Fix JSON marshalling

Signed-off-by: Marco Pracucci <[email protected]>

Author: pracucci

config/headers.go

@@ -17,6 +17,7 @@
 package config
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/http"
 	"os"
@@ -50,17 +51,22 @@ var reservedHeaders = map[string]struct{}{
 
 // Headers represents the configuration for HTTP headers.
 type Headers struct {
-	Headers map[string]Header `yaml:",inline" json:",inline"`
+	Headers map[string]Header `yaml:",inline"`
 	dir     string
 }
 
-// Headers represents the configuration for HTTP headers.
+// Header represents the configuration for a single HTTP header.
 type Header struct {
 	Values  []string `yaml:"values,omitempty" json:"values,omitempty"`
 	Secrets []Secret `yaml:"secrets,omitempty" json:"secrets,omitempty"`
 	Files   []string `yaml:"files,omitempty" json:"files,omitempty"`
 }
 
+func (h Headers) MarshalJSON() ([]byte, error) {
+	// Inline the Headers map when serializing JSON because json encoder doesn't support "inline" directive.
+	return json.Marshal(h.Headers)
+}
+
 // SetDirectory records the directory to make headers file relative to the
 // configuration file.
 func (h *Headers) SetDirectory(dir string) {

config/http_config_test.go

@@ -2014,7 +2014,6 @@ func TestHTTPClientConfig_Marshal(t *testing.T) {
 			ProxyConfig: ProxyConfig{
 				ProxyURL: URL{proxyURL},
 			},
-			HTTPHeaders: &Headers{},
 		}
 
 		t.Run("YAML", func(t *testing.T) {
@@ -2024,7 +2023,7 @@ func TestHTTPClientConfig_Marshal(t *testing.T) {
 proxy_url: "http://localhost:8080"
 follow_redirects: false
 enable_http2: false
-http_headers: {}
+http_headers: null
 `, string(actualYAML))
 
 			// Unmarshalling the YAML should get the same struct in input.
@@ -2042,7 +2041,7 @@ http_headers: {}
 				"tls_config":{"insecure_skip_verify":false},
 				"follow_redirects":false,
 				"enable_http2":false,
-				"http_headers":{}
+				"http_headers":null
 			}`, string(actualJSON))
 
 			// Unmarshalling the JSON should get the same struct in input.