78 lines
2.4 KiB
Go
78 lines
2.4 KiB
Go
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/*
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Copyright 2020 VMware, Inc.
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SPDX-License-Identifier: Apache-2.0
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*/
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package config
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import (
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"fmt"
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"io"
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"io/ioutil"
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"os"
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authenticationv1beta1 "k8s.io/api/authentication/v1beta1"
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utilnet "k8s.io/apimachinery/pkg/util/net"
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"k8s.io/apiserver/pkg/authentication/authenticator"
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"k8s.io/apiserver/plugin/pkg/authenticator/token/webhook"
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"k8s.io/client-go/tools/clientcmd"
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clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
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"github.com/suzerain-io/placeholder-name/pkg/config/api"
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)
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// NewWebhook creates a webhook from the provided API server url and caBundle
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// used to validate TLS connections.
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func NewWebhook(spec api.WebhookConfigSpec) (*webhook.WebhookTokenAuthenticator, error) {
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kubeconfig, err := ioutil.TempFile("", "placeholder-name-webhook-kubeconfig-*")
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if err != nil {
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return nil, fmt.Errorf("create temp file: %w", err)
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}
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defer os.Remove(kubeconfig.Name())
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if err := anonymousKubeconfig(spec.URL, spec.CABundle, kubeconfig); err != nil {
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return nil, fmt.Errorf("anonymous kubeconfig: %w", err)
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}
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// We use v1beta1 instead of v1 since v1beta1 is more prevalent in our desired
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// integration points.
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version := authenticationv1beta1.SchemeGroupVersion.Version
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// At the current time, we don't provide any audiences because we simply don't
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// have any requirements to do so. This can be changed in the future as
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// requirements change.
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var implicitAuds authenticator.Audiences
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// We set this to nil because we would only need this to support some of the
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// custom proxy stuff used by the API server.
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var customDial utilnet.DialFunc
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return webhook.New(kubeconfig.Name(), version, implicitAuds, customDial)
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}
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// anonymousKubeconfig writes a kubeconfig file to the provided io.Writer that
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// will "use" anonymous auth to talk to a Kube API server at the provided url
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// with the provided caBundle.
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func anonymousKubeconfig(url string, caBundle []byte, out io.Writer) error {
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config := clientcmdapi.NewConfig()
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config.Clusters["anonymous-cluster"] = &clientcmdapi.Cluster{
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Server: url,
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CertificateAuthorityData: caBundle,
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}
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config.Contexts["anonymous"] = &clientcmdapi.Context{
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Cluster: "anonymous-cluster",
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}
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config.CurrentContext = "anonymous"
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data, err := clientcmd.Write(*config)
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if err != nil {
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return fmt.Errorf("marshal config: %w", err)
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}
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if _, err := out.Write(data); err != nil {
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return fmt.Errorf("write config: %w", err)
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}
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return nil
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}
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