fallback to URL.Host if Request.Host is empty (#2661)

* fallback to URL.Host if Request.Host is empty

* changelog

* previous versions

CHANGELOG.md

@@ -44,6 +44,7 @@ This update is a breaking change of the unstable Metrics API. Code instrumented
 - Unify path cleaning functionally in the `otlpmetric` and `otlptrace` config. (#2639)
 - Change the debug message from the `sdk/trace.BatchSpanProcessor` to reflect the count is cumulative. (#2640)
 - Introduce new internal envconfig package for OTLP exporters (#2608)
+- If `http.Request.Host` is empty, fall back to use `URL.Host` when populating `http.host` in the `semconv` packages. (#2661)
 
 ### Fixed
 

semconv/v1.4.0/http.go

@@ -166,6 +166,8 @@ func httpBasicAttributesFromHTTPRequest(request *http.Request) []attribute.KeyVa
 
 	if request.Host != "" {
 		attrs = append(attrs, HTTPHostKey.String(request.Host))
+	} else if request.URL != nil && request.URL.Host != "" {
+		attrs = append(attrs, HTTPHostKey.String(request.URL.Host))
 	}
 
 	flavor := ""

semconv/v1.4.0/http_test.go

@@ -705,6 +705,31 @@ func TestHTTPServerAttributesFromHTTPRequest(t *testing.T) {
 				attribute.String("http.host", "example.com"),
 			},
 		},
+		{
+			name:       "with host fallback",
+			serverName: "my-server-name",
+			route:      "/user/:id",
+			method:     "GET",
+			requestURI: "/user/123",
+			proto:      "HTTP/1.0",
+			remoteAddr: "",
+			host:       "",
+			url: &url.URL{
+				Host: "example.com",
+				Path: "/user/123",
+			},
+			header: nil,
+			tls:    withTLS,
+			expected: []attribute.KeyValue{
+				attribute.String("http.method", "GET"),
+				attribute.String("http.target", "/user/123"),
+				attribute.String("http.scheme", "https"),
+				attribute.String("http.flavor", "1.0"),
+				attribute.String("http.server_name", "my-server-name"),
+				attribute.String("http.route", "/user/:id"),
+				attribute.String("http.host", "example.com"),
+			},
+		},
 		{
 			name:       "with user agent",
 			serverName: "my-server-name",
@@ -1042,6 +1067,28 @@ func TestHTTPClientAttributesFromHTTPRequest(t *testing.T) {
 				attribute.String("http.host", "example.com"),
 			},
 		},
+		{
+			name:       "with host fallback",
+			method:     "GET",
+			requestURI: "/user/123",
+			proto:      "HTTP/1.0",
+			remoteAddr: "",
+			host:       "",
+			url: &url.URL{
+				Scheme: "https",
+				Host:   "example.com",
+				Path:   "/user/123",
+			},
+			header: nil,
+			tls:    withTLS,
+			expected: []attribute.KeyValue{
+				attribute.String("http.method", "GET"),
+				attribute.String("http.url", "https://example.com/user/123"),
+				attribute.String("http.scheme", "https"),
+				attribute.String("http.flavor", "1.0"),
+				attribute.String("http.host", "example.com"),
+			},
+		},
 		{
 			name:       "with user agent",
 			method:     "GET",

semconv/v1.5.0/http.go

@@ -166,6 +166,8 @@ func httpBasicAttributesFromHTTPRequest(request *http.Request) []attribute.KeyVa
 
 	if request.Host != "" {
 		attrs = append(attrs, HTTPHostKey.String(request.Host))
+	} else if request.URL != nil && request.URL.Host != "" {
+		attrs = append(attrs, HTTPHostKey.String(request.URL.Host))
 	}
 
 	flavor := ""

semconv/v1.5.0/http_test.go

@@ -705,6 +705,31 @@ func TestHTTPServerAttributesFromHTTPRequest(t *testing.T) {
 				attribute.String("http.host", "example.com"),
 			},
 		},
+		{
+			name:       "with host fallback",
+			serverName: "my-server-name",
+			route:      "/user/:id",
+			method:     "GET",
+			requestURI: "/user/123",
+			proto:      "HTTP/1.0",
+			remoteAddr: "",
+			host:       "",
+			url: &url.URL{
+				Host: "example.com",
+				Path: "/user/123",
+			},
+			header: nil,
+			tls:    withTLS,
+			expected: []attribute.KeyValue{
+				attribute.String("http.method", "GET"),
+				attribute.String("http.target", "/user/123"),
+				attribute.String("http.scheme", "https"),
+				attribute.String("http.flavor", "1.0"),
+				attribute.String("http.server_name", "my-server-name"),
+				attribute.String("http.route", "/user/:id"),
+				attribute.String("http.host", "example.com"),
+			},
+		},
 		{
 			name:       "with user agent",
 			serverName: "my-server-name",
@@ -1042,6 +1067,28 @@ func TestHTTPClientAttributesFromHTTPRequest(t *testing.T) {
 				attribute.String("http.host", "example.com"),
 			},
 		},
+		{
+			name:       "with host fallback",
+			method:     "GET",
+			requestURI: "/user/123",
+			proto:      "HTTP/1.0",
+			remoteAddr: "",
+			host:       "",
+			url: &url.URL{
+				Scheme: "https",
+				Host:   "example.com",
+				Path:   "/user/123",
+			},
+			header: nil,
+			tls:    withTLS,
+			expected: []attribute.KeyValue{
+				attribute.String("http.method", "GET"),
+				attribute.String("http.url", "https://example.com/user/123"),
+				attribute.String("http.scheme", "https"),
+				attribute.String("http.flavor", "1.0"),
+				attribute.String("http.host", "example.com"),
+			},
+		},
 		{
 			name:       "with user agent",
 			method:     "GET",

semconv/v1.6.1/http.go

@@ -166,6 +166,8 @@ func httpBasicAttributesFromHTTPRequest(request *http.Request) []attribute.KeyVa
 
 	if request.Host != "" {
 		attrs = append(attrs, HTTPHostKey.String(request.Host))
+	} else if request.URL != nil && request.URL.Host != "" {
+		attrs = append(attrs, HTTPHostKey.String(request.URL.Host))
 	}
 
 	flavor := ""

semconv/v1.6.1/http_test.go

@@ -704,6 +704,31 @@ func TestHTTPServerAttributesFromHTTPRequest(t *testing.T) {
 				attribute.String("http.host", "example.com"),
 			},
 		},
+		{
+			name:       "with host fallback",
+			serverName: "my-server-name",
+			route:      "/user/:id",
+			method:     "GET",
+			requestURI: "/user/123",
+			proto:      "HTTP/1.0",
+			remoteAddr: "",
+			host:       "",
+			url: &url.URL{
+				Host: "example.com",
+				Path: "/user/123",
+			},
+			header: nil,
+			tls:    withTLS,
+			expected: []attribute.KeyValue{
+				attribute.String("http.method", "GET"),
+				attribute.String("http.target", "/user/123"),
+				attribute.String("http.scheme", "https"),
+				attribute.String("http.flavor", "1.0"),
+				attribute.String("http.server_name", "my-server-name"),
+				attribute.String("http.route", "/user/:id"),
+				attribute.String("http.host", "example.com"),
+			},
+		},
 		{
 			name:       "with user agent",
 			serverName: "my-server-name",
@@ -1041,6 +1066,28 @@ func TestHTTPClientAttributesFromHTTPRequest(t *testing.T) {
 				attribute.String("http.host", "example.com"),
 			},
 		},
+		{
+			name:       "with host fallback",
+			method:     "GET",
+			requestURI: "/user/123",
+			proto:      "HTTP/1.0",
+			remoteAddr: "",
+			host:       "",
+			url: &url.URL{
+				Scheme: "https",
+				Host:   "example.com",
+				Path:   "/user/123",
+			},
+			header: nil,
+			tls:    withTLS,
+			expected: []attribute.KeyValue{
+				attribute.String("http.method", "GET"),
+				attribute.String("http.url", "https://example.com/user/123"),
+				attribute.String("http.scheme", "https"),
+				attribute.String("http.flavor", "1.0"),
+				attribute.String("http.host", "example.com"),
+			},
+		},
 		{
 			name:       "with user agent",
 			method:     "GET",

semconv/v1.7.0/http.go

@@ -167,6 +167,8 @@ func httpBasicAttributesFromHTTPRequest(request *http.Request) []attribute.KeyVa
 
 	if request.Host != "" {
 		attrs = append(attrs, HTTPHostKey.String(request.Host))
+	} else if request.URL != nil && request.URL.Host != "" {
+		attrs = append(attrs, HTTPHostKey.String(request.URL.Host))
 	}
 
 	flavor := ""

semconv/v1.7.0/http_test.go

@@ -705,6 +705,31 @@ func TestHTTPServerAttributesFromHTTPRequest(t *testing.T) {
 				attribute.String("http.host", "example.com"),
 			},
 		},
+		{
+			name:       "with host fallback",
+			serverName: "my-server-name",
+			route:      "/user/:id",
+			method:     "GET",
+			requestURI: "/user/123",
+			proto:      "HTTP/1.0",
+			remoteAddr: "",
+			host:       "",
+			url: &url.URL{
+				Host: "example.com",
+				Path: "/user/123",
+			},
+			header: nil,
+			tls:    withTLS,
+			expected: []attribute.KeyValue{
+				attribute.String("http.method", "GET"),
+				attribute.String("http.target", "/user/123"),
+				attribute.String("http.scheme", "https"),
+				attribute.String("http.flavor", "1.0"),
+				attribute.String("http.server_name", "my-server-name"),
+				attribute.String("http.route", "/user/:id"),
+				attribute.String("http.host", "example.com"),
+			},
+		},
 		{
 			name:       "with user agent",
 			serverName: "my-server-name",
@@ -1042,6 +1067,28 @@ func TestHTTPClientAttributesFromHTTPRequest(t *testing.T) {
 				attribute.String("http.host", "example.com"),
 			},
 		},
+		{
+			name:       "with host fallback",
+			method:     "GET",
+			requestURI: "/user/123",
+			proto:      "HTTP/1.0",
+			remoteAddr: "",
+			host:       "",
+			url: &url.URL{
+				Scheme: "https",
+				Host:   "example.com",
+				Path:   "/user/123",
+			},
+			header: nil,
+			tls:    withTLS,
+			expected: []attribute.KeyValue{
+				attribute.String("http.method", "GET"),
+				attribute.String("http.url", "https://example.com/user/123"),
+				attribute.String("http.scheme", "https"),
+				attribute.String("http.flavor", "1.0"),
+				attribute.String("http.host", "example.com"),
+			},
+		},
 		{
 			name:       "with user agent",
 			method:     "GET",