fixed transparent host and added test case

caddyhttp/proxy/upstream.go

@@ -26,6 +26,7 @@ type staticUpstream struct {
 	Hosts              HostPool
 	Policy             Policy
 	insecureSkipVerify bool
+	transparent        bool
 
 	FailTimeout time.Duration
 	MaxFails    int32
@@ -54,6 +55,7 @@ func NewStaticUpstreams(c caddyfile.Dispenser) ([]Upstream, error) {
 			FailTimeout:       10 * time.Second,
 			MaxFails:          1,
 			MaxConns:          0,
+			transparent:       false,
 		}
 
 		if !c.Args(&upstream.from) {
@@ -69,19 +71,6 @@ func NewStaticUpstreams(c caddyfile.Dispenser) ([]Upstream, error) {
 			to = append(to, parsed...)
 		}
 
-		if len(to) == 0 {
-			return upstreams, c.ArgErr()
-		}
-
-		upstream.Hosts = make([]*UpstreamHost, len(to))
-		for i, host := range to {
-			uh, err := upstream.NewHost(host)
-			if err != nil {
-				return upstreams, err
-			}
-			upstream.Hosts[i] = uh
-		}
-
 		for c.NextBlock() {
 			switch c.Val() {
 			case "upstream":
@@ -100,6 +89,23 @@ func NewStaticUpstreams(c caddyfile.Dispenser) ([]Upstream, error) {
 			}
 		}
 
+		if len(to) == 0 {
+			return upstreams, c.ArgErr()
+		}
+
+		upstream.Hosts = make([]*UpstreamHost, len(to))
+		for i, host := range to {
+			uh, err := upstream.NewHost(host)
+			if err != nil {
+				return upstreams, err
+			}
+			upstream.Hosts[i] = uh
+		}
+
+		if upstream.transparent {
+			upstream.upstreamHeaders.Add("Host", upstream.Hosts[0].Name)
+		}
+
 		if upstream.HealthCheck.Path != "" {
 			upstream.HealthCheck.Client = http.Client{
 				Timeout: upstream.HealthCheck.Timeout,
@@ -287,7 +293,7 @@ func parseBlock(c *caddyfile.Dispenser, u *staticUpstream) error {
 		}
 		u.downstreamHeaders.Add(header, value)
 	case "transparent":
-		u.upstreamHeaders.Add("Host", u.Hosts[0].Name)
+		u.transparent = true
 		u.upstreamHeaders.Add("X-Real-IP", "{remote}")
 		u.upstreamHeaders.Add("X-Forwarded-For", "{remote}")
 		u.upstreamHeaders.Add("X-Forwarded-Proto", "{scheme}")

caddyhttp/proxy/upstream_test.go

@@ -213,6 +213,10 @@ func TestParseBlock(t *testing.T) {
 				t.Errorf("Test %d: Could not find the Host header", i+1)
 			}
 
+			if v, _ := headers["Host"]; v[0] != upstream.Select().Name {
+				t.Errorf("Test %d: Host not match first hostname in upstream", i+1)
+			}
+
 			if _, ok := headers["X-Real-Ip"]; !ok {
 				t.Errorf("Test %d: Could not find the X-Real-Ip header", i+1)
 			}