rcmgr: fix JSON marshalling of ResourceManagerStat peer map (#2156)

p2p/host/resource-manager/extapi.go

@@ -2,6 +2,7 @@ package rcmgr
 
 import (
 	"bytes"
+	"encoding/json"
 	"sort"
 	"strings"
 
@@ -35,6 +36,23 @@ type ResourceManagerStat struct {
 	Peers     map[peer.ID]network.ScopeStat
 }
 
+func (s ResourceManagerStat) MarshalJSON() ([]byte, error) {
+	// we want to marshal the encoded peer id
+	encodedPeerMap := make(map[string]network.ScopeStat, len(s.Peers))
+	for p, v := range s.Peers {
+		encodedPeerMap[p.String()] = v
+	}
+
+	type Alias ResourceManagerStat
+	return json.Marshal(&struct {
+		*Alias
+		Peers map[string]network.ScopeStat `json:",omitempty"`
+	}{
+		Alias: (*Alias)(&s),
+		Peers: encodedPeerMap,
+	})
+}
+
 var _ ResourceManagerState = (*resourceManager)(nil)
 
 func (s *resourceScope) Limit() Limit {

p2p/host/resource-manager/extapi_test.go

@@ -0,0 +1,26 @@
+package rcmgr
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/libp2p/go-libp2p/core/network"
+	"github.com/libp2p/go-libp2p/core/peer"
+	"github.com/stretchr/testify/require"
+)
+
+func TestResourceManagerStatRoundTrip(t *testing.T) {
+	validPeerID, err := peer.Decode("QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN")
+	require.NoError(t, err)
+
+	n := ResourceManagerStat{
+		Peers: map[peer.ID]network.ScopeStat{validPeerID: {}},
+	}
+	b, err := json.Marshal(n)
+	require.NoError(t, err)
+
+	rt := ResourceManagerStat{}
+	require.NoError(t, json.Unmarshal(b, &rt))
+
+	require.Equal(t, n, rt)
+}