Reintroduce a specific dialler for unix sockets

61f6c92779a70d577727e7eefa337409effd69ef removed the Dialer for unix
socket. This was done because a change to the GRPC library caused the
Dialer to stop working, and because the default implementation works as
expected for users not using a proxy.

Unfortunately this led to a regression for users with HTTP or
HTTPS proxy configurations exposed via the `http_proxy` or `https_proxy`
environment variables.

For this reason, we reintroduce the dialer for Unix socket connections.

1 files changed, 62 insertions, 8 deletions

diff --git a/client/dial.go b/client/dial.go
index d0a51c0c1..fe4a3e683 100644
--- a/client/dial.go
+++ b/client/dial.go
@@ -1,6 +1,10 @@
 package client
 
 import (
+	"fmt"
+	"net"
+	"time"
+
 	"google.golang.org/grpc/credentials"
 
 	"net/url"
@@ -11,14 +15,30 @@ import (
 // DefaultDialOpts hold the default DialOptions for connection to Gitaly over UNIX-socket
 var DefaultDialOpts = []grpc.DialOption{}
 
+type connectionType int
+
+const (
+	invalidConnection connectionType = iota
+	tcpConnection
+	tlsConnection
+	unixConnection
+)
+
 // Dial gitaly
 func Dial(rawAddress string, connOpts []grpc.DialOption) (*grpc.ClientConn, error) {
-	canonicalAddress, err := parseAddress(rawAddress)
-	if err != nil {
-		return nil, err
-	}
+	var canonicalAddress string
+	var err error
+
+	switch getConnectionType(rawAddress) {
+	case invalidConnection:
+		return nil, fmt.Errorf("invalid connection string: %s", rawAddress)
+
+	case tlsConnection:
+		canonicalAddress, err = extractHostFromRemoteURL(rawAddress) // Ensure the form: "host:port" ...
+		if err != nil {
+			return nil, err
+		}
 
-	if isTLS(rawAddress) {
 		certPool, err := systemCertPool()
 		if err != nil {
 			return nil, err
@@ -26,8 +46,29 @@ func Dial(rawAddress string, connOpts []grpc.DialOption) (*grpc.ClientConn, erro
 
 		creds := credentials.NewClientTLSFromCert(certPool, "")
 		connOpts = append(connOpts, grpc.WithTransportCredentials(creds))
-	} else {
+
+	case tcpConnection:
+		canonicalAddress, err = extractHostFromRemoteURL(rawAddress) // Ensure the form: "host:port" ...
+		if err != nil {
+			return nil, err
+		}
 		connOpts = append(connOpts, grpc.WithInsecure())
+
+	case unixConnection:
+		canonicalAddress = rawAddress // This will be overriden by the custom dialer...
+		connOpts = append(
+			connOpts,
+			grpc.WithInsecure(),
+			grpc.WithDialer(func(addr string, timeout time.Duration) (net.Conn, error) {
+				path, err := extractPathFromSocketURL(addr)
+				if err != nil {
+					return nil, err
+				}
+
+				return net.DialTimeout("unix", path, timeout)
+			}),
+		)
+
 	}
 
 	conn, err := grpc.Dial(canonicalAddress, connOpts...)
@@ -38,7 +79,20 @@ func Dial(rawAddress string, connOpts []grpc.DialOption) (*grpc.ClientConn, erro
 	return conn, nil
 }
 
-func isTLS(rawAddress string) bool {
+func getConnectionType(rawAddress string) connectionType {
 	u, err := url.Parse(rawAddress)
-	return err == nil && u.Scheme == "tls"
+	if err != nil {
+		return invalidConnection
+	}
+
+	switch u.Scheme {
+	case "tls":
+		return tlsConnection
+	case "unix":
+		return unixConnection
+	case "tcp":
+		return tcpConnection
+	default:
+		return invalidConnection
+	}
 }