swarm: codebase split from go-ethereum (#1405)

network/simulation/bucket.go

@@ -0,0 +1,79 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import "github.com/ethereum/go-ethereum/p2p/enode"
+
+// BucketKey is the type that should be used for keys in simulation buckets.
+type BucketKey string
+
+// NodeItem returns an item set in ServiceFunc function for a particular node.
+func (s *Simulation) NodeItem(id enode.ID, key interface{}) (value interface{}, ok bool) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if _, ok := s.buckets[id]; !ok {
+		return nil, false
+	}
+	return s.buckets[id].Load(key)
+}
+
+// SetNodeItem sets a new item associated with the node with provided NodeID.
+// Buckets should be used to avoid managing separate simulation global state.
+func (s *Simulation) SetNodeItem(id enode.ID, key interface{}, value interface{}) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.buckets[id].Store(key, value)
+}
+
+// NodesItems returns a map of items from all nodes that are all set under the
+// same BucketKey.
+func (s *Simulation) NodesItems(key interface{}) (values map[enode.ID]interface{}) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	ids := s.NodeIDs()
+	values = make(map[enode.ID]interface{}, len(ids))
+	for _, id := range ids {
+		if _, ok := s.buckets[id]; !ok {
+			continue
+		}
+		if v, ok := s.buckets[id].Load(key); ok {
+			values[id] = v
+		}
+	}
+	return values
+}
+
+// UpNodesItems returns a map of items with the same BucketKey from all nodes that are up.
+func (s *Simulation) UpNodesItems(key interface{}) (values map[enode.ID]interface{}) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	ids := s.UpNodeIDs()
+	values = make(map[enode.ID]interface{})
+	for _, id := range ids {
+		if _, ok := s.buckets[id]; !ok {
+			continue
+		}
+		if v, ok := s.buckets[id].Load(key); ok {
+			values[id] = v
+		}
+	}
+	return values
+}

network/simulation/bucket_test.go

@@ -0,0 +1,155 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/node"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+)
+
+// TestServiceBucket tests all bucket functionality using subtests.
+// It constructs a simulation of two nodes by adding items to their buckets
+// in ServiceFunc constructor, then by SetNodeItem. Testing UpNodesItems
+// is done by stopping one node and validating availability of its items.
+func TestServiceBucket(t *testing.T) {
+	testKey := "Key"
+	testValue := "Value"
+
+	sim := New(map[string]ServiceFunc{
+		"noop": func(ctx *adapters.ServiceContext, b *sync.Map) (node.Service, func(), error) {
+			b.Store(testKey, testValue+ctx.Config.ID.String())
+			return newNoopService(), nil, nil
+		},
+	})
+	defer sim.Close()
+
+	id1, err := sim.AddNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	id2, err := sim.AddNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Run("ServiceFunc bucket Store", func(t *testing.T) {
+		v, ok := sim.NodeItem(id1, testKey)
+		if !ok {
+			t.Fatal("bucket item not found")
+		}
+		s, ok := v.(string)
+		if !ok {
+			t.Fatal("bucket item value is not string")
+		}
+		if s != testValue+id1.String() {
+			t.Fatalf("expected %q, got %q", testValue+id1.String(), s)
+		}
+
+		v, ok = sim.NodeItem(id2, testKey)
+		if !ok {
+			t.Fatal("bucket item not found")
+		}
+		s, ok = v.(string)
+		if !ok {
+			t.Fatal("bucket item value is not string")
+		}
+		if s != testValue+id2.String() {
+			t.Fatalf("expected %q, got %q", testValue+id2.String(), s)
+		}
+	})
+
+	customKey := "anotherKey"
+	customValue := "anotherValue"
+
+	t.Run("SetNodeItem", func(t *testing.T) {
+		sim.SetNodeItem(id1, customKey, customValue)
+
+		v, ok := sim.NodeItem(id1, customKey)
+		if !ok {
+			t.Fatal("bucket item not found")
+		}
+		s, ok := v.(string)
+		if !ok {
+			t.Fatal("bucket item value is not string")
+		}
+		if s != customValue {
+			t.Fatalf("expected %q, got %q", customValue, s)
+		}
+
+		_, ok = sim.NodeItem(id2, customKey)
+		if ok {
+			t.Fatal("bucket item should not be found")
+		}
+	})
+
+	if err := sim.StopNode(id2); err != nil {
+		t.Fatal(err)
+	}
+
+	t.Run("UpNodesItems", func(t *testing.T) {
+		items := sim.UpNodesItems(testKey)
+
+		v, ok := items[id1]
+		if !ok {
+			t.Errorf("node 1 item not found")
+		}
+		s, ok := v.(string)
+		if !ok {
+			t.Fatal("node 1 item value is not string")
+		}
+		if s != testValue+id1.String() {
+			t.Fatalf("expected %q, got %q", testValue+id1.String(), s)
+		}
+
+		_, ok = items[id2]
+		if ok {
+			t.Errorf("node 2 item should not be found")
+		}
+	})
+
+	t.Run("NodeItems", func(t *testing.T) {
+		items := sim.NodesItems(testKey)
+
+		v, ok := items[id1]
+		if !ok {
+			t.Errorf("node 1 item not found")
+		}
+		s, ok := v.(string)
+		if !ok {
+			t.Fatal("node 1 item value is not string")
+		}
+		if s != testValue+id1.String() {
+			t.Fatalf("expected %q, got %q", testValue+id1.String(), s)
+		}
+
+		v, ok = items[id2]
+		if !ok {
+			t.Errorf("node 2 item not found")
+		}
+		s, ok = v.(string)
+		if !ok {
+			t.Fatal("node 1 item value is not string")
+		}
+		if s != testValue+id2.String() {
+			t.Fatalf("expected %q, got %q", testValue+id2.String(), s)
+		}
+	})
+}

network/simulation/events.go

@@ -0,0 +1,217 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"context"
+	"sync"
+
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/ethereum/go-ethereum/p2p/simulations"
+)
+
+// PeerEvent is the type of the channel returned by Simulation.PeerEvents.
+type PeerEvent struct {
+	// NodeID is the ID of node that the event is caught on.
+	NodeID enode.ID
+	// PeerID is the ID of the peer node that the event is caught on.
+	PeerID enode.ID
+	// Event is the event that is caught.
+	Event *simulations.Event
+	// Error is the error that may have happened during event watching.
+	Error error
+}
+
+// PeerEventsFilter defines a filter on PeerEvents to exclude messages with
+// defined properties. Use PeerEventsFilter methods to set required options.
+type PeerEventsFilter struct {
+	eventType simulations.EventType
+
+	connUp *bool
+
+	msgReceive *bool
+	protocol   *string
+	msgCode    *uint64
+}
+
+// NewPeerEventsFilter returns a new PeerEventsFilter instance.
+func NewPeerEventsFilter() *PeerEventsFilter {
+	return &PeerEventsFilter{}
+}
+
+// Connect sets the filter to events when two nodes connect.
+func (f *PeerEventsFilter) Connect() *PeerEventsFilter {
+	f.eventType = simulations.EventTypeConn
+	b := true
+	f.connUp = &b
+	return f
+}
+
+// Drop sets the filter to events when two nodes disconnect.
+func (f *PeerEventsFilter) Drop() *PeerEventsFilter {
+	f.eventType = simulations.EventTypeConn
+	b := false
+	f.connUp = &b
+	return f
+}
+
+// ReceivedMessages sets the filter to only messages that are received.
+func (f *PeerEventsFilter) ReceivedMessages() *PeerEventsFilter {
+	f.eventType = simulations.EventTypeMsg
+	b := true
+	f.msgReceive = &b
+	return f
+}
+
+// SentMessages sets the filter to only messages that are sent.
+func (f *PeerEventsFilter) SentMessages() *PeerEventsFilter {
+	f.eventType = simulations.EventTypeMsg
+	b := false
+	f.msgReceive = &b
+	return f
+}
+
+// Protocol sets the filter to only one message protocol.
+func (f *PeerEventsFilter) Protocol(p string) *PeerEventsFilter {
+	f.eventType = simulations.EventTypeMsg
+	f.protocol = &p
+	return f
+}
+
+// MsgCode sets the filter to only one msg code.
+func (f *PeerEventsFilter) MsgCode(c uint64) *PeerEventsFilter {
+	f.eventType = simulations.EventTypeMsg
+	f.msgCode = &c
+	return f
+}
+
+// PeerEvents returns a channel of events that are captured by admin peerEvents
+// subscription nodes with provided NodeIDs. Additional filters can be set to ignore
+// events that are not relevant.
+func (s *Simulation) PeerEvents(ctx context.Context, ids []enode.ID, filters ...*PeerEventsFilter) <-chan PeerEvent {
+	eventC := make(chan PeerEvent)
+
+	// wait group to make sure all subscriptions to admin peerEvents are established
+	// before this function returns.
+	var subsWG sync.WaitGroup
+	for _, id := range ids {
+		s.shutdownWG.Add(1)
+		subsWG.Add(1)
+		go func(id enode.ID) {
+			defer s.shutdownWG.Done()
+
+			events := make(chan *simulations.Event)
+			sub := s.Net.Events().Subscribe(events)
+			defer sub.Unsubscribe()
+
+			subsWG.Done()
+
+			for {
+				select {
+				case <-ctx.Done():
+					if err := ctx.Err(); err != nil {
+						select {
+						case eventC <- PeerEvent{NodeID: id, Error: err}:
+						case <-s.Done():
+						}
+					}
+					return
+				case <-s.Done():
+					return
+				case e := <-events:
+					// ignore control events
+					if e.Control {
+						continue
+					}
+					match := len(filters) == 0 // if there are no filters match all events
+					for _, f := range filters {
+						if f.eventType == simulations.EventTypeConn && e.Conn != nil {
+							if *f.connUp != e.Conn.Up {
+								continue
+							}
+							// all connection filter parameters matched, break the loop
+							match = true
+							break
+						}
+						if f.eventType == simulations.EventTypeMsg && e.Msg != nil {
+							if f.msgReceive != nil && *f.msgReceive != e.Msg.Received {
+								continue
+							}
+							if f.protocol != nil && *f.protocol != e.Msg.Protocol {
+								continue
+							}
+							if f.msgCode != nil && *f.msgCode != e.Msg.Code {
+								continue
+							}
+							// all message filter parameters matched, break the loop
+							match = true
+							break
+						}
+					}
+					var peerID enode.ID
+					switch e.Type {
+					case simulations.EventTypeConn:
+						peerID = e.Conn.One
+						if peerID == id {
+							peerID = e.Conn.Other
+						}
+					case simulations.EventTypeMsg:
+						peerID = e.Msg.One
+						if peerID == id {
+							peerID = e.Msg.Other
+						}
+					}
+					if match {
+						select {
+						case eventC <- PeerEvent{NodeID: id, PeerID: peerID, Event: e}:
+						case <-ctx.Done():
+							if err := ctx.Err(); err != nil {
+								select {
+								case eventC <- PeerEvent{NodeID: id, PeerID: peerID, Error: err}:
+								case <-s.Done():
+								}
+							}
+							return
+						case <-s.Done():
+							return
+						}
+					}
+				case err := <-sub.Err():
+					if err != nil {
+						select {
+						case eventC <- PeerEvent{NodeID: id, Error: err}:
+						case <-ctx.Done():
+							if err := ctx.Err(); err != nil {
+								select {
+								case eventC <- PeerEvent{NodeID: id, Error: err}:
+								case <-s.Done():
+								}
+							}
+							return
+						case <-s.Done():
+							return
+						}
+					}
+				}
+			}
+		}(id)
+	}
+
+	// wait all subscriptions
+	subsWG.Wait()
+	return eventC
+}

network/simulation/events_test.go

@@ -0,0 +1,107 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"context"
+	"sync"
+	"testing"
+	"time"
+)
+
+// TestPeerEvents creates simulation, adds two nodes,
+// register for peer events, connects nodes in a chain
+// and waits for the number of connection events to
+// be received.
+func TestPeerEvents(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	_, err := sim.AddNodes(2)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	events := sim.PeerEvents(ctx, sim.NodeIDs())
+
+	// two nodes -> two connection events
+	expectedEventCount := 2
+
+	var wg sync.WaitGroup
+	wg.Add(expectedEventCount)
+
+	go func() {
+		for e := range events {
+			if e.Error != nil {
+				if e.Error == context.Canceled {
+					return
+				}
+				t.Error(e.Error)
+				continue
+			}
+			wg.Done()
+		}
+	}()
+
+	err = sim.Net.ConnectNodesChain(sim.NodeIDs())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	wg.Wait()
+}
+
+func TestPeerEventsTimeout(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	_, err := sim.AddNodes(2)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel()
+	events := sim.PeerEvents(ctx, sim.NodeIDs())
+
+	done := make(chan struct{})
+	errC := make(chan error)
+	go func() {
+		for e := range events {
+			if e.Error == context.Canceled {
+				return
+			}
+			if e.Error == context.DeadlineExceeded {
+				close(done)
+				return
+			} else {
+				errC <- e.Error
+			}
+		}
+	}()
+
+	select {
+	case <-time.After(time.Second):
+		t.Fatal("no context deadline received")
+	case err := <-errC:
+		t.Fatal(err)
+	case <-done:
+		// all good, context deadline detected
+	}
+}

network/simulation/example_test.go

@@ -0,0 +1,141 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation_test
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/node"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+	"github.com/ethersphere/swarm/network"
+	"github.com/ethersphere/swarm/network/simulation"
+)
+
+// Every node can have a Kademlia associated using the node bucket under
+// BucketKeyKademlia key. This allows to use WaitTillHealthy to block until
+// all nodes have the their Kademlias healthy.
+func ExampleSimulation_WaitTillHealthy() {
+
+	sim := simulation.New(map[string]simulation.ServiceFunc{
+		"bzz": func(ctx *adapters.ServiceContext, b *sync.Map) (node.Service, func(), error) {
+			addr := network.NewAddr(ctx.Config.Node())
+			hp := network.NewHiveParams()
+			hp.Discovery = false
+			config := &network.BzzConfig{
+				OverlayAddr:  addr.Over(),
+				UnderlayAddr: addr.Under(),
+				HiveParams:   hp,
+			}
+			kad := network.NewKademlia(addr.Over(), network.NewKadParams())
+			// store kademlia in node's bucket under BucketKeyKademlia
+			// so that it can be found by WaitTillHealthy method.
+			b.Store(simulation.BucketKeyKademlia, kad)
+			return network.NewBzz(config, kad, nil, nil, nil), nil, nil
+		},
+	})
+	defer sim.Close()
+
+	_, err := sim.AddNodesAndConnectRing(10)
+	if err != nil {
+		// handle error properly...
+		panic(err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+	ill, err := sim.WaitTillHealthy(ctx)
+	if err != nil {
+		// inspect the latest detected not healthy kademlias
+		for id, kad := range ill {
+			fmt.Println("Node", id)
+			fmt.Println(kad.String())
+		}
+		// handle error...
+	}
+
+	// continue with the test
+
+}
+
+// Watch all peer events in the simulation network, buy receiving from a channel.
+func ExampleSimulation_PeerEvents() {
+	sim := simulation.New(nil)
+	defer sim.Close()
+
+	events := sim.PeerEvents(context.Background(), sim.NodeIDs())
+
+	go func() {
+		for e := range events {
+			if e.Error != nil {
+				log.Error("peer event", "err", e.Error)
+				continue
+			}
+			log.Info("peer event", "node", e.NodeID, "peer", e.PeerID, "type", e.Event.Type)
+		}
+	}()
+}
+
+// Detect when a nodes drop a peer.
+func ExampleSimulation_PeerEvents_disconnections() {
+	sim := simulation.New(nil)
+	defer sim.Close()
+
+	disconnections := sim.PeerEvents(
+		context.Background(),
+		sim.NodeIDs(),
+		simulation.NewPeerEventsFilter().Drop(),
+	)
+
+	go func() {
+		for d := range disconnections {
+			if d.Error != nil {
+				log.Error("peer drop", "err", d.Error)
+				continue
+			}
+			log.Warn("peer drop", "node", d.NodeID, "peer", d.PeerID)
+		}
+	}()
+}
+
+// Watch multiple types of events or messages. In this case, they differ only
+// by MsgCode, but filters can be set for different types or protocols, too.
+func ExampleSimulation_PeerEvents_multipleFilters() {
+	sim := simulation.New(nil)
+	defer sim.Close()
+
+	msgs := sim.PeerEvents(
+		context.Background(),
+		sim.NodeIDs(),
+		// Watch when bzz messages 1 and 4 are received.
+		simulation.NewPeerEventsFilter().ReceivedMessages().Protocol("bzz").MsgCode(1),
+		simulation.NewPeerEventsFilter().ReceivedMessages().Protocol("bzz").MsgCode(4),
+	)
+
+	go func() {
+		for m := range msgs {
+			if m.Error != nil {
+				log.Error("bzz message", "err", m.Error)
+				continue
+			}
+			log.Info("bzz message", "node", m.NodeID, "peer", m.PeerID)
+		}
+	}()
+}

network/simulation/http.go

@@ -0,0 +1,68 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/p2p/simulations"
+)
+
+// Package defaults.
+var (
+	DefaultHTTPSimAddr = ":8888"
+)
+
+//WithServer implements the builder pattern constructor for Simulation to
+//start with a HTTP server
+func (s *Simulation) WithServer(addr string) *Simulation {
+	//assign default addr if nothing provided
+	if addr == "" {
+		addr = DefaultHTTPSimAddr
+	}
+	log.Info(fmt.Sprintf("Initializing simulation server on %s...", addr))
+	//initialize the HTTP server
+	s.handler = simulations.NewServer(s.Net)
+	s.runC = make(chan struct{})
+	//add swarm specific routes to the HTTP server
+	s.addSimulationRoutes()
+	s.httpSrv = &http.Server{
+		Addr:    addr,
+		Handler: s.handler,
+	}
+	go func() {
+		err := s.httpSrv.ListenAndServe()
+		if err != nil {
+			log.Error("Error starting the HTTP server", "error", err)
+		}
+	}()
+	return s
+}
+
+//register additional HTTP routes
+func (s *Simulation) addSimulationRoutes() {
+	s.handler.POST("/runsim", s.RunSimulation)
+}
+
+// RunSimulation is the actual POST endpoint runner
+func (s *Simulation) RunSimulation(w http.ResponseWriter, req *http.Request) {
+	log.Debug("RunSimulation endpoint running")
+	s.runC <- struct{}{}
+	w.WriteHeader(http.StatusOK)
+}

network/simulation/http_test.go

@@ -0,0 +1,110 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/node"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+)
+
+func TestSimulationWithHTTPServer(t *testing.T) {
+	log.Debug("Init simulation")
+
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+	defer cancel()
+
+	sim := New(
+		map[string]ServiceFunc{
+			"noop": func(_ *adapters.ServiceContext, b *sync.Map) (node.Service, func(), error) {
+				return newNoopService(), nil, nil
+			},
+		}).WithServer(DefaultHTTPSimAddr)
+	defer sim.Close()
+	log.Debug("Done.")
+
+	_, err := sim.AddNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	log.Debug("Starting sim round and let it time out...")
+	//first test that running without sending to the channel will actually
+	//block the simulation, so let it time out
+	result := sim.Run(ctx, func(ctx context.Context, sim *Simulation) error {
+		log.Debug("Just start the sim without any action and wait for the timeout")
+		//ensure with a Sleep that simulation doesn't terminate before the timeout
+		time.Sleep(2 * time.Second)
+		return nil
+	})
+
+	if result.Error != nil {
+		if result.Error.Error() == "context deadline exceeded" {
+			log.Debug("Expected timeout error received")
+		} else {
+			t.Fatal(result.Error)
+		}
+	}
+
+	//now run it again and send the expected signal on the waiting channel,
+	//then close the simulation
+	log.Debug("Starting sim round and wait for frontend signal...")
+	//this time the timeout should be long enough so that it doesn't kick in too early
+	ctx, cancel2 := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel2()
+	errC := make(chan error, 1)
+	go triggerSimulationRun(t, errC)
+	result = sim.Run(ctx, func(ctx context.Context, sim *Simulation) error {
+		log.Debug("This run waits for the run signal from `frontend`...")
+		//ensure with a Sleep that simulation doesn't terminate before the signal is received
+		time.Sleep(2 * time.Second)
+		return nil
+	})
+	if result.Error != nil {
+		t.Fatal(result.Error)
+	}
+	if err := <-errC; err != nil {
+		t.Fatal(err)
+	}
+	log.Debug("Test terminated successfully")
+}
+
+func triggerSimulationRun(t *testing.T, errC chan error) {
+	//We need to first wait for the sim HTTP server to start running...
+	time.Sleep(2 * time.Second)
+	//then we can send the signal
+
+	log.Debug("Sending run signal to simulation: POST /runsim...")
+	resp, err := http.Post(fmt.Sprintf("http://localhost%s/runsim", DefaultHTTPSimAddr), "application/json", nil)
+	if err != nil {
+		errC <- fmt.Errorf("Request failed: %v", err)
+		return
+	}
+	log.Debug("Signal sent")
+	if resp.StatusCode != http.StatusOK {
+		errC <- fmt.Errorf("err %s", resp.Status)
+		return
+	}
+	errC <- resp.Body.Close()
+}

network/simulation/kademlia.go

@@ -0,0 +1,203 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"context"
+	"encoding/binary"
+	"encoding/hex"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/ethereum/go-ethereum/p2p/simulations"
+	"github.com/ethersphere/swarm/network"
+)
+
+// BucketKeyKademlia is the key to be used for storing the kademlia
+// instance for particular node, usually inside the ServiceFunc function.
+var BucketKeyKademlia BucketKey = "kademlia"
+
+// WaitTillHealthy is blocking until the health of all kademlias is true.
+// If error is not nil, a map of kademlia that was found not healthy is returned.
+// TODO: Check correctness since change in kademlia depth calculation logic
+func (s *Simulation) WaitTillHealthy(ctx context.Context) (ill map[enode.ID]*network.Kademlia, err error) {
+	// Prepare PeerPot map for checking Kademlia health
+	var ppmap map[string]*network.PeerPot
+	kademlias := s.kademlias()
+	addrs := make([][]byte, 0, len(kademlias))
+	// TODO verify that all kademlias have same params
+	for _, k := range kademlias {
+		addrs = append(addrs, k.BaseAddr())
+	}
+	ppmap = network.NewPeerPotMap(s.neighbourhoodSize, addrs)
+
+	// Wait for healthy Kademlia on every node before checking files
+	ticker := time.NewTicker(200 * time.Millisecond)
+	defer ticker.Stop()
+
+	ill = make(map[enode.ID]*network.Kademlia)
+	for {
+		select {
+		case <-ctx.Done():
+			return ill, ctx.Err()
+		case <-ticker.C:
+			for k := range ill {
+				delete(ill, k)
+			}
+			log.Debug("kademlia health check", "addr count", len(addrs), "kad len", len(kademlias))
+			for id, k := range kademlias {
+				//PeerPot for this node
+				addr := common.Bytes2Hex(k.BaseAddr())
+				pp := ppmap[addr]
+				//call Healthy RPC
+				h := k.GetHealthInfo(pp)
+				//print info
+				log.Debug(k.String())
+				log.Debug("kademlia", "connectNN", h.ConnectNN, "knowNN", h.KnowNN)
+				log.Debug("kademlia", "health", h.ConnectNN && h.KnowNN, "addr", hex.EncodeToString(k.BaseAddr()), "node", id)
+				log.Debug("kademlia", "ill condition", !h.ConnectNN, "addr", hex.EncodeToString(k.BaseAddr()), "node", id)
+				if !h.Healthy() {
+					ill[id] = k
+				}
+			}
+			if len(ill) == 0 {
+				return nil, nil
+			}
+		}
+	}
+}
+
+// kademlias returns all Kademlia instances that are set
+// in simulation bucket.
+func (s *Simulation) kademlias() (ks map[enode.ID]*network.Kademlia) {
+	items := s.UpNodesItems(BucketKeyKademlia)
+	log.Debug("kademlia len items", "len", len(items))
+	ks = make(map[enode.ID]*network.Kademlia, len(items))
+	for id, v := range items {
+		k, ok := v.(*network.Kademlia)
+		if !ok {
+			continue
+		}
+		ks[id] = k
+	}
+	return ks
+}
+
+// WaitTillSnapshotRecreated is blocking until all the connections specified
+// in the snapshot are registered in the kademlia.
+// It differs from WaitTillHealthy, which waits only until all the kademlias are
+// healthy (it might happen even before all the connections are established).
+func (s *Simulation) WaitTillSnapshotRecreated(ctx context.Context, snap *simulations.Snapshot) error {
+	expected := getSnapshotConnections(snap.Conns)
+	ticker := time.NewTicker(150 * time.Millisecond)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-ticker.C:
+			actual := s.getActualConnections()
+			if isAllDeployed(expected, actual) {
+				return nil
+			}
+		}
+	}
+}
+
+func (s *Simulation) getActualConnections() (res []uint64) {
+	kademlias := s.kademlias()
+	for base, k := range kademlias {
+		k.EachConn(base[:], 256, func(p *network.Peer, _ int) bool {
+			res = append(res, getConnectionHash(base, p.ID()))
+			return true
+		})
+	}
+
+	// only list those connections that appear twice (both peers should recognize connection as active)
+	res = removeDuplicatesAndSingletons(res)
+	return res
+}
+
+func getSnapshotConnections(conns []simulations.Conn) (res []uint64) {
+	for _, c := range conns {
+		res = append(res, getConnectionHash(c.One, c.Other))
+	}
+	return res
+}
+
+// returns an integer connection identifier (similar to 8-byte hash)
+func getConnectionHash(a, b enode.ID) uint64 {
+	var h [8]byte
+	for i := 0; i < 8; i++ {
+		h[i] = a[i] ^ b[i]
+	}
+	res := binary.LittleEndian.Uint64(h[:])
+	return res
+}
+
+// returns true if all connections in expected are listed in actual
+func isAllDeployed(expected []uint64, actual []uint64) bool {
+	if len(expected) == 0 {
+		return true
+	}
+
+	exp := make([]uint64, len(expected))
+	copy(exp, expected)
+	for _, c := range actual {
+		// remove value c from exp
+		for i := 0; i < len(exp); i++ {
+			if exp[i] == c {
+				exp = removeListElement(exp, i)
+				if len(exp) == 0 {
+					return true
+				}
+			}
+		}
+	}
+	return len(exp) == 0
+}
+
+func removeListElement(arr []uint64, i int) []uint64 {
+	last := len(arr) - 1
+	arr[i] = arr[last]
+	arr = arr[:last]
+	return arr
+}
+
+func removeDuplicatesAndSingletons(arr []uint64) []uint64 {
+	for i := 0; i < len(arr); {
+		found := false
+		for j := i + 1; j < len(arr); j++ {
+			if arr[i] == arr[j] {
+				arr = removeListElement(arr, j) // remove duplicate
+				found = true
+				break
+			}
+		}
+
+		if found {
+			i++
+		} else {
+			arr = removeListElement(arr, i) // remove singleton
+		}
+	}
+
+	return arr
+}

network/simulation/kademlia_test.go

@@ -0,0 +1,310 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"context"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/node"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+	"github.com/ethersphere/swarm/network"
+)
+
+/*
+	TestWaitTillHealthy tests that we indeed get a healthy network after we wait for it.
+	For this to be tested, a bit of a snake tail bite needs to happen:
+		* First we create a first simulation
+		* Run it as nodes connected in a ring
+		* Wait until the network is healthy
+		* Then we create a snapshot
+		* With this snapshot we create a new simulation
+		* This simulation is expected to have a healthy configuration, as it uses the snapshot
+		* Thus we just iterate all nodes and check that their kademlias are healthy
+		* If all kademlias are healthy, the test succeeded, otherwise it failed
+*/
+func TestWaitTillHealthy(t *testing.T) {
+	t.Skip("this test is flaky; disabling till underlying problem is solved")
+	testNodesNum := 10
+
+	// create the first simulation
+	sim := New(createSimServiceMap(true))
+
+	// connect and...
+	nodeIDs, err := sim.AddNodesAndConnectRing(testNodesNum)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// array of all overlay addresses
+	var addrs [][]byte
+	// iterate once to be able to build the peer map
+	for _, node := range nodeIDs {
+		//get the kademlia overlay address from this ID
+		a := node.Bytes()
+		//append it to the array of all overlay addresses
+		addrs = append(addrs, a)
+	}
+	// build a PeerPot only once
+	pp := network.NewPeerPotMap(network.NewKadParams().NeighbourhoodSize, addrs)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 120*time.Second)
+	defer cancel()
+
+	// ...wait until healthy
+	ill, err := sim.WaitTillHealthy(ctx)
+	if err != nil {
+		for id, kad := range ill {
+			t.Log("Node", id)
+			t.Log(kad.String())
+		}
+		t.Fatal(err)
+	}
+
+	// now create a snapshot of this network
+	snap, err := sim.Net.Snapshot()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// close the initial simulation
+	sim.Close()
+	// create a control simulation
+	controlSim := New(createSimServiceMap(false))
+	defer controlSim.Close()
+
+	// load the snapshot into this control simulation
+	err = controlSim.Net.Load(snap)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = controlSim.WaitTillHealthy(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, node := range nodeIDs {
+		// ...get its kademlia
+		item, ok := controlSim.NodeItem(node, BucketKeyKademlia)
+		if !ok {
+			t.Fatal("No kademlia bucket item")
+		}
+		kad := item.(*network.Kademlia)
+		// get its base address
+		kid := common.Bytes2Hex(kad.BaseAddr())
+
+		//get the health info
+		info := kad.GetHealthInfo(pp[kid])
+		log.Trace("Health info", "info", info)
+		// check that it is healthy
+		healthy := info.Healthy()
+		if !healthy {
+			t.Fatalf("Expected node %v of control simulation to be healthy, but it is not, unhealthy kademlias: %v", node, kad.String())
+		}
+	}
+}
+
+// createSimServiceMap returns the services map
+// this function will create the sim services with or without discovery enabled
+// based on the flag passed
+func createSimServiceMap(discovery bool) map[string]ServiceFunc {
+	return map[string]ServiceFunc{
+		"bzz": func(ctx *adapters.ServiceContext, b *sync.Map) (node.Service, func(), error) {
+			addr := network.NewAddr(ctx.Config.Node())
+			hp := network.NewHiveParams()
+			hp.Discovery = discovery
+			config := &network.BzzConfig{
+				OverlayAddr:  addr.Over(),
+				UnderlayAddr: addr.Under(),
+				HiveParams:   hp,
+			}
+			kad := network.NewKademlia(addr.Over(), network.NewKadParams())
+			// store kademlia in node's bucket under BucketKeyKademlia
+			// so that it can be found by WaitTillHealthy method.
+			b.Store(BucketKeyKademlia, kad)
+			return network.NewBzz(config, kad, nil, nil, nil), nil, nil
+		},
+	}
+}
+
+// TestWaitTillSnapshotRecreated tests that we indeed have a network
+// configuration specified in the snapshot file, after we wait for it.
+//
+// First we create a first simulation
+// Run it as nodes connected in a ring
+// Wait until the network is healthy
+// Then we create a snapshot
+// With this snapshot we create a new simulation
+// Call WaitTillSnapshotRecreated() function and wait until it returns
+// Iterate the nodes and check if all the connections are successfully recreated
+func TestWaitTillSnapshotRecreated(t *testing.T) {
+	t.Skip("test is flaky. disabling until underlying problem is addressed")
+	var err error
+	sim := New(createSimServiceMap(true))
+	_, err = sim.AddNodesAndConnectRing(16)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+	_, err = sim.WaitTillHealthy(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	originalConnections := sim.getActualConnections()
+	snap, err := sim.Net.Snapshot()
+	sim.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	controlSim := New(createSimServiceMap(false))
+	defer controlSim.Close()
+	err = controlSim.Net.Load(snap)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = controlSim.WaitTillSnapshotRecreated(ctx, snap)
+	if err != nil {
+		t.Fatal(err)
+	}
+	controlConnections := controlSim.getActualConnections()
+
+	for _, c := range originalConnections {
+		if !exist(controlConnections, c) {
+			t.Fatal("connection was not recreated")
+		}
+	}
+}
+
+// exist returns true if val is found in arr
+func exist(arr []uint64, val uint64) bool {
+	for _, c := range arr {
+		if c == val {
+			return true
+		}
+	}
+	return false
+}
+
+func TestRemoveDuplicatesAndSingletons(t *testing.T) {
+	singletons := []uint64{
+		0x3c127c6f6cb026b0,
+		0x0f45190d72e71fc5,
+		0xb0184c02449e0bb6,
+		0xa85c7b84239c54d3,
+		0xe3b0c44298fc1c14,
+		0x9afbf4c8996fb924,
+		0x27ae41e4649b934c,
+		0xa495991b7852b855,
+	}
+
+	doubles := []uint64{
+		0x1b879f878de7fc7a,
+		0xc6791470521bdab4,
+		0xdd34b0ee39bbccc6,
+		0x4d904fbf0f31da10,
+		0x6403c2560432c8f8,
+		0x18954e33cf3ad847,
+		0x90db00e98dc7a8a6,
+		0x92886b0dfcc1809b,
+	}
+
+	var arr []uint64
+	arr = append(arr, doubles...)
+	arr = append(arr, singletons...)
+	arr = append(arr, doubles...)
+	arr = removeDuplicatesAndSingletons(arr)
+
+	for _, i := range singletons {
+		if exist(arr, i) {
+			t.Fatalf("singleton not removed: %d", i)
+		}
+	}
+
+	for _, i := range doubles {
+		if !exist(arr, i) {
+			t.Fatalf("wrong value removed: %d", i)
+		}
+	}
+
+	for j := 0; j < len(doubles); j++ {
+		v := doubles[j] + singletons[j]
+		if exist(arr, v) {
+			t.Fatalf("non-existing value found, index: %d", j)
+		}
+	}
+}
+
+func TestIsAllDeployed(t *testing.T) {
+	a := []uint64{
+		0x3c127c6f6cb026b0,
+		0x0f45190d72e71fc5,
+		0xb0184c02449e0bb6,
+		0xa85c7b84239c54d3,
+		0xe3b0c44298fc1c14,
+		0x9afbf4c8996fb924,
+		0x27ae41e4649b934c,
+		0xa495991b7852b855,
+	}
+
+	b := []uint64{
+		0x1b879f878de7fc7a,
+		0xc6791470521bdab4,
+		0xdd34b0ee39bbccc6,
+		0x4d904fbf0f31da10,
+		0x6403c2560432c8f8,
+		0x18954e33cf3ad847,
+		0x90db00e98dc7a8a6,
+		0x92886b0dfcc1809b,
+	}
+
+	var c []uint64
+	c = append(c, a...)
+	c = append(c, b...)
+
+	if !isAllDeployed(a, c) {
+		t.Fatal("isAllDeployed failed")
+	}
+
+	if !isAllDeployed(b, c) {
+		t.Fatal("isAllDeployed failed")
+	}
+
+	if isAllDeployed(c, a) {
+		t.Fatal("isAllDeployed failed: false positive")
+	}
+
+	if isAllDeployed(c, b) {
+		t.Fatal("isAllDeployed failed: false positive")
+	}
+
+	c = c[2:]
+
+	if isAllDeployed(a, c) {
+		t.Fatal("isAllDeployed failed: false positive")
+	}
+
+	if !isAllDeployed(b, c) {
+		t.Fatal("isAllDeployed failed")
+	}
+}

network/simulation/node.go

@@ -0,0 +1,341 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"bytes"
+	"context"
+	"crypto/ecdsa"
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"math/rand"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/ethereum/go-ethereum/p2p/simulations"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+	"github.com/ethersphere/swarm/network"
+)
+
+var (
+	BucketKeyBzzPrivateKey BucketKey = "bzzprivkey"
+)
+
+// NodeIDs returns NodeIDs for all nodes in the network.
+func (s *Simulation) NodeIDs() (ids []enode.ID) {
+	nodes := s.Net.GetNodes()
+	ids = make([]enode.ID, len(nodes))
+	for i, node := range nodes {
+		ids[i] = node.ID()
+	}
+	return ids
+}
+
+// UpNodeIDs returns NodeIDs for nodes that are up in the network.
+func (s *Simulation) UpNodeIDs() (ids []enode.ID) {
+	nodes := s.Net.GetNodes()
+	for _, node := range nodes {
+		if node.Up() {
+			ids = append(ids, node.ID())
+		}
+	}
+	return ids
+}
+
+// DownNodeIDs returns NodeIDs for nodes that are stopped in the network.
+func (s *Simulation) DownNodeIDs() (ids []enode.ID) {
+	nodes := s.Net.GetNodes()
+	for _, node := range nodes {
+		if !node.Up() {
+			ids = append(ids, node.ID())
+		}
+	}
+	return ids
+}
+
+// AddNodeOption defines the option that can be passed
+// to Simulation.AddNode method.
+type AddNodeOption func(*adapters.NodeConfig)
+
+// AddNodeWithMsgEvents sets the EnableMsgEvents option
+// to NodeConfig.
+func AddNodeWithMsgEvents(enable bool) AddNodeOption {
+	return func(o *adapters.NodeConfig) {
+		o.EnableMsgEvents = enable
+	}
+}
+
+// AddNodeWithService specifies a service that should be
+// started on a node. This option can be repeated as variadic
+// argument toe AddNode and other add node related methods.
+// If AddNodeWithService is not specified, all services will be started.
+func AddNodeWithService(serviceName string) AddNodeOption {
+	return func(o *adapters.NodeConfig) {
+		o.Services = append(o.Services, serviceName)
+	}
+}
+
+// AddNode creates a new node with random configuration,
+// applies provided options to the config and adds the node to network.
+// By default all services will be started on a node. If one or more
+// AddNodeWithService option are provided, only specified services will be started.
+func (s *Simulation) AddNode(opts ...AddNodeOption) (id enode.ID, err error) {
+	conf := adapters.RandomNodeConfig()
+	for _, o := range opts {
+		o(conf)
+	}
+	if len(conf.Services) == 0 {
+		conf.Services = s.serviceNames
+	}
+
+	// add ENR records to the underlying node
+	// most importantly the bzz overlay address
+	//
+	// for now we have no way of setting bootnodes or lightnodes in sims
+	// so we just let them be set to false
+	// they should perhaps be possible to override them with AddNodeOption
+	bzzPrivateKey, err := BzzPrivateKeyFromConfig(conf)
+	if err != nil {
+		return enode.ID{}, err
+	}
+
+	enodeParams := &network.EnodeParams{
+		PrivateKey: bzzPrivateKey,
+	}
+	record, err := network.NewEnodeRecord(enodeParams)
+	conf.Record = *record
+
+	// Add the bzz address to the node config
+	node, err := s.Net.NewNodeWithConfig(conf)
+	if err != nil {
+		return id, err
+	}
+	s.buckets[node.ID()] = new(sync.Map)
+	s.SetNodeItem(node.ID(), BucketKeyBzzPrivateKey, bzzPrivateKey)
+
+	return node.ID(), s.Net.Start(node.ID())
+}
+
+// AddNodes creates new nodes with random configurations,
+// applies provided options to the config and adds nodes to network.
+func (s *Simulation) AddNodes(count int, opts ...AddNodeOption) (ids []enode.ID, err error) {
+	ids = make([]enode.ID, 0, count)
+	for i := 0; i < count; i++ {
+		id, err := s.AddNode(opts...)
+		if err != nil {
+			return nil, err
+		}
+		ids = append(ids, id)
+	}
+	return ids, nil
+}
+
+// AddNodesAndConnectFull is a helpper method that combines
+// AddNodes and ConnectNodesFull. Only new nodes will be connected.
+func (s *Simulation) AddNodesAndConnectFull(count int, opts ...AddNodeOption) (ids []enode.ID, err error) {
+	if count < 2 {
+		return nil, errors.New("count of nodes must be at least 2")
+	}
+	ids, err = s.AddNodes(count, opts...)
+	if err != nil {
+		return nil, err
+	}
+	err = s.Net.ConnectNodesFull(ids)
+	if err != nil {
+		return nil, err
+	}
+	return ids, nil
+}
+
+// AddNodesAndConnectChain is a helpper method that combines
+// AddNodes and ConnectNodesChain. The chain will be continued from the last
+// added node, if there is one in simulation using ConnectToLastNode method.
+func (s *Simulation) AddNodesAndConnectChain(count int, opts ...AddNodeOption) (ids []enode.ID, err error) {
+	if count < 2 {
+		return nil, errors.New("count of nodes must be at least 2")
+	}
+	id, err := s.AddNode(opts...)
+	if err != nil {
+		return nil, err
+	}
+	err = s.Net.ConnectToLastNode(id)
+	if err != nil {
+		return nil, err
+	}
+	ids, err = s.AddNodes(count-1, opts...)
+	if err != nil {
+		return nil, err
+	}
+	ids = append([]enode.ID{id}, ids...)
+	err = s.Net.ConnectNodesChain(ids)
+	if err != nil {
+		return nil, err
+	}
+	return ids, nil
+}
+
+// AddNodesAndConnectRing is a helpper method that combines
+// AddNodes and ConnectNodesRing.
+func (s *Simulation) AddNodesAndConnectRing(count int, opts ...AddNodeOption) (ids []enode.ID, err error) {
+	if count < 2 {
+		return nil, errors.New("count of nodes must be at least 2")
+	}
+	ids, err = s.AddNodes(count, opts...)
+	if err != nil {
+		return nil, err
+	}
+	err = s.Net.ConnectNodesRing(ids)
+	if err != nil {
+		return nil, err
+	}
+	return ids, nil
+}
+
+// AddNodesAndConnectStar is a helpper method that combines
+// AddNodes and ConnectNodesStar.
+func (s *Simulation) AddNodesAndConnectStar(count int, opts ...AddNodeOption) (ids []enode.ID, err error) {
+	if count < 2 {
+		return nil, errors.New("count of nodes must be at least 2")
+	}
+	ids, err = s.AddNodes(count, opts...)
+	if err != nil {
+		return nil, err
+	}
+	err = s.Net.ConnectNodesStar(ids[1:], ids[0])
+	if err != nil {
+		return nil, err
+	}
+	return ids, nil
+}
+
+// UploadSnapshot uploads a snapshot to the simulation
+// This method tries to open the json file provided, applies the config to all nodes
+// and then loads the snapshot into the Simulation network
+func (s *Simulation) UploadSnapshot(ctx context.Context, snapshotFile string, opts ...AddNodeOption) error {
+	f, err := os.Open(snapshotFile)
+	if err != nil {
+		return err
+	}
+
+	jsonbyte, err := ioutil.ReadAll(f)
+	f.Close()
+	if err != nil {
+		return err
+	}
+	var snap simulations.Snapshot
+	if err := json.Unmarshal(jsonbyte, &snap); err != nil {
+		return err
+	}
+
+	//the snapshot probably has the property EnableMsgEvents not set
+	//set it to true (we need this to wait for messages before uploading)
+	for i := range snap.Nodes {
+		snap.Nodes[i].Node.Config.EnableMsgEvents = true
+		snap.Nodes[i].Node.Config.Services = s.serviceNames
+		for _, o := range opts {
+			o(snap.Nodes[i].Node.Config)
+		}
+	}
+
+	if err := s.Net.Load(&snap); err != nil {
+		return err
+	}
+	return s.WaitTillSnapshotRecreated(ctx, &snap)
+}
+
+// StartNode starts a node by NodeID.
+func (s *Simulation) StartNode(id enode.ID) (err error) {
+	return s.Net.Start(id)
+}
+
+// StartRandomNode starts a random node.
+func (s *Simulation) StartRandomNode() (id enode.ID, err error) {
+	n := s.Net.GetRandomDownNode()
+	if n == nil {
+		return id, ErrNodeNotFound
+	}
+	return n.ID(), s.Net.Start(n.ID())
+}
+
+// StartRandomNodes starts random nodes.
+func (s *Simulation) StartRandomNodes(count int) (ids []enode.ID, err error) {
+	ids = make([]enode.ID, 0, count)
+	for i := 0; i < count; i++ {
+		n := s.Net.GetRandomDownNode()
+		if n == nil {
+			return nil, ErrNodeNotFound
+		}
+		err = s.Net.Start(n.ID())
+		if err != nil {
+			return nil, err
+		}
+		ids = append(ids, n.ID())
+	}
+	return ids, nil
+}
+
+// StopNode stops a node by NodeID.
+func (s *Simulation) StopNode(id enode.ID) (err error) {
+	return s.Net.Stop(id)
+}
+
+// StopRandomNode stops a random node.
+func (s *Simulation) StopRandomNode() (id enode.ID, err error) {
+	n := s.Net.GetRandomUpNode()
+	if n == nil {
+		return id, ErrNodeNotFound
+	}
+	return n.ID(), s.Net.Stop(n.ID())
+}
+
+// StopRandomNodes stops random nodes.
+func (s *Simulation) StopRandomNodes(count int) (ids []enode.ID, err error) {
+	ids = make([]enode.ID, 0, count)
+	for i := 0; i < count; i++ {
+		n := s.Net.GetRandomUpNode()
+		if n == nil {
+			return nil, ErrNodeNotFound
+		}
+		err = s.Net.Stop(n.ID())
+		if err != nil {
+			return nil, err
+		}
+		ids = append(ids, n.ID())
+	}
+	return ids, nil
+}
+
+// seed the random generator for Simulation.randomNode.
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+// derive a private key for swarm for the node key
+// returns the private key used to generate the bzz key
+func BzzPrivateKeyFromConfig(conf *adapters.NodeConfig) (*ecdsa.PrivateKey, error) {
+	// pad the seed key some arbitrary data as ecdsa.GenerateKey takes 40 bytes seed data
+	privKeyBuf := append(crypto.FromECDSA(conf.PrivateKey), []byte{0x62, 0x7a, 0x7a, 0x62, 0x7a, 0x7a, 0x62, 0x7a}...)
+	bzzPrivateKey, err := ecdsa.GenerateKey(crypto.S256(), bytes.NewReader(privKeyBuf))
+	if err != nil {
+		return nil, err
+	}
+	return bzzPrivateKey, nil
+}

network/simulation/node_test.go

@@ -0,0 +1,446 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"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"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+	"github.com/ethersphere/swarm/network"
+)
+
+func TestUpDownNodeIDs(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	ids, err := sim.AddNodes(10)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	gotIDs := sim.NodeIDs()
+
+	if !equalNodeIDs(ids, gotIDs) {
+		t.Error("returned nodes are not equal to added ones")
+	}
+
+	stoppedIDs, err := sim.StopRandomNodes(3)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	gotIDs = sim.UpNodeIDs()
+
+	for _, id := range gotIDs {
+		if !sim.Net.GetNode(id).Up() {
+			t.Errorf("node %s should not be down", id)
+		}
+	}
+
+	if !equalNodeIDs(ids, append(gotIDs, stoppedIDs...)) {
+		t.Error("returned nodes are not equal to added ones")
+	}
+
+	gotIDs = sim.DownNodeIDs()
+
+	for _, id := range gotIDs {
+		if sim.Net.GetNode(id).Up() {
+			t.Errorf("node %s should not be up", id)
+		}
+	}
+
+	if !equalNodeIDs(stoppedIDs, gotIDs) {
+		t.Error("returned nodes are not equal to the stopped ones")
+	}
+}
+
+func equalNodeIDs(one, other []enode.ID) bool {
+	if len(one) != len(other) {
+		return false
+	}
+	var count int
+	for _, a := range one {
+		var found bool
+		for _, b := range other {
+			if a == b {
+				found = true
+				break
+			}
+		}
+		if found {
+			count++
+		} else {
+			return false
+		}
+	}
+	return count == len(one)
+}
+
+func TestAddNode(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	id, err := sim.AddNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	n := sim.Net.GetNode(id)
+	if n == nil {
+		t.Fatal("node not found")
+	}
+
+	if !n.Up() {
+		t.Error("node not started")
+	}
+}
+
+func TestAddNodeWithMsgEvents(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	id, err := sim.AddNode(AddNodeWithMsgEvents(true))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !sim.Net.GetNode(id).Config.EnableMsgEvents {
+		t.Error("EnableMsgEvents is false")
+	}
+
+	id, err = sim.AddNode(AddNodeWithMsgEvents(false))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if sim.Net.GetNode(id).Config.EnableMsgEvents {
+		t.Error("EnableMsgEvents is true")
+	}
+}
+
+func TestAddNodeWithService(t *testing.T) {
+	sim := New(map[string]ServiceFunc{
+		"noop1": noopServiceFunc,
+		"noop2": noopServiceFunc,
+	})
+	defer sim.Close()
+
+	id, err := sim.AddNode(AddNodeWithService("noop1"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	n := sim.Net.GetNode(id).Node.(*adapters.SimNode)
+	if n.Service("noop1") == nil {
+		t.Error("service noop1 not found on node")
+	}
+	if n.Service("noop2") != nil {
+		t.Error("service noop2 should not be found on node")
+	}
+}
+
+func TestAddNodeMultipleServices(t *testing.T) {
+	sim := New(map[string]ServiceFunc{
+		"noop1": noopServiceFunc,
+		"noop2": noopService2Func,
+	})
+	defer sim.Close()
+
+	id, err := sim.AddNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	n := sim.Net.GetNode(id).Node.(*adapters.SimNode)
+	if n.Service("noop1") == nil {
+		t.Error("service noop1 not found on node")
+	}
+	if n.Service("noop2") == nil {
+		t.Error("service noop2 not found on node")
+	}
+}
+
+func TestAddNodeDuplicateServiceError(t *testing.T) {
+	sim := New(map[string]ServiceFunc{
+		"noop1": noopServiceFunc,
+		"noop2": noopServiceFunc,
+	})
+	defer sim.Close()
+
+	wantErr := "duplicate service: *simulation.noopService"
+	_, err := sim.AddNode()
+	if err.Error() != wantErr {
+		t.Errorf("got error %q, want %q", err, wantErr)
+	}
+}
+
+func TestAddNodes(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	nodesCount := 12
+
+	ids, err := sim.AddNodes(nodesCount)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	count := len(ids)
+	if count != nodesCount {
+		t.Errorf("expected %v nodes, got %v", nodesCount, count)
+	}
+
+	count = len(sim.Net.GetNodes())
+	if count != nodesCount {
+		t.Errorf("expected %v nodes, got %v", nodesCount, count)
+	}
+}
+
+func TestAddNodesAndConnectFull(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	n := 12
+
+	ids, err := sim.AddNodesAndConnectFull(n)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	simulations.VerifyFull(t, sim.Net, ids)
+}
+
+func TestAddNodesAndConnectChain(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	_, err := sim.AddNodesAndConnectChain(12)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// add another set of nodes to test
+	// if two chains are connected
+	_, err = sim.AddNodesAndConnectChain(7)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	simulations.VerifyChain(t, sim.Net, sim.UpNodeIDs())
+}
+
+func TestAddNodesAndConnectRing(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	ids, err := sim.AddNodesAndConnectRing(12)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	simulations.VerifyRing(t, sim.Net, ids)
+}
+
+func TestAddNodesAndConnectStar(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	ids, err := sim.AddNodesAndConnectStar(12)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	simulations.VerifyStar(t, sim.Net, ids, 0)
+}
+
+//To test that uploading a snapshot works
+func TestUploadSnapshot(t *testing.T) {
+	log.Debug("Creating simulation")
+	s := New(map[string]ServiceFunc{
+		"bzz": func(ctx *adapters.ServiceContext, b *sync.Map) (node.Service, func(), error) {
+			addr := network.NewAddr(ctx.Config.Node())
+			hp := network.NewHiveParams()
+			hp.Discovery = false
+			config := &network.BzzConfig{
+				OverlayAddr:  addr.Over(),
+				UnderlayAddr: addr.Under(),
+				HiveParams:   hp,
+			}
+			kad := network.NewKademlia(addr.Over(), network.NewKadParams())
+			b.Store(BucketKeyKademlia, kad)
+			return network.NewBzz(config, kad, nil, nil, nil), nil, nil
+		},
+	})
+	defer s.Close()
+
+	nodeCount := 16
+	log.Debug("Uploading snapshot")
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	err := s.UploadSnapshot(ctx, fmt.Sprintf("../stream/testing/snapshot_%d.json", nodeCount))
+	if err != nil {
+		t.Fatalf("Error uploading snapshot to simulation network: %v", err)
+	}
+
+	log.Debug("Starting simulation...")
+	s.Run(ctx, func(ctx context.Context, sim *Simulation) error {
+		log.Debug("Checking")
+		nodes := sim.UpNodeIDs()
+		if len(nodes) != nodeCount {
+			t.Fatal("Simulation network node number doesn't match snapshot node number")
+		}
+		return nil
+	})
+	log.Debug("Done.")
+}
+
+func TestStartStopNode(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	id, err := sim.AddNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	n := sim.Net.GetNode(id)
+	if n == nil {
+		t.Fatal("node not found")
+	}
+	if !n.Up() {
+		t.Error("node not started")
+	}
+
+	err = sim.StopNode(id)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if n.Up() {
+		t.Error("node not stopped")
+	}
+
+	waitForPeerEventPropagation()
+
+	err = sim.StartNode(id)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !n.Up() {
+		t.Error("node not started")
+	}
+}
+
+func TestStartStopRandomNode(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	_, err := sim.AddNodes(3)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	id, err := sim.StopRandomNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	n := sim.Net.GetNode(id)
+	if n == nil {
+		t.Fatal("node not found")
+	}
+	if n.Up() {
+		t.Error("node not stopped")
+	}
+
+	id2, err := sim.StopRandomNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	waitForPeerEventPropagation()
+
+	idStarted, err := sim.StartRandomNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if idStarted != id && idStarted != id2 {
+		t.Error("unexpected started node ID")
+	}
+}
+
+func TestStartStopRandomNodes(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	_, err := sim.AddNodes(10)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ids, err := sim.StopRandomNodes(3)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, id := range ids {
+		n := sim.Net.GetNode(id)
+		if n == nil {
+			t.Fatal("node not found")
+		}
+		if n.Up() {
+			t.Error("node not stopped")
+		}
+	}
+
+	waitForPeerEventPropagation()
+
+	ids, err = sim.StartRandomNodes(2)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, id := range ids {
+		n := sim.Net.GetNode(id)
+		if n == nil {
+			t.Fatal("node not found")
+		}
+		if !n.Up() {
+			t.Error("node not started")
+		}
+	}
+}
+
+func waitForPeerEventPropagation() {
+	// Sleep here to ensure that Network.watchPeerEvents defer function
+	// has set the `node.Up() = false` before we start the node again.
+	//
+	// The same node is stopped and started again, and upon start
+	// watchPeerEvents is started in a goroutine. If the node is stopped
+	// and then very quickly started, that goroutine may be scheduled later
+	// then start and force `node.Up() = false` in its defer function.
+	// This will make this test unreliable.
+	time.Sleep(1 * time.Second)
+}

network/simulation/service.go

@@ -0,0 +1,65 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"github.com/ethereum/go-ethereum/node"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+)
+
+// Service returns a single Service by name on a particular node
+// with provided id.
+func (s *Simulation) Service(name string, id enode.ID) node.Service {
+	simNode, ok := s.Net.GetNode(id).Node.(*adapters.SimNode)
+	if !ok {
+		return nil
+	}
+	services := simNode.ServiceMap()
+	if len(services) == 0 {
+		return nil
+	}
+	return services[name]
+}
+
+// RandomService returns a single Service by name on a
+// randomly chosen node that is up.
+func (s *Simulation) RandomService(name string) node.Service {
+	n := s.Net.GetRandomUpNode().Node.(*adapters.SimNode)
+	if n == nil {
+		return nil
+	}
+	return n.Service(name)
+}
+
+// Services returns all services with a provided name
+// from nodes that are up.
+func (s *Simulation) Services(name string) (services map[enode.ID]node.Service) {
+	nodes := s.Net.GetNodes()
+	services = make(map[enode.ID]node.Service)
+	for _, node := range nodes {
+		if !node.Up() {
+			continue
+		}
+		simNode, ok := node.Node.(*adapters.SimNode)
+		if !ok {
+			continue
+		}
+		services[node.ID()] = simNode.Service(name)
+	}
+	return services
+}

network/simulation/service_test.go

@@ -0,0 +1,46 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"testing"
+)
+
+func TestService(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	id, err := sim.AddNode()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, ok := sim.Service("noop", id).(*noopService)
+	if !ok {
+		t.Fatalf("service is not of %T type", &noopService{})
+	}
+
+	_, ok = sim.RandomService("noop").(*noopService)
+	if !ok {
+		t.Fatalf("service is not of %T type", &noopService{})
+	}
+
+	_, ok = sim.Services("noop")[id].(*noopService)
+	if !ok {
+		t.Fatalf("service is not of %T type", &noopService{})
+	}
+}

network/simulation/simulation.go

@@ -0,0 +1,218 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"sync"
+	"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"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+	"github.com/ethersphere/swarm/network"
+)
+
+// Common errors that are returned by functions in this package.
+var (
+	ErrNodeNotFound = errors.New("node not found")
+)
+
+// Simulation provides methods on network, nodes and services
+// to manage them.
+type Simulation struct {
+	// Net is exposed as a way to access lower level functionalities
+	// of p2p/simulations.Network.
+	Net *simulations.Network
+
+	serviceNames      []string
+	cleanupFuncs      []func()
+	buckets           map[enode.ID]*sync.Map
+	shutdownWG        sync.WaitGroup
+	done              chan struct{}
+	mu                sync.RWMutex
+	neighbourhoodSize int
+
+	httpSrv *http.Server        //attach a HTTP server via SimulationOptions
+	handler *simulations.Server //HTTP handler for the server
+	runC    chan struct{}       //channel where frontend signals it is ready
+}
+
+// ServiceFunc is used in New to declare new service constructor.
+// The first argument provides ServiceContext from the adapters package
+// giving for example the access to NodeID. Second argument is the sync.Map
+// where all "global" state related to the service should be kept.
+// All cleanups needed for constructed service and any other constructed
+// objects should ne provided in a single returned cleanup function.
+// Returned cleanup function will be called by Close function
+// after network shutdown.
+type ServiceFunc func(ctx *adapters.ServiceContext, bucket *sync.Map) (s node.Service, cleanup func(), err error)
+
+// New creates a new simulation instance
+// Services map must have unique keys as service names and
+// every ServiceFunc must return a node.Service of the unique type.
+// This restriction is required by node.Node.Start() function
+// which is used to start node.Service returned by ServiceFunc.
+func New(services map[string]ServiceFunc) (s *Simulation) {
+	s = &Simulation{
+		buckets:           make(map[enode.ID]*sync.Map),
+		done:              make(chan struct{}),
+		neighbourhoodSize: network.NewKadParams().NeighbourhoodSize,
+	}
+
+	adapterServices := make(map[string]adapters.ServiceFunc, len(services))
+	for name, serviceFunc := range services {
+		// Scope this variables correctly
+		// as they will be in the adapterServices[name] function accessed later.
+		name, serviceFunc := name, serviceFunc
+		s.serviceNames = append(s.serviceNames, name)
+		adapterServices[name] = func(ctx *adapters.ServiceContext) (node.Service, error) {
+			s.mu.Lock()
+			defer s.mu.Unlock()
+			b, ok := s.buckets[ctx.Config.ID]
+			if !ok {
+				b = new(sync.Map)
+			}
+			service, cleanup, err := serviceFunc(ctx, b)
+			if err != nil {
+				return nil, err
+			}
+			if cleanup != nil {
+				s.cleanupFuncs = append(s.cleanupFuncs, cleanup)
+			}
+			s.buckets[ctx.Config.ID] = b
+			return service, nil
+		}
+	}
+
+	s.Net = simulations.NewNetwork(
+		adapters.NewTCPAdapter(adapterServices),
+		&simulations.NetworkConfig{ID: "0"},
+	)
+
+	return s
+}
+
+// RunFunc is the function that will be called
+// on Simulation.Run method call.
+type RunFunc func(context.Context, *Simulation) error
+
+// Result is the returned value of Simulation.Run method.
+type Result struct {
+	Duration time.Duration
+	Error    error
+}
+
+// Run calls the RunFunc function while taking care of
+// cancellation provided through the Context.
+func (s *Simulation) Run(ctx context.Context, f RunFunc) (r Result) {
+	//if the option is set to run a HTTP server with the simulation,
+	//init the server and start it
+	start := time.Now()
+	if s.httpSrv != nil {
+		log.Info("Waiting for frontend to be ready...(send POST /runsim to HTTP server)")
+		//wait for the frontend to connect
+		select {
+		case <-s.runC:
+		case <-ctx.Done():
+			return Result{
+				Duration: time.Since(start),
+				Error:    ctx.Err(),
+			}
+		}
+		log.Info("Received signal from frontend - starting simulation run.")
+	}
+	errc := make(chan error)
+	quit := make(chan struct{})
+	defer close(quit)
+	go func() {
+		select {
+		case errc <- f(ctx, s):
+		case <-quit:
+		}
+	}()
+	var err error
+	select {
+	case <-ctx.Done():
+		err = ctx.Err()
+	case err = <-errc:
+	}
+	return Result{
+		Duration: time.Since(start),
+		Error:    err,
+	}
+}
+
+// Maximal number of parallel calls to cleanup functions on
+// Simulation.Close.
+var maxParallelCleanups = 10
+
+// Close calls all cleanup functions that are returned by
+// ServiceFunc, waits for all of them to finish and other
+// functions that explicitly block shutdownWG
+// (like Simulation.PeerEvents) and shuts down the network
+// at the end. It is used to clean all resources from the
+// simulation.
+func (s *Simulation) Close() {
+	close(s.done)
+
+	sem := make(chan struct{}, maxParallelCleanups)
+	s.mu.RLock()
+	cleanupFuncs := make([]func(), len(s.cleanupFuncs))
+	for i, f := range s.cleanupFuncs {
+		if f != nil {
+			cleanupFuncs[i] = f
+		}
+	}
+	s.mu.RUnlock()
+	var cleanupWG sync.WaitGroup
+	for _, cleanup := range cleanupFuncs {
+		cleanupWG.Add(1)
+		sem <- struct{}{}
+		go func(cleanup func()) {
+			defer cleanupWG.Done()
+			defer func() { <-sem }()
+
+			cleanup()
+		}(cleanup)
+	}
+	cleanupWG.Wait()
+
+	if s.httpSrv != nil {
+		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+		defer cancel()
+		err := s.httpSrv.Shutdown(ctx)
+		if err != nil {
+			log.Error("Error shutting down HTTP server!", "err", err)
+		}
+		close(s.runC)
+	}
+
+	s.shutdownWG.Wait()
+	s.Net.Shutdown()
+}
+
+// Done returns a channel that is closed when the simulation
+// is closed by Close method. It is useful for signaling termination
+// of all possible goroutines that are created within the test.
+func (s *Simulation) Done() <-chan struct{} {
+	return s.done
+}

network/simulation/simulation_test.go

@@ -0,0 +1,203 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package simulation
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/node"
+	"github.com/ethereum/go-ethereum/p2p/simulations"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+	"github.com/mattn/go-colorable"
+)
+
+var (
+	loglevel = flag.Int("loglevel", 2, "verbosity of logs")
+)
+
+func init() {
+	flag.Parse()
+	log.PrintOrigins(true)
+	log.Root().SetHandler(log.LvlFilterHandler(log.Lvl(*loglevel), log.StreamHandler(colorable.NewColorableStderr(), log.TerminalFormat(true))))
+}
+
+// TestRun tests if Run method calls RunFunc and if it handles context properly.
+func TestRun(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	defer sim.Close()
+
+	t.Run("call", func(t *testing.T) {
+		expect := "something"
+		var got string
+		r := sim.Run(context.Background(), func(ctx context.Context, sim *Simulation) error {
+			got = expect
+			return nil
+		})
+
+		if r.Error != nil {
+			t.Errorf("unexpected error: %v", r.Error)
+		}
+		if got != expect {
+			t.Errorf("expected %q, got %q", expect, got)
+		}
+	})
+
+	t.Run("cancellation", func(t *testing.T) {
+		ctx, cancel := context.WithTimeout(context.Background(), 50*time.Millisecond)
+		defer cancel()
+
+		r := sim.Run(ctx, func(ctx context.Context, sim *Simulation) error {
+			time.Sleep(time.Second)
+			return nil
+		})
+
+		if r.Error != context.DeadlineExceeded {
+			t.Errorf("unexpected error: %v", r.Error)
+		}
+	})
+
+	t.Run("context value and duration", func(t *testing.T) {
+		ctx := context.WithValue(context.Background(), "hey", "there")
+		sleep := 50 * time.Millisecond
+
+		r := sim.Run(ctx, func(ctx context.Context, sim *Simulation) error {
+			if ctx.Value("hey") != "there" {
+				return errors.New("expected context value not passed")
+			}
+			time.Sleep(sleep)
+			return nil
+		})
+
+		if r.Error != nil {
+			t.Errorf("unexpected error: %v", r.Error)
+		}
+		if r.Duration < sleep {
+			t.Errorf("reported run duration less then expected: %s", r.Duration)
+		}
+	})
+}
+
+// TestClose tests are Close method triggers all close functions and are all nodes not up anymore.
+func TestClose(t *testing.T) {
+	var mu sync.Mutex
+	var cleanupCount int
+
+	sleep := 50 * time.Millisecond
+
+	sim := New(map[string]ServiceFunc{
+		"noop": func(ctx *adapters.ServiceContext, b *sync.Map) (node.Service, func(), error) {
+			return newNoopService(), func() {
+				time.Sleep(sleep)
+				mu.Lock()
+				defer mu.Unlock()
+				cleanupCount++
+			}, nil
+		},
+	})
+
+	nodeCount := 30
+
+	_, err := sim.AddNodes(nodeCount)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var upNodeCount int
+	for _, n := range sim.Net.GetNodes() {
+		if n.Up() {
+			upNodeCount++
+		}
+	}
+	if upNodeCount != nodeCount {
+		t.Errorf("all nodes should be up, insted only %v are up", upNodeCount)
+	}
+
+	sim.Close()
+
+	if cleanupCount != nodeCount {
+		t.Errorf("number of cleanups expected %v, got %v", nodeCount, cleanupCount)
+	}
+
+	upNodeCount = 0
+	for _, n := range sim.Net.GetNodes() {
+		if n.Up() {
+			upNodeCount++
+		}
+	}
+	if upNodeCount != 0 {
+		t.Errorf("all nodes should be down, insted %v are up", upNodeCount)
+	}
+}
+
+// TestDone checks if Close method triggers the closing of done channel.
+func TestDone(t *testing.T) {
+	sim := New(noopServiceFuncMap)
+	sleep := 50 * time.Millisecond
+	timeout := 2 * time.Second
+
+	start := time.Now()
+	go func() {
+		time.Sleep(sleep)
+		sim.Close()
+	}()
+
+	select {
+	case <-time.After(timeout):
+		t.Error("done channel closing timed out")
+	case <-sim.Done():
+		if d := time.Since(start); d < sleep {
+			t.Errorf("done channel closed sooner then expected: %s", d)
+		}
+	}
+}
+
+// a helper map for usual services that do not do anything
+var noopServiceFuncMap = map[string]ServiceFunc{
+	"noop": noopServiceFunc,
+}
+
+// a helper function for most basic noop service
+func noopServiceFunc(_ *adapters.ServiceContext, _ *sync.Map) (node.Service, func(), error) {
+	return newNoopService(), nil, nil
+}
+
+func newNoopService() node.Service {
+	return &noopService{}
+}
+
+// a helper function for most basic Noop service
+// of a different type then NoopService to test
+// multiple services on one node.
+func noopService2Func(_ *adapters.ServiceContext, _ *sync.Map) (node.Service, func(), error) {
+	return new(noopService2), nil, nil
+}
+
+// NoopService2 is the service that does not do anything
+// but implements node.Service interface.
+type noopService2 struct {
+	simulations.NoopService
+}
+
+type noopService struct {
+	simulations.NoopService
+}