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client.go
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client.go
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// Package etcdclient implements etcd client utilities.
package etcdclient
import (
"context"
"fmt"
"time"
"github.com/aws/aws-k8s-tester/pkg/logutil"
"go.etcd.io/etcd/clientv3"
"go.etcd.io/etcd/clientv3/concurrency"
"go.etcd.io/etcd/mvcc/mvccpb"
"go.uber.org/zap"
)
// Config defines etcd client config.
type Config struct {
Logger *zap.Logger
EtcdClientConfig clientv3.Config
}
type etcd struct {
cfg Config
cli *clientv3.Client
}
func New(cfg Config) (Etcd, error) {
if cfg.Logger == nil {
var err error
cfg.Logger, err = logutil.GetDefaultZapLogger()
if err != nil {
return nil, err
}
}
if cfg.EtcdClientConfig.LogConfig == nil {
lcfg := logutil.GetDefaultZapLoggerConfig()
cfg.EtcdClientConfig.LogConfig = &lcfg
}
cli, err := clientv3.New(cfg.EtcdClientConfig)
if err != nil {
return nil, err
}
return &etcd{cfg: cfg, cli: cli}, nil
}
// Etcd defines etcd client operations.
type Etcd interface {
Put(timeout time.Duration, k, v string, leaseTTL time.Duration) error
Get(timeout time.Duration, k string) ([]*mvccpb.KeyValue, error)
Campaign(pfx string, timeout time.Duration) (ok bool, err error)
List(pfx string, listBatchLimit int64, listBatchInterval time.Duration) (rs []*mvccpb.KeyValue, err error)
Close()
}
func (e *etcd) Close() {
e.cfg.Logger.Info("closed client", zap.Error(e.cli.Close()))
}
func (e *etcd) Put(timeout time.Duration, k, v string, leaseTTL time.Duration) error {
ctx, cancel := context.WithTimeout(context.Background(), timeout)
gresp, err := e.cli.Grant(ctx, int64(leaseTTL.Seconds()))
cancel()
if err != nil {
e.cfg.Logger.Warn("failed to grant a lease", zap.Error(err))
return err
}
e.cfg.Logger.Info("writing", zap.String("key", k), zap.String("lease-id", fmt.Sprintf("%x", int64(gresp.ID))), zap.Duration("ttl", leaseTTL))
ctx, cancel = context.WithTimeout(context.Background(), timeout)
_, err = e.cli.Put(ctx, k, v, clientv3.WithLease(gresp.ID))
cancel()
if err == nil {
e.cfg.Logger.Info("wrote", zap.String("key", k))
} else {
e.cfg.Logger.Warn("failed to write", zap.String("key", k), zap.Error(err))
ctx, cancel = context.WithTimeout(context.Background(), timeout)
_, gerr := e.cli.Revoke(ctx, gresp.ID)
cancel()
e.cfg.Logger.Warn("revoked lease", zap.Error(gerr))
}
return err
}
func (e *etcd) Get(timeout time.Duration, k string) ([]*mvccpb.KeyValue, error) {
e.cfg.Logger.Info("getting", zap.String("key", k))
ctx, cancel := context.WithTimeout(context.Background(), timeout)
resp, err := e.cli.Get(ctx, k)
cancel()
if err != nil {
return nil, err
}
e.cfg.Logger.Info("got", zap.String("key", k), zap.Int("kvs", len(resp.Kvs)))
return resp.Kvs, err
}
func (e *etcd) Campaign(pfx string, timeout time.Duration) (ok bool, err error) {
s, err := concurrency.NewSession(e.cli)
if err != nil {
return false, err
}
defer s.Close()
ev := concurrency.NewElection(s, pfx)
e.cfg.Logger.Info("campaigning", zap.String("prefix", pfx))
ctx, cancel := context.WithTimeout(context.Background(), timeout)
err = ev.Campaign(ctx, "hello")
cancel()
if err == nil {
e.cfg.Logger.Info("elected as a leader")
} else {
e.cfg.Logger.Warn("failed to campaign", zap.Error(err))
}
return err == nil, nil
}
func (e *etcd) List(pfx string, listBatchLimit int64, listBatchInterval time.Duration) (rs []*mvccpb.KeyValue, err error) {
if listBatchLimit == 0 {
return nil, fmt.Errorf("invalid list batch limit %d", listBatchLimit)
}
// see "k8s.io/apiserver/pkg/storage/etcd3" to see how kube-apiserver paginates
// https://github.com/kubernetes/kubernetes/blob/master/staging/src/k8s.io/apiserver/pkg/storage/etcd3/store.go
opts := []clientv3.OpOption{
clientv3.WithRange(clientv3.GetPrefixRangeEnd(pfx)),
clientv3.WithLimit(listBatchLimit),
}
key, resp := pfx, &clientv3.GetResponse{More: true}
for {
ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
resp, err = e.cli.Get(ctx, key, opts...)
cancel()
if err != nil {
return nil, err
}
e.cfg.Logger.Info("getting response", zap.String("start-key", key), zap.Int("kvs", len(resp.Kvs)), zap.Bool("more", resp.More))
if len(resp.Kvs) == 0 {
break
}
rs = append(rs, resp.Kvs...)
if !resp.More {
break
}
lastKey := resp.Kvs[len(resp.Kvs)-1].Key
key = string(lastKey) + "\x00"
time.Sleep(listBatchInterval)
}
e.cfg.Logger.Info("got response", zap.Int("kvs", len(rs)))
return rs, err
}