DVT-1057 replace block data structure with LRU cache to fix memory leak

cmd/monitor/monitor.go

@@ -8,6 +8,7 @@ import (
 	"sync"
 	"time"
 
+	lru "github.com/hashicorp/golang-lru"
 	"github.com/maticnetwork/polygon-cli/util"
 
 	_ "embed"
@@ -41,9 +42,8 @@ type (
 		PeerCount    uint64
 		GasPrice     *big.Int
 		PendingCount uint64
+		BlockCache   *lru.Cache
 
-		Blocks            map[string]rpctypes.PolyBlock `json:"-"`
-		BlocksLock        sync.RWMutex                  `json:"-"`
 		MaxBlockRetrieved *big.Int
 		MinBlockRetrieved *big.Int
 	}
@@ -91,31 +91,35 @@ func monitor(ctx context.Context) error {
 	ec := ethclient.NewClient(rpc)
 
 	ms := new(monitorStatus)
+	ms.BlockCache, _ = lru.New(1000)
 	ms.MaxBlockRetrieved = big.NewInt(0)
-	ms.BlocksLock.Lock()
-	ms.Blocks = make(map[string]rpctypes.PolyBlock, 0)
-	ms.BlocksLock.Unlock()
+
 	ms.ChainID = big.NewInt(0)
 	ms.PendingCount = 0
 	observedPendingTxs = make(historicalRange, 0)
 
 	isUiRendered := false
 	errChan := make(chan error)
 	go func() {
-		for {
-			err = fetchBlocks(ctx, ec, ms, rpc, isUiRendered)
-			if err != nil {
-				continue
-			}
+		select {
+		case <-ctx.Done(): // listens for a cancellation signal
+			return // exit the goroutine when the context is done
+		default:
+			for {
+				err = fetchBlocks(ctx, ec, ms, rpc, isUiRendered)
+				if err != nil {
+					continue
+				}
 
-			if !isUiRendered {
-				go func() {
-					errChan <- renderMonitorUI(ctx, ec, ms, rpc)
-				}()
-				isUiRendered = true
-			}
+				if !isUiRendered {
+					go func() {
+						errChan <- renderMonitorUI(ctx, ec, ms, rpc)
+					}()
+					isUiRendered = true
+				}
 
-			time.Sleep(interval)
+				time.Sleep(interval)
+			}
 		}
 	}()
 
@@ -220,6 +224,8 @@ func appendOlderBlocks(ctx context.Context, ms *monitorStatus, rpc *ethrpc.Clien
 	return nil
 }
 
+const maxHistoricalPoints = 1000 // Set a limit to the number of historical points
+
 func fetchBlocks(ctx context.Context, ec *ethclient.Client, ms *monitorStatus, rpc *ethrpc.Client, isUiRendered bool) (err error) {
 	var cs *chainState
 	cs, err = getChainState(ctx, ec)
@@ -228,6 +234,10 @@ func fetchBlocks(ctx context.Context, ec *ethclient.Client, ms *monitorStatus, r
 		time.Sleep(interval)
 		return err
 	}
+	if len(observedPendingTxs) >= maxHistoricalPoints {
+		// Remove the oldest data point
+		observedPendingTxs = observedPendingTxs[1:]
+	}
 	observedPendingTxs = append(observedPendingTxs, historicalDataPoint{SampleTime: time.Now(), SampleValue: float64(cs.PendingCount)})
 
 	log.Debug().Uint64("PeerCount", cs.PeerCount).Uint64("ChainID", cs.ChainID.Uint64()).Uint64("HeadBlock", cs.HeadBlock).Uint64("GasPrice", cs.GasPrice.Uint64()).Msg("Fetching blocks")
@@ -307,9 +317,7 @@ func (ms *monitorStatus) getBlockRange(ctx context.Context, from, to *big.Int, r
 		}
 		pb := rpctypes.NewPolyBlock(b.Result.(*rpctypes.RawBlockResponse))
 
-		ms.BlocksLock.Lock()
-		ms.Blocks[pb.Number().String()] = pb
-		ms.BlocksLock.Unlock()
+		ms.BlockCache.Add(pb.Number().String(), pb)
 
 		if ms.MaxBlockRetrieved.Cmp(pb.Number()) == -1 {
 			ms.MaxBlockRetrieved = pb.Number()
@@ -416,18 +424,24 @@ func setUISkeleton() (blockTable *widgets.List, grid *ui.Grid, blockGrid *ui.Gri
 }
 
 func updateAllBlocks(ms *monitorStatus) []rpctypes.PolyBlock {
-	// default
-	blocks := make([]rpctypes.PolyBlock, 0)
-
-	ms.BlocksLock.RLock()
-	for _, b := range ms.Blocks {
-		blocks = append(blocks, b)
+	var blocks []rpctypes.PolyBlock
+
+	// Retrieve all current items from the LRU cache.
+	// Since the cache has no inherent order, we will need to sort them if necessary.
+	for _, key := range ms.BlockCache.Keys() {
+		if value, ok := ms.BlockCache.Peek(key); ok {
+			block, ok := value.(rpctypes.PolyBlock)
+			if ok {
+				blocks = append(blocks, block)
+			}
+		}
 	}
-	ms.BlocksLock.RUnlock()
 
-	allBlocks := metrics.SortableBlocks(blocks)
+	// Assuming blocks need to be sorted, you'd sort them here.
+	// This assumes that metrics.SortableBlocks is a type that can be sorted.
+	sort.Sort(metrics.SortableBlocks(blocks))
 
-	return allBlocks
+	return blocks
 }
 
 func renderMonitorUI(ctx context.Context, ec *ethclient.Client, ms *monitorStatus, rpc *ethrpc.Client) error {
@@ -512,7 +526,8 @@ func renderMonitorUI(ctx context.Context, ec *ethclient.Client, ms *monitorStatu
 
 	currentBn := ms.HeadBlock
 	uiEvents := ui.PollEvents()
-	ticker := time.NewTicker(time.Second).C
+	ticker := time.NewTicker(time.Second)
+	defer ticker.Stop()
 
 	redraw(ms)
 
@@ -653,7 +668,7 @@ func renderMonitorUI(ctx context.Context, ec *ethclient.Client, ms *monitorStatu
 			if !forceRedraw {
 				redraw(ms)
 			}
-		case <-ticker:
+		case <-ticker.C:
 			if currentBn != ms.HeadBlock {
 				currentBn = ms.HeadBlock
 				redraw(ms)

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/ethereum/go-ethereum v1.13.2
 	github.com/gizak/termui/v3 v3.1.0
 	github.com/google/gofuzz v1.2.0
+	github.com/hashicorp/golang-lru v1.0.2
 	github.com/jedib0t/go-pretty/v6 v6.4.8
 	github.com/libp2p/go-libp2p v0.31.0
 	github.com/oasisprotocol/curve25519-voi v0.0.0-20230904125328-1f23a7beb09a

go.sum

@@ -294,6 +294,10 @@ github.com/hashicorp/go-bexpr v0.1.10/go.mod h1:oxlubA2vC/gFVfX1A6JGp7ls7uCDlfJn
 github.com/hashicorp/go-version v1.2.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
+github.com/hashicorp/golang-lru v0.5.4 h1:YDjusn29QI/Das2iO9M0BHnIbxPeyuCHsjMW+lJfyTc=
+github.com/hashicorp/golang-lru v0.5.4/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
+github.com/hashicorp/golang-lru v1.0.2 h1:dV3g9Z/unq5DpblPpw+Oqcv4dU/1omnb4Ok8iPY6p1c=
+github.com/hashicorp/golang-lru v1.0.2/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
 github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
 github.com/holiman/billy v0.0.0-20230718173358-1c7e68d277a7 h1:3JQNjnMRil1yD0IfZKHF9GxxWKDJGj8I0IqOUol//sw=