Remove omitempty in order to permit update with empty values (#233)

service_user.go

@@ -1,8 +1,10 @@
 package aiven
 
 import (
+	"encoding/json"
 	"errors"
 	"fmt"
+	"reflect"
 )
 
 const (
@@ -23,12 +25,12 @@ type (
 	}
 
 	AccessControl struct {
-		M3Group                  *string  `json:"m3_group,omitempty"`
-		RedisACLCategories       []string `json:"redis_acl_categories,omitempty"`
-		RedisACLCommands         []string `json:"redis_acl_commands,omitempty"`
-		RedisACLKeys             []string `json:"redis_acl_keys,omitempty"`
-		RedisACLChannels         []string `json:"redis_acl_channels,omitempty"`
-		PostgresAllowReplication *bool    `json:"pg_allow_replication,omitempty"`
+		M3Group                  *string  `json:"m3_group"`
+		RedisACLCategories       []string `json:"redis_acl_categories"`
+		RedisACLCommands         []string `json:"redis_acl_commands"`
+		RedisACLKeys             []string `json:"redis_acl_keys"`
+		RedisACLChannels         []string `json:"redis_acl_channels"`
+		PostgresAllowReplication *bool    `json:"pg_allow_replication"`
 	}
 
 	// ServiceUsersHandler is the client that interacts with the ServiceUsers
@@ -59,6 +61,28 @@ type (
 	}
 )
 
+// MarshalJSON implements a custom marshalling process for AccessControl where only null fields are omitted
+func (ac AccessControl) MarshalJSON() ([]byte, error) {
+	out := make(map[string]interface{})
+
+	fields := reflect.TypeOf(ac)
+	values := reflect.ValueOf(ac)
+
+	for i := 0; i < fields.NumField(); i++ {
+		field := fields.Field(i)
+		value := values.Field(i)
+
+		switch value.Kind() {
+		case reflect.Pointer, reflect.Slice: // *string, *bool, []string
+			if !value.IsNil() {
+				jsonName := field.Tag.Get("json")
+				out[jsonName] = value.Interface()
+			}
+		}
+	}
+	return json.Marshal(out)
+}
+
 // Create creates the given User on Aiven.
 func (h *ServiceUsersHandler) Create(project, service string, req CreateServiceUserRequest) (*ServiceUser, error) {
 	path := buildPath("project", project, "service", service, "user")

service_user_test.go

@@ -0,0 +1,63 @@
+package aiven
+
+import (
+	"bytes"
+	"encoding/json"
+	"reflect"
+	"testing"
+)
+
+// TestAccessControlMarshalJSON test AccessControl JSON marshalling process
+func TestAccessControlMarshalJSON(t *testing.T) {
+	strPtr := func(s string) *string {
+		return &s
+	}
+	type notEmpty struct {
+		M3Group      string   `json:"m3_group"`
+		RedisACLKeys []string `json:"redis_acl_keys"`
+	}
+
+	tests := []struct {
+		name     string
+		input    *AccessControl
+		wantType interface{}
+		want     interface{}
+	}{
+		{
+			name:     "empty",
+			input:    &AccessControl{},
+			wantType: &map[string]interface{}{},
+			want:     &map[string]interface{}{},
+		},
+		{
+			name: "notempty",
+			input: &AccessControl{
+				M3Group:      strPtr("foo"),
+				RedisACLKeys: []string{"bar"},
+			},
+			wantType: &notEmpty{},
+			want: &notEmpty{
+				M3Group:      "foo",
+				RedisACLKeys: []string{"bar"},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			b, err := json.Marshal(tt.input)
+			if err != nil {
+				t.Errorf("MarshalJSON() error = %v", err)
+				return
+			}
+
+			dec := json.NewDecoder(bytes.NewReader(b))
+			dec.DisallowUnknownFields()
+			if err := dec.Decode(tt.wantType); err != nil {
+				t.Errorf("Decode() error = %v", err)
+			}
+			if !reflect.DeepEqual(tt.wantType, tt.want) {
+				t.Errorf("DeepEqual() got = %+v, want = %+v", tt.wantType, tt.want)
+			}
+		})
+	}
+}