restapi client: support talking to unix sockets

Setting APIAddr to a Unix socket multiaddress will just work.

api/rest/client/client.go

@@ -292,6 +292,8 @@ func (c *defaultClient) setupHTTPClient() error {
 	switch {
 	case IsPeerAddress(c.config.APIAddr):
 		err = c.enableLibp2p()
+	case isUnixSocketAddress(c.config.APIAddr):
+		err = c.enableUnix()
 	case c.config.SSL:
 		err = c.enableTLS()
 	default:
@@ -318,13 +320,15 @@ func (c *defaultClient) setupHTTPClient() error {
 func (c *defaultClient) setupHostname() error {
 	// Extract host:port form APIAddr or use Host:Port.
 	// For libp2p, hostname is set in enableLibp2p()
-	if IsPeerAddress(c.config.APIAddr) {
+	// For unix sockets, hostname set in enableUnix()
+	if IsPeerAddress(c.config.APIAddr) || isUnixSocketAddress(c.config.APIAddr) {
 		return nil
 	}
 	_, hostname, err := manet.DialArgs(c.config.APIAddr)
 	if err != nil {
 		return err
 	}
+
 	c.hostname = hostname
 	return nil
 }
@@ -361,3 +365,13 @@ func IsPeerAddress(addr ma.Multiaddr) bool {
 	dnsaddr, err2 := addr.ValueForProtocol(madns.DnsaddrProtocol.Code)
 	return (pid != "" && err == nil) || (dnsaddr != "" && err2 == nil)
 }
+
+// isUnixSocketAddress returns if the given address corresponds to a
+// unix socket.
+func isUnixSocketAddress(addr ma.Multiaddr) bool {
+	if addr == nil {
+		return false
+	}
+	value, err := addr.ValueForProtocol(ma.P_UNIX)
+	return (value != "" && err == nil)
+}

api/rest/client/transports.go

@@ -18,6 +18,8 @@ import (
 	secio "github.com/libp2p/go-libp2p-secio"
 	libp2ptls "github.com/libp2p/go-libp2p-tls"
 	madns "github.com/multiformats/go-multiaddr-dns"
+	manet "github.com/multiformats/go-multiaddr-net"
+	"github.com/tv42/httpunix"
 )
 
 // This is essentially a http.DefaultTransport. We should not mess
@@ -110,3 +112,19 @@ func (c *defaultClient) enableTLS() error {
 	c.net = "https"
 	return nil
 }
+
+func (c *defaultClient) enableUnix() error {
+	c.defaultTransport()
+	unixTransport := &httpunix.Transport{
+		DialTimeout: time.Second,
+	}
+	_, addr, err := manet.DialArgs(c.config.APIAddr)
+	if err != nil {
+		return err
+	}
+	unixTransport.RegisterLocation("restapi", addr)
+	c.transport.RegisterProtocol(httpunix.Scheme, unixTransport)
+	c.net = httpunix.Scheme
+	c.hostname = "restapi"
+	return nil
+}

go.mod

@@ -70,6 +70,7 @@ require (
 	github.com/pkg/errors v0.8.1
 	github.com/prometheus/client_golang v1.1.0
 	github.com/rs/cors v1.7.0
+	github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926
 	github.com/ugorji/go/codec v1.1.7
 	github.com/urfave/cli v1.22.1
 	go.opencensus.io v0.22.1

go.sum

@@ -825,6 +825,7 @@ github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXf
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/syndtr/goleveldb v1.0.0/go.mod h1:ZVVdQEZoIme9iO1Ch2Jdy24qqXrMMOU6lpPAyBWyWuQ=
+github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926 h1:G3dpKMzFDjgEh2q1Z7zUUtKa8ViPtH+ocF0bE0g00O8=
 github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926/go.mod h1:9ESjWnEqriFuLhtthL60Sar/7RFoluCcXsuvEwTV5KM=
 github.com/ugorji/go v1.1.4 h1:j4s+tAvLfL3bZyefP2SEWmhBzmuIlH/eqNuPdFPgngw=
 github.com/ugorji/go v1.1.4/go.mod h1:uQMGLiO92mf5W77hV/PUCpI3pbzQx3CRekS0kk+RGrc=