github.com/bcnmy/go-ethereum@v1.10.27/p2p/simulations/mocker.go (about)

     1  // Copyright 2017 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  // Package simulations simulates p2p networks.
    18  // A mocker simulates starting and stopping real nodes in a network.
    19  package simulations
    20  
    21  import (
    22  	"fmt"
    23  	"math/rand"
    24  	"sync"
    25  	"time"
    26  
    27  	"github.com/ethereum/go-ethereum/log"
    28  	"github.com/ethereum/go-ethereum/p2p/enode"
    29  	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
    30  )
    31  
    32  //a map of mocker names to its function
    33  var mockerList = map[string]func(net *Network, quit chan struct{}, nodeCount int){
    34  	"startStop":     startStop,
    35  	"probabilistic": probabilistic,
    36  	"boot":          boot,
    37  }
    38  
    39  //Lookup a mocker by its name, returns the mockerFn
    40  func LookupMocker(mockerType string) func(net *Network, quit chan struct{}, nodeCount int) {
    41  	return mockerList[mockerType]
    42  }
    43  
    44  //Get a list of mockers (keys of the map)
    45  //Useful for frontend to build available mocker selection
    46  func GetMockerList() []string {
    47  	list := make([]string, 0, len(mockerList))
    48  	for k := range mockerList {
    49  		list = append(list, k)
    50  	}
    51  	return list
    52  }
    53  
    54  //The boot mockerFn only connects the node in a ring and doesn't do anything else
    55  func boot(net *Network, quit chan struct{}, nodeCount int) {
    56  	_, err := connectNodesInRing(net, nodeCount)
    57  	if err != nil {
    58  		panic("Could not startup node network for mocker")
    59  	}
    60  }
    61  
    62  //The startStop mockerFn stops and starts nodes in a defined period (ticker)
    63  func startStop(net *Network, quit chan struct{}, nodeCount int) {
    64  	nodes, err := connectNodesInRing(net, nodeCount)
    65  	if err != nil {
    66  		panic("Could not startup node network for mocker")
    67  	}
    68  	tick := time.NewTicker(10 * time.Second)
    69  	defer tick.Stop()
    70  	for {
    71  		select {
    72  		case <-quit:
    73  			log.Info("Terminating simulation loop")
    74  			return
    75  		case <-tick.C:
    76  			id := nodes[rand.Intn(len(nodes))]
    77  			log.Info("stopping node", "id", id)
    78  			if err := net.Stop(id); err != nil {
    79  				log.Error("error stopping node", "id", id, "err", err)
    80  				return
    81  			}
    82  
    83  			select {
    84  			case <-quit:
    85  				log.Info("Terminating simulation loop")
    86  				return
    87  			case <-time.After(3 * time.Second):
    88  			}
    89  
    90  			log.Debug("starting node", "id", id)
    91  			if err := net.Start(id); err != nil {
    92  				log.Error("error starting node", "id", id, "err", err)
    93  				return
    94  			}
    95  		}
    96  	}
    97  }
    98  
    99  //The probabilistic mocker func has a more probabilistic pattern
   100  //(the implementation could probably be improved):
   101  //nodes are connected in a ring, then a varying number of random nodes is selected,
   102  //mocker then stops and starts them in random intervals, and continues the loop
   103  func probabilistic(net *Network, quit chan struct{}, nodeCount int) {
   104  	nodes, err := connectNodesInRing(net, nodeCount)
   105  	if err != nil {
   106  		select {
   107  		case <-quit:
   108  			//error may be due to abortion of mocking; so the quit channel is closed
   109  			return
   110  		default:
   111  			panic("Could not startup node network for mocker")
   112  		}
   113  	}
   114  	for {
   115  		select {
   116  		case <-quit:
   117  			log.Info("Terminating simulation loop")
   118  			return
   119  		default:
   120  		}
   121  		var lowid, highid int
   122  		var wg sync.WaitGroup
   123  		randWait := time.Duration(rand.Intn(5000)+1000) * time.Millisecond
   124  		rand1 := rand.Intn(nodeCount - 1)
   125  		rand2 := rand.Intn(nodeCount - 1)
   126  		if rand1 <= rand2 {
   127  			lowid = rand1
   128  			highid = rand2
   129  		} else if rand1 > rand2 {
   130  			highid = rand1
   131  			lowid = rand2
   132  		}
   133  		var steps = highid - lowid
   134  		wg.Add(steps)
   135  		for i := lowid; i < highid; i++ {
   136  			select {
   137  			case <-quit:
   138  				log.Info("Terminating simulation loop")
   139  				return
   140  			case <-time.After(randWait):
   141  			}
   142  			log.Debug(fmt.Sprintf("node %v shutting down", nodes[i]))
   143  			err := net.Stop(nodes[i])
   144  			if err != nil {
   145  				log.Error("Error stopping node", "node", nodes[i])
   146  				wg.Done()
   147  				continue
   148  			}
   149  			go func(id enode.ID) {
   150  				time.Sleep(randWait)
   151  				err := net.Start(id)
   152  				if err != nil {
   153  					log.Error("Error starting node", "node", id)
   154  				}
   155  				wg.Done()
   156  			}(nodes[i])
   157  		}
   158  		wg.Wait()
   159  	}
   160  }
   161  
   162  //connect nodeCount number of nodes in a ring
   163  func connectNodesInRing(net *Network, nodeCount int) ([]enode.ID, error) {
   164  	ids := make([]enode.ID, nodeCount)
   165  	for i := 0; i < nodeCount; i++ {
   166  		conf := adapters.RandomNodeConfig()
   167  		node, err := net.NewNodeWithConfig(conf)
   168  		if err != nil {
   169  			log.Error("Error creating a node!", "err", err)
   170  			return nil, err
   171  		}
   172  		ids[i] = node.ID()
   173  	}
   174  
   175  	for _, id := range ids {
   176  		if err := net.Start(id); err != nil {
   177  			log.Error("Error starting a node!", "err", err)
   178  			return nil, err
   179  		}
   180  		log.Debug(fmt.Sprintf("node %v starting up", id))
   181  	}
   182  	for i, id := range ids {
   183  		peerID := ids[(i+1)%len(ids)]
   184  		if err := net.Connect(id, peerID); err != nil {
   185  			log.Error("Error connecting a node to a peer!", "err", err)
   186  			return nil, err
   187  		}
   188  	}
   189  
   190  	return ids, nil
   191  }