Merge pull request #35151 from thaJeztah/always-return-version-information

Always return version and server headers

api/server/middleware/version.go

@@ -43,6 +43,10 @@ func (e versionUnsupportedError) InvalidParameter() {}
 // WrapHandler returns a new handler function wrapping the previous one in the request chain.
 func (v VersionMiddleware) WrapHandler(handler func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error) func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
 	return func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
+		w.Header().Set("Server", fmt.Sprintf("Docker/%s (%s)", v.serverVersion, runtime.GOOS))
+		w.Header().Set("API-Version", v.defaultVersion)
+		w.Header().Set("OSType", runtime.GOOS)
+
 		apiVersion := vars["version"]
 		if apiVersion == "" {
 			apiVersion = v.defaultVersion
@@ -53,11 +57,6 @@ func (v VersionMiddleware) WrapHandler(handler func(ctx context.Context, w http.
 		if versions.GreaterThan(apiVersion, v.defaultVersion) {
 			return versionUnsupportedError{version: apiVersion, maxVersion: v.defaultVersion}
 		}
-
-		header := fmt.Sprintf("Docker/%s (%s)", v.serverVersion, runtime.GOOS)
-		w.Header().Set("Server", header)
-		w.Header().Set("API-Version", v.defaultVersion)
-		w.Header().Set("OSType", runtime.GOOS)
 		// nolint: golint
 		ctx = context.WithValue(ctx, "api-version", apiVersion)
 		return handler(ctx, w, r, vars)

api/server/middleware/version_test.go

@@ -3,10 +3,12 @@ package middleware
 import (
 	"net/http"
 	"net/http/httptest"
+	"runtime"
 	"strings"
 	"testing"
 
 	"github.com/docker/docker/api/server/httputils"
+	"github.com/stretchr/testify/assert"
 	"golang.org/x/net/context"
 )
 
@@ -80,3 +82,31 @@ func TestVersionMiddlewareVersionTooNew(t *testing.T) {
 		t.Fatalf("Expected too new client error, got %v", err)
 	}
 }
+
+func TestVersionMiddlewareWithErrorsReturnsHeaders(t *testing.T) {
+	handler := func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
+		if httputils.VersionFromContext(ctx) == "" {
+			t.Fatal("Expected version, got empty string")
+		}
+		return nil
+	}
+
+	defaultVersion := "1.10.0"
+	minVersion := "1.2.0"
+	m := NewVersionMiddleware(defaultVersion, defaultVersion, minVersion)
+	h := m.WrapHandler(handler)
+
+	req, _ := http.NewRequest("GET", "/containers/json", nil)
+	resp := httptest.NewRecorder()
+	ctx := context.Background()
+
+	vars := map[string]string{"version": "0.1"}
+	err := h(ctx, resp, req, vars)
+
+	assert.Error(t, err)
+	hdr := resp.Result().Header
+	assert.Contains(t, hdr.Get("Server"), "Docker/"+defaultVersion)
+	assert.Contains(t, hdr.Get("Server"), runtime.GOOS)
+	assert.Equal(t, hdr.Get("API-Version"), defaultVersion)
+	assert.Equal(t, hdr.Get("OSType"), runtime.GOOS)
+}