Fix parsing dynamic config numbers (#231)

server/commands.go

@@ -27,6 +27,7 @@
 package server
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"net"
@@ -353,8 +354,21 @@ func getDynamicConfigValues(input []string) (map[dynamicconfig.Key][]dynamicconf
 		key := dynamicconfig.Key(keyVal[0])
 		// We don't support constraints currently
 		var val dynamicconfig.ConstrainedValue
-		if err := json.Unmarshal([]byte(keyVal[1]), &val.Value); err != nil {
-			return nil, fmt.Errorf("invalid JSON value for key %q: %w", key, err)
+		dec := json.NewDecoder(bytes.NewReader([]byte(keyVal[1])))
+		dec.UseNumber()
+		if err := dec.Decode(&val.Value); err != nil || dec.InputOffset() != int64(len(keyVal[1])) {
+			return nil, fmt.Errorf("invalid JSON value for key %q", key)
+		}
+		if num, ok := val.Value.(json.Number); ok {
+			if v, err := num.Int64(); err == nil {
+				// dynamic config only accepts int type, not int32 nor int64
+				val.Value = int(v)
+			} else if v, err := num.Float64(); err == nil {
+				val.Value = v
+			} else {
+				// should not be possible: decoded json.Number must be parsable to int64 or float64
+				return nil, fmt.Errorf("invalid JSON value for key %q", key)
+			}
 		}
 		ret[key] = append(ret[key], val)
 	}

server/commands_test.go

@@ -59,9 +59,9 @@ func TestGetDynamicConfigValues(t *testing.T) {
 	assertBadVal("foo=bar")
 	assertBadVal("foo=123a")
 
-	assertGoodVals(v{"foo": {123.0}}, "foo=123")
+	assertGoodVals(v{"foo": {123}}, "foo=123")
 	assertGoodVals(
-		v{"foo": {123.0, []interface{}{"123", false}}, "bar": {"baz"}, "qux": {true}},
+		v{"foo": {123, []interface{}{"123", false}}, "bar": {"baz"}, "qux": {true}},
 		"foo=123", `bar="baz"`, "qux=true", `foo=["123", false]`,
 	)
 }