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// Copyright 2015 The etcd 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 client
import (
"context"
"encoding/json"
"errors"
"fmt"
"go.etcd.io/etcd/pkg/pathutil"
"net/http"
"net/url"
"strconv"
"strings"
"time"
)
const (
ErrorCodeKeyNotFound = 100
ErrorCodeTestFailed = 101
ErrorCodeNotFile = 102
ErrorCodeNotDir = 104
ErrorCodeNodeExist = 105
ErrorCodeRootROnly = 107
ErrorCodeDirNotEmpty = 108
ErrorCodeUnauthorized = 110
ErrorCodePrevValueRequired = 201
ErrorCodeTTLNaN = 202
ErrorCodeIndexNaN = 203
ErrorCodeInvalidField = 209
ErrorCodeInvalidForm = 210
ErrorCodeRaftInternal = 300
ErrorCodeLeaderElect = 301
ErrorCodeWatcherCleared = 400
ErrorCodeEventIndexCleared = 401
)
type Error struct {
Code int `json:"errorCode"`
Message string `json:"message"`
Cause string `json:"cause"`
Index uint64 `json:"index"`
}
func (e Error) Error() string {
return fmt.Sprintf("%v: %v (%v) [%v]", e.Code, e.Message, e.Cause, e.Index)
}
var (
ErrInvalidJSON = errors.New("client: response is invalid json. The endpoint is probably not valid etcd cluster endpoint")
ErrEmptyBody = errors.New("client: response body is empty")
)
// PrevExistType is used to define an existence condition when setting
// or deleting Nodes.
type PrevExistType string
const (
PrevIgnore = PrevExistType("")
PrevExist = PrevExistType("true")
PrevNoExist = PrevExistType("false")
)
var (
defaultV2KeysPrefix = "/v2/keys"
)
// NewKeysAPI builds a KeysAPI that interacts with etcd's key-value
// API over HTTP.
func NewKeysAPI(c Client) KeysAPI {
return NewKeysAPIWithPrefix(c, defaultV2KeysPrefix)
}
// NewKeysAPIWithPrefix acts like NewKeysAPI, but allows the caller
// to provide a custom base URL path. This should only be used in
// very rare cases.
func NewKeysAPIWithPrefix(c Client, p string) KeysAPI {
return &httpKeysAPI{
client: c,
prefix: p,
}
}
type KeysAPI interface {
// Get retrieves a set of Nodes from etcd
Get(ctx context.Context, key string, opts *GetOptions) (*Response, error)
// Set assigns a new value to a Node identified by a given key. The caller
// may define a set of conditions in the SetOptions. If SetOptions.Dir=true
// then value is ignored.
Set(ctx context.Context, key, value string, opts *SetOptions) (*Response, error)
// Delete removes a Node identified by the given key, optionally destroying
// all of its children as well. The caller may define a set of required
// conditions in an DeleteOptions object.
Delete(ctx context.Context, key string, opts *DeleteOptions) (*Response, error)
// Create is an alias for Set w/ PrevExist=false
Create(ctx context.Context, key, value string) (*Response, error)
// CreateInOrder is used to atomically create in-order keys within the given directory.
CreateInOrder(ctx context.Context, dir, value string, opts *CreateInOrderOptions) (*Response, error)
// Update is an alias for Set w/ PrevExist=true
Update(ctx context.Context, key, value string) (*Response, error)
// Watcher builds a new Watcher targeted at a specific Node identified
// by the given key. The Watcher may be configured at creation time
// through a WatcherOptions object. The returned Watcher is designed
// to emit events that happen to a Node, and optionally to its children.
Watcher(key string, opts *WatcherOptions) Watcher
}
type WatcherOptions struct {
// AfterIndex defines the index after-which the Watcher should
// start emitting events. For example, if a value of 5 is
// provided, the first event will have an index >= 6.
//
// Setting AfterIndex to 0 (default) means that the Watcher
// should start watching for events starting at the current
// index, whatever that may be.
AfterIndex uint64
// Recursive specifies whether or not the Watcher should emit
// events that occur in children of the given keyspace. If set
// to false (default), events will be limited to those that
// occur for the exact key.
Recursive bool
}
type CreateInOrderOptions struct {
// TTL defines a period of time after-which the Node should
// expire and no longer exist. Values <= 0 are ignored. Given
// that the zero-value is ignored, TTL cannot be used to set
// a TTL of 0.
TTL time.Duration
}
type SetOptions struct {
// PrevValue specifies what the current value of the Node must
// be in order for the Set operation to succeed.
//
// Leaving this field empty means that the caller wishes to
// ignore the current value of the Node. This cannot be used
// to compare the Node's current value to an empty string.
//
// PrevValue is ignored if Dir=true
PrevValue string
// PrevIndex indicates what the current ModifiedIndex of the
// Node must be in order for the Set operation to succeed.
//
// If PrevIndex is set to 0 (default), no comparison is made.
PrevIndex uint64
// PrevExist specifies whether the Node must currently exist
// (PrevExist) or not (PrevNoExist). If the caller does not
// care about existence, set PrevExist to PrevIgnore, or simply
// leave it unset.
PrevExist PrevExistType
// TTL defines a period of time after-which the Node should
// expire and no longer exist. Values <= 0 are ignored. Given
// that the zero-value is ignored, TTL cannot be used to set
// a TTL of 0.
TTL time.Duration
// Refresh set to true means a TTL value can be updated
// without firing a watch or changing the node value. A
// value must not be provided when refreshing a key.
Refresh bool
// Dir specifies whether or not this Node should be created as a directory.
Dir bool
// NoValueOnSuccess specifies whether the response contains the current value of the Node.
// If set, the response will only contain the current value when the request fails.
NoValueOnSuccess bool
}
type GetOptions struct {
// Recursive defines whether or not all children of the Node
// should be returned.
Recursive bool
// Sort instructs the server whether or not to sort the Nodes.
// If true, the Nodes are sorted alphabetically by key in
// ascending order (A to z). If false (default), the Nodes will
// not be sorted and the ordering used should not be considered
// predictable.
Sort bool
// Quorum specifies whether it gets the latest committed value that
// has been applied in quorum of members, which ensures external
// consistency (or linearizability).
Quorum bool
}
type DeleteOptions struct {
// PrevValue specifies what the current value of the Node must
// be in order for the Delete operation to succeed.
//
// Leaving this field empty means that the caller wishes to
// ignore the current value of the Node. This cannot be used
// to compare the Node's current value to an empty string.
PrevValue string
// PrevIndex indicates what the current ModifiedIndex of the
// Node must be in order for the Delete operation to succeed.
//
// If PrevIndex is set to 0 (default), no comparison is made.
PrevIndex uint64
// Recursive defines whether or not all children of the Node
// should be deleted. If set to true, all children of the Node
// identified by the given key will be deleted. If left unset
// or explicitly set to false, only a single Node will be
// deleted.
Recursive bool
// Dir specifies whether or not this Node should be removed as a directory.
Dir bool
}
type Watcher interface {
// Next blocks until an etcd event occurs, then returns a Response
// representing that event. The behavior of Next depends on the
// WatcherOptions used to construct the Watcher. Next is designed to
// be called repeatedly, each time blocking until a subsequent event
// is available.
//
// If the provided context is cancelled, Next will return a non-nil
// error. Any other failures encountered while waiting for the next
// event (connection issues, deserialization failures, etc) will
// also result in a non-nil error.
Next(context.Context) (*Response, error)
}
type Response struct {
// Action is the name of the operation that occurred. Possible values
// include get, set, delete, update, create, compareAndSwap,
// compareAndDelete and expire.
Action string `json:"action"`
// Node represents the state of the relevant etcd Node.
Node *Node `json:"node"`
// PrevNode represents the previous state of the Node. PrevNode is non-nil
// only if the Node existed before the action occurred and the action
// caused a change to the Node.
PrevNode *Node `json:"prevNode"`
// Index holds the cluster-level index at the time the Response was generated.
// This index is not tied to the Node(s) contained in this Response.
Index uint64 `json:"-"`
// ClusterID holds the cluster-level ID reported by the server. This
// should be different for different etcd clusters.
ClusterID string `json:"-"`
}
type Node struct {
// Key represents the unique location of this Node (e.g. "/foo/bar").
Key string `json:"key"`
// Dir reports whether node describes a directory.
Dir bool `json:"dir,omitempty"`
// Value is the current data stored on this Node. If this Node
// is a directory, Value will be empty.
Value string `json:"value"`
// Nodes holds the children of this Node, only if this Node is a directory.
// This slice of will be arbitrarily deep (children, grandchildren, great-
// grandchildren, etc.) if a recursive Get or Watch request were made.
Nodes Nodes `json:"nodes"`
// CreatedIndex is the etcd index at-which this Node was created.
CreatedIndex uint64 `json:"createdIndex"`
// ModifiedIndex is the etcd index at-which this Node was last modified.
ModifiedIndex uint64 `json:"modifiedIndex"`
// Expiration is the server side expiration time of the key.
Expiration *time.Time `json:"expiration,omitempty"`
// TTL is the time to live of the key in second.
TTL int64 `json:"ttl,omitempty"`
}
func (n *Node) String() string {
return fmt.Sprintf("{Key: %s, CreatedIndex: %d, ModifiedIndex: %d, TTL: %d}", n.Key, n.CreatedIndex, n.ModifiedIndex, n.TTL)
}
// TTLDuration returns the Node's TTL as a time.Duration object
func (n *Node) TTLDuration() time.Duration {
return time.Duration(n.TTL) * time.Second
}
type Nodes []*Node
// interfaces for sorting
func (ns Nodes) Len() int { return len(ns) }
func (ns Nodes) Less(i, j int) bool { return ns[i].Key < ns[j].Key }
func (ns Nodes) Swap(i, j int) { ns[i], ns[j] = ns[j], ns[i] }
type httpKeysAPI struct {
client httpClient
prefix string
}
func (k *httpKeysAPI) Set(ctx context.Context, key, val string, opts *SetOptions) (*Response, error) {
act := &setAction{
Prefix: k.prefix,
Key: key,
Value: val,
}
if opts != nil {
act.PrevValue = opts.PrevValue
act.PrevIndex = opts.PrevIndex
act.PrevExist = opts.PrevExist
act.TTL = opts.TTL
act.Refresh = opts.Refresh
act.Dir = opts.Dir
act.NoValueOnSuccess = opts.NoValueOnSuccess
}
doCtx := ctx
if act.PrevExist == PrevNoExist {
doCtx = context.WithValue(doCtx, &oneShotCtxValue, &oneShotCtxValue)
}
resp, body, err := k.client.Do(doCtx, act)
if err != nil {
return nil, err
}
return unmarshalHTTPResponse(resp.StatusCode, resp.Header, body)
}
func (k *httpKeysAPI) Create(ctx context.Context, key, val string) (*Response, error) {
return k.Set(ctx, key, val, &SetOptions{PrevExist: PrevNoExist})
}
func (k *httpKeysAPI) CreateInOrder(ctx context.Context, dir, val string, opts *CreateInOrderOptions) (*Response, error) {
act := &createInOrderAction{
Prefix: k.prefix,
Dir: dir,
Value: val,
}
if opts != nil {
act.TTL = opts.TTL
}
resp, body, err := k.client.Do(ctx, act)
if err != nil {
return nil, err
}
return unmarshalHTTPResponse(resp.StatusCode, resp.Header, body)
}
func (k *httpKeysAPI) Update(ctx context.Context, key, val string) (*Response, error) {
return k.Set(ctx, key, val, &SetOptions{PrevExist: PrevExist})
}
func (k *httpKeysAPI) Delete(ctx context.Context, key string, opts *DeleteOptions) (*Response, error) {
act := &deleteAction{
Prefix: k.prefix,
Key: key,
}
if opts != nil {
act.PrevValue = opts.PrevValue
act.PrevIndex = opts.PrevIndex
act.Dir = opts.Dir
act.Recursive = opts.Recursive
}
doCtx := context.WithValue(ctx, &oneShotCtxValue, &oneShotCtxValue)
resp, body, err := k.client.Do(doCtx, act)
if err != nil {
return nil, err
}
return unmarshalHTTPResponse(resp.StatusCode, resp.Header, body)
}
func (k *httpKeysAPI) Get(ctx context.Context, key string, opts *GetOptions) (*Response, error) {
act := &getAction{
Prefix: k.prefix,
Key: key,
}
if opts != nil {
act.Recursive = opts.Recursive
act.Sorted = opts.Sort
act.Quorum = opts.Quorum
}
resp, body, err := k.client.Do(ctx, act)
if err != nil {
return nil, err
}
return unmarshalHTTPResponse(resp.StatusCode, resp.Header, body)
}
func (k *httpKeysAPI) Watcher(key string, opts *WatcherOptions) Watcher {
act := waitAction{
Prefix: k.prefix,
Key: key,
}
if opts != nil {
act.Recursive = opts.Recursive
if opts.AfterIndex > 0 {
act.WaitIndex = opts.AfterIndex + 1
}
}
return &httpWatcher{
client: k.client,
nextWait: act,
}
}
type httpWatcher struct {
client httpClient
nextWait waitAction
}
func (hw *httpWatcher) Next(ctx context.Context) (*Response, error) {
for {
httpresp, body, err := hw.client.Do(ctx, &hw.nextWait)
if err != nil {
return nil, err
}
resp, err := unmarshalHTTPResponse(httpresp.StatusCode, httpresp.Header, body)
if err != nil {
if err == ErrEmptyBody {
continue
}
return nil, err
}
hw.nextWait.WaitIndex = resp.Node.ModifiedIndex + 1
return resp, nil
}
}
// v2KeysURL forms a URL representing the location of a key.
// The endpoint argument represents the base URL of an etcd
// server. The prefix is the path needed to route from the
// provided endpoint's path to the root of the keys API
// (typically "/v2/keys").
func v2KeysURL(ep url.URL, prefix, key string) *url.URL {
// We concatenate all parts together manually. We cannot use
// path.Join because it does not reserve trailing slash.
// We call CanonicalURLPath to further cleanup the path.
if prefix != "" && prefix[0] != '/' {
prefix = "/" + prefix
}
if key != "" && key[0] != '/' {
key = "/" + key
}
ep.Path = pathutil.CanonicalURLPath(ep.Path + prefix + key)
return &ep
}
type getAction struct {
Prefix string
Key string
Recursive bool
Sorted bool
Quorum bool
}
func (g *getAction) HTTPRequest(ep url.URL) *http.Request {
u := v2KeysURL(ep, g.Prefix, g.Key)
params := u.Query()
params.Set("recursive", strconv.FormatBool(g.Recursive))
params.Set("sorted", strconv.FormatBool(g.Sorted))
params.Set("quorum", strconv.FormatBool(g.Quorum))
u.RawQuery = params.Encode()
req, _ := http.NewRequest("GET", u.String(), nil)
return req
}
type waitAction struct {
Prefix string
Key string
WaitIndex uint64
Recursive bool
}
func (w *waitAction) HTTPRequest(ep url.URL) *http.Request {
u := v2KeysURL(ep, w.Prefix, w.Key)
params := u.Query()
params.Set("wait", "true")
params.Set("waitIndex", strconv.FormatUint(w.WaitIndex, 10))
params.Set("recursive", strconv.FormatBool(w.Recursive))
u.RawQuery = params.Encode()
req, _ := http.NewRequest("GET", u.String(), nil)
return req
}
type setAction struct {
Prefix string
Key string
Value string
PrevValue string
PrevIndex uint64
PrevExist PrevExistType
TTL time.Duration
Refresh bool
Dir bool
NoValueOnSuccess bool
}
func (a *setAction) HTTPRequest(ep url.URL) *http.Request {
u := v2KeysURL(ep, a.Prefix, a.Key)
params := u.Query()
form := url.Values{}
// we're either creating a directory or setting a key
if a.Dir {
params.Set("dir", strconv.FormatBool(a.Dir))
} else {
// These options are only valid for setting a key
if a.PrevValue != "" {
params.Set("prevValue", a.PrevValue)
}
form.Add("value", a.Value)
}
// Options which apply to both setting a key and creating a dir
if a.PrevIndex != 0 {
params.Set("prevIndex", strconv.FormatUint(a.PrevIndex, 10))
}
if a.PrevExist != PrevIgnore {
params.Set("prevExist", string(a.PrevExist))
}
if a.TTL > 0 {
form.Add("ttl", strconv.FormatUint(uint64(a.TTL.Seconds()), 10))
}
if a.Refresh {
form.Add("refresh", "true")
}
if a.NoValueOnSuccess {
params.Set("noValueOnSuccess", strconv.FormatBool(a.NoValueOnSuccess))
}
u.RawQuery = params.Encode()
body := strings.NewReader(form.Encode())
req, _ := http.NewRequest("PUT", u.String(), body)
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
return req
}
type deleteAction struct {
Prefix string
Key string
PrevValue string
PrevIndex uint64
Dir bool
Recursive bool
}
func (a *deleteAction) HTTPRequest(ep url.URL) *http.Request {
u := v2KeysURL(ep, a.Prefix, a.Key)
params := u.Query()
if a.PrevValue != "" {
params.Set("prevValue", a.PrevValue)
}
if a.PrevIndex != 0 {
params.Set("prevIndex", strconv.FormatUint(a.PrevIndex, 10))
}
if a.Dir {
params.Set("dir", "true")
}
if a.Recursive {
params.Set("recursive", "true")
}
u.RawQuery = params.Encode()
req, _ := http.NewRequest("DELETE", u.String(), nil)
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
return req
}
type createInOrderAction struct {
Prefix string
Dir string
Value string
TTL time.Duration
}
func (a *createInOrderAction) HTTPRequest(ep url.URL) *http.Request {
u := v2KeysURL(ep, a.Prefix, a.Dir)
form := url.Values{}
form.Add("value", a.Value)
if a.TTL > 0 {
form.Add("ttl", strconv.FormatUint(uint64(a.TTL.Seconds()), 10))
}
body := strings.NewReader(form.Encode())
req, _ := http.NewRequest("POST", u.String(), body)
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
return req
}
func unmarshalHTTPResponse(code int, header http.Header, body []byte) (res *Response, err error) {
switch code {
case http.StatusOK, http.StatusCreated:
if len(body) == 0 {
return nil, ErrEmptyBody
}
res, err = unmarshalSuccessfulKeysResponse(header, body)
default:
err = unmarshalFailedKeysResponse(body)
}
return res, err
}
var jsonIterator = caseSensitiveJsonIterator()
func unmarshalSuccessfulKeysResponse(header http.Header, body []byte) (*Response, error) {
var res Response
err := jsonIterator.Unmarshal(body, &res)
if err != nil {
return nil, ErrInvalidJSON
}
if header.Get("X-Etcd-Index") != "" {
res.Index, err = strconv.ParseUint(header.Get("X-Etcd-Index"), 10, 64)
if err != nil {
return nil, err
}
}
res.ClusterID = header.Get("X-Etcd-Cluster-ID")
return &res, nil
}
func unmarshalFailedKeysResponse(body []byte) error {
var etcdErr Error
if err := json.Unmarshal(body, &etcdErr); err != nil {
return ErrInvalidJSON
}
return etcdErr
}
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