feat: add prefix feature

Author: 110y

internal/config.go

@@ -5,6 +5,7 @@ const (
 	configKeyHeader                 = "header"
 	configKeyKey                    = "key"
 	configKeyValue                  = "value"
+	configKeyPrefix                 = "prefix"
 )
 
 type pluginConfiguration struct {
@@ -16,6 +17,7 @@ type requestHeaderToRename struct {
 }
 
 type headerValue struct {
-	key   string
-	value string
+	key    string
+	value  string
+	prefix string
 }

internal/http.go

@@ -17,7 +17,7 @@ type httpContext struct {
 
 func (c *httpContext) OnHttpRequestHeaders(_ int, _ bool) types.Action {
 	for _, requestHeaderToRename := range c.configuration.requestHeadersToRename {
-		if err := c.renameRequestHeader(requestHeaderToRename.header.key, requestHeaderToRename.header.value); err != nil {
+		if err := c.renameRequestHeader(requestHeaderToRename.header); err != nil {
 			setErrorHTTPResponseWithLog("failed to rename the header: %s", err)
 			return types.ActionPause
 		}
@@ -26,22 +26,27 @@ func (c *httpContext) OnHttpRequestHeaders(_ int, _ bool) types.Action {
 	return types.ActionContinue
 }
 
-func (c *httpContext) renameRequestHeader(origName, newName string) error {
-	value, err := proxywasm.GetHttpRequestHeader(origName)
+func (c *httpContext) renameRequestHeader(h headerValue) error {
+	value, err := proxywasm.GetHttpRequestHeader(h.key)
 	if err != nil {
 		if err == types.ErrorStatusNotFound {
 			return nil
 		}
 
-		return fmt.Errorf("failed to get the original header, `%s`: %w", origName, err)
+		return fmt.Errorf("failed to get the original header, `%s`: %w", h.key, err)
 	}
 
-	if err := proxywasm.ReplaceHttpRequestHeader(newName, value); err != nil {
-		return fmt.Errorf("failed to set the new header, `%s`: %w", newName, err)
+	newValue := value
+	if h.prefix != "" {
+		newValue = h.prefix + value
 	}
 
-	if err := proxywasm.RemoveHttpRequestHeader(origName); err != nil {
-		return fmt.Errorf("failed to delete the original header, `%s`: %w", origName, err)
+	if err := proxywasm.ReplaceHttpRequestHeader(h.value, newValue); err != nil {
+		return fmt.Errorf("failed to set the new header, `%s`: %w", h.value, err)
+	}
+
+	if err := proxywasm.RemoveHttpRequestHeader(h.key); err != nil {
+		return fmt.Errorf("failed to delete the original header, `%s`: %w", h.key, err)
 	}
 
 	return nil

internal/plugin.go

@@ -75,10 +75,13 @@ func getPluginConfiguration() (*pluginConfiguration, error) {
 			return nil, errors.New("the header value for renaming is empty")
 		}
 
+		prefix := h.Get(configKeyPrefix).String()
+
 		headersToRename[i] = requestHeaderToRename{
 			header: headerValue{
-				key:   key,
-				value: value,
+				key:    key,
+				value:  value,
+				prefix: prefix,
 			},
 		}
 	}

test/e2e_test.go

@@ -24,6 +24,7 @@ func TestE2E(t *testing.T) {
 
 	req.Header.Set("original-header-1", "original-header-value-1")
 	req.Header.Set("original-header-2", "original-header-value-2")
+	req.Header.Set("original-header-3", "original-header-value-3")
 
 	res, err := http.DefaultClient.Do(req)
 	if err != nil {
@@ -82,6 +83,20 @@ func TestE2E(t *testing.T) {
 		t.Error("original-header-2 header should be removed")
 		return
 	}
+
+	newHeader3, ok := echores.Headers["new-header-3"]
+	if !ok {
+		t.Error("new-header-3 header is not found")
+		return
+	}
+	if len(newHeader3.Value) != 1 {
+		t.Errorf("new-header-3 header has invalid number of values: %d", len(newHeader3.Value))
+		return
+	}
+	if newHeader3.Value[0] != "bearer original-header-value-3" {
+		t.Errorf("the value for new-header-3 is expected to be `bearer original-header-value3`, but got `%s`", newHeader3.Value[0])
+		return
+	}
 }
 
 func createHTTPRequest(host string) (*http.Request, error) {

test/envoy.yaml

@@ -58,6 +58,13 @@ static_resources:
                                       "key": "original-header-2",
                                       "value": "new-header-2"
                                     }
+                                  },
+                                  {
+                                    "header": {
+                                      "key": "original-header-3",
+                                      "value": "new-header-3",
+                                      "prefix": "bearer "
+                                    }
                                   }
                                 ]
                               }