rcmgr: fix: Ignore zero values when marshalling Limits. (#1998)

p2p/host/resource-manager/limit.go

@@ -87,14 +87,14 @@ func NewFixedLimiter(conf LimitConfig) Limiter {
 
 // BaseLimit is a mixin type for basic resource limits.
 type BaseLimit struct {
-	Streams         int
-	StreamsInbound  int
-	StreamsOutbound int
-	Conns           int
-	ConnsInbound    int
-	ConnsOutbound   int
-	FD              int
-	Memory          int64
+	Streams         int   `json:",omitempty"`
+	StreamsInbound  int   `json:",omitempty"`
+	StreamsOutbound int   `json:",omitempty"`
+	Conns           int   `json:",omitempty"`
+	ConnsInbound    int   `json:",omitempty"`
+	ConnsOutbound   int   `json:",omitempty"`
+	FD              int   `json:",omitempty"`
+	Memory          int64 `json:",omitempty"`
 }
 
 // Apply overwrites all zero-valued limits with the values of l2
@@ -128,16 +128,16 @@ func (l *BaseLimit) Apply(l2 BaseLimit) {
 
 // BaseLimitIncrease is the increase per GiB of allowed memory.
 type BaseLimitIncrease struct {
-	Streams         int
-	StreamsInbound  int
-	StreamsOutbound int
-	Conns           int
-	ConnsInbound    int
-	ConnsOutbound   int
+	Streams         int `json:",omitempty"`
+	StreamsInbound  int `json:",omitempty"`
+	StreamsOutbound int `json:",omitempty"`
+	Conns           int `json:",omitempty"`
+	ConnsInbound    int `json:",omitempty"`
+	ConnsOutbound   int `json:",omitempty"`
 	// Memory is in bytes. Values over 1>>30 (1GiB) don't make sense.
-	Memory int64
+	Memory int64 `json:",omitempty"`
 	// FDFraction is expected to be >= 0 and <= 1.
-	FDFraction float64
+	FDFraction float64 `json:",omitempty"`
 }
 
 // Apply overwrites all zero-valued limits with the values of l2

p2p/host/resource-manager/limit_test.go

@@ -1,6 +1,7 @@
 package rcmgr
 
 import (
+	"encoding/json"
 	"runtime"
 	"testing"
 
@@ -141,3 +142,21 @@ func TestReadmeExample(t *testing.T) {
 	require.Equal(t, 384, limitConf.System.Conns)
 	require.Equal(t, 1000, limitConf.System.FD)
 }
+
+func TestSerializeJSON(t *testing.T) {
+	bl := BaseLimit{
+		Streams: 10,
+	}
+
+	out, err := json.Marshal(bl)
+	require.NoError(t, err)
+	require.Equal(t, "{\"Streams\":10}", string(out))
+
+	bli := BaseLimitIncrease{
+		Streams: 10,
+	}
+
+	out, err = json.Marshal(bli)
+	require.NoError(t, err)
+	require.Equal(t, "{\"Streams\":10}", string(out))
+}