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client.go
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client.go
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// Copyright 2017 Quentin Machu & eco authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package etcd
import (
"context"
"crypto/tls"
"errors"
"fmt"
"strings"
"sync"
"time"
"go.etcd.io/etcd/api/v3/etcdserverpb"
"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
"go.etcd.io/etcd/client/v3"
"go.etcd.io/etcd/client/v3/concurrency"
"go.etcd.io/etcd/server/v3/mvcc"
"go.uber.org/zap"
"github.com/quentin-m/etcd-cloud-operator/pkg/logger"
)
type Client struct {
*clientv3.Client
clientsAddresses []string
autoSync bool
SC SecurityConfig
TC *tls.Config
}
// NewClient creates a new etcd client wrapper.
//
// The client must be closed.
func NewClient(clientsAddresses []string, sc SecurityConfig, autoSync bool) (*Client, error) {
tc, err := sc.ClientConfig()
if err != nil {
return nil, fmt.Errorf("failed to read client transport security: %s", err)
}
var autoSyncInterval time.Duration
if autoSync {
autoSyncInterval = defaultAutoSync
}
client, err := clientv3.New(clientv3.Config{
Endpoints: ClientsURLs(clientsAddresses, sc.TLSEnabled()),
DialTimeout: defaultDialTimeout,
TLS: tc,
AutoSyncInterval: autoSyncInterval,
LogConfig: logger.Config,
})
if err != nil {
return nil, err
}
client.WithLogger(zap.L())
return &Client{
Client: client,
autoSync: autoSync,
clientsAddresses: clientsAddresses,
SC: sc,
TC: tc,
}, nil
}
func (c *Client) Members() ([]*etcdserverpb.Member, error) {
ctx, cancel := context.WithTimeout(context.Background(), defaultRequestTimeout)
defer cancel()
memberList, err := c.MemberList(ctx)
if err != nil {
return []*etcdserverpb.Member{}, err
}
return memberList.Members, nil
}
func (c *Client) ForEachMember(f func(*Client, *etcdserverpb.Member) error) error {
members, err := c.Members()
if err != nil {
return err
}
// For each member, create a client for them and execute the given command in parallel.
errChan := make(chan string, len(members))
for _, member := range members {
go func(member *etcdserverpb.Member) {
client, err := NewClient([]string{URL2Address(member.PeerURLs[0])}, c.SC, false)
if err != nil {
errChan <- fmt.Sprintf("[%s]: %s", member.Name, err)
return
}
defer client.Close()
if err := f(client, member); err != nil {
errChan <- fmt.Sprintf("[%s]: %s", member.Name, err)
}
errChan <- ""
}(member)
}
// Synchronize, and aggregate the errors.
var errAgg []string
for i := 0; i < len(members); i++ {
if mErr := <-errChan; len(mErr) > 0 {
errAgg = append(errAgg, mErr)
}
}
if len(errAgg) > 0 {
return errors.New(strings.Join(errAgg, ","))
}
return nil
}
func (c *Client) AddMember(name string, pURLs []string) (uint64, func(), error) {
unlock, err := c.Lock("/eco/"+name+"/join", defaultRequestTimeout)
if err != nil {
return 0, nil, err
}
ctx, cancel := context.WithTimeout(context.Background(), defaultRequestTimeout)
defer cancel()
resp, err := c.MemberAdd(ctx, pURLs)
if err != nil {
unlock()
return 0, nil, err
}
return resp.Member.ID, unlock, nil
}
func (c *Client) RemoveMember(name string, id uint64) error {
unlock, err := c.Lock("/eco/"+name+"/join", defaultRequestTimeout)
if err != nil {
return fmt.Errorf("failed to acquire lock: %v", err)
}
defer unlock()
ctx, cancel := context.WithTimeout(context.Background(), defaultRequestTimeout)
defer cancel()
_, err = c.MemberRemove(ctx, id)
if err != nil && err != rpctypes.ErrMemberNotFound {
return err
}
return nil
}
func (c *Client) Lock(name string, maxWait time.Duration) (func(), error) {
session, err := concurrency.NewSession(c.Client)
if err != nil {
return nil, err
}
mutex := concurrency.NewMutex(session, name)
ctx, cancel := context.WithTimeout(context.Background(), maxWait)
defer cancel()
err = mutex.Lock(ctx)
if err != nil {
session.Close()
return nil, err
}
unlock := func() {
ctx, cancel := context.WithTimeout(context.Background(), defaultRequestTimeout)
mutex.Unlock(ctx)
cancel()
session.Close()
}
return unlock, nil
}
// IsHealthy verifies if the cluster is healthy / has quorum, or when a single address is given and autoSync is off,
// if the member behind that address is responsive (and not that the overall cluster is operating).
//
// For checking the health of the entire cluster, IsHealthy simply leverages linearizable reads, which are reads
// that must go through raft. Even if a few members are unreachable or isolated, IsHealthy is able to respond
// correctly thanks to the smart underlying balancer in the client.
func (c *Client) IsHealthy(retries int, timeout time.Duration) bool {
opOptions := []clientv3.OpOption{}
if len(c.clientsAddresses) == 0 && !c.autoSync {
opOptions = append(opOptions, clientv3.WithSerializable())
}
for i := 0; i < retries; i++ {
ctx, cancel := context.WithTimeout(context.Background(), timeout)
_, err := c.Get(ctx, "health")
cancel()
if err == nil || err == rpctypes.ErrPermissionDenied || err == rpctypes.ErrGRPCCompacted {
return true
}
}
return false
}
func (c *Client) GetHighestRevision() (int64, error) {
revs, _, err := c.GetRevisionsHashes()
if err != nil {
return -1, err
}
var maxRev int64
for _, rev := range revs {
if rev > maxRev {
maxRev = rev
}
}
return maxRev, nil
}
func (c *Client) IsConsistent() error {
var (
revs map[string]int64
hashes map[string]int64
err error
)
for i := 0; i < 15; i++ {
revs, hashes, err = c.GetRevisionsHashes()
if err != nil || !getSameValue(revs) || !getSameValue(hashes) {
time.Sleep(time.Second)
continue
}
return nil
}
return fmt.Errorf("cluster is inconsistent: [revisions: %v] and [hashes: %v]", revs, hashes)
}
func (c *Client) GetRevisionsHashes() (map[string]int64, map[string]int64, error) {
var rhMutex sync.Mutex
revs := make(map[string]int64)
hashes := make(map[string]int64)
ctx, cancel := context.WithTimeout(context.Background(), 2*defaultRequestTimeout)
defer cancel()
f := func(c *Client, m *etcdserverpb.Member) error {
cURL := ClientURL(URL2Address(m.PeerURLs[0]), c.SC.TLSEnabled())
s, err := c.Status(ctx, cURL)
if err != nil {
return fmt.Errorf("failed to get Status: %v", err)
}
h, err := c.Maintenance.HashKV(ctx, cURL, 0)
if err != nil {
return fmt.Errorf("failed to get HashKV: %v", err)
}
rhMutex.Lock()
defer rhMutex.Unlock()
revs[m.Name] = s.Header.Revision
hashes[m.Name] = int64(h.Hash)
return nil
}
return revs, hashes, c.ForEachMember(f)
}
func (c *Client) Cleanup() error {
// Get the current revision of the cluster.
rev, err := c.GetHighestRevision()
if err != nil {
return err
}
// Compact.
ctx, cancel := context.WithTimeout(context.Background(), 300*time.Second)
defer cancel()
if _, err := c.Client.Compact(ctx, rev); err != nil && !strings.Contains(err.Error(), mvcc.ErrCompacted.Error()) {
return fmt.Errorf("failed to compact: %v", err)
}
// Defrag each member one after the other.
var mu sync.Mutex
f := func(c *Client, m *etcdserverpb.Member) error {
mu.Lock()
defer mu.Unlock()
if _, err := c.Defragment(ctx, ClientURL(URL2Address(m.PeerURLs[0]), c.SC.TLSEnabled())); err != nil {
return fmt.Errorf("failed to defragment: %v", err)
}
return nil
}
return c.ForEachMember(f)
}