clientv3

package
v3.3.20 Latest Latest
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 Go to latest Published: Apr 1, 2020 License: Apache-2.0 Imports: 36 Imported by: 0

Documentation

Overview

Package clientv3 implements the official Go etcd client for v3.

Create client using `clientv3.New`: 

// expect dial time-out on ipv4 blackhole
_, err := clientv3.New(clientv3.Config{
	Endpoints:   []string{"http://254.0.0.1:12345"},
	DialTimeout: 2 * time.Second
})

// etcd clientv3 >= v3.2.10, grpc/grpc-go >= v1.7.3
if err == context.DeadlineExceeded {
	// handle errors
}

// etcd clientv3 <= v3.2.9, grpc/grpc-go <= v1.2.1
if err == grpc.ErrClientConnTimeout {
	// handle errors
}

cli, err := clientv3.New(clientv3.Config{
	Endpoints:   []string{"localhost:2379", "localhost:22379", "localhost:32379"},
	DialTimeout: 5 * time.Second,
})
if err != nil {
	// handle error!
}
defer cli.Close()

Make sure to close the client after using it. If the client is not closed, the connection will have leaky goroutines.

To specify a client request timeout, wrap the context with context.WithTimeout: 

ctx, cancel := context.WithTimeout(context.Background(), timeout)
resp, err := kvc.Put(ctx, "sample_key", "sample_value")
cancel()
if err != nil {
    // handle error!
}
// use the response

The Client has internal state (watchers and leases), so Clients should be reused instead of created as needed. Clients are safe for concurrent use by multiple goroutines.

etcd client returns 3 types of errors:

  1. context error: canceled or deadline exceeded.
  2. gRPC status error: e.g. when clock drifts in server-side before client's context deadline exceeded.
  3. gRPC error: see https://github.com/coreos/etcd/blob/master/etcdserver/api/v3rpc/rpctypes/error.go

Here is the example code to handle client errors: 

resp, err := kvc.Put(ctx, "", "")
if err != nil {
	if err == context.Canceled {
		// ctx is canceled by another routine
	} else if err == context.DeadlineExceeded {
		// ctx is attached with a deadline and it exceeded
	} else if ev, ok := status.FromError(err); ok {
		code := ev.Code()
		if code == codes.DeadlineExceeded {
			// server-side context might have timed-out first (due to clock skew)
			// while original client-side context is not timed-out yet
		}
	} else if verr, ok := err.(*v3rpc.ErrEmptyKey); ok {
		// process (verr.Errors)
	} else {
		// bad cluster endpoints, which are not etcd servers
	}
}

go func() { cli.Close() }()
_, err := kvc.Get(ctx, "a")
if err != nil {
	if err == context.Canceled {
		// grpc balancer calls 'Get' with an inflight client.Close
	} else if err == grpc.ErrClientConnClosing {
		// grpc balancer calls 'Get' after client.Close.
	}
}
Example 
package main

import (
	"context"
	"log"
	"os"
	"time"

	"github.com/coreos/etcd/clientv3"

	"google.golang.org/grpc/grpclog"
)

var (
	dialTimeout = 5 * time.Second

	endpoints = []string{"localhost:2379", "localhost:22379", "localhost:32379"}
)

func main() {
	clientv3.SetLogger(grpclog.NewLoggerV2(os.Stderr, os.Stderr, os.Stderr))

	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close() // make sure to close the client

	_, err = cli.Put(context.TODO(), "foo", "bar")
	if err != nil {
		log.Fatal(err)
	}
}

Output:

Index

Examples

Constants

View Source 
const (
	PermRead      = authpb.READ
	PermWrite     = authpb.WRITE
	PermReadWrite = authpb.READWRITE
)
View Source 
const (
	EventTypeDelete = mvccpb.DELETE
	EventTypePut    = mvccpb.PUT
)
View Source 
const MaxLeaseTTL = 9000000000

MaxLeaseTTL is the maximum lease TTL value

Variables

View Source 
var (
	ErrNoAvailableEndpoints = errors.New("etcdclient: no available endpoints")
	ErrOldCluster           = errors.New("etcdclient: old cluster version")
)
View Source 
var LeaseResponseChSize = 16

LeaseResponseChSize is the size of buffer to store unsent lease responses. WARNING: DO NOT UPDATE. Only for testing purposes.

Functions

func GetLogger added in v3.1.0 

func GetLogger() logutil.Logger

GetLogger returns the current logutil.Logger.

func GetPrefixRangeEnd added in v3.0.2 

func GetPrefixRangeEnd(prefix string) string

GetPrefixRangeEnd gets the range end of the prefix. 'Get(foo, WithPrefix())' is equal to 'Get(foo, WithRange(GetPrefixRangeEnd(foo))'.

func IsConnCanceled added in v3.3.15 

func IsConnCanceled(err error) bool

IsConnCanceled returns true, if error is from a closed gRPC connection. ref. https://github.com/grpc/grpc-go/pull/1854

func NewLogger added in v3.3.0 

func NewLogger(gl grpclog.LoggerV2) logutil.Logger

NewLogger returns a new Logger with logutil.Logger.

func RetryAuthClient added in v3.0.5 

func RetryAuthClient(c *Client) pb.AuthClient

RetryAuthClient implements a AuthClient.

func RetryClusterClient added in v3.0.5 

func RetryClusterClient(c *Client) pb.ClusterClient

RetryClusterClient implements a ClusterClient.

func RetryKVClient added in v3.0.5 

func RetryKVClient(c *Client) pb.KVClient

RetryKVClient implements a KVClient.

func RetryLeaseClient added in v3.0.5 

func RetryLeaseClient(c *Client) pb.LeaseClient

RetryLeaseClient implements a LeaseClient.

func RetryMaintenanceClient added in v3.2.10 

func RetryMaintenanceClient(c *Client, conn *grpc.ClientConn) pb.MaintenanceClient

RetryMaintenanceClient implements a Maintenance.

func SetLogger added in v3.1.0 

func SetLogger(l grpclog.LoggerV2)

SetLogger sets client-side Logger.

func WithRequireLeader 

func WithRequireLeader(ctx context.Context) context.Context

WithRequireLeader requires client requests to only succeed when the cluster has a leader.

Types

type AlarmMember 

type AlarmMember pb.AlarmMember

type AlarmResponse 

type AlarmResponse pb.AlarmResponse

type Auth 

type Auth interface {
	// AuthEnable enables auth of an etcd cluster.
	AuthEnable(ctx context.Context) (*AuthEnableResponse, error)

	// AuthDisable disables auth of an etcd cluster.
	AuthDisable(ctx context.Context) (*AuthDisableResponse, error)

	// UserAdd adds a new user to an etcd cluster.
	UserAdd(ctx context.Context, name string, password string) (*AuthUserAddResponse, error)

	// UserDelete deletes a user from an etcd cluster.
	UserDelete(ctx context.Context, name string) (*AuthUserDeleteResponse, error)

	// UserChangePassword changes a password of a user.
	UserChangePassword(ctx context.Context, name string, password string) (*AuthUserChangePasswordResponse, error)

	// UserGrantRole grants a role to a user.
	UserGrantRole(ctx context.Context, user string, role string) (*AuthUserGrantRoleResponse, error)

	// UserGet gets a detailed information of a user.
	UserGet(ctx context.Context, name string) (*AuthUserGetResponse, error)

	// UserList gets a list of all users.
	UserList(ctx context.Context) (*AuthUserListResponse, error)

	// UserRevokeRole revokes a role of a user.
	UserRevokeRole(ctx context.Context, name string, role string) (*AuthUserRevokeRoleResponse, error)

	// RoleAdd adds a new role to an etcd cluster.
	RoleAdd(ctx context.Context, name string) (*AuthRoleAddResponse, error)

	// RoleGrantPermission grants a permission to a role.
	RoleGrantPermission(ctx context.Context, name string, key, rangeEnd string, permType PermissionType) (*AuthRoleGrantPermissionResponse, error)

	// RoleGet gets a detailed information of a role.
	RoleGet(ctx context.Context, role string) (*AuthRoleGetResponse, error)

	// RoleList gets a list of all roles.
	RoleList(ctx context.Context) (*AuthRoleListResponse, error)

	// RoleRevokePermission revokes a permission from a role.
	RoleRevokePermission(ctx context.Context, role string, key, rangeEnd string) (*AuthRoleRevokePermissionResponse, error)

	// RoleDelete deletes a role.
	RoleDelete(ctx context.Context, role string) (*AuthRoleDeleteResponse, error)
}
Example 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

if _, err = cli.RoleAdd(context.TODO(), "root"); err != nil {
	log.Fatal(err)
}
if _, err = cli.UserAdd(context.TODO(), "root", "123"); err != nil {
	log.Fatal(err)
}
if _, err = cli.UserGrantRole(context.TODO(), "root", "root"); err != nil {
	log.Fatal(err)
}

if _, err = cli.RoleAdd(context.TODO(), "r"); err != nil {
	log.Fatal(err)
}

if _, err = cli.RoleGrantPermission(
	context.TODO(),
	"r",   // role name
	"foo", // key
	"zoo", // range end
	clientv3.PermissionType(clientv3.PermReadWrite),
); err != nil {
	log.Fatal(err)
}
if _, err = cli.UserAdd(context.TODO(), "u", "123"); err != nil {
	log.Fatal(err)
}
if _, err = cli.UserGrantRole(context.TODO(), "u", "r"); err != nil {
	log.Fatal(err)
}
if _, err = cli.AuthEnable(context.TODO()); err != nil {
	log.Fatal(err)
}

cliAuth, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
	Username:    "u",
	Password:    "123",
})
if err != nil {
	log.Fatal(err)
}
defer cliAuth.Close()

if _, err = cliAuth.Put(context.TODO(), "foo1", "bar"); err != nil {
	log.Fatal(err)
}

_, err = cliAuth.Txn(context.TODO()).
	If(clientv3.Compare(clientv3.Value("zoo1"), ">", "abc")).
	Then(clientv3.OpPut("zoo1", "XYZ")).
	Else(clientv3.OpPut("zoo1", "ABC")).
	Commit()
fmt.Println(err)

// now check the permission with the root account
rootCli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
	Username:    "root",
	Password:    "123",
})
if err != nil {
	log.Fatal(err)
}
defer rootCli.Close()

resp, err := rootCli.RoleGet(context.TODO(), "r")
if err != nil {
	log.Fatal(err)
}
fmt.Printf("user u permission: key %q, range end %q\n", resp.Perm[0].Key, resp.Perm[0].RangeEnd)

if _, err = rootCli.AuthDisable(context.TODO()); err != nil {
	log.Fatal(err)
}

Output:

etcdserver: permission denied
user u permission: key "foo", range end "zoo"

func NewAuth 

func NewAuth(c *Client) Auth

type AuthDisableResponse 

type AuthDisableResponse pb.AuthDisableResponse

type AuthEnableResponse 

type AuthEnableResponse pb.AuthEnableResponse

type AuthRoleAddResponse 

type AuthRoleAddResponse pb.AuthRoleAddResponse

type AuthRoleDeleteResponse 

type AuthRoleDeleteResponse pb.AuthRoleDeleteResponse

type AuthRoleGetResponse 

type AuthRoleGetResponse pb.AuthRoleGetResponse

type AuthRoleGrantPermissionResponse 

type AuthRoleGrantPermissionResponse pb.AuthRoleGrantPermissionResponse

type AuthRoleListResponse 

type AuthRoleListResponse pb.AuthRoleListResponse

type AuthRoleRevokePermissionResponse 

type AuthRoleRevokePermissionResponse pb.AuthRoleRevokePermissionResponse

type AuthUserAddResponse 

type AuthUserAddResponse pb.AuthUserAddResponse

type AuthUserChangePasswordResponse 

type AuthUserChangePasswordResponse pb.AuthUserChangePasswordResponse

type AuthUserDeleteResponse 

type AuthUserDeleteResponse pb.AuthUserDeleteResponse

type AuthUserGetResponse 

type AuthUserGetResponse pb.AuthUserGetResponse

type AuthUserGrantRoleResponse 

type AuthUserGrantRoleResponse pb.AuthUserGrantRoleResponse

type AuthUserListResponse 

type AuthUserListResponse pb.AuthUserListResponse

type AuthUserRevokeRoleResponse 

type AuthUserRevokeRoleResponse pb.AuthUserRevokeRoleResponse

type AuthenticateResponse 

type AuthenticateResponse pb.AuthenticateResponse

type Client 

type Client struct {
	Cluster
	KV
	Lease
	Watcher
	Auth
	Maintenance

	// Username is a user name for authentication.
	Username string
	// Password is a password for authentication.
	Password string
	// contains filtered or unexported fields
}

Client provides and manages an etcd v3 client session.

Example (Metrics) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints: endpoints,
	DialOptions: []grpc.DialOption{
		grpc.WithUnaryInterceptor(grpcprom.UnaryClientInterceptor),
		grpc.WithStreamInterceptor(grpcprom.StreamClientInterceptor),
	},
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

// get a key so it shows up in the metrics as a range RPC
cli.Get(context.TODO(), "test_key")

// listen for all Prometheus metrics
ln, err := net.Listen("tcp", ":0")
if err != nil {
	log.Fatal(err)
}
donec := make(chan struct{})
go func() {
	defer close(donec)
	http.Serve(ln, promhttp.Handler())
}()
defer func() {
	ln.Close()
	<-donec
}()

// make an http request to fetch all Prometheus metrics
url := "http://" + ln.Addr().String() + "/metrics"
resp, err := http.Get(url)
if err != nil {
	log.Fatalf("fetch error: %v", err)
}
b, err := ioutil.ReadAll(resp.Body)
resp.Body.Close()
if err != nil {
	log.Fatalf("fetch error: reading %s: %v", url, err)
}

// confirm range request in metrics
for _, l := range strings.Split(string(b), "\n") {
	if strings.Contains(l, `grpc_client_started_total{grpc_method="Range"`) {
		fmt.Println(l)
		break
	}
}

Output:

	grpc_client_started_total{grpc_method="Range",grpc_service="etcdserverpb.KV",grpc_type="unary"} 1

func New 

func New(cfg Config) (*Client, error)

New creates a new etcdv3 client from a given configuration.

func NewCtxClient added in v3.2.0 

func NewCtxClient(ctx context.Context) *Client

NewCtxClient creates a client with a context but no underlying grpc connection. This is useful for embedded cases that override the service interface implementations and do not need connection management.

func NewFromURL 

func NewFromURL(url string) (*Client, error)

NewFromURL creates a new etcdv3 client from a URL.

func NewFromURLs added in v3.3.15 

func NewFromURLs(urls []string) (*Client, error)

NewFromURLs creates a new etcdv3 client from URLs.

func (*Client) ActiveConnection 

func (c *Client) ActiveConnection() *grpc.ClientConn

ActiveConnection returns the current in-use connection

func (*Client) Close 

func (c *Client) Close() error

Close shuts down the client's etcd connections.

func (*Client) Ctx 

func (c *Client) Ctx() context.Context

Ctx is a context for "out of band" messages (e.g., for sending "clean up" message when another context is canceled). It is canceled on client Close().

func (*Client) Dial 

func (c *Client) Dial(ep string) (*grpc.ClientConn, error)

Dial connects to a single endpoint using the client's config.

func (*Client) Endpoints 

func (c *Client) Endpoints() []string

Endpoints lists the registered endpoints for the client.

func (*Client) SetEndpoints added in v3.1.0 

func (c *Client) SetEndpoints(eps ...string)

SetEndpoints updates client's endpoints.

func (*Client) Sync added in v3.1.0 

func (c *Client) Sync(ctx context.Context) error

Sync synchronizes client's endpoints with the known endpoints from the etcd membership.

type Cluster 

type Cluster interface {
	// MemberList lists the current cluster membership.
	MemberList(ctx context.Context) (*MemberListResponse, error)

	// MemberAdd adds a new member into the cluster.
	MemberAdd(ctx context.Context, peerAddrs []string) (*MemberAddResponse, error)

	// MemberRemove removes an existing member from the cluster.
	MemberRemove(ctx context.Context, id uint64) (*MemberRemoveResponse, error)

	// MemberUpdate updates the peer addresses of the member.
	MemberUpdate(ctx context.Context, id uint64, peerAddrs []string) (*MemberUpdateResponse, error)
}
Example (MemberAdd) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints[:2],
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

peerURLs := endpoints[2:]
mresp, err := cli.MemberAdd(context.Background(), peerURLs)
if err != nil {
	log.Fatal(err)
}
fmt.Println("added member.PeerURLs:", mresp.Member.PeerURLs)
// added member.PeerURLs: [http://localhost:32380]

Output:
Example (MemberList) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

resp, err := cli.MemberList(context.Background())
if err != nil {
	log.Fatal(err)
}
fmt.Println("members:", len(resp.Members))

Output:

members: 3
Example (MemberRemove) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints[1:],
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

resp, err := cli.MemberList(context.Background())
if err != nil {
	log.Fatal(err)
}

_, err = cli.MemberRemove(context.Background(), resp.Members[0].ID)
if err != nil {
	log.Fatal(err)
}

Output:
Example (MemberUpdate) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

resp, err := cli.MemberList(context.Background())
if err != nil {
	log.Fatal(err)
}

peerURLs := []string{"http://localhost:12380"}
_, err = cli.MemberUpdate(context.Background(), resp.Members[0].ID, peerURLs)
if err != nil {
	log.Fatal(err)
}

Output:

func NewCluster 

func NewCluster(c *Client) Cluster

func NewClusterFromClusterClient added in v3.2.0 

func NewClusterFromClusterClient(remote pb.ClusterClient, c *Client) Cluster

type Cmp 

type Cmp pb.Compare

func Compare 

func Compare(cmp Cmp, result string, v interface{}) Cmp

func CreateRevision 

func CreateRevision(key string) Cmp

func LeaseValue added in v3.3.0 

func LeaseValue(key string) Cmp

LeaseValue compares a key's LeaseID to a value of your choosing. The empty LeaseID is 0, otherwise known as `NoLease`.

func ModRevision 

func ModRevision(key string) Cmp

func Value 

func Value(key string) Cmp

func Version 

func Version(key string) Cmp

func (*Cmp) KeyBytes added in v3.2.0 

func (cmp *Cmp) KeyBytes() []byte

KeyBytes returns the byte slice holding with the comparison key.

func (*Cmp) ValueBytes added in v3.2.0 

func (cmp *Cmp) ValueBytes() []byte

ValueBytes returns the byte slice holding the comparison value, if any.

func (*Cmp) WithKeyBytes added in v3.2.0 

func (cmp *Cmp) WithKeyBytes(key []byte)

WithKeyBytes sets the byte slice for the comparison key.

func (Cmp) WithPrefix added in v3.3.0 

func (cmp Cmp) WithPrefix() Cmp

WithPrefix sets the comparison to scan all keys prefixed by the key.

func (Cmp) WithRange added in v3.3.0 

func (cmp Cmp) WithRange(end string) Cmp

WithRange sets the comparison to scan the range [key, end).

func (*Cmp) WithValueBytes added in v3.2.0 

func (cmp *Cmp) WithValueBytes(v []byte)

WithValueBytes sets the byte slice for the comparison's value.

type CompactOp 

type CompactOp struct {
	// contains filtered or unexported fields
}

CompactOp represents a compact operation.

func OpCompact 

func OpCompact(rev int64, opts ...CompactOption) CompactOp

OpCompact wraps slice CompactOption to create a CompactOp.

type CompactOption 

type CompactOption func(*CompactOp)

CompactOption configures compact operation.

func WithCompactPhysical 

func WithCompactPhysical() CompactOption

WithCompactPhysical makes Compact wait until all compacted entries are removed from the etcd server's storage.

type CompactResponse 

type CompactResponse pb.CompactionResponse

type CompareResult 

type CompareResult int

type CompareTarget 

type CompareTarget int
const (
	CompareVersion CompareTarget = iota
	CompareCreated
	CompareModified
	CompareValue
)

type Config 

type Config struct {
	// Endpoints is a list of URLs.
	Endpoints []string `json:"endpoints"`

	// AutoSyncInterval is the interval to update endpoints with its latest members.
	// 0 disables auto-sync. By default auto-sync is disabled.
	AutoSyncInterval time.Duration `json:"auto-sync-interval"`

	// DialTimeout is the timeout for failing to establish a connection.
	DialTimeout time.Duration `json:"dial-timeout"`

	// DialKeepAliveTime is the time after which client pings the server to see if
	// transport is alive.
	DialKeepAliveTime time.Duration `json:"dial-keep-alive-time"`

	// DialKeepAliveTimeout is the time that the client waits for a response for the
	// keep-alive probe. If the response is not received in this time, the connection is closed.
	DialKeepAliveTimeout time.Duration `json:"dial-keep-alive-timeout"`

	// MaxCallSendMsgSize is the client-side request send limit in bytes.
	// If 0, it defaults to 2.0 MiB (2 * 1024 * 1024).
	// Make sure that "MaxCallSendMsgSize" < server-side default send/recv limit.
	// ("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").
	MaxCallSendMsgSize int

	// MaxCallRecvMsgSize is the client-side response receive limit.
	// If 0, it defaults to "math.MaxInt32", because range response can
	// easily exceed request send limits.
	// Make sure that "MaxCallRecvMsgSize" >= server-side default send/recv limit.
	// ("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").
	MaxCallRecvMsgSize int

	// TLS holds the client secure credentials, if any.
	TLS *tls.Config

	// Username is a user name for authentication.
	Username string `json:"username"`

	// Password is a password for authentication.
	Password string `json:"password"`

	// RejectOldCluster when set will refuse to create a client against an outdated cluster.
	RejectOldCluster bool `json:"reject-old-cluster"`

	// DialOptions is a list of dial options for the grpc client (e.g., for interceptors).
	// For example, pass "grpc.WithBlock()" to block until the underlying connection is up.
	// Without this, Dial returns immediately and connecting the server happens in background.
	DialOptions []grpc.DialOption

	// LogConfig configures client-side logger.
	// If nil, use the default logger.
	// TODO: configure gRPC logger
	LogConfig *zap.Config

	// Context is the default client context; it can be used to cancel grpc dial out and
	// other operations that do not have an explicit context.
	Context context.Context

	// PermitWithoutStream when set will allow client to send keepalive pings to server without any active streams(RPCs).
	PermitWithoutStream bool `json:"permit-without-stream"`
}
Example (WithTLS) 
package main

import (
	"context"
	"log"
	"time"

	"github.com/coreos/etcd/clientv3"
	"github.com/coreos/etcd/pkg/transport"
)

var (
	dialTimeout = 5 * time.Second

	endpoints = []string{"localhost:2379", "localhost:22379", "localhost:32379"}
)

func main() {
	tlsInfo := transport.TLSInfo{
		CertFile:      "/tmp/test-certs/test-name-1.pem",
		KeyFile:       "/tmp/test-certs/test-name-1-key.pem",
		TrustedCAFile: "/tmp/test-certs/trusted-ca.pem",
	}
	tlsConfig, err := tlsInfo.ClientConfig()
	if err != nil {
		log.Fatal(err)
	}
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
		TLS:         tlsConfig,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close() // make sure to close the client

	_, err = cli.Put(context.TODO(), "foo", "bar")
	if err != nil {
		log.Fatal(err)
	}
}

Output:

type DefragmentResponse 

type DefragmentResponse pb.DefragmentResponse

type DeleteResponse 

type DeleteResponse pb.DeleteRangeResponse

func (*DeleteResponse) OpResponse added in v3.2.10 

func (resp *DeleteResponse) OpResponse() OpResponse

type ErrKeepAliveHalted added in v3.1.0 

type ErrKeepAliveHalted struct {
	Reason error
}

ErrKeepAliveHalted is returned if client keep alive loop halts with an unexpected error.

This usually means that automatic lease renewal via KeepAlive is broken, but KeepAliveOnce will still work as expected.

func (ErrKeepAliveHalted) Error added in v3.1.0 

func (e ErrKeepAliveHalted) Error() string

type Event 

type Event mvccpb.Event

func (*Event) IsCreate 

func (e *Event) IsCreate() bool

IsCreate returns true if the event tells that the key is newly created.

func (*Event) IsModify 

func (e *Event) IsModify() bool

IsModify returns true if the event tells that a new value is put on existing key.

type GetResponse 

type GetResponse pb.RangeResponse

func (*GetResponse) OpResponse added in v3.2.10 

func (resp *GetResponse) OpResponse() OpResponse

type HashKVResponse added in v3.3.0 

type HashKVResponse pb.HashKVResponse

type KV 

type KV interface {
	// Put puts a key-value pair into etcd.
	// Note that key,value can be plain bytes array and string is
	// an immutable representation of that bytes array.
	// To get a string of bytes, do string([]byte{0x10, 0x20}).
	Put(ctx context.Context, key, val string, opts ...OpOption) (*PutResponse, error)

	// Get retrieves keys.
	// By default, Get will return the value for "key", if any.
	// When passed WithRange(end), Get will return the keys in the range [key, end).
	// When passed WithFromKey(), Get returns keys greater than or equal to key.
	// When passed WithRev(rev) with rev > 0, Get retrieves keys at the given revision;
	// if the required revision is compacted, the request will fail with ErrCompacted .
	// When passed WithLimit(limit), the number of returned keys is bounded by limit.
	// When passed WithSort(), the keys will be sorted.
	Get(ctx context.Context, key string, opts ...OpOption) (*GetResponse, error)

	// Delete deletes a key, or optionally using WithRange(end), [key, end).
	Delete(ctx context.Context, key string, opts ...OpOption) (*DeleteResponse, error)

	// Compact compacts etcd KV history before the given rev.
	Compact(ctx context.Context, rev int64, opts ...CompactOption) (*CompactResponse, error)

	// Do applies a single Op on KV without a transaction.
	// Do is useful when creating arbitrary operations to be issued at a
	// later time; the user can range over the operations, calling Do to
	// execute them. Get/Put/Delete, on the other hand, are best suited
	// for when the operation should be issued at the time of declaration.
	Do(ctx context.Context, op Op) (OpResponse, error)

	// Txn creates a transaction.
	Txn(ctx context.Context) Txn
}
Example (Compact) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
resp, err := cli.Get(ctx, "foo")
cancel()
if err != nil {
	log.Fatal(err)
}
compRev := resp.Header.Revision // specify compact revision of your choice

ctx, cancel = context.WithTimeout(context.Background(), requestTimeout)
_, err = cli.Compact(ctx, compRev)
cancel()
if err != nil {
	log.Fatal(err)
}

Output:
Example (Delete) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
defer cancel()

// count keys about to be deleted
gresp, err := cli.Get(ctx, "key", clientv3.WithPrefix())
if err != nil {
	log.Fatal(err)
}

// delete the keys
dresp, err := cli.Delete(ctx, "key", clientv3.WithPrefix())
if err != nil {
	log.Fatal(err)
}

fmt.Println("Deleted all keys:", int64(len(gresp.Kvs)) == dresp.Deleted)

Output:

Deleted all keys: true
Example (Do) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

ops := []clientv3.Op{
	clientv3.OpPut("put-key", "123"),
	clientv3.OpGet("put-key"),
	clientv3.OpPut("put-key", "456")}

for _, op := range ops {
	if _, err := cli.Do(context.TODO(), op); err != nil {
		log.Fatal(err)
	}
}

Output:
Example (Get) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

_, err = cli.Put(context.TODO(), "foo", "bar")
if err != nil {
	log.Fatal(err)
}

ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
resp, err := cli.Get(ctx, "foo")
cancel()
if err != nil {
	log.Fatal(err)
}
for _, ev := range resp.Kvs {
	fmt.Printf("%s : %s\n", ev.Key, ev.Value)
}

Output:

foo : bar
Example (GetSortedPrefix) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

for i := range make([]int, 3) {
	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	_, err = cli.Put(ctx, fmt.Sprintf("key_%d", i), "value")
	cancel()
	if err != nil {
		log.Fatal(err)
	}
}

ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
resp, err := cli.Get(ctx, "key", clientv3.WithPrefix(), clientv3.WithSort(clientv3.SortByKey, clientv3.SortDescend))
cancel()
if err != nil {
	log.Fatal(err)
}
for _, ev := range resp.Kvs {
	fmt.Printf("%s : %s\n", ev.Key, ev.Value)
}

Output:

key_2 : value
key_1 : value
key_0 : value
Example (GetWithRev) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

presp, err := cli.Put(context.TODO(), "foo", "bar1")
if err != nil {
	log.Fatal(err)
}
_, err = cli.Put(context.TODO(), "foo", "bar2")
if err != nil {
	log.Fatal(err)
}

ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
resp, err := cli.Get(ctx, "foo", clientv3.WithRev(presp.Header.Revision))
cancel()
if err != nil {
	log.Fatal(err)
}
for _, ev := range resp.Kvs {
	fmt.Printf("%s : %s\n", ev.Key, ev.Value)
}

Output:

foo : bar1
Example (Put) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
_, err = cli.Put(ctx, "sample_key", "sample_value")
cancel()
if err != nil {
	log.Fatal(err)
}

Output:
Example (PutErrorHandling) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
_, err = cli.Put(ctx, "", "sample_value")
cancel()
if err != nil {
	switch err {
	case context.Canceled:
		fmt.Printf("ctx is canceled by another routine: %v\n", err)
	case context.DeadlineExceeded:
		fmt.Printf("ctx is attached with a deadline is exceeded: %v\n", err)
	case rpctypes.ErrEmptyKey:
		fmt.Printf("client-side error: %v\n", err)
	default:
		fmt.Printf("bad cluster endpoints, which are not etcd servers: %v\n", err)
	}
}

Output:

client-side error: etcdserver: key is not provided
Example (Txn) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

kvc := clientv3.NewKV(cli)

_, err = kvc.Put(context.TODO(), "key", "xyz")
if err != nil {
	log.Fatal(err)
}

ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
_, err = kvc.Txn(ctx).
	// txn value comparisons are lexical
	If(clientv3.Compare(clientv3.Value("key"), ">", "abc")).
	// the "Then" runs, since "xyz" > "abc"
	Then(clientv3.OpPut("key", "XYZ")).
	// the "Else" does not run
	Else(clientv3.OpPut("key", "ABC")).
	Commit()
cancel()
if err != nil {
	log.Fatal(err)
}

gresp, err := kvc.Get(context.TODO(), "key")
cancel()
if err != nil {
	log.Fatal(err)
}
for _, ev := range gresp.Kvs {
	fmt.Printf("%s : %s\n", ev.Key, ev.Value)
}

Output:

key : XYZ

func NewKV 

func NewKV(c *Client) KV

func NewKVFromKVClient added in v3.1.0 

func NewKVFromKVClient(remote pb.KVClient, c *Client) KV

type Lease 

type Lease interface {
	// Grant creates a new lease.
	Grant(ctx context.Context, ttl int64) (*LeaseGrantResponse, error)

	// Revoke revokes the given lease.
	Revoke(ctx context.Context, id LeaseID) (*LeaseRevokeResponse, error)

	// TimeToLive retrieves the lease information of the given lease ID.
	TimeToLive(ctx context.Context, id LeaseID, opts ...LeaseOption) (*LeaseTimeToLiveResponse, error)

	// Leases retrieves all leases.
	Leases(ctx context.Context) (*LeaseLeasesResponse, error)

	// KeepAlive keeps the given lease alive forever. If the keepalive response
	// posted to the channel is not consumed immediately, the lease client will
	// continue sending keep alive requests to the etcd server at least every
	// second until latest response is consumed.
	//
	// The returned "LeaseKeepAliveResponse" channel closes if underlying keep
	// alive stream is interrupted in some way the client cannot handle itself;
	// given context "ctx" is canceled or timed out. "LeaseKeepAliveResponse"
	// from this closed channel is nil.
	//
	// If client keep alive loop halts with an unexpected error (e.g. "etcdserver:
	// no leader") or canceled by the caller (e.g. context.Canceled), the error
	// is returned. Otherwise, it retries.
	//
	// TODO(v4.0): post errors to last keep alive message before closing
	// (see https://github.com/coreos/etcd/pull/7866)
	KeepAlive(ctx context.Context, id LeaseID) (<-chan *LeaseKeepAliveResponse, error)

	// KeepAliveOnce renews the lease once. The response corresponds to the
	// first message from calling KeepAlive. If the response has a recoverable
	// error, KeepAliveOnce will retry the RPC with a new keep alive message.
	//
	// In most of the cases, Keepalive should be used instead of KeepAliveOnce.
	KeepAliveOnce(ctx context.Context, id LeaseID) (*LeaseKeepAliveResponse, error)

	// Close releases all resources Lease keeps for efficient communication
	// with the etcd server.
	Close() error
}
Example (Grant) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

// minimum lease TTL is 5-second
resp, err := cli.Grant(context.TODO(), 5)
if err != nil {
	log.Fatal(err)
}

// after 5 seconds, the key 'foo' will be removed
_, err = cli.Put(context.TODO(), "foo", "bar", clientv3.WithLease(resp.ID))
if err != nil {
	log.Fatal(err)
}

Output:
Example (KeepAlive) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

resp, err := cli.Grant(context.TODO(), 5)
if err != nil {
	log.Fatal(err)
}

_, err = cli.Put(context.TODO(), "foo", "bar", clientv3.WithLease(resp.ID))
if err != nil {
	log.Fatal(err)
}

// the key 'foo' will be kept forever
ch, kaerr := cli.KeepAlive(context.TODO(), resp.ID)
if kaerr != nil {
	log.Fatal(kaerr)
}

ka := <-ch
fmt.Println("ttl:", ka.TTL)

Output:

ttl: 5
Example (KeepAliveOnce) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

resp, err := cli.Grant(context.TODO(), 5)
if err != nil {
	log.Fatal(err)
}

_, err = cli.Put(context.TODO(), "foo", "bar", clientv3.WithLease(resp.ID))
if err != nil {
	log.Fatal(err)
}

// to renew the lease only once
ka, kaerr := cli.KeepAliveOnce(context.TODO(), resp.ID)
if kaerr != nil {
	log.Fatal(kaerr)
}

fmt.Println("ttl:", ka.TTL)

Output:

ttl: 5
Example (Revoke) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

resp, err := cli.Grant(context.TODO(), 5)
if err != nil {
	log.Fatal(err)
}

_, err = cli.Put(context.TODO(), "foo", "bar", clientv3.WithLease(resp.ID))
if err != nil {
	log.Fatal(err)
}

// revoking lease expires the key attached to its lease ID
_, err = cli.Revoke(context.TODO(), resp.ID)
if err != nil {
	log.Fatal(err)
}

gresp, err := cli.Get(context.TODO(), "foo")
if err != nil {
	log.Fatal(err)
}
fmt.Println("number of keys:", len(gresp.Kvs))

Output:

number of keys: 0

func NewLease 

func NewLease(c *Client) Lease

func NewLeaseFromLeaseClient added in v3.2.0 

func NewLeaseFromLeaseClient(remote pb.LeaseClient, c *Client, keepAliveTimeout time.Duration) Lease

type LeaseGrantResponse 

type LeaseGrantResponse struct {
	*pb.ResponseHeader
	ID    LeaseID
	TTL   int64
	Error string
}

LeaseGrantResponse wraps the protobuf message LeaseGrantResponse.

type LeaseID 

type LeaseID int64
const (

	// NoLease is a lease ID for the absence of a lease.
	NoLease LeaseID = 0
)

type LeaseKeepAliveResponse 

type LeaseKeepAliveResponse struct {
	*pb.ResponseHeader
	ID  LeaseID
	TTL int64
}

LeaseKeepAliveResponse wraps the protobuf message LeaseKeepAliveResponse.

type LeaseLeasesResponse added in v3.3.0 

type LeaseLeasesResponse struct {
	*pb.ResponseHeader
	Leases []LeaseStatus `json:"leases"`
}

LeaseLeasesResponse wraps the protobuf message LeaseLeasesResponse.

type LeaseOp added in v3.1.0 

type LeaseOp struct {
	// contains filtered or unexported fields
}

LeaseOp represents an Operation that lease can execute.

type LeaseOption added in v3.1.0 

type LeaseOption func(*LeaseOp)

LeaseOption configures lease operations.

func WithAttachedKeys added in v3.1.0 

func WithAttachedKeys() LeaseOption

WithAttachedKeys makes TimeToLive list the keys attached to the given lease ID.

type LeaseRevokeResponse 

type LeaseRevokeResponse pb.LeaseRevokeResponse

type LeaseStatus added in v3.2.10 

type LeaseStatus struct {
	ID LeaseID `json:"id"`
}

LeaseStatus represents a lease status.

type LeaseTimeToLiveResponse added in v3.1.0 

type LeaseTimeToLiveResponse struct {
	*pb.ResponseHeader
	ID LeaseID `json:"id"`

	// TTL is the remaining TTL in seconds for the lease; the lease will expire in under TTL+1 seconds. Expired lease will return -1.
	TTL int64 `json:"ttl"`

	// GrantedTTL is the initial granted time in seconds upon lease creation/renewal.
	GrantedTTL int64 `json:"granted-ttl"`

	// Keys is the list of keys attached to this lease.
	Keys [][]byte `json:"keys"`
}

LeaseTimeToLiveResponse wraps the protobuf message LeaseTimeToLiveResponse.

type Maintenance 

type Maintenance interface {
	// AlarmList gets all active alarms.
	AlarmList(ctx context.Context) (*AlarmResponse, error)

	// AlarmDisarm disarms a given alarm.
	AlarmDisarm(ctx context.Context, m *AlarmMember) (*AlarmResponse, error)

	// Defragment releases wasted space from internal fragmentation on a given etcd member.
	// Defragment is only needed when deleting a large number of keys and want to reclaim
	// the resources.
	// Defragment is an expensive operation. User should avoid defragmenting multiple members
	// at the same time.
	// To defragment multiple members in the cluster, user need to call defragment multiple
	// times with different endpoints.
	Defragment(ctx context.Context, endpoint string) (*DefragmentResponse, error)

	// Status gets the status of the endpoint.
	Status(ctx context.Context, endpoint string) (*StatusResponse, error)

	// HashKV returns a hash of the KV state at the time of the RPC.
	// If revision is zero, the hash is computed on all keys. If the revision
	// is non-zero, the hash is computed on all keys at or below the given revision.
	HashKV(ctx context.Context, endpoint string, rev int64) (*HashKVResponse, error)

	// Snapshot provides a reader for a point-in-time snapshot of etcd.
	// If the context "ctx" is canceled or timed out, reading from returned
	// "io.ReadCloser" would error out (e.g. context.Canceled, context.DeadlineExceeded).
	Snapshot(ctx context.Context) (io.ReadCloser, error)

	// MoveLeader requests current leader to transfer its leadership to the transferee.
	// Request must be made to the leader.
	MoveLeader(ctx context.Context, transfereeID uint64) (*MoveLeaderResponse, error)
}
Example (Defragment) 
for _, ep := range endpoints {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   []string{ep},
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	if _, err = cli.Defragment(context.TODO(), ep); err != nil {
		log.Fatal(err)
	}
}

Output:
Example (Status) 
for _, ep := range endpoints {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   []string{ep},
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	resp, err := cli.Status(context.Background(), ep)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("endpoint: %s / Leader: %v\n", ep, resp.Header.MemberId == resp.Leader)
}
// endpoint: localhost:2379 / Leader: false
// endpoint: localhost:22379 / Leader: false
// endpoint: localhost:32379 / Leader: true

Output:

func NewMaintenance 

func NewMaintenance(c *Client) Maintenance

func NewMaintenanceFromMaintenanceClient added in v3.2.0 

func NewMaintenanceFromMaintenanceClient(remote pb.MaintenanceClient, c *Client) Maintenance

type Member 

type Member pb.Member

type MemberAddResponse 

type MemberAddResponse pb.MemberAddResponse

type MemberListResponse 

type MemberListResponse pb.MemberListResponse

type MemberRemoveResponse 

type MemberRemoveResponse pb.MemberRemoveResponse

type MemberUpdateResponse 

type MemberUpdateResponse pb.MemberUpdateResponse

type MoveLeaderResponse added in v3.3.0 

type MoveLeaderResponse pb.MoveLeaderResponse

type Op 

type Op struct {
	// contains filtered or unexported fields
}

Op represents an Operation that kv can execute.

func OpDelete 

func OpDelete(key string, opts ...OpOption) Op

func OpGet 

func OpGet(key string, opts ...OpOption) Op

func OpPut 

func OpPut(key, val string, opts ...OpOption) Op

func OpTxn added in v3.2.10 

func OpTxn(cmps []Cmp, thenOps []Op, elseOps []Op) Op

func (Op) IsCountOnly added in v3.2.10 

func (op Op) IsCountOnly() bool

IsCountOnly returns whether countOnly is set.

func (Op) IsDelete added in v3.2.10 

func (op Op) IsDelete() bool

IsDelete returns true iff the operation is a Delete.

func (Op) IsGet added in v3.2.10 

func (op Op) IsGet() bool

IsGet returns true iff the operation is a Get.

func (Op) IsKeysOnly added in v3.2.10 

func (op Op) IsKeysOnly() bool

IsKeysOnly returns whether keysOnly is set.

func (Op) IsPut added in v3.2.10 

func (op Op) IsPut() bool

IsPut returns true iff the operation is a Put.

func (Op) IsSerializable added in v3.2.10 

func (op Op) IsSerializable() bool

IsSerializable returns true if the serializable field is true.

func (Op) IsTxn added in v3.2.10 

func (op Op) IsTxn() bool

func (Op) KeyBytes added in v3.2.0 

func (op Op) KeyBytes() []byte

KeyBytes returns the byte slice holding the Op's key.

func (Op) MaxCreateRev added in v3.2.10 

func (op Op) MaxCreateRev() int64

MaxCreateRev returns the operation's maximum create revision.

func (Op) MaxModRev added in v3.2.10 

func (op Op) MaxModRev() int64

MaxModRev returns the operation's maximum modify revision.

func (Op) MinCreateRev added in v3.2.10 

func (op Op) MinCreateRev() int64

MinCreateRev returns the operation's minimum create revision.

func (Op) MinModRev added in v3.2.10 

func (op Op) MinModRev() int64

MinModRev returns the operation's minimum modify revision.

func (Op) RangeBytes added in v3.2.0 

func (op Op) RangeBytes() []byte

RangeBytes returns the byte slice holding with the Op's range end, if any.

func (Op) Rev added in v3.2.10 

func (op Op) Rev() int64

Rev returns the requested revision, if any.

func (Op) Txn added in v3.2.10 

func (op Op) Txn() ([]Cmp, []Op, []Op)

func (Op) ValueBytes added in v3.2.0 

func (op Op) ValueBytes() []byte

ValueBytes returns the byte slice holding the Op's value, if any.

func (*Op) WithKeyBytes added in v3.2.0 

func (op *Op) WithKeyBytes(key []byte)

WithKeyBytes sets the byte slice for the Op's key.

func (*Op) WithRangeBytes added in v3.2.0 

func (op *Op) WithRangeBytes(end []byte)

WithRangeBytes sets the byte slice for the Op's range end.

func (*Op) WithValueBytes added in v3.2.0 

func (op *Op) WithValueBytes(v []byte)

WithValueBytes sets the byte slice for the Op's value.

type OpOption 

type OpOption func(*Op)

OpOption configures Operations like Get, Put, Delete.

func WithCountOnly 

func WithCountOnly() OpOption

WithCountOnly makes the 'Get' request return only the count of keys.

func WithCreatedNotify added in v3.1.0 

func WithCreatedNotify() OpOption

WithCreatedNotify makes watch server sends the created event.

func WithFilterDelete added in v3.1.0 

func WithFilterDelete() OpOption

WithFilterDelete discards DELETE events from the watcher.

func WithFilterPut added in v3.1.0 

func WithFilterPut() OpOption

WithFilterPut discards PUT events from the watcher.

func WithFirstCreate 

func WithFirstCreate() []OpOption

WithFirstCreate gets the key with the oldest creation revision in the request range.

func WithFirstKey 

func WithFirstKey() []OpOption

WithFirstKey gets the lexically first key in the request range.

func WithFirstRev 

func WithFirstRev() []OpOption

WithFirstRev gets the key with the oldest modification revision in the request range.

func WithFragment added in v3.3.15 

func WithFragment() OpOption

WithFragment to receive raw watch response with fragmentation. Fragmentation is disabled by default. If fragmentation is enabled, etcd watch server will split watch response before sending to clients when the total size of watch events exceed server-side request limit. The default server-side request limit is 1.5 MiB, which can be configured as "--max-request-bytes" flag value + gRPC-overhead 512 bytes. See "etcdserver/api/v3rpc/watch.go" for more details.

func WithFromKey 

func WithFromKey() OpOption

WithFromKey specifies the range of 'Get', 'Delete', 'Watch' requests to be equal or greater than the key in the argument.

func WithIgnoreLease added in v3.2.0 

func WithIgnoreLease() OpOption

WithIgnoreLease updates the key using its current lease. This option can not be combined with WithLease. Returns an error if the key does not exist.

func WithIgnoreValue added in v3.2.0 

func WithIgnoreValue() OpOption

WithIgnoreValue updates the key using its current value. This option can not be combined with non-empty values. Returns an error if the key does not exist.

func WithKeysOnly 

func WithKeysOnly() OpOption

WithKeysOnly makes the 'Get' request return only the keys and the corresponding values will be omitted.

func WithLastCreate 

func WithLastCreate() []OpOption

WithLastCreate gets the key with the latest creation revision in the request range.

func WithLastKey 

func WithLastKey() []OpOption

WithLastKey gets the lexically last key in the request range.

func WithLastRev 

func WithLastRev() []OpOption

WithLastRev gets the key with the latest modification revision in the request range.

func WithLease 

func WithLease(leaseID LeaseID) OpOption

WithLease attaches a lease ID to a key in 'Put' request.

func WithLimit 

func WithLimit(n int64) OpOption

WithLimit limits the number of results to return from 'Get' request. If WithLimit is given a 0 limit, it is treated as no limit.

func WithMaxCreateRev added in v3.1.0 

func WithMaxCreateRev(rev int64) OpOption

WithMaxCreateRev filters out keys for Get with creation revisions greater than the given revision.

func WithMaxModRev added in v3.1.0 

func WithMaxModRev(rev int64) OpOption

WithMaxModRev filters out keys for Get with modification revisions greater than the given revision.

func WithMinCreateRev added in v3.1.0 

func WithMinCreateRev(rev int64) OpOption

WithMinCreateRev filters out keys for Get with creation revisions less than the given revision.

func WithMinModRev added in v3.1.0 

func WithMinModRev(rev int64) OpOption

WithMinModRev filters out keys for Get with modification revisions less than the given revision.

func WithPrefix 

func WithPrefix() OpOption

WithPrefix enables 'Get', 'Delete', or 'Watch' requests to operate on the keys with matching prefix. For example, 'Get(foo, WithPrefix())' can return 'foo1', 'foo2', and so on.

func WithPrevKV added in v3.0.11 

func WithPrevKV() OpOption

WithPrevKV gets the previous key-value pair before the event happens. If the previous KV is already compacted, nothing will be returned.

func WithProgressNotify 

func WithProgressNotify() OpOption

WithProgressNotify makes watch server send periodic progress updates every 10 minutes when there is no incoming events. Progress updates have zero events in WatchResponse.

func WithRange 

func WithRange(endKey string) OpOption

WithRange specifies the range of 'Get', 'Delete', 'Watch' requests. For example, 'Get' requests with 'WithRange(end)' returns the keys in the range [key, end). endKey must be lexicographically greater than start key.

func WithRev 

func WithRev(rev int64) OpOption

WithRev specifies the store revision for 'Get' request. Or the start revision of 'Watch' request.

func WithSerializable 

func WithSerializable() OpOption

WithSerializable makes 'Get' request serializable. By default, it's linearizable. Serializable requests are better for lower latency requirement.

func WithSort 

func WithSort(target SortTarget, order SortOrder) OpOption

WithSort specifies the ordering in 'Get' request. It requires 'WithRange' and/or 'WithPrefix' to be specified too. 'target' specifies the target to sort by: key, version, revisions, value. 'order' can be either 'SortNone', 'SortAscend', 'SortDescend'.

type OpResponse 

type OpResponse struct {
	// contains filtered or unexported fields
}

func (OpResponse) Del 

func (op OpResponse) Del() *DeleteResponse

func (OpResponse) Get 

func (op OpResponse) Get() *GetResponse

func (OpResponse) Put 

func (op OpResponse) Put() *PutResponse

func (OpResponse) Txn added in v3.2.10 

func (op OpResponse) Txn() *TxnResponse

type Permission added in v3.1.0 

type Permission authpb.Permission

type PermissionType 

type PermissionType authpb.Permission_Type

func StrToPermissionType 

func StrToPermissionType(s string) (PermissionType, error)

type PutResponse 

type PutResponse pb.PutResponse

func (*PutResponse) OpResponse added in v3.2.10 

func (resp *PutResponse) OpResponse() OpResponse

type SortOption 

type SortOption struct {
	Target SortTarget
	Order  SortOrder
}

type SortOrder 

type SortOrder int
const (
	SortNone SortOrder = iota
	SortAscend
	SortDescend
)

type SortTarget 

type SortTarget int
const (
	SortByKey SortTarget = iota
	SortByVersion
	SortByCreateRevision
	SortByModRevision
	SortByValue
)

type StatusResponse 

type StatusResponse pb.StatusResponse

type TransportCredentialsWithDialer added in v3.3.16 

type TransportCredentialsWithDialer interface {
	grpccredentials.TransportCredentials
	Dialer(ctx context.Context, dialEp string) (net.Conn, error)
}

TransportCredentialsWithDialer is for a gRPC load balancer workaround. See credentials.transportCredential for details.

type Txn 

type Txn interface {
	// If takes a list of comparison. If all comparisons passed in succeed,
	// the operations passed into Then() will be executed. Or the operations
	// passed into Else() will be executed.
	If(cs ...Cmp) Txn

	// Then takes a list of operations. The Ops list will be executed, if the
	// comparisons passed in If() succeed.
	Then(ops ...Op) Txn

	// Else takes a list of operations. The Ops list will be executed, if the
	// comparisons passed in If() fail.
	Else(ops ...Op) Txn

	// Commit tries to commit the transaction.
	Commit() (*TxnResponse, error)
}

Txn is the interface that wraps mini-transactions. 

Txn(context.TODO()).If(
 Compare(Value(k1), ">", v1),
 Compare(Version(k1), "=", 2)
).Then(
 OpPut(k2,v2), OpPut(k3,v3)
).Else(
 OpPut(k4,v4), OpPut(k5,v5)
).Commit()

type TxnResponse 

type TxnResponse pb.TxnResponse

func (*TxnResponse) OpResponse added in v3.2.10 

func (resp *TxnResponse) OpResponse() OpResponse

type WatchChan 

type WatchChan <-chan WatchResponse

type WatchResponse 

type WatchResponse struct {
	Header pb.ResponseHeader
	Events []*Event

	// CompactRevision is the minimum revision the watcher may receive.
	CompactRevision int64

	// Canceled is used to indicate watch failure.
	// If the watch failed and the stream was about to close, before the channel is closed,
	// the channel sends a final response that has Canceled set to true with a non-nil Err().
	Canceled bool

	// Created is used to indicate the creation of the watcher.
	Created bool
	// contains filtered or unexported fields
}

func (*WatchResponse) Err 

func (wr *WatchResponse) Err() error

Err is the error value if this WatchResponse holds an error.

func (*WatchResponse) IsProgressNotify 

func (wr *WatchResponse) IsProgressNotify() bool

IsProgressNotify returns true if the WatchResponse is progress notification.

type Watcher 

type Watcher interface {
	// Watch watches on a key or prefix. The watched events will be returned
	// through the returned channel. If revisions waiting to be sent over the
	// watch are compacted, then the watch will be canceled by the server, the
	// client will post a compacted error watch response, and the channel will close.
	// If the context "ctx" is canceled or timed out, returned "WatchChan" is closed,
	// and "WatchResponse" from this closed channel has zero events and nil "Err()".
	// The context "ctx" MUST be canceled, as soon as watcher is no longer being used,
	// to release the associated resources.
	//
	// If the context is "context.Background/TODO", returned "WatchChan" will
	// not be closed and block until event is triggered, except when server
	// returns a non-recoverable error (e.g. ErrCompacted).
	// For example, when context passed with "WithRequireLeader" and the
	// connected server has no leader (e.g. due to network partition),
	// error "etcdserver: no leader" (ErrNoLeader) will be returned,
	// and then "WatchChan" is closed with non-nil "Err()".
	// In order to prevent a watch stream being stuck in a partitioned node,
	// make sure to wrap context with "WithRequireLeader".
	//
	// Otherwise, as long as the context has not been canceled or timed out,
	// watch will retry on other recoverable errors forever until reconnected.
	//
	// TODO: explicitly set context error in the last "WatchResponse" message and close channel?
	// Currently, client contexts are overwritten with "valCtx" that never closes.
	// TODO(v3.4): configure watch retry policy, limit maximum retry number
	// (see https://github.com/etcd-io/etcd/issues/8980)
	Watch(ctx context.Context, key string, opts ...OpOption) WatchChan

	// RequestProgress requests a progress notify response be sent in all watch channels.
	RequestProgress(ctx context.Context) error

	// Close closes the watcher and cancels all watch requests.
	Close() error
}
Example (Watch) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

rch := cli.Watch(context.Background(), "foo")
for wresp := range rch {
	for _, ev := range wresp.Events {
		fmt.Printf("%s %q : %q\n", ev.Type, ev.Kv.Key, ev.Kv.Value)
	}
}
// PUT "foo" : "bar"

Output:
Example (WatchWithPrefix) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

rch := cli.Watch(context.Background(), "foo", clientv3.WithPrefix())
for wresp := range rch {
	for _, ev := range wresp.Events {
		fmt.Printf("%s %q : %q\n", ev.Type, ev.Kv.Key, ev.Kv.Value)
	}
}
// PUT "foo1" : "bar"

Output:
Example (WatchWithProgressNotify) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}

rch := cli.Watch(context.Background(), "foo", clientv3.WithProgressNotify())
wresp := <-rch
fmt.Printf("wresp.Header.Revision: %d\n", wresp.Header.Revision)
fmt.Println("wresp.IsProgressNotify:", wresp.IsProgressNotify())
// wresp.Header.Revision: 0
// wresp.IsProgressNotify: true

Output:
Example (WatchWithRange) 
cli, err := clientv3.New(clientv3.Config{
	Endpoints:   endpoints,
	DialTimeout: dialTimeout,
})
if err != nil {
	log.Fatal(err)
}
defer cli.Close()

// watches within ['foo1', 'foo4'), in lexicographical order
rch := cli.Watch(context.Background(), "foo1", clientv3.WithRange("foo4"))
for wresp := range rch {
	for _, ev := range wresp.Events {
		fmt.Printf("%s %q : %q\n", ev.Type, ev.Kv.Key, ev.Kv.Value)
	}
}
// PUT "foo1" : "bar"
// PUT "foo2" : "bar"
// PUT "foo3" : "bar"

Output:

func NewWatchFromWatchClient added in v3.1.0 

func NewWatchFromWatchClient(wc pb.WatchClient, c *Client) Watcher

func NewWatcher 

func NewWatcher(c *Client) Watcher

Source Files

View all Source files

Directories

Path Synopsis
Package balancer implements client balancer.
 Package balancer implements client balancer.
connectivity
Package connectivity implements client connectivity operations.
 Package connectivity implements client connectivity operations.
picker
Package picker defines/implements client balancer picker policy.
 Package picker defines/implements client balancer picker policy.
resolver/endpoint
Package endpoint resolves etcd entpoints using grpc targets of the form 'endpoint://<id>/<endpoint>'.
 Package endpoint resolves etcd entpoints using grpc targets of the form 'endpoint://<id>/<endpoint>'.
Package clientv3util contains utility functions derived from clientv3.
 Package clientv3util contains utility functions derived from clientv3.
Package concurrency implements concurrency operations on top of etcd such as distributed locks, barriers, and elections.
 Package concurrency implements concurrency operations on top of etcd such as distributed locks, barriers, and elections.
Package credentials implements gRPC credential interface with etcd specific logic.
 Package credentials implements gRPC credential interface with etcd specific logic.
Package integration implements tests built upon embedded etcd, and focuses on correctness of etcd client.
 Package integration implements tests built upon embedded etcd, and focuses on correctness of etcd client.
Package leasing serves linearizable reads from a local cache by acquiring exclusive write access to keys through a client-side leasing protocol.
 Package leasing serves linearizable reads from a local cache by acquiring exclusive write access to keys through a client-side leasing protocol.
Package mirror implements etcd mirroring operations.
 Package mirror implements etcd mirroring operations.
Package namespace is a clientv3 wrapper that translates all keys to begin with a given prefix.
 Package namespace is a clientv3 wrapper that translates all keys to begin with a given prefix.
Package naming provides an etcd-backed gRPC resolver for discovering gRPC services.
 Package naming provides an etcd-backed gRPC resolver for discovering gRPC services.
Package ordering is a clientv3 wrapper that caches response header revisions to detect ordering violations from stale responses.
 Package ordering is a clientv3 wrapper that caches response header revisions to detect ordering violations from stale responses.
Package snapshot implements utilities around etcd snapshot.
 Package snapshot implements utilities around etcd snapshot.
Package yaml handles yaml-formatted clientv3 configuration data.
 Package yaml handles yaml-formatted clientv3 configuration data.

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