119 lines
3.8 KiB
Go
119 lines
3.8 KiB
Go
/*
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Copyright 2019 The Jetstack cert-manager contributors.
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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 handlers
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"net/http"
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"sort"
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"github.com/go-logr/logr"
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"github.com/mattbaird/jsonpatch"
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admissionv1 "k8s.io/api/admission/v1"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/runtime/serializer"
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apijson "k8s.io/apimachinery/pkg/runtime/serializer/json"
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logf "github.com/jetstack/cert-manager/pkg/logs"
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)
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type SchemeBackedDefaulter struct {
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log logr.Logger
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scheme *runtime.Scheme
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codec runtime.Codec
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}
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func NewSchemeBackedDefaulter(log logr.Logger, scheme *runtime.Scheme) *SchemeBackedDefaulter {
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factory := serializer.NewCodecFactory(scheme)
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serializer := apijson.NewSerializerWithOptions(apijson.DefaultMetaFactory, scheme, scheme, apijson.SerializerOptions{})
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encoder := factory.WithoutConversion().EncoderForVersion(serializer, nil)
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decoder := factory.UniversalDeserializer()
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return &SchemeBackedDefaulter{
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log: log,
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scheme: scheme,
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codec: runtime.NewCodec(encoder, decoder),
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}
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}
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func (c *SchemeBackedDefaulter) Mutate(admissionSpec *admissionv1.AdmissionRequest) *admissionv1.AdmissionResponse {
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status := &admissionv1.AdmissionResponse{}
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status.UID = admissionSpec.UID
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// decode the raw object data
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obj, _, err := c.codec.Decode(admissionSpec.Object.Raw, nil, nil)
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if err != nil {
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status.Result = &metav1.Status{
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Status: metav1.StatusFailure, Code: http.StatusInternalServerError, Reason: metav1.StatusReasonInternalError,
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Message: fmt.Sprintf("Failed to decode object: %v", err.Error()),
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}
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return status
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}
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// create a copy of the resource
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defaultedObj := obj.DeepCopyObject()
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// apply defaults to the object
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c.scheme.Default(defaultedObj)
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// encode the default object to JSON
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buf := bytes.Buffer{}
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if err := c.codec.Encode(defaultedObj, &buf); err != nil {
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status.Result = &metav1.Status{
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Status: metav1.StatusFailure, Code: http.StatusInternalServerError, Reason: metav1.StatusReasonInternalError,
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Message: fmt.Sprintf("Failed to encode defaulted data: %v", err.Error()),
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}
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return status
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}
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// create a merge patch between the old and the new json data
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ops, err := jsonpatch.CreatePatch(admissionSpec.Object.Raw, buf.Bytes())
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if err != nil {
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status.Result = &metav1.Status{
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Status: metav1.StatusFailure, Code: http.StatusInternalServerError, Reason: metav1.StatusReasonInternalError,
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Message: fmt.Sprintf("Failed to generate json patch: %v", err.Error()),
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}
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return status
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}
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// sort options by path to ensure the output of CreatePatch is deterministic
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sortOps(ops)
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patch, err := json.Marshal(ops)
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if err != nil {
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status.Result = &metav1.Status{
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Status: metav1.StatusFailure, Code: http.StatusInternalServerError, Reason: metav1.StatusReasonInternalError,
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Message: fmt.Sprintf("Failed to generate json patch: %v", err.Error()),
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}
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return status
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}
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// set the AdmissionReview status
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jsonPatchType := admissionv1.PatchTypeJSONPatch
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status.Patch = patch
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status.PatchType = &jsonPatchType
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status.Allowed = true
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c.log.V(logf.DebugLevel).Info("generated patch", "patch", string(patch))
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return status
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}
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func sortOps(ops []jsonpatch.JsonPatchOperation) {
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sort.Slice(ops, func(i, j int) bool {
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return ops[i].Path < ops[j].Path
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})
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}
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