Reintroduce a specific dialler for unix sockets1447-fix

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, 47 insertions, 4 deletions

diff --git a/client/dial.go b/client/dial.go
index d0a51c0c1..96915d811 100644
--- a/client/dial.go
+++ b/client/dial.go
@@ -1,6 +1,9 @@
 package client
 
 import (
+	"net"
+	"time"
+
 	"google.golang.org/grpc/credentials"
 
 	"net/url"
@@ -11,6 +14,14 @@ import (
 // DefaultDialOpts hold the default DialOptions for connection to Gitaly over UNIX-socket
 var DefaultDialOpts = []grpc.DialOption{}
 
+type connectionType int
+
+const (
+	tcpConnection  connectionType = iota
+	tlsConnection                 = iota
+	unixConnection                = iota
+)
+
 // Dial gitaly
 func Dial(rawAddress string, connOpts []grpc.DialOption) (*grpc.ClientConn, error) {
 	canonicalAddress, err := parseAddress(rawAddress)
@@ -18,7 +29,13 @@ func Dial(rawAddress string, connOpts []grpc.DialOption) (*grpc.ClientConn, erro
 		return nil, err
 	}
 
-	if isTLS(rawAddress) {
+	connectionType, err := getConnectionType(rawAddress)
+	if err != nil {
+		return nil, err
+	}
+
+	switch connectionType {
+	case tlsConnection:
 		certPool, err := systemCertPool()
 		if err != nil {
 			return nil, err
@@ -26,8 +43,22 @@ func Dial(rawAddress string, connOpts []grpc.DialOption) (*grpc.ClientConn, erro
 
 		creds := credentials.NewClientTLSFromCert(certPool, "")
 		connOpts = append(connOpts, grpc.WithTransportCredentials(creds))
-	} else {
+	case tcpConnection:
 		connOpts = append(connOpts, grpc.WithInsecure())
+	case unixConnection:
+		connOpts = append(
+			connOpts,
+			grpc.WithInsecure(),
+			grpc.WithDialer(func(addr string, timeout time.Duration) (net.Conn, error) {
+				u, err := url.Parse(addr)
+				if err != nil {
+					return nil, err
+				}
+
+				return net.DialTimeout("unix", u.Path, timeout)
+			}),
+		)
+
 	}
 
 	conn, err := grpc.Dial(canonicalAddress, connOpts...)
@@ -38,7 +69,19 @@ func Dial(rawAddress string, connOpts []grpc.DialOption) (*grpc.ClientConn, erro
 	return conn, nil
 }
 
-func isTLS(rawAddress string) bool {
+func getConnectionType(rawAddress string) (connectionType, error) {
 	u, err := url.Parse(rawAddress)
-	return err == nil && u.Scheme == "tls"
+	if err != nil {
+		return tcpConnection, err
+	}
+
+	if u.Scheme == "tls" {
+		return tlsConnection, nil
+	}
+
+	if u.Scheme == "unix" {
+		return unixConnection, nil
+	}
+
+	return tcpConnection, nil
 }