feat: return error response bodies in config svc

kong/config_service.go

@@ -13,7 +13,7 @@ type AbstractConfigService interface {
 	// API endpoint using the provided reader which should contain the JSON
 	// serialized body that adheres to the configuration format specified at:
 	// https://docs.konghq.com/gateway/latest/production/deployment-topologies/db-less-and-declarative-config/#declarative-configuration-format
-	ReloadDeclarativeRawConfig(ctx context.Context, config io.Reader, checkHash bool) error
+	ReloadDeclarativeRawConfig(ctx context.Context, config io.Reader, checkHash bool) ([]byte, error)
 }
 
 // ConfigService handles Config in Kong.
@@ -27,7 +27,7 @@ func (c *ConfigService) ReloadDeclarativeRawConfig(
 	ctx context.Context,
 	config io.Reader,
 	checkHash bool,
-) error {
+) ([]byte, error) {
 	type sendConfigParams struct {
 		CheckHash int `url:"check_hash"`
 	}
@@ -37,29 +37,30 @@ func (c *ConfigService) ReloadDeclarativeRawConfig(
 	}
 	req, err := c.client.NewRequest("POST", "/config", sendConfigParams{CheckHash: checkHashI}, config)
 	if err != nil {
-		return fmt.Errorf("creating new HTTP request for /config: %w", err)
+		return fmt.Errorf("creating new HTTP request for /config: %w", err), []byte{}
 	}
 
 	resp, err := c.client.DoRAW(ctx, req)
 	if err != nil {
-		return fmt.Errorf("failed posting new config to /config: %w", err)
+		return fmt.Errorf("failed posting new config to /config: %w", err), []byte{}
 	}
 	defer resp.Body.Close()
 
+	var b []byte
 	if resp.StatusCode < 200 || resp.StatusCode >= 400 {
-		b, err := io.ReadAll(resp.Body)
+		b, err = io.ReadAll(resp.Body)
 		if err != nil {
 			return fmt.Errorf(
 				"failed posting new config to /config: got status code %d (and failed to read the response body): %w",
 				resp.StatusCode, err,
-			)
+			), []byte{}
 		}
 
 		return fmt.Errorf(
 			"failed posting new config to /config: got status code %d, body: %s",
 			resp.StatusCode, b,
-		)
+		), b
 	}
 
-	return nil
+	return nil, b
 }

kong/config_service_test.go

@@ -76,7 +76,7 @@ func TestConfigService(t *testing.T) {
 			b, err := json.Marshal(tt.config)
 			require.NoError(t, err)
 
-			if err := client.Configs.ReloadDeclarativeRawConfig(ctx, bytes.NewBuffer(b), true); (err != nil) != tt.wantErr {
+			if err, _ := client.Configs.ReloadDeclarativeRawConfig(ctx, bytes.NewBuffer(b), true); (err != nil) != tt.wantErr {
 				t.Errorf("Client.SendConfig() error = %v, wantErr %v", err, tt.wantErr)
 			}
 		})