/
etcd.go
114 lines (90 loc) · 2.05 KB
/
etcd.go
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package etcd
import (
"context"
"errors"
"time"
clientv3 "go.etcd.io/etcd/client/v3"
)
type Config struct {
// etcd endpoints
Endpoints []string
// timeout
DialTimeout time.Duration
// prefix request option
Prefix bool
// limit request option
Limit bool
// number of limited pairs
NLimit int64
// key, key with prefix, etc.
Key string
}
// Etcd implements the etcd config provider.
type Etcd struct {
client *clientv3.Client
cfg Config
}
// Provider returns a provider that takes etcd config.
func Provider(cfg Config) *Etcd {
eCfg := clientv3.Config{
Endpoints: cfg.Endpoints,
DialTimeout: cfg.DialTimeout,
}
c, err := clientv3.New(eCfg)
if err != nil {
return nil
}
return &Etcd{client: c, cfg: cfg}
}
// ReadBytes is not supported by etcd provider.
func (e *Etcd) ReadBytes() ([]byte, error) {
return nil, errors.New("etcd provider does not support this method")
}
// Read returns a nested config map.
func (e *Etcd) Read() (map[string]interface{}, error) {
ctx, cancel := context.WithTimeout(context.Background(), e.cfg.DialTimeout)
defer cancel()
var resp *clientv3.GetResponse
if e.cfg.Prefix {
if e.cfg.Limit {
r, err := e.client.Get(ctx, e.cfg.Key, clientv3.WithPrefix(), clientv3.WithLimit(e.cfg.NLimit))
if err != nil {
return nil, err
}
resp = r
} else {
r, err := e.client.Get(ctx, e.cfg.Key, clientv3.WithPrefix())
if err != nil {
return nil, err
}
resp = r
}
} else {
r, err := e.client.Get(ctx, e.cfg.Key)
if err != nil {
return nil, err
}
resp = r
}
mp := make(map[string]interface{}, len(resp.Kvs))
for _, r := range resp.Kvs {
mp[string(r.Key)] = string(r.Value)
}
return mp, nil
}
func (e *Etcd) Watch(cb func(event interface{}, err error)) error {
var w clientv3.WatchChan
go func() {
if e.cfg.Prefix {
w = e.client.Watch(context.Background(), e.cfg.Key, clientv3.WithPrefix())
} else {
w = e.client.Watch(context.Background(), e.cfg.Key)
}
for wresp := range w {
for _, ev := range wresp.Events {
cb(ev, nil)
}
}
}()
return nil
}