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// Copyright 2017 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 simulations
import (
"context"
"fmt"
"testing"
"time"
"github.com/ethereum/go-ethereum/p2p/discover"
"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
)
// 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
func TestNetworkSimulation(t *testing.T) {
// create simulation network with 20 testService nodes
adapter := adapters.NewSimAdapter(adapters.Services{
"test": newTestService,
})
network := NewNetwork(adapter, &NetworkConfig{
DefaultService: "test",
})
defer network.Shutdown()
nodeCount := 20
ids := make([]discover.NodeID, 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()
}
// perform a check which connects the nodes in a ring (so each node is
// connected to exactly two peers) and then checks that all nodes
// performed two handshakes by checking their peerCount
action := func(_ context.Context) error {
for i, id := range ids {
peerID := ids[(i+1)%len(ids)]
if err := network.Connect(id, peerID); err != nil {
return err
}
}
return nil
}
check := func(ctx context.Context, id discover.NodeID) (bool, error) {
// check we haven't run out of time
select {
case <-ctx.Done():
return false, ctx.Err()
default:
}
// get the node
node := network.GetNode(id)
if node == nil {
return false, fmt.Errorf("unknown node: %s", id)
}
// check it has exactly two peers
client, err := node.Client()
if err != nil {
return false, err
}
var peerCount int64
if err := client.CallContext(ctx, &peerCount, "test_peerCount"); err != nil {
return false, err
}
switch {
case peerCount < 2:
return false, nil
case peerCount == 2:
return true, nil
default:
return false, fmt.Errorf("unexpected peerCount: %d", peerCount)
}
}
timeout := 30 * time.Second
ctx, cancel := context.WithTimeout(context.Background(), timeout)
defer cancel()
// trigger a check every 100ms
trigger := make(chan discover.NodeID)
go triggerChecks(ctx, ids, trigger, 100*time.Millisecond)
result := NewSimulation(network).Run(ctx, &Step{
Action: action,
Trigger: trigger,
Expect: &Expectation{
Nodes: ids,
Check: check,
},
})
if result.Error != nil {
t.Fatalf("simulation failed: %s", result.Error)
}
// take a network snapshot and check it contains the correct topology
snap, err := network.Snapshot()
if err != nil {
t.Fatal(err)
}
if len(snap.Nodes) != nodeCount {
t.Fatalf("expected snapshot to contain %d nodes, got %d", nodeCount, len(snap.Nodes))
}
if len(snap.Conns) != nodeCount {
t.Fatalf("expected snapshot to contain %d connections, got %d", nodeCount, len(snap.Conns))
}
for i, id := range ids {
conn := snap.Conns[i]
if conn.One != id {
t.Fatalf("expected conn[%d].One to be %s, got %s", i, id, conn.One)
}
peerID := ids[(i+1)%len(ids)]
if conn.Other != peerID {
t.Fatalf("expected conn[%d].Other to be %s, got %s", i, peerID, conn.Other)
}
}
}
func triggerChecks(ctx context.Context, ids []discover.NodeID, trigger chan discover.NodeID, interval time.Duration) {
tick := time.NewTicker(interval)
defer tick.Stop()
for {
select {
case <-tick.C:
for _, id := range ids {
select {
case trigger <- id:
case <-ctx.Done():
return
}
}
case <-ctx.Done():
return
}
}
}
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