107 lines
3.4 KiB
Go
Executable File
107 lines
3.4 KiB
Go
Executable File
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// Package webhook implements a generic HTTP webhook plugin.
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package webhook
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import (
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"fmt"
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"time"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/runtime/schema"
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runtimeserializer "k8s.io/apimachinery/pkg/runtime/serializer"
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"k8s.io/apimachinery/pkg/util/wait"
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"k8s.io/client-go/pkg/api"
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apierrors "k8s.io/client-go/pkg/api/errors"
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"k8s.io/client-go/rest"
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"k8s.io/client-go/tools/clientcmd"
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_ "k8s.io/client-go/pkg/apis/authorization/install"
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)
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type GenericWebhook struct {
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RestClient *rest.RESTClient
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initialBackoff time.Duration
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}
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// NewGenericWebhook creates a new GenericWebhook from the provided kubeconfig file.
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func NewGenericWebhook(kubeConfigFile string, groupVersions []schema.GroupVersion, initialBackoff time.Duration) (*GenericWebhook, error) {
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for _, groupVersion := range groupVersions {
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if !api.Registry.IsEnabledVersion(groupVersion) {
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return nil, fmt.Errorf("webhook plugin requires enabling extension resource: %s", groupVersion)
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}
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}
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loadingRules := clientcmd.NewDefaultClientConfigLoadingRules()
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loadingRules.ExplicitPath = kubeConfigFile
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loader := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, &clientcmd.ConfigOverrides{})
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clientConfig, err := loader.ClientConfig()
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if err != nil {
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return nil, err
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}
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codec := api.Codecs.LegacyCodec(groupVersions...)
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clientConfig.ContentConfig.NegotiatedSerializer = runtimeserializer.NegotiatedSerializerWrapper(runtime.SerializerInfo{Serializer: codec})
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restClient, err := rest.UnversionedRESTClientFor(clientConfig)
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if err != nil {
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return nil, err
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}
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// TODO(ericchiang): Can we ensure remote service is reachable?
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return &GenericWebhook{restClient, initialBackoff}, nil
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}
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// WithExponentialBackoff will retry webhookFn() up to 5 times with exponentially increasing backoff when
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// it returns an error for which apierrors.SuggestsClientDelay() or apierrors.IsInternalError() returns true.
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func (g *GenericWebhook) WithExponentialBackoff(webhookFn func() rest.Result) rest.Result {
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var result rest.Result
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WithExponentialBackoff(g.initialBackoff, func() error {
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result = webhookFn()
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return result.Error()
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})
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return result
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}
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// WithExponentialBackoff will retry webhookFn() up to 5 times with exponentially increasing backoff when
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// it returns an error for which apierrors.SuggestsClientDelay() or apierrors.IsInternalError() returns true.
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func WithExponentialBackoff(initialBackoff time.Duration, webhookFn func() error) error {
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backoff := wait.Backoff{
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Duration: initialBackoff,
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Factor: 1.5,
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Jitter: 0.2,
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Steps: 5,
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}
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var err error
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wait.ExponentialBackoff(backoff, func() (bool, error) {
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err = webhookFn()
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if _, shouldRetry := apierrors.SuggestsClientDelay(err); shouldRetry {
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return false, nil
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}
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if apierrors.IsInternalError(err) {
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return false, nil
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}
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if err != nil {
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return false, err
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}
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return true, nil
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})
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return err
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}
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