p2p/simulation: Test snapshot correctness and minimal benchmark (#18287)

* p2p/simulation: WIP minimal snapshot test

* p2p/simulation: Add snapshot create, load and verify to snapshot test

* build: add test tag for tests

* p2p/simulations, build: Revert travis change, build test sym always

* p2p/simulations: Add comments, timeout check on additional events

* p2p/simulation: Add benchmark template for minimal peer protocol init

* p2p/simulations: Remove unused code

* p2p/simulation: Correct timer reset

* p2p/simulations: Put snapshot check events in buffer and call blocking

* p2p/simulations: TestSnapshot fail if Load function returns early

* p2p/simulations: TestSnapshot wait for all connections before returning

* p2p/simulation: Revert to before wait for snap load (5e75594)

* p2p/simulations: add "conns after load" subtest to TestSnapshot

and nudge

2 files changed, 336 insertions, 26 deletions

diff --git a/p2p/simulations/network_test.go b/p2p/simulations/network_test.go
index f34935265..b7852addb 100644
--- a/p2p/simulations/network_test.go
+++ b/p2p/simulations/network_test.go
@@ -18,14 +18,266 @@ package simulations
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
+	"strconv"
+	"strings"
 	"testing"
 	"time"
 
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/node"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
 )
 
+// Tests that a created snapshot with a minimal service only contains the expected connections
+// and that a network when loaded with this snapshot only contains those same connections
+func TestSnapshot(t *testing.T) {
+
+	// PART I
+	// create snapshot from ring network
+
+	// this is a minimal service, whose protocol will take exactly one message OR close of connection before quitting
+	adapter := adapters.NewSimAdapter(adapters.Services{
+		"noopwoop": func(ctx *adapters.ServiceContext) (node.Service, error) {
+			return NewNoopService(nil), nil
+		},
+	})
+
+	// create network
+	network := NewNetwork(adapter, &NetworkConfig{
+		DefaultService: "noopwoop",
+	})
+	// \todo consider making a member of network, set to true threadsafe when shutdown
+	runningOne := true
+	defer func() {
+		if runningOne {
+			network.Shutdown()
+		}
+	}()
+
+	// create and start nodes
+	nodeCount := 20
+	ids := make([]enode.ID, nodeCount)
+	for i := 0; i < nodeCount; i++ {
+		conf := adapters.RandomNodeConfig()
+		node, err := network.NewNodeWithConfig(conf)
+		if err != nil {
+			t.Fatalf("error creating node: %s", err)
+		}
+		if err := network.Start(node.ID()); err != nil {
+			t.Fatalf("error starting node: %s", err)
+		}
+		ids[i] = node.ID()
+	}
+
+	// subscribe to peer events
+	evC := make(chan *Event)
+	sub := network.Events().Subscribe(evC)
+	defer sub.Unsubscribe()
+
+	// connect nodes in a ring
+	// spawn separate thread to avoid deadlock in the event listeners
+	go func() {
+		for i, id := range ids {
+			peerID := ids[(i+1)%len(ids)]
+			if err := network.Connect(id, peerID); err != nil {
+				t.Fatal(err)
+			}
+		}
+	}()
+
+	// collect connection events up to expected number
+	ctx, cancel := context.WithTimeout(context.TODO(), time.Second)
+	defer cancel()
+	checkIds := make(map[enode.ID][]enode.ID)
+	connEventCount := nodeCount
+OUTER:
+	for {
+		select {
+		case <-ctx.Done():
+			t.Fatal(ctx.Err())
+		case ev := <-evC:
+			if ev.Type == EventTypeConn && !ev.Control {
+
+				// fail on any disconnect
+				if !ev.Conn.Up {
+					t.Fatalf("unexpected disconnect: %v -> %v", ev.Conn.One, ev.Conn.Other)
+				}
+				checkIds[ev.Conn.One] = append(checkIds[ev.Conn.One], ev.Conn.Other)
+				checkIds[ev.Conn.Other] = append(checkIds[ev.Conn.Other], ev.Conn.One)
+				connEventCount--
+				log.Debug("ev", "count", connEventCount)
+				if connEventCount == 0 {
+					break OUTER
+				}
+			}
+		}
+	}
+
+	// create snapshot of current network
+	snap, err := network.Snapshot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	j, err := json.Marshal(snap)
+	if err != nil {
+		t.Fatal(err)
+	}
+	log.Debug("snapshot taken", "nodes", len(snap.Nodes), "conns", len(snap.Conns), "json", string(j))
+
+	// verify that the snap element numbers check out
+	if len(checkIds) != len(snap.Conns) || len(checkIds) != len(snap.Nodes) {
+		t.Fatalf("snapshot wrong node,conn counts %d,%d != %d", len(snap.Nodes), len(snap.Conns), len(checkIds))
+	}
+
+	// shut down sim network
+	runningOne = false
+	sub.Unsubscribe()
+	network.Shutdown()
+
+	// check that we have all the expected connections in the snapshot
+	for nodid, nodConns := range checkIds {
+		for _, nodConn := range nodConns {
+			var match bool
+			for _, snapConn := range snap.Conns {
+				if snapConn.One == nodid && snapConn.Other == nodConn {
+					match = true
+					break
+				} else if snapConn.Other == nodid && snapConn.One == nodConn {
+					match = true
+					break
+				}
+			}
+			if !match {
+				t.Fatalf("snapshot missing conn %v -> %v", nodid, nodConn)
+			}
+		}
+	}
+	log.Info("snapshot checked")
+
+	// PART II
+	// load snapshot and verify that exactly same connections are formed
+
+	adapter = adapters.NewSimAdapter(adapters.Services{
+		"noopwoop": func(ctx *adapters.ServiceContext) (node.Service, error) {
+			return NewNoopService(nil), nil
+		},
+	})
+	network = NewNetwork(adapter, &NetworkConfig{
+		DefaultService: "noopwoop",
+	})
+	defer func() {
+		network.Shutdown()
+	}()
+
+	// subscribe to peer events
+	// every node up and conn up event will generate one additional control event
+	// therefore multiply the count by two
+	evC = make(chan *Event, (len(snap.Conns)*2)+(len(snap.Nodes)*2))
+	sub = network.Events().Subscribe(evC)
+	defer sub.Unsubscribe()
+
+	// load the snapshot
+	// spawn separate thread to avoid deadlock in the event listeners
+	err = network.Load(snap)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// collect connection events up to expected number
+	ctx, cancel = context.WithTimeout(context.TODO(), time.Second*3)
+	defer cancel()
+
+	connEventCount = nodeCount
+
+OUTER_TWO:
+	for {
+		select {
+		case <-ctx.Done():
+			t.Fatal(ctx.Err())
+		case ev := <-evC:
+			if ev.Type == EventTypeConn && !ev.Control {
+
+				// fail on any disconnect
+				if !ev.Conn.Up {
+					t.Fatalf("unexpected disconnect: %v -> %v", ev.Conn.One, ev.Conn.Other)
+				}
+				log.Debug("conn", "on", ev.Conn.One, "other", ev.Conn.Other)
+				checkIds[ev.Conn.One] = append(checkIds[ev.Conn.One], ev.Conn.Other)
+				checkIds[ev.Conn.Other] = append(checkIds[ev.Conn.Other], ev.Conn.One)
+				connEventCount--
+				log.Debug("ev", "count", connEventCount)
+				if connEventCount == 0 {
+					break OUTER_TWO
+				}
+			}
+		}
+	}
+
+	// check that we have all expected connections in the network
+	for _, snapConn := range snap.Conns {
+		var match bool
+		for nodid, nodConns := range checkIds {
+			for _, nodConn := range nodConns {
+				if snapConn.One == nodid && snapConn.Other == nodConn {
+					match = true
+					break
+				} else if snapConn.Other == nodid && snapConn.One == nodConn {
+					match = true
+					break
+				}
+			}
+		}
+		if !match {
+			t.Fatalf("network missing conn %v -> %v", snapConn.One, snapConn.Other)
+		}
+	}
+
+	// verify that network didn't generate any other additional connection events after the ones we have collected within a reasonable period of time
+	ctx, cancel = context.WithTimeout(context.TODO(), time.Second)
+	defer cancel()
+	select {
+	case <-ctx.Done():
+	case ev := <-evC:
+		if ev.Type == EventTypeConn {
+			t.Fatalf("Superfluous conn found %v -> %v", ev.Conn.One, ev.Conn.Other)
+		}
+	}
+
+	// This test validates if all connections from the snapshot
+	// are created in the network.
+	t.Run("conns after load", func(t *testing.T) {
+		// Create new network.
+		n := NewNetwork(
+			adapters.NewSimAdapter(adapters.Services{
+				"noopwoop": func(ctx *adapters.ServiceContext) (node.Service, error) {
+					return NewNoopService(nil), nil
+				},
+			}),
+			&NetworkConfig{
+				DefaultService: "noopwoop",
+			},
+		)
+		defer n.Shutdown()
+
+		// Load the same snapshot.
+		err := n.Load(snap)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Check every connection from the snapshot
+		// if it is in the network, too.
+		for _, c := range snap.Conns {
+			if n.GetConn(c.One, c.Other) == nil {
+				t.Errorf("missing connection: %s -> %s", c.One, c.Other)
+			}
+		}
+	})
+}
+
 // TestNetworkSimulation creates a multi-node simulation network with each node
 // connected in a ring topology, checks that all nodes successfully handshake
 // with each other and that a snapshot fully represents the desired topology
@@ -158,3 +410,78 @@ func triggerChecks(ctx context.Context, ids []enode.ID, trigger chan enode.ID, i
 		}
 	}
 }
+
+// \todo: refactor to implement shapshots
+// and connect configuration methods once these are moved from
+// swarm/network/simulations/connect.go
+func BenchmarkMinimalService(b *testing.B) {
+	b.Run("ring/32", benchmarkMinimalServiceTmp)
+}
+
+func benchmarkMinimalServiceTmp(b *testing.B) {
+
+	// stop timer to discard setup time pollution
+	args := strings.Split(b.Name(), "/")
+	nodeCount, err := strconv.ParseInt(args[2], 10, 16)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	for i := 0; i < b.N; i++ {
+		// this is a minimal service, whose protocol will close a channel upon run of protocol
+		// making it possible to bench the time it takes for the service to start and protocol actually to be run
+		protoCMap := make(map[enode.ID]map[enode.ID]chan struct{})
+		adapter := adapters.NewSimAdapter(adapters.Services{
+			"noopwoop": func(ctx *adapters.ServiceContext) (node.Service, error) {
+				protoCMap[ctx.Config.ID] = make(map[enode.ID]chan struct{})
+				svc := NewNoopService(protoCMap[ctx.Config.ID])
+				return svc, nil
+			},
+		})
+
+		// create network
+		network := NewNetwork(adapter, &NetworkConfig{
+			DefaultService: "noopwoop",
+		})
+		defer network.Shutdown()
+
+		// create and start nodes
+		ids := make([]enode.ID, nodeCount)
+		for i := 0; i < int(nodeCount); i++ {
+			conf := adapters.RandomNodeConfig()
+			node, err := network.NewNodeWithConfig(conf)
+			if err != nil {
+				b.Fatalf("error creating node: %s", err)
+			}
+			if err := network.Start(node.ID()); err != nil {
+				b.Fatalf("error starting node: %s", err)
+			}
+			ids[i] = node.ID()
+		}
+
+		// ready, set, go
+		b.ResetTimer()
+
+		// connect nodes in a ring
+		for i, id := range ids {
+			peerID := ids[(i+1)%len(ids)]
+			if err := network.Connect(id, peerID); err != nil {
+				b.Fatal(err)
+			}
+		}
+
+		// wait for all protocols to signal to close down
+		ctx, cancel := context.WithTimeout(context.TODO(), time.Second)
+		defer cancel()
+		for nodid, peers := range protoCMap {
+			for peerid, peerC := range peers {
+				log.Debug("getting ", "node", nodid, "peer", peerid)
+				select {
+				case <-ctx.Done():
+					b.Fatal(ctx.Err())
+				case <-peerC:
+				}
+			}
+		}
+	}
+}
diff --git a/swarm/network/simulation/simulation_test.go b/swarm/network/simulation/simulation_test.go
index ca8599d7c..4667a2abc 100644
--- a/swarm/network/simulation/simulation_test.go
+++ b/swarm/network/simulation/simulation_test.go
@@ -26,9 +26,8 @@ import (
 
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/node"
-	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/p2p/simulations"
 	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
-	"github.com/ethereum/go-ethereum/rpc"
 	colorable "github.com/mattn/go-colorable"
 )
 
@@ -182,39 +181,23 @@ func noopServiceFunc(ctx *adapters.ServiceContext, b *sync.Map) (node.Service, f
 	return newNoopService(), nil, nil
 }
 
-// noopService is the service that does not do anything
-// but implements node.Service interface.
-type noopService struct{}
-
 func newNoopService() node.Service {
 	return &noopService{}
 }
 
-func (t *noopService) Protocols() []p2p.Protocol {
-	return []p2p.Protocol{}
-}
-
-func (t *noopService) APIs() []rpc.API {
-	return []rpc.API{}
-}
-
-func (t *noopService) Start(server *p2p.Server) error {
-	return nil
-}
-
-func (t *noopService) Stop() error {
-	return nil
-}
-
-// a helper function for most basic noop service
-// of a different type then noopService to test
+// a helper function for most basic Noop service
+// of a different type then NoopService to test
 // multiple services on one node.
 func noopService2Func(ctx *adapters.ServiceContext, b *sync.Map) (node.Service, func(), error) {
 	return new(noopService2), nil, nil
 }
 
-// noopService2 is the service that does not do anything
+// NoopService2 is the service that does not do anything
 // but implements node.Service interface.
 type noopService2 struct {
-	noopService
+	simulations.NoopService
+}
+
+type noopService struct {
+	simulations.NoopService
 }