	// UserAgent is the identifier this node will send to other peers when
+	// identifying itself, e.g. via the identify protocol.
+	//
+	// Set it via the UserAgent option function.
+	UserAgent string
+
 	PeerKey crypto.PrivKey
 
 	Transports         []TptC
@@ -120,6 +126,7 @@ func (cfg *Config) NewNode(ctx context.Context) (host.Host, error) {
 		AddrsFactory: cfg.AddrsFactory,
 		NATManager:   cfg.NATManager,
 		EnablePing:   !cfg.DisablePing,
+		UserAgent:    cfg.UserAgent,
 	})
 
 	if err != nil {

options.go

@@ -319,3 +319,11 @@ var NoTransports = func(cfg *Config) error {
 	cfg.Transports = []config.TptC{}
 	return nil
 }
+
+// UserAgent sets the libp2p user-agent sent along with the identify protocol
+func UserAgent(userAgent string) Option {
+	return func(cfg *Config) error {
+		cfg.UserAgent = userAgent
+		return nil
+	}
+}

p2p/host/basic/basic_host.go

@@ -100,10 +100,6 @@ type HostOpts struct {
 	// If below 0, timeouts on streams will be deactivated.
 	NegotiationTimeout time.Duration
 
-	// IdentifyService holds an implementation of the /ipfs/id/ protocol.
-	// If omitted, a new *identify.IDService will be used.
-	IdentifyService *identify.IDService
-
 	// AddrsFactory holds a function which can be used to override or filter the result of Addrs.
 	// If omitted, there's no override or filtering, and the results of Addrs and AllAddrs are the same.
 	AddrsFactory AddrsFactory
@@ -121,6 +117,9 @@ type HostOpts struct {
 
 	// EnablePing indicates whether to instantiate the ping service
 	EnablePing bool
+
+	// UserAgent sets the user-agent for the host. Defaults to ClientVersion.
+	UserAgent string
 }
 
 // NewHost constructs a new *BasicHost and activates it by attaching its stream and connection handlers to the given inet.Network.
@@ -154,12 +153,12 @@ func NewHost(ctx context.Context, net network.Network, opts *HostOpts) (*BasicHo
 		h.mux = opts.MultistreamMuxer
 	}
 
-	if opts.IdentifyService != nil {
-		h.ids = opts.IdentifyService
-	} else {
-		// we can't set this as a default above because it depends on the *BasicHost.
-		h.ids = identify.NewIDService(goprocessctx.WithProcessClosing(ctx, h.proc), h)
-	}
+	// we can't set this as a default above because it depends on the *BasicHost.
+	h.ids = identify.NewIDService(
+		goprocessctx.WithProcessClosing(ctx, h.proc),
+		h,
+		identify.UserAgent(opts.UserAgent),
+	)
 
 	if uint64(opts.NegotiationTimeout) != 0 {
 		h.negtimeout = opts.NegotiationTimeout

p2p/protocol/identify/id.go

@@ -2,6 +2,8 @@ package identify
 
 import (
 	"context"
+	"fmt"
+	"runtime/debug"
 	"sync"
 	"time"
 
@@ -31,9 +33,27 @@ const ID = "/ipfs/id/1.0.0"
 
 // LibP2PVersion holds the current protocol version for a client running this code
 // TODO(jbenet): fix the versioning mess.
+// XXX: Don't change this till 2020. You'll break all go-ipfs versions prior to
+// 0.4.17 which asserted an exact version match.
 const LibP2PVersion = "ipfs/0.1.0"
 
-var ClientVersion = "go-libp2p/3.3.4"
+// ClientVersion is the default user agent.
+//
+// Deprecated: Set this with the UserAgent option.
+var ClientVersion = "github.com/libp2p/go-libp2p"
+
+func init() {
+	bi, ok := debug.ReadBuildInfo()
+	if !ok {
+		return
+	}
+	version := bi.Main.Version
+	if version == "(devel)" {
+		ClientVersion = bi.Main.Path
+	} else {
+		ClientVersion = fmt.Sprintf("%s@%s", bi.Main.Path, bi.Main.Version)
+	}
+}
 
 // transientTTL is a short ttl for invalidated previously connected addrs
 const transientTTL = 10 * time.Second
@@ -47,7 +67,8 @@ const transientTTL = 10 * time.Second
 //  * Our IPFS Agent Version
 //  * Our public Listen Addresses
 type IDService struct {
-	Host host.Host
+	Host      host.Host
+	UserAgent string
 
 	ctx context.Context
 
@@ -70,9 +91,21 @@ type IDService struct {
 
 // NewIDService constructs a new *IDService and activates it by
 // attaching its stream handler to the given host.Host.
-func NewIDService(ctx context.Context, h host.Host) *IDService {
+func NewIDService(ctx context.Context, h host.Host, opts ...Option) *IDService {
+	var cfg config
+	for _, opt := range opts {
+		opt(&cfg)
+	}
+
+	userAgent := ClientVersion
+	if cfg.userAgent != "" {
+		userAgent = cfg.userAgent
+	}
+
 	s := &IDService{
-		Host:          h,
+		Host:      h,
+		UserAgent: userAgent,
+
 		ctx:           ctx,
 		currid:        make(map[network.Conn]chan struct{}),
 		observedAddrs: NewObservedAddrSet(ctx),
@@ -306,7 +339,7 @@ func (ids *IDService) populateMessage(mes *pb.Identify, c network.Conn) {
 
 	// set protocol versions
 	pv := LibP2PVersion
-	av := ClientVersion
+	av := ids.UserAgent
 	mes.ProtocolVersion = &pv
 	mes.AgentVersion = &av
 }

p2p/protocol/identify/id_test.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/libp2p/go-eventbus"
+	libp2p "github.com/libp2p/go-libp2p"
 	ic "github.com/libp2p/go-libp2p-core/crypto"
 	"github.com/libp2p/go-libp2p-core/event"
 	"github.com/libp2p/go-libp2p-core/helpers"
@@ -367,3 +368,40 @@ func TestIdentifyDeltaWhileIdentifyingConn(t *testing.T) {
 		t.Fatalf("timed out while waiting for an event for the protocol changes in h2")
 	}
 }
+
+func TestUserAgent(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	h1, err := libp2p.New(
+		ctx,
+		libp2p.UserAgent("foo"),
+		libp2p.ListenAddrStrings("/ip4/127.0.0.1/tcp/0"),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer h1.Close()
+
+	h2, err := libp2p.New(
+		ctx,
+		libp2p.UserAgent("bar"),
+		libp2p.ListenAddrStrings("/ip4/127.0.0.1/tcp/0"),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer h2.Close()
+
+	err = h1.Connect(ctx, peer.AddrInfo{ID: h2.ID(), Addrs: h2.Addrs()})
+	if err != nil {
+		t.Fatal(err)
+	}
+	av, err := h1.Peerstore().Get(h2.ID(), "AgentVersion")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if ver, ok := av.(string); !ok || ver != "bar" {
+		t.Errorf("expected agent version %q, got %q", "bar", av)
+	}
+}

p2p/protocol/identify/opts.go

@@ -0,0 +1,15 @@
+package identify
+
+type config struct {
+	userAgent string
+}
+
+// Option is an option function for identify.
+type Option func(*config)
+
+// UserAgent sets the user agent this node will identify itself with to peers.
+func UserAgent(ua string) Option {
+	return func(cfg *config) {
+		cfg.userAgent = ua
+	}
+}