swarm: network simulation for swarm tests (#769)

* cmd/swarm: minor cli flag text adjustments

* cmd/swarm, swarm/storage, swarm: fix  mingw on windows test issues

* cmd/swarm: support for smoke tests on the production swarm cluster

* cmd/swarm/swarm-smoke: simplify cluster logic as per suggestion

* changed colour of landing page

* landing page reacts to enter keypress

* swarm/api/http: sticky footer for swarm landing page using flex

* swarm/api/http: sticky footer for error pages and fix for multiple choices

* swarm: propagate ctx to internal apis (#754)

* swarm/simnet: add basic node/service functions

* swarm/netsim: add buckets for global state and kademlia health check

* swarm/netsim: Use sync.Map as bucket and provide cleanup function for...

* swarm, swarm/netsim: adjust SwarmNetworkTest

* swarm/netsim: fix tests

* swarm: added visualization option to sim net redesign

* swarm/netsim: support multiple services per node

* swarm/netsim: remove redundant return statement

* swarm/netsim: add comments

* swarm: shutdown HTTP in Simulation.Close

* swarm: sim HTTP server timeout

* swarm/netsim: add more simulation methods and peer events examples

* swarm/netsim: add WaitKademlia example

* swarm/netsim: fix comments

* swarm/netsim: terminate peer events goroutines on simulation done

* swarm, swarm/netsim: naming updates

* swarm/netsim: return not healthy kademlias on WaitTillHealthy

* swarm: fix WaitTillHealthy call in testSwarmNetwork

* swarm/netsim: allow bucket to have any type for a key

* swarm: Added snapshots to new netsim

* swarm/netsim: add more tests for bucket

* swarm/netsim: move http related things into separate files

* swarm/netsim: add AddNodeWithService option

* swarm/netsim: add more tests and Start* methods

* swarm/netsim: add peer events and kademlia tests

* swarm/netsim: fix some tests flakiness

* swarm/netsim: improve random nodes selection, fix TestStartStop* tests

* swarm/netsim: remove time measurement from TestClose to avoid flakiness

* swarm/netsim: builder pattern for netsim HTTP server (#773)

* swarm/netsim: add connect related tests

* swarm/netsim: add comment for TestPeerEvents

* swarm: rename netsim package to network/simulation

1 files changed, 140 insertions, 0 deletions

diff --git a/swarm/network/simulation/example_test.go b/swarm/network/simulation/example_test.go
new file mode 100644
index 000000000..2a8116921
--- /dev/null
+++ b/swarm/network/simulation/example_test.go
@@ -0,0 +1,140 @@
+// 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"
+	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
+	"github.com/ethereum/go-ethereum/swarm/network"
+	"github.com/ethereum/go-ethereum/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 Kadmlias 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.NewAddrFromNodeID(ctx.Config.ID)
+			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, 2)
+	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.Event.Peer, "msgcode", e.Event.MsgCode)
+		}
+	}()
+}
+
+// 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().Type(p2p.PeerEventTypeDrop),
+	)
+
+	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.Event.Peer)
+		}
+	}()
+}
+
+// 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().Type(p2p.PeerEventTypeMsgRecv).Protocol("bzz").MsgCode(1),
+		simulation.NewPeerEventsFilter().Type(p2p.PeerEventTypeMsgRecv).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.Event.Peer)
+		}
+	}()
+}