gitee.com/liuxuezhan/go-micro-v1.18.0@v1.0.0/sync/leader/etcd/etcd.go (about)

     1  package etcd
     2  
     3  import (
     4  	"context"
     5  	"log"
     6  	"path"
     7  	"strings"
     8  
     9  	client "github.com/coreos/etcd/clientv3"
    10  	cc "github.com/coreos/etcd/clientv3/concurrency"
    11  	"gitee.com/liuxuezhan/go-micro-v1.18.0/sync/leader"
    12  )
    13  
    14  type etcdLeader struct {
    15  	opts   leader.Options
    16  	path   string
    17  	client *client.Client
    18  }
    19  
    20  type etcdElected struct {
    21  	s  *cc.Session
    22  	e  *cc.Election
    23  	id string
    24  }
    25  
    26  func (e *etcdLeader) Elect(id string, opts ...leader.ElectOption) (leader.Elected, error) {
    27  	var options leader.ElectOptions
    28  	for _, o := range opts {
    29  		o(&options)
    30  	}
    31  
    32  	// make path
    33  	path := path.Join(e.path, strings.Replace(id, "/", "-", -1))
    34  
    35  	s, err := cc.NewSession(e.client)
    36  	if err != nil {
    37  		return nil, err
    38  	}
    39  
    40  	l := cc.NewElection(s, path)
    41  
    42  	if err := l.Campaign(context.TODO(), id); err != nil {
    43  		return nil, err
    44  	}
    45  
    46  	return &etcdElected{
    47  		e:  l,
    48  		id: id,
    49  	}, nil
    50  }
    51  
    52  func (e *etcdLeader) Follow() chan string {
    53  	ch := make(chan string)
    54  
    55  	s, err := cc.NewSession(e.client)
    56  	if err != nil {
    57  		return ch
    58  	}
    59  
    60  	l := cc.NewElection(s, e.path)
    61  	ech := l.Observe(context.Background())
    62  
    63  	go func() {
    64  		for r := range ech {
    65  			ch <- string(r.Kvs[0].Value)
    66  		}
    67  	}()
    68  
    69  	return ch
    70  }
    71  
    72  func (e *etcdLeader) String() string {
    73  	return "etcd"
    74  }
    75  
    76  func (e *etcdElected) Reelect() error {
    77  	return e.e.Campaign(context.TODO(), e.id)
    78  }
    79  
    80  func (e *etcdElected) Revoked() chan bool {
    81  	ch := make(chan bool, 1)
    82  	ech := e.e.Observe(context.Background())
    83  
    84  	go func() {
    85  		for r := range ech {
    86  			if string(r.Kvs[0].Value) != e.id {
    87  				ch <- true
    88  				close(ch)
    89  				return
    90  			}
    91  		}
    92  	}()
    93  
    94  	return ch
    95  }
    96  
    97  func (e *etcdElected) Resign() error {
    98  	return e.e.Resign(context.Background())
    99  }
   100  
   101  func (e *etcdElected) Id() string {
   102  	return e.id
   103  }
   104  
   105  func NewLeader(opts ...leader.Option) leader.Leader {
   106  	var options leader.Options
   107  	for _, o := range opts {
   108  		o(&options)
   109  	}
   110  
   111  	var endpoints []string
   112  
   113  	for _, addr := range options.Nodes {
   114  		if len(addr) > 0 {
   115  			endpoints = append(endpoints, addr)
   116  		}
   117  	}
   118  
   119  	if len(endpoints) == 0 {
   120  		endpoints = []string{"http://127.0.0.1:2379"}
   121  	}
   122  
   123  	// TODO: parse addresses
   124  	c, err := client.New(client.Config{
   125  		Endpoints: endpoints,
   126  	})
   127  	if err != nil {
   128  		log.Fatal(err)
   129  	}
   130  
   131  	return &etcdLeader{
   132  		path:   "/micro/leader",
   133  		client: c,
   134  		opts:   options,
   135  	}
   136  }