peridot/vendor/k8s.io/client-go/rest/request.go
2022-07-07 22:13:21 +02:00

1434 lines
44 KiB
Go

/*
Copyright 2014 The Kubernetes 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 rest
import (
"bytes"
"context"
"encoding/hex"
"fmt"
"io"
"io/ioutil"
"mime"
"net/http"
"net/url"
"path"
"reflect"
"strconv"
"strings"
"sync"
"time"
"golang.org/x/net/http2"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apimachinery/pkg/runtime/serializer/streaming"
utilclock "k8s.io/apimachinery/pkg/util/clock"
"k8s.io/apimachinery/pkg/util/net"
"k8s.io/apimachinery/pkg/watch"
restclientwatch "k8s.io/client-go/rest/watch"
"k8s.io/client-go/tools/metrics"
"k8s.io/client-go/util/flowcontrol"
"k8s.io/klog/v2"
)
var (
// longThrottleLatency defines threshold for logging requests. All requests being
// throttled (via the provided rateLimiter) for more than longThrottleLatency will
// be logged.
longThrottleLatency = 50 * time.Millisecond
// extraLongThrottleLatency defines the threshold for logging requests at log level 2.
extraLongThrottleLatency = 1 * time.Second
)
// HTTPClient is an interface for testing a request object.
type HTTPClient interface {
Do(req *http.Request) (*http.Response, error)
}
// ResponseWrapper is an interface for getting a response.
// The response may be either accessed as a raw data (the whole output is put into memory) or as a stream.
type ResponseWrapper interface {
DoRaw(context.Context) ([]byte, error)
Stream(context.Context) (io.ReadCloser, error)
}
// RequestConstructionError is returned when there's an error assembling a request.
type RequestConstructionError struct {
Err error
}
// Error returns a textual description of 'r'.
func (r *RequestConstructionError) Error() string {
return fmt.Sprintf("request construction error: '%v'", r.Err)
}
var noBackoff = &NoBackoff{}
// Request allows for building up a request to a server in a chained fashion.
// Any errors are stored until the end of your call, so you only have to
// check once.
type Request struct {
c *RESTClient
warningHandler WarningHandler
rateLimiter flowcontrol.RateLimiter
backoff BackoffManager
timeout time.Duration
// generic components accessible via method setters
verb string
pathPrefix string
subpath string
params url.Values
headers http.Header
// structural elements of the request that are part of the Kubernetes API conventions
namespace string
namespaceSet bool
resource string
resourceName string
subresource string
// output
err error
body io.Reader
retry WithRetry
}
// NewRequest creates a new request helper object for accessing runtime.Objects on a server.
func NewRequest(c *RESTClient) *Request {
var backoff BackoffManager
if c.createBackoffMgr != nil {
backoff = c.createBackoffMgr()
}
if backoff == nil {
backoff = noBackoff
}
var pathPrefix string
if c.base != nil {
pathPrefix = path.Join("/", c.base.Path, c.versionedAPIPath)
} else {
pathPrefix = path.Join("/", c.versionedAPIPath)
}
var timeout time.Duration
if c.Client != nil {
timeout = c.Client.Timeout
}
r := &Request{
c: c,
rateLimiter: c.rateLimiter,
backoff: backoff,
timeout: timeout,
pathPrefix: pathPrefix,
retry: &withRetry{maxRetries: 10},
warningHandler: c.warningHandler,
}
switch {
case len(c.content.AcceptContentTypes) > 0:
r.SetHeader("Accept", c.content.AcceptContentTypes)
case len(c.content.ContentType) > 0:
r.SetHeader("Accept", c.content.ContentType+", */*")
}
return r
}
// NewRequestWithClient creates a Request with an embedded RESTClient for use in test scenarios.
func NewRequestWithClient(base *url.URL, versionedAPIPath string, content ClientContentConfig, client *http.Client) *Request {
return NewRequest(&RESTClient{
base: base,
versionedAPIPath: versionedAPIPath,
content: content,
Client: client,
})
}
// Verb sets the verb this request will use.
func (r *Request) Verb(verb string) *Request {
r.verb = verb
return r
}
// Prefix adds segments to the relative beginning to the request path. These
// items will be placed before the optional Namespace, Resource, or Name sections.
// Setting AbsPath will clear any previously set Prefix segments
func (r *Request) Prefix(segments ...string) *Request {
if r.err != nil {
return r
}
r.pathPrefix = path.Join(r.pathPrefix, path.Join(segments...))
return r
}
// Suffix appends segments to the end of the path. These items will be placed after the prefix and optional
// Namespace, Resource, or Name sections.
func (r *Request) Suffix(segments ...string) *Request {
if r.err != nil {
return r
}
r.subpath = path.Join(r.subpath, path.Join(segments...))
return r
}
// Resource sets the resource to access (<resource>/[ns/<namespace>/]<name>)
func (r *Request) Resource(resource string) *Request {
if r.err != nil {
return r
}
if len(r.resource) != 0 {
r.err = fmt.Errorf("resource already set to %q, cannot change to %q", r.resource, resource)
return r
}
if msgs := IsValidPathSegmentName(resource); len(msgs) != 0 {
r.err = fmt.Errorf("invalid resource %q: %v", resource, msgs)
return r
}
r.resource = resource
return r
}
// BackOff sets the request's backoff manager to the one specified,
// or defaults to the stub implementation if nil is provided
func (r *Request) BackOff(manager BackoffManager) *Request {
if manager == nil {
r.backoff = &NoBackoff{}
return r
}
r.backoff = manager
return r
}
// WarningHandler sets the handler this client uses when warning headers are encountered.
// If set to nil, this client will use the default warning handler (see SetDefaultWarningHandler).
func (r *Request) WarningHandler(handler WarningHandler) *Request {
r.warningHandler = handler
return r
}
// Throttle receives a rate-limiter and sets or replaces an existing request limiter
func (r *Request) Throttle(limiter flowcontrol.RateLimiter) *Request {
r.rateLimiter = limiter
return r
}
// SubResource sets a sub-resource path which can be multiple segments after the resource
// name but before the suffix.
func (r *Request) SubResource(subresources ...string) *Request {
if r.err != nil {
return r
}
subresource := path.Join(subresources...)
if len(r.subresource) != 0 {
r.err = fmt.Errorf("subresource already set to %q, cannot change to %q", r.subresource, subresource)
return r
}
for _, s := range subresources {
if msgs := IsValidPathSegmentName(s); len(msgs) != 0 {
r.err = fmt.Errorf("invalid subresource %q: %v", s, msgs)
return r
}
}
r.subresource = subresource
return r
}
// Name sets the name of a resource to access (<resource>/[ns/<namespace>/]<name>)
func (r *Request) Name(resourceName string) *Request {
if r.err != nil {
return r
}
if len(resourceName) == 0 {
r.err = fmt.Errorf("resource name may not be empty")
return r
}
if len(r.resourceName) != 0 {
r.err = fmt.Errorf("resource name already set to %q, cannot change to %q", r.resourceName, resourceName)
return r
}
if msgs := IsValidPathSegmentName(resourceName); len(msgs) != 0 {
r.err = fmt.Errorf("invalid resource name %q: %v", resourceName, msgs)
return r
}
r.resourceName = resourceName
return r
}
// Namespace applies the namespace scope to a request (<resource>/[ns/<namespace>/]<name>)
func (r *Request) Namespace(namespace string) *Request {
if r.err != nil {
return r
}
if r.namespaceSet {
r.err = fmt.Errorf("namespace already set to %q, cannot change to %q", r.namespace, namespace)
return r
}
if msgs := IsValidPathSegmentName(namespace); len(msgs) != 0 {
r.err = fmt.Errorf("invalid namespace %q: %v", namespace, msgs)
return r
}
r.namespaceSet = true
r.namespace = namespace
return r
}
// NamespaceIfScoped is a convenience function to set a namespace if scoped is true
func (r *Request) NamespaceIfScoped(namespace string, scoped bool) *Request {
if scoped {
return r.Namespace(namespace)
}
return r
}
// AbsPath overwrites an existing path with the segments provided. Trailing slashes are preserved
// when a single segment is passed.
func (r *Request) AbsPath(segments ...string) *Request {
if r.err != nil {
return r
}
r.pathPrefix = path.Join(r.c.base.Path, path.Join(segments...))
if len(segments) == 1 && (len(r.c.base.Path) > 1 || len(segments[0]) > 1) && strings.HasSuffix(segments[0], "/") {
// preserve any trailing slashes for legacy behavior
r.pathPrefix += "/"
}
return r
}
// RequestURI overwrites existing path and parameters with the value of the provided server relative
// URI.
func (r *Request) RequestURI(uri string) *Request {
if r.err != nil {
return r
}
locator, err := url.Parse(uri)
if err != nil {
r.err = err
return r
}
r.pathPrefix = locator.Path
if len(locator.Query()) > 0 {
if r.params == nil {
r.params = make(url.Values)
}
for k, v := range locator.Query() {
r.params[k] = v
}
}
return r
}
// Param creates a query parameter with the given string value.
func (r *Request) Param(paramName, s string) *Request {
if r.err != nil {
return r
}
return r.setParam(paramName, s)
}
// VersionedParams will take the provided object, serialize it to a map[string][]string using the
// implicit RESTClient API version and the default parameter codec, and then add those as parameters
// to the request. Use this to provide versioned query parameters from client libraries.
// VersionedParams will not write query parameters that have omitempty set and are empty. If a
// parameter has already been set it is appended to (Params and VersionedParams are additive).
func (r *Request) VersionedParams(obj runtime.Object, codec runtime.ParameterCodec) *Request {
return r.SpecificallyVersionedParams(obj, codec, r.c.content.GroupVersion)
}
func (r *Request) SpecificallyVersionedParams(obj runtime.Object, codec runtime.ParameterCodec, version schema.GroupVersion) *Request {
if r.err != nil {
return r
}
params, err := codec.EncodeParameters(obj, version)
if err != nil {
r.err = err
return r
}
for k, v := range params {
if r.params == nil {
r.params = make(url.Values)
}
r.params[k] = append(r.params[k], v...)
}
return r
}
func (r *Request) setParam(paramName, value string) *Request {
if r.params == nil {
r.params = make(url.Values)
}
r.params[paramName] = append(r.params[paramName], value)
return r
}
func (r *Request) SetHeader(key string, values ...string) *Request {
if r.headers == nil {
r.headers = http.Header{}
}
r.headers.Del(key)
for _, value := range values {
r.headers.Add(key, value)
}
return r
}
// Timeout makes the request use the given duration as an overall timeout for the
// request. Additionally, if set passes the value as "timeout" parameter in URL.
func (r *Request) Timeout(d time.Duration) *Request {
if r.err != nil {
return r
}
r.timeout = d
return r
}
// MaxRetries makes the request use the given integer as a ceiling of retrying upon receiving
// "Retry-After" headers and 429 status-code in the response. The default is 10 unless this
// function is specifically called with a different value.
// A zero maxRetries prevent it from doing retires and return an error immediately.
func (r *Request) MaxRetries(maxRetries int) *Request {
r.retry.SetMaxRetries(maxRetries)
return r
}
// Body makes the request use obj as the body. Optional.
// If obj is a string, try to read a file of that name.
// If obj is a []byte, send it directly.
// If obj is an io.Reader, use it directly.
// If obj is a runtime.Object, marshal it correctly, and set Content-Type header.
// If obj is a runtime.Object and nil, do nothing.
// Otherwise, set an error.
func (r *Request) Body(obj interface{}) *Request {
if r.err != nil {
return r
}
switch t := obj.(type) {
case string:
data, err := ioutil.ReadFile(t)
if err != nil {
r.err = err
return r
}
glogBody("Request Body", data)
r.body = bytes.NewReader(data)
case []byte:
glogBody("Request Body", t)
r.body = bytes.NewReader(t)
case io.Reader:
r.body = t
case runtime.Object:
// callers may pass typed interface pointers, therefore we must check nil with reflection
if reflect.ValueOf(t).IsNil() {
return r
}
encoder, err := r.c.content.Negotiator.Encoder(r.c.content.ContentType, nil)
if err != nil {
r.err = err
return r
}
data, err := runtime.Encode(encoder, t)
if err != nil {
r.err = err
return r
}
glogBody("Request Body", data)
r.body = bytes.NewReader(data)
r.SetHeader("Content-Type", r.c.content.ContentType)
default:
r.err = fmt.Errorf("unknown type used for body: %+v", obj)
}
return r
}
// URL returns the current working URL.
func (r *Request) URL() *url.URL {
p := r.pathPrefix
if r.namespaceSet && len(r.namespace) > 0 {
p = path.Join(p, "namespaces", r.namespace)
}
if len(r.resource) != 0 {
p = path.Join(p, strings.ToLower(r.resource))
}
// Join trims trailing slashes, so preserve r.pathPrefix's trailing slash for backwards compatibility if nothing was changed
if len(r.resourceName) != 0 || len(r.subpath) != 0 || len(r.subresource) != 0 {
p = path.Join(p, r.resourceName, r.subresource, r.subpath)
}
finalURL := &url.URL{}
if r.c.base != nil {
*finalURL = *r.c.base
}
finalURL.Path = p
query := url.Values{}
for key, values := range r.params {
for _, value := range values {
query.Add(key, value)
}
}
// timeout is handled specially here.
if r.timeout != 0 {
query.Set("timeout", r.timeout.String())
}
finalURL.RawQuery = query.Encode()
return finalURL
}
// finalURLTemplate is similar to URL(), but will make all specific parameter values equal
// - instead of name or namespace, "{name}" and "{namespace}" will be used, and all query
// parameters will be reset. This creates a copy of the url so as not to change the
// underlying object.
func (r Request) finalURLTemplate() url.URL {
newParams := url.Values{}
v := []string{"{value}"}
for k := range r.params {
newParams[k] = v
}
r.params = newParams
url := r.URL()
segments := strings.Split(url.Path, "/")
groupIndex := 0
index := 0
trimmedBasePath := ""
if url != nil && r.c.base != nil && strings.Contains(url.Path, r.c.base.Path) {
p := strings.TrimPrefix(url.Path, r.c.base.Path)
if !strings.HasPrefix(p, "/") {
p = "/" + p
}
// store the base path that we have trimmed so we can append it
// before returning the URL
trimmedBasePath = r.c.base.Path
segments = strings.Split(p, "/")
groupIndex = 1
}
if len(segments) <= 2 {
return *url
}
const CoreGroupPrefix = "api"
const NamedGroupPrefix = "apis"
isCoreGroup := segments[groupIndex] == CoreGroupPrefix
isNamedGroup := segments[groupIndex] == NamedGroupPrefix
if isCoreGroup {
// checking the case of core group with /api/v1/... format
index = groupIndex + 2
} else if isNamedGroup {
// checking the case of named group with /apis/apps/v1/... format
index = groupIndex + 3
} else {
// this should not happen that the only two possibilities are /api... and /apis..., just want to put an
// outlet here in case more API groups are added in future if ever possible:
// https://kubernetes.io/docs/concepts/overview/kubernetes-api/#api-groups
// if a wrong API groups name is encountered, return the {prefix} for url.Path
url.Path = "/{prefix}"
url.RawQuery = ""
return *url
}
//switch segLength := len(segments) - index; segLength {
switch {
// case len(segments) - index == 1:
// resource (with no name) do nothing
case len(segments)-index == 2:
// /$RESOURCE/$NAME: replace $NAME with {name}
segments[index+1] = "{name}"
case len(segments)-index == 3:
if segments[index+2] == "finalize" || segments[index+2] == "status" {
// /$RESOURCE/$NAME/$SUBRESOURCE: replace $NAME with {name}
segments[index+1] = "{name}"
} else {
// /namespace/$NAMESPACE/$RESOURCE: replace $NAMESPACE with {namespace}
segments[index+1] = "{namespace}"
}
case len(segments)-index >= 4:
segments[index+1] = "{namespace}"
// /namespace/$NAMESPACE/$RESOURCE/$NAME: replace $NAMESPACE with {namespace}, $NAME with {name}
if segments[index+3] != "finalize" && segments[index+3] != "status" {
// /$RESOURCE/$NAME/$SUBRESOURCE: replace $NAME with {name}
segments[index+3] = "{name}"
}
}
url.Path = path.Join(trimmedBasePath, path.Join(segments...))
return *url
}
func (r *Request) tryThrottleWithInfo(ctx context.Context, retryInfo string) error {
if r.rateLimiter == nil {
return nil
}
now := time.Now()
err := r.rateLimiter.Wait(ctx)
latency := time.Since(now)
var message string
switch {
case len(retryInfo) > 0:
message = fmt.Sprintf("Waited for %v, %s - request: %s:%s", latency, retryInfo, r.verb, r.URL().String())
default:
message = fmt.Sprintf("Waited for %v due to client-side throttling, not priority and fairness, request: %s:%s", latency, r.verb, r.URL().String())
}
if latency > longThrottleLatency {
klog.V(3).Info(message)
}
if latency > extraLongThrottleLatency {
// If the rate limiter latency is very high, the log message should be printed at a higher log level,
// but we use a throttled logger to prevent spamming.
globalThrottledLogger.Infof("%s", message)
}
metrics.RateLimiterLatency.Observe(ctx, r.verb, r.finalURLTemplate(), latency)
return err
}
func (r *Request) tryThrottle(ctx context.Context) error {
return r.tryThrottleWithInfo(ctx, "")
}
type throttleSettings struct {
logLevel klog.Level
minLogInterval time.Duration
lastLogTime time.Time
lock sync.RWMutex
}
type throttledLogger struct {
clock utilclock.PassiveClock
settings []*throttleSettings
}
var globalThrottledLogger = &throttledLogger{
clock: utilclock.RealClock{},
settings: []*throttleSettings{
{
logLevel: 2,
minLogInterval: 1 * time.Second,
}, {
logLevel: 0,
minLogInterval: 10 * time.Second,
},
},
}
func (b *throttledLogger) attemptToLog() (klog.Level, bool) {
for _, setting := range b.settings {
if bool(klog.V(setting.logLevel).Enabled()) {
// Return early without write locking if possible.
if func() bool {
setting.lock.RLock()
defer setting.lock.RUnlock()
return b.clock.Since(setting.lastLogTime) >= setting.minLogInterval
}() {
setting.lock.Lock()
defer setting.lock.Unlock()
if b.clock.Since(setting.lastLogTime) >= setting.minLogInterval {
setting.lastLogTime = b.clock.Now()
return setting.logLevel, true
}
}
return -1, false
}
}
return -1, false
}
// Infof will write a log message at each logLevel specified by the receiver's throttleSettings
// as long as it hasn't written a log message more recently than minLogInterval.
func (b *throttledLogger) Infof(message string, args ...interface{}) {
if logLevel, ok := b.attemptToLog(); ok {
klog.V(logLevel).Infof(message, args...)
}
}
// Watch attempts to begin watching the requested location.
// Returns a watch.Interface, or an error.
func (r *Request) Watch(ctx context.Context) (watch.Interface, error) {
// We specifically don't want to rate limit watches, so we
// don't use r.rateLimiter here.
if r.err != nil {
return nil, r.err
}
client := r.c.Client
if client == nil {
client = http.DefaultClient
}
isErrRetryableFunc := func(request *http.Request, err error) bool {
// The watch stream mechanism handles many common partial data errors, so closed
// connections can be retried in many cases.
if net.IsProbableEOF(err) || net.IsTimeout(err) {
return true
}
return false
}
var retryAfter *RetryAfter
url := r.URL().String()
for {
req, err := r.newHTTPRequest(ctx)
if err != nil {
return nil, err
}
r.backoff.Sleep(r.backoff.CalculateBackoff(r.URL()))
if retryAfter != nil {
// We are retrying the request that we already send to apiserver
// at least once before.
// This request should also be throttled with the client-internal rate limiter.
if err := r.tryThrottleWithInfo(ctx, retryAfter.Reason); err != nil {
return nil, err
}
retryAfter = nil
}
resp, err := client.Do(req)
updateURLMetrics(ctx, r, resp, err)
if r.c.base != nil {
if err != nil {
r.backoff.UpdateBackoff(r.c.base, err, 0)
} else {
r.backoff.UpdateBackoff(r.c.base, err, resp.StatusCode)
}
}
if err == nil && resp.StatusCode == http.StatusOK {
return r.newStreamWatcher(resp)
}
done, transformErr := func() (bool, error) {
defer readAndCloseResponseBody(resp)
var retry bool
retryAfter, retry = r.retry.NextRetry(req, resp, err, isErrRetryableFunc)
if retry {
err := r.retry.BeforeNextRetry(ctx, r.backoff, retryAfter, url, r.body)
if err == nil {
return false, nil
}
klog.V(4).Infof("Could not retry request - %v", err)
}
if resp == nil {
// the server must have sent us an error in 'err'
return true, nil
}
if result := r.transformResponse(resp, req); result.err != nil {
return true, result.err
}
return true, fmt.Errorf("for request %s, got status: %v", url, resp.StatusCode)
}()
if done {
if isErrRetryableFunc(req, err) {
return watch.NewEmptyWatch(), nil
}
if err == nil {
// if the server sent us an HTTP Response object,
// we need to return the error object from that.
err = transformErr
}
return nil, err
}
}
}
func (r *Request) newStreamWatcher(resp *http.Response) (watch.Interface, error) {
contentType := resp.Header.Get("Content-Type")
mediaType, params, err := mime.ParseMediaType(contentType)
if err != nil {
klog.V(4).Infof("Unexpected content type from the server: %q: %v", contentType, err)
}
objectDecoder, streamingSerializer, framer, err := r.c.content.Negotiator.StreamDecoder(mediaType, params)
if err != nil {
return nil, err
}
handleWarnings(resp.Header, r.warningHandler)
frameReader := framer.NewFrameReader(resp.Body)
watchEventDecoder := streaming.NewDecoder(frameReader, streamingSerializer)
return watch.NewStreamWatcher(
restclientwatch.NewDecoder(watchEventDecoder, objectDecoder),
// use 500 to indicate that the cause of the error is unknown - other error codes
// are more specific to HTTP interactions, and set a reason
errors.NewClientErrorReporter(http.StatusInternalServerError, r.verb, "ClientWatchDecoding"),
), nil
}
// updateURLMetrics is a convenience function for pushing metrics.
// It also handles corner cases for incomplete/invalid request data.
func updateURLMetrics(ctx context.Context, req *Request, resp *http.Response, err error) {
url := "none"
if req.c.base != nil {
url = req.c.base.Host
}
// Errors can be arbitrary strings. Unbound label cardinality is not suitable for a metric
// system so we just report them as `<error>`.
if err != nil {
metrics.RequestResult.Increment(ctx, "<error>", req.verb, url)
} else {
//Metrics for failure codes
metrics.RequestResult.Increment(ctx, strconv.Itoa(resp.StatusCode), req.verb, url)
}
}
// Stream formats and executes the request, and offers streaming of the response.
// Returns io.ReadCloser which could be used for streaming of the response, or an error
// Any non-2xx http status code causes an error. If we get a non-2xx code, we try to convert the body into an APIStatus object.
// If we can, we return that as an error. Otherwise, we create an error that lists the http status and the content of the response.
func (r *Request) Stream(ctx context.Context) (io.ReadCloser, error) {
if r.err != nil {
return nil, r.err
}
if err := r.tryThrottle(ctx); err != nil {
return nil, err
}
client := r.c.Client
if client == nil {
client = http.DefaultClient
}
var retryAfter *RetryAfter
url := r.URL().String()
for {
req, err := r.newHTTPRequest(ctx)
if err != nil {
return nil, err
}
if r.body != nil {
req.Body = ioutil.NopCloser(r.body)
}
r.backoff.Sleep(r.backoff.CalculateBackoff(r.URL()))
if retryAfter != nil {
// We are retrying the request that we already send to apiserver
// at least once before.
// This request should also be throttled with the client-internal rate limiter.
if err := r.tryThrottleWithInfo(ctx, retryAfter.Reason); err != nil {
return nil, err
}
retryAfter = nil
}
resp, err := client.Do(req)
updateURLMetrics(ctx, r, resp, err)
if r.c.base != nil {
if err != nil {
r.backoff.UpdateBackoff(r.URL(), err, 0)
} else {
r.backoff.UpdateBackoff(r.URL(), err, resp.StatusCode)
}
}
if err != nil {
// we only retry on an HTTP response with 'Retry-After' header
return nil, err
}
switch {
case (resp.StatusCode >= 200) && (resp.StatusCode < 300):
handleWarnings(resp.Header, r.warningHandler)
return resp.Body, nil
default:
done, transformErr := func() (bool, error) {
defer resp.Body.Close()
var retry bool
retryAfter, retry = r.retry.NextRetry(req, resp, err, neverRetryError)
if retry {
err := r.retry.BeforeNextRetry(ctx, r.backoff, retryAfter, url, r.body)
if err == nil {
return false, nil
}
klog.V(4).Infof("Could not retry request - %v", err)
}
result := r.transformResponse(resp, req)
if err := result.Error(); err != nil {
return true, err
}
return true, fmt.Errorf("%d while accessing %v: %s", result.statusCode, url, string(result.body))
}()
if done {
return nil, transformErr
}
}
}
}
// requestPreflightCheck looks for common programmer errors on Request.
//
// We tackle here two programmer mistakes. The first one is to try to create
// something(POST) using an empty string as namespace with namespaceSet as
// true. If namespaceSet is true then namespace should also be defined. The
// second mistake is, when under the same circumstances, the programmer tries
// to GET, PUT or DELETE a named resource(resourceName != ""), again, if
// namespaceSet is true then namespace must not be empty.
func (r *Request) requestPreflightCheck() error {
if !r.namespaceSet {
return nil
}
if len(r.namespace) > 0 {
return nil
}
switch r.verb {
case "POST":
return fmt.Errorf("an empty namespace may not be set during creation")
case "GET", "PUT", "DELETE":
if len(r.resourceName) > 0 {
return fmt.Errorf("an empty namespace may not be set when a resource name is provided")
}
}
return nil
}
func (r *Request) newHTTPRequest(ctx context.Context) (*http.Request, error) {
url := r.URL().String()
req, err := http.NewRequest(r.verb, url, r.body)
if err != nil {
return nil, err
}
req = req.WithContext(ctx)
req.Header = r.headers
return req, nil
}
// request connects to the server and invokes the provided function when a server response is
// received. It handles retry behavior and up front validation of requests. It will invoke
// fn at most once. It will return an error if a problem occurred prior to connecting to the
// server - the provided function is responsible for handling server errors.
func (r *Request) request(ctx context.Context, fn func(*http.Request, *http.Response)) error {
//Metrics for total request latency
start := time.Now()
defer func() {
metrics.RequestLatency.Observe(ctx, r.verb, r.finalURLTemplate(), time.Since(start))
}()
if r.err != nil {
klog.V(4).Infof("Error in request: %v", r.err)
return r.err
}
if err := r.requestPreflightCheck(); err != nil {
return err
}
client := r.c.Client
if client == nil {
client = http.DefaultClient
}
// Throttle the first try before setting up the timeout configured on the
// client. We don't want a throttled client to return timeouts to callers
// before it makes a single request.
if err := r.tryThrottle(ctx); err != nil {
return err
}
if r.timeout > 0 {
var cancel context.CancelFunc
ctx, cancel = context.WithTimeout(ctx, r.timeout)
defer cancel()
}
// Right now we make about ten retry attempts if we get a Retry-After response.
var retryAfter *RetryAfter
for {
req, err := r.newHTTPRequest(ctx)
if err != nil {
return err
}
r.backoff.Sleep(r.backoff.CalculateBackoff(r.URL()))
if retryAfter != nil {
// We are retrying the request that we already send to apiserver
// at least once before.
// This request should also be throttled with the client-internal rate limiter.
if err := r.tryThrottleWithInfo(ctx, retryAfter.Reason); err != nil {
return err
}
retryAfter = nil
}
resp, err := client.Do(req)
updateURLMetrics(ctx, r, resp, err)
if err != nil {
r.backoff.UpdateBackoff(r.URL(), err, 0)
} else {
r.backoff.UpdateBackoff(r.URL(), err, resp.StatusCode)
}
done := func() bool {
defer readAndCloseResponseBody(resp)
// if the the server returns an error in err, the response will be nil.
f := func(req *http.Request, resp *http.Response) {
if resp == nil {
return
}
fn(req, resp)
}
var retry bool
retryAfter, retry = r.retry.NextRetry(req, resp, err, func(req *http.Request, err error) bool {
// "Connection reset by peer" or "apiserver is shutting down" are usually a transient errors.
// Thus in case of "GET" operations, we simply retry it.
// We are not automatically retrying "write" operations, as they are not idempotent.
if r.verb != "GET" {
return false
}
// For connection errors and apiserver shutdown errors retry.
if net.IsConnectionReset(err) || net.IsProbableEOF(err) {
return true
}
return false
})
if retry {
err := r.retry.BeforeNextRetry(ctx, r.backoff, retryAfter, req.URL.String(), r.body)
if err == nil {
return false
}
klog.V(4).Infof("Could not retry request - %v", err)
}
f(req, resp)
return true
}()
if done {
return err
}
}
}
// Do formats and executes the request. Returns a Result object for easy response
// processing.
//
// Error type:
// * If the server responds with a status: *errors.StatusError or *errors.UnexpectedObjectError
// * http.Client.Do errors are returned directly.
func (r *Request) Do(ctx context.Context) Result {
var result Result
err := r.request(ctx, func(req *http.Request, resp *http.Response) {
result = r.transformResponse(resp, req)
})
if err != nil {
return Result{err: err}
}
return result
}
// DoRaw executes the request but does not process the response body.
func (r *Request) DoRaw(ctx context.Context) ([]byte, error) {
var result Result
err := r.request(ctx, func(req *http.Request, resp *http.Response) {
result.body, result.err = ioutil.ReadAll(resp.Body)
glogBody("Response Body", result.body)
if resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent {
result.err = r.transformUnstructuredResponseError(resp, req, result.body)
}
})
if err != nil {
return nil, err
}
return result.body, result.err
}
// transformResponse converts an API response into a structured API object
func (r *Request) transformResponse(resp *http.Response, req *http.Request) Result {
var body []byte
if resp.Body != nil {
data, err := ioutil.ReadAll(resp.Body)
switch err.(type) {
case nil:
body = data
case http2.StreamError:
// This is trying to catch the scenario that the server may close the connection when sending the
// response body. This can be caused by server timeout due to a slow network connection.
// TODO: Add test for this. Steps may be:
// 1. client-go (or kubectl) sends a GET request.
// 2. Apiserver sends back the headers and then part of the body
// 3. Apiserver closes connection.
// 4. client-go should catch this and return an error.
klog.V(2).Infof("Stream error %#v when reading response body, may be caused by closed connection.", err)
streamErr := fmt.Errorf("stream error when reading response body, may be caused by closed connection. Please retry. Original error: %w", err)
return Result{
err: streamErr,
}
default:
klog.Errorf("Unexpected error when reading response body: %v", err)
unexpectedErr := fmt.Errorf("unexpected error when reading response body. Please retry. Original error: %w", err)
return Result{
err: unexpectedErr,
}
}
}
glogBody("Response Body", body)
// verify the content type is accurate
var decoder runtime.Decoder
contentType := resp.Header.Get("Content-Type")
if len(contentType) == 0 {
contentType = r.c.content.ContentType
}
if len(contentType) > 0 {
var err error
mediaType, params, err := mime.ParseMediaType(contentType)
if err != nil {
return Result{err: errors.NewInternalError(err)}
}
decoder, err = r.c.content.Negotiator.Decoder(mediaType, params)
if err != nil {
// if we fail to negotiate a decoder, treat this as an unstructured error
switch {
case resp.StatusCode == http.StatusSwitchingProtocols:
// no-op, we've been upgraded
case resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent:
return Result{err: r.transformUnstructuredResponseError(resp, req, body)}
}
return Result{
body: body,
contentType: contentType,
statusCode: resp.StatusCode,
warnings: handleWarnings(resp.Header, r.warningHandler),
}
}
}
switch {
case resp.StatusCode == http.StatusSwitchingProtocols:
// no-op, we've been upgraded
case resp.StatusCode < http.StatusOK || resp.StatusCode > http.StatusPartialContent:
// calculate an unstructured error from the response which the Result object may use if the caller
// did not return a structured error.
retryAfter, _ := retryAfterSeconds(resp)
err := r.newUnstructuredResponseError(body, isTextResponse(resp), resp.StatusCode, req.Method, retryAfter)
return Result{
body: body,
contentType: contentType,
statusCode: resp.StatusCode,
decoder: decoder,
err: err,
warnings: handleWarnings(resp.Header, r.warningHandler),
}
}
return Result{
body: body,
contentType: contentType,
statusCode: resp.StatusCode,
decoder: decoder,
warnings: handleWarnings(resp.Header, r.warningHandler),
}
}
// truncateBody decides if the body should be truncated, based on the glog Verbosity.
func truncateBody(body string) string {
max := 0
switch {
case bool(klog.V(10).Enabled()):
return body
case bool(klog.V(9).Enabled()):
max = 10240
case bool(klog.V(8).Enabled()):
max = 1024
}
if len(body) <= max {
return body
}
return body[:max] + fmt.Sprintf(" [truncated %d chars]", len(body)-max)
}
// glogBody logs a body output that could be either JSON or protobuf. It explicitly guards against
// allocating a new string for the body output unless necessary. Uses a simple heuristic to determine
// whether the body is printable.
func glogBody(prefix string, body []byte) {
if klog.V(8).Enabled() {
if bytes.IndexFunc(body, func(r rune) bool {
return r < 0x0a
}) != -1 {
klog.Infof("%s:\n%s", prefix, truncateBody(hex.Dump(body)))
} else {
klog.Infof("%s: %s", prefix, truncateBody(string(body)))
}
}
}
// maxUnstructuredResponseTextBytes is an upper bound on how much output to include in the unstructured error.
const maxUnstructuredResponseTextBytes = 2048
// transformUnstructuredResponseError handles an error from the server that is not in a structured form.
// It is expected to transform any response that is not recognizable as a clear server sent error from the
// K8S API using the information provided with the request. In practice, HTTP proxies and client libraries
// introduce a level of uncertainty to the responses returned by servers that in common use result in
// unexpected responses. The rough structure is:
//
// 1. Assume the server sends you something sane - JSON + well defined error objects + proper codes
// - this is the happy path
// - when you get this output, trust what the server sends
// 2. Guard against empty fields / bodies in received JSON and attempt to cull sufficient info from them to
// generate a reasonable facsimile of the original failure.
// - Be sure to use a distinct error type or flag that allows a client to distinguish between this and error 1 above
// 3. Handle true disconnect failures / completely malformed data by moving up to a more generic client error
// 4. Distinguish between various connection failures like SSL certificates, timeouts, proxy errors, unexpected
// initial contact, the presence of mismatched body contents from posted content types
// - Give these a separate distinct error type and capture as much as possible of the original message
//
// TODO: introduce transformation of generic http.Client.Do() errors that separates 4.
func (r *Request) transformUnstructuredResponseError(resp *http.Response, req *http.Request, body []byte) error {
if body == nil && resp.Body != nil {
if data, err := ioutil.ReadAll(&io.LimitedReader{R: resp.Body, N: maxUnstructuredResponseTextBytes}); err == nil {
body = data
}
}
retryAfter, _ := retryAfterSeconds(resp)
return r.newUnstructuredResponseError(body, isTextResponse(resp), resp.StatusCode, req.Method, retryAfter)
}
// newUnstructuredResponseError instantiates the appropriate generic error for the provided input. It also logs the body.
func (r *Request) newUnstructuredResponseError(body []byte, isTextResponse bool, statusCode int, method string, retryAfter int) error {
// cap the amount of output we create
if len(body) > maxUnstructuredResponseTextBytes {
body = body[:maxUnstructuredResponseTextBytes]
}
message := "unknown"
if isTextResponse {
message = strings.TrimSpace(string(body))
}
var groupResource schema.GroupResource
if len(r.resource) > 0 {
groupResource.Group = r.c.content.GroupVersion.Group
groupResource.Resource = r.resource
}
return errors.NewGenericServerResponse(
statusCode,
method,
groupResource,
r.resourceName,
message,
retryAfter,
true,
)
}
// isTextResponse returns true if the response appears to be a textual media type.
func isTextResponse(resp *http.Response) bool {
contentType := resp.Header.Get("Content-Type")
if len(contentType) == 0 {
return true
}
media, _, err := mime.ParseMediaType(contentType)
if err != nil {
return false
}
return strings.HasPrefix(media, "text/")
}
// retryAfterSeconds returns the value of the Retry-After header and true, or 0 and false if
// the header was missing or not a valid number.
func retryAfterSeconds(resp *http.Response) (int, bool) {
if h := resp.Header.Get("Retry-After"); len(h) > 0 {
if i, err := strconv.Atoi(h); err == nil {
return i, true
}
}
return 0, false
}
// Result contains the result of calling Request.Do().
type Result struct {
body []byte
warnings []net.WarningHeader
contentType string
err error
statusCode int
decoder runtime.Decoder
}
// Raw returns the raw result.
func (r Result) Raw() ([]byte, error) {
return r.body, r.err
}
// Get returns the result as an object, which means it passes through the decoder.
// If the returned object is of type Status and has .Status != StatusSuccess, the
// additional information in Status will be used to enrich the error.
func (r Result) Get() (runtime.Object, error) {
if r.err != nil {
// Check whether the result has a Status object in the body and prefer that.
return nil, r.Error()
}
if r.decoder == nil {
return nil, fmt.Errorf("serializer for %s doesn't exist", r.contentType)
}
// decode, but if the result is Status return that as an error instead.
out, _, err := r.decoder.Decode(r.body, nil, nil)
if err != nil {
return nil, err
}
switch t := out.(type) {
case *metav1.Status:
// any status besides StatusSuccess is considered an error.
if t.Status != metav1.StatusSuccess {
return nil, errors.FromObject(t)
}
}
return out, nil
}
// StatusCode returns the HTTP status code of the request. (Only valid if no
// error was returned.)
func (r Result) StatusCode(statusCode *int) Result {
*statusCode = r.statusCode
return r
}
// Into stores the result into obj, if possible. If obj is nil it is ignored.
// If the returned object is of type Status and has .Status != StatusSuccess, the
// additional information in Status will be used to enrich the error.
func (r Result) Into(obj runtime.Object) error {
if r.err != nil {
// Check whether the result has a Status object in the body and prefer that.
return r.Error()
}
if r.decoder == nil {
return fmt.Errorf("serializer for %s doesn't exist", r.contentType)
}
if len(r.body) == 0 {
return fmt.Errorf("0-length response with status code: %d and content type: %s",
r.statusCode, r.contentType)
}
out, _, err := r.decoder.Decode(r.body, nil, obj)
if err != nil || out == obj {
return err
}
// if a different object is returned, see if it is Status and avoid double decoding
// the object.
switch t := out.(type) {
case *metav1.Status:
// any status besides StatusSuccess is considered an error.
if t.Status != metav1.StatusSuccess {
return errors.FromObject(t)
}
}
return nil
}
// WasCreated updates the provided bool pointer to whether the server returned
// 201 created or a different response.
func (r Result) WasCreated(wasCreated *bool) Result {
*wasCreated = r.statusCode == http.StatusCreated
return r
}
// Error returns the error executing the request, nil if no error occurred.
// If the returned object is of type Status and has Status != StatusSuccess, the
// additional information in Status will be used to enrich the error.
// See the Request.Do() comment for what errors you might get.
func (r Result) Error() error {
// if we have received an unexpected server error, and we have a body and decoder, we can try to extract
// a Status object.
if r.err == nil || !errors.IsUnexpectedServerError(r.err) || len(r.body) == 0 || r.decoder == nil {
return r.err
}
// attempt to convert the body into a Status object
// to be backwards compatible with old servers that do not return a version, default to "v1"
out, _, err := r.decoder.Decode(r.body, &schema.GroupVersionKind{Version: "v1"}, nil)
if err != nil {
klog.V(5).Infof("body was not decodable (unable to check for Status): %v", err)
return r.err
}
switch t := out.(type) {
case *metav1.Status:
// because we default the kind, we *must* check for StatusFailure
if t.Status == metav1.StatusFailure {
return errors.FromObject(t)
}
}
return r.err
}
// Warnings returns any warning headers received in the response
func (r Result) Warnings() []net.WarningHeader {
return r.warnings
}
// NameMayNotBe specifies strings that cannot be used as names specified as path segments (like the REST API or etcd store)
var NameMayNotBe = []string{".", ".."}
// NameMayNotContain specifies substrings that cannot be used in names specified as path segments (like the REST API or etcd store)
var NameMayNotContain = []string{"/", "%"}
// IsValidPathSegmentName validates the name can be safely encoded as a path segment
func IsValidPathSegmentName(name string) []string {
for _, illegalName := range NameMayNotBe {
if name == illegalName {
return []string{fmt.Sprintf(`may not be '%s'`, illegalName)}
}
}
var errors []string
for _, illegalContent := range NameMayNotContain {
if strings.Contains(name, illegalContent) {
errors = append(errors, fmt.Sprintf(`may not contain '%s'`, illegalContent))
}
}
return errors
}
// IsValidPathSegmentPrefix validates the name can be used as a prefix for a name which will be encoded as a path segment
// It does not check for exact matches with disallowed names, since an arbitrary suffix might make the name valid
func IsValidPathSegmentPrefix(name string) []string {
var errors []string
for _, illegalContent := range NameMayNotContain {
if strings.Contains(name, illegalContent) {
errors = append(errors, fmt.Sprintf(`may not contain '%s'`, illegalContent))
}
}
return errors
}
// ValidatePathSegmentName validates the name can be safely encoded as a path segment
func ValidatePathSegmentName(name string, prefix bool) []string {
if prefix {
return IsValidPathSegmentPrefix(name)
}
return IsValidPathSegmentName(name)
}