path: root/swarm/network/simulation/example_test.go

// 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.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, 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)
        }
    }()
}