api: return 400 in case of non-existent config fields (#2425)

internal/conf/conf.go

@@ -335,7 +335,9 @@ func (conf *Conf) Check() error {
 	return nil
 }
 
-// UnmarshalJSON implements json.Unmarshaler. It is used to set default values.
+// UnmarshalJSON implements json.Unmarshaler. It is used to:
+// - force DisallowUnknownFields
+// - set default values
 func (conf *Conf) UnmarshalJSON(b []byte) error {
 	// general
 	conf.LogLevel = LogLevel(logger.Info)

internal/conf/path.go

@@ -447,7 +447,9 @@ func (pconf PathConf) HasOnDemandPublisher() bool {
 	return pconf.RunOnDemand != ""
 }
 
-// UnmarshalJSON implements json.Unmarshaler. It is used to set default values.
+// UnmarshalJSON implements json.Unmarshaler. It is used to:
+// - force DisallowUnknownFields
+// - set default values
 func (pconf *PathConf) UnmarshalJSON(b []byte) error {
 	// General
 	pconf.Source = "publisher"

internal/core/api.go

@@ -63,7 +63,9 @@ func generateStructWithOptionalFields(model interface{}) interface{} {
 
 func loadConfData(ctx *gin.Context) (interface{}, error) {
 	in := generateStructWithOptionalFields(conf.Conf{})
-	err := json.NewDecoder(ctx.Request.Body).Decode(in)
+	d := json.NewDecoder(ctx.Request.Body)
+	d.DisallowUnknownFields()
+	err := d.Decode(in)
 	if err != nil {
 		return nil, err
 	}
@@ -73,7 +75,9 @@ func loadConfData(ctx *gin.Context) (interface{}, error) {
 
 func loadConfPathData(ctx *gin.Context) (interface{}, error) {
 	in := generateStructWithOptionalFields(conf.PathConf{})
-	err := json.NewDecoder(ctx.Request.Body).Decode(in)
+	d := json.NewDecoder(ctx.Request.Body)
+	d.DisallowUnknownFields()
+	err := d.Decode(in)
 	if err != nil {
 		return nil, err
 	}

internal/core/api_test.go

@@ -155,6 +155,29 @@ func TestAPIConfigSet(t *testing.T) {
 	require.Equal(t, []interface{}{"tcp"}, out["protocols"])
 }
 
+func TestAPIConfigSetUnknownField(t *testing.T) {
+	p, ok := newInstance("api: yes\n")
+	require.Equal(t, true, ok)
+	defer p.Close()
+
+	b := map[string]interface{}{
+		"test": "asd",
+	}
+
+	byts, err := json.Marshal(b)
+	require.NoError(t, err)
+
+	hc := &http.Client{Transport: &http.Transport{}}
+
+	req, err := http.NewRequest("POST", "http://localhost:9997/v2/config/set", bytes.NewReader(byts))
+	require.NoError(t, err)
+
+	res, err := hc.Do(req)
+	require.NoError(t, err)
+	defer res.Body.Close()
+	require.Equal(t, http.StatusBadRequest, res.StatusCode)
+}
+
 func TestAPIConfigPathsAdd(t *testing.T) {
 	p, ok := newInstance("api: yes\n")
 	require.Equal(t, true, ok)
@@ -179,6 +202,29 @@ func TestAPIConfigPathsAdd(t *testing.T) {
 	require.Equal(t, "10s", out.Paths["my/path"].SourceOnDemandStartTimeout)
 }
 
+func TestAPIConfigPathsAddUnknownField(t *testing.T) {
+	p, ok := newInstance("api: yes\n")
+	require.Equal(t, true, ok)
+	defer p.Close()
+
+	b := map[string]interface{}{
+		"test": "asd",
+	}
+
+	byts, err := json.Marshal(b)
+	require.NoError(t, err)
+
+	hc := &http.Client{Transport: &http.Transport{}}
+
+	req, err := http.NewRequest("POST", "http://localhost:9997/v2/config/paths/add/my/path", bytes.NewReader(byts))
+	require.NoError(t, err)
+
+	res, err := hc.Do(req)
+	require.NoError(t, err)
+	defer res.Body.Close()
+	require.Equal(t, http.StatusBadRequest, res.StatusCode)
+}
+
 func TestAPIConfigPathsEdit(t *testing.T) {
 	p, ok := newInstance("api: yes\n")
 	require.Equal(t, true, ok)