|
| 1 | +/* |
| 2 | +Copyright 2024 The Kubernetes Authors. |
| 3 | +
|
| 4 | +Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | +you may not use this file except in compliance with the License. |
| 6 | +You may obtain a copy of the License at |
| 7 | +
|
| 8 | + http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | +
|
| 10 | +Unless required by applicable law or agreed to in writing, software |
| 11 | +distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | +See the License for the specific language governing permissions and |
| 14 | +limitations under the License. |
| 15 | +*/ |
| 16 | + |
| 17 | +package webhook |
| 18 | + |
| 19 | +import ( |
| 20 | + "errors" |
| 21 | + "net/http" |
| 22 | + "net/url" |
| 23 | + "strings" |
| 24 | + |
| 25 | + "github.com/go-logr/logr" |
| 26 | + "k8s.io/apimachinery/pkg/runtime" |
| 27 | + "k8s.io/apimachinery/pkg/runtime/schema" |
| 28 | + "k8s.io/client-go/rest" |
| 29 | + "k8s.io/klog/v2" |
| 30 | + |
| 31 | + "sigs.k8s.io/controller-runtime/pkg/client/apiutil" |
| 32 | + "sigs.k8s.io/controller-runtime/pkg/manager" |
| 33 | + "sigs.k8s.io/controller-runtime/pkg/webhook/admission" |
| 34 | + "sigs.k8s.io/controller-runtime/pkg/webhook/conversion" |
| 35 | +) |
| 36 | + |
| 37 | +// This code is copied from https://github.com/kubernetes-sigs/controller-runtime/blob/896f6ded750155f9ecfdf4d8e10a26fc3fb78384/pkg/builder/webhook.go |
| 38 | +// with one modification to get full control of the construction of patches: |
| 39 | +// replacing CustomDefaulter with an admission.Handler. |
| 40 | +// TODO(#3137): remove this file |
| 41 | + |
| 42 | +// WebhookBuilder builds a Webhook. |
| 43 | +type WebhookBuilder struct { |
| 44 | + apiType runtime.Object |
| 45 | + mutationHandler admission.Handler |
| 46 | + customValidator admission.CustomValidator |
| 47 | + gvk schema.GroupVersionKind |
| 48 | + mgr manager.Manager |
| 49 | + config *rest.Config |
| 50 | + recoverPanic *bool |
| 51 | + logConstructor func(base logr.Logger, req *admission.Request) logr.Logger |
| 52 | + err error |
| 53 | +} |
| 54 | + |
| 55 | +// WebhookManagedBy returns a new webhook builder. |
| 56 | +func WebhookManagedBy(m manager.Manager) *WebhookBuilder { |
| 57 | + return &WebhookBuilder{mgr: m} |
| 58 | +} |
| 59 | + |
| 60 | +// TODO(droot): update the GoDoc for conversion. |
| 61 | + |
| 62 | +// For takes a runtime.Object which should be a CR. |
| 63 | +// If the given object implements the admission.Defaulter interface, a MutatingWebhook will be wired for this type. |
| 64 | +// If the given object implements the admission.Validator interface, a ValidatingWebhook will be wired for this type. |
| 65 | +func (blder *WebhookBuilder) For(apiType runtime.Object) *WebhookBuilder { |
| 66 | + if blder.apiType != nil { |
| 67 | + blder.err = errors.New("For(...) should only be called once, could not assign multiple objects for webhook registration") |
| 68 | + } |
| 69 | + blder.apiType = apiType |
| 70 | + return blder |
| 71 | +} |
| 72 | + |
| 73 | +// WithDefaulter takes an admission.CustomDefaulter interface, a MutatingWebhook will be wired for this type. |
| 74 | +func (blder *WebhookBuilder) WithMutationHandler(h admission.Handler) *WebhookBuilder { |
| 75 | + blder.mutationHandler = h |
| 76 | + return blder |
| 77 | +} |
| 78 | + |
| 79 | +// WithValidator takes a admission.CustomValidator interface, a ValidatingWebhook will be wired for this type. |
| 80 | +func (blder *WebhookBuilder) WithValidator(validator admission.CustomValidator) *WebhookBuilder { |
| 81 | + blder.customValidator = validator |
| 82 | + return blder |
| 83 | +} |
| 84 | + |
| 85 | +// WithLogConstructor overrides the webhook's LogConstructor. |
| 86 | +func (blder *WebhookBuilder) WithLogConstructor(logConstructor func(base logr.Logger, req *admission.Request) logr.Logger) *WebhookBuilder { |
| 87 | + blder.logConstructor = logConstructor |
| 88 | + return blder |
| 89 | +} |
| 90 | + |
| 91 | +// RecoverPanic indicates whether panics caused by the webhook should be recovered. |
| 92 | +// Defaults to true. |
| 93 | +func (blder *WebhookBuilder) RecoverPanic(recoverPanic bool) *WebhookBuilder { |
| 94 | + blder.recoverPanic = &recoverPanic |
| 95 | + return blder |
| 96 | +} |
| 97 | + |
| 98 | +// Complete builds the webhook. |
| 99 | +func (blder *WebhookBuilder) Complete() error { |
| 100 | + // Set the Config |
| 101 | + blder.loadRestConfig() |
| 102 | + |
| 103 | + // Configure the default LogConstructor |
| 104 | + blder.setLogConstructor() |
| 105 | + |
| 106 | + // Set the Webhook if needed |
| 107 | + return blder.registerWebhooks() |
| 108 | +} |
| 109 | + |
| 110 | +func (blder *WebhookBuilder) loadRestConfig() { |
| 111 | + if blder.config == nil { |
| 112 | + blder.config = blder.mgr.GetConfig() |
| 113 | + } |
| 114 | +} |
| 115 | + |
| 116 | +func (blder *WebhookBuilder) setLogConstructor() { |
| 117 | + if blder.logConstructor == nil { |
| 118 | + blder.logConstructor = func(base logr.Logger, req *admission.Request) logr.Logger { |
| 119 | + log := base.WithValues( |
| 120 | + "webhookGroup", blder.gvk.Group, |
| 121 | + "webhookKind", blder.gvk.Kind, |
| 122 | + ) |
| 123 | + if req != nil { |
| 124 | + return log.WithValues( |
| 125 | + blder.gvk.Kind, klog.KRef(req.Namespace, req.Name), |
| 126 | + "namespace", req.Namespace, "name", req.Name, |
| 127 | + "resource", req.Resource, "user", req.UserInfo.Username, |
| 128 | + "requestID", req.UID, |
| 129 | + ) |
| 130 | + } |
| 131 | + return log |
| 132 | + } |
| 133 | + } |
| 134 | +} |
| 135 | + |
| 136 | +func (blder *WebhookBuilder) registerWebhooks() error { |
| 137 | + typ, err := blder.getType() |
| 138 | + if err != nil { |
| 139 | + return err |
| 140 | + } |
| 141 | + |
| 142 | + blder.gvk, err = apiutil.GVKForObject(typ, blder.mgr.GetScheme()) |
| 143 | + if err != nil { |
| 144 | + return err |
| 145 | + } |
| 146 | + |
| 147 | + // Register webhook(s) for type |
| 148 | + blder.registerDefaultingWebhook() |
| 149 | + blder.registerValidatingWebhook() |
| 150 | + |
| 151 | + err = blder.registerConversionWebhook() |
| 152 | + if err != nil { |
| 153 | + return err |
| 154 | + } |
| 155 | + return blder.err |
| 156 | +} |
| 157 | + |
| 158 | +// registerDefaultingWebhook registers a defaulting webhook if necessary. |
| 159 | +func (blder *WebhookBuilder) registerDefaultingWebhook() { |
| 160 | + mwh := blder.getDefaultingWebhook() |
| 161 | + if mwh != nil { |
| 162 | + mwh.LogConstructor = blder.logConstructor |
| 163 | + path := generateMutatePath(blder.gvk) |
| 164 | + |
| 165 | + // Checking if the path is already registered. |
| 166 | + // If so, just skip it. |
| 167 | + if !blder.isAlreadyHandled(path) { |
| 168 | + log := blder.mgr.GetLogger() |
| 169 | + log.Info("Registering a mutating webhook", |
| 170 | + "GVK", blder.gvk, |
| 171 | + "path", path) |
| 172 | + blder.mgr.GetWebhookServer().Register(path, mwh) |
| 173 | + } |
| 174 | + } |
| 175 | +} |
| 176 | + |
| 177 | +func (blder *WebhookBuilder) getDefaultingWebhook() *admission.Webhook { |
| 178 | + if handler := blder.mutationHandler; handler != nil { |
| 179 | + w := &admission.Webhook{ |
| 180 | + Handler: handler, |
| 181 | + } |
| 182 | + if blder.recoverPanic != nil { |
| 183 | + w = w.WithRecoverPanic(*blder.recoverPanic) |
| 184 | + } |
| 185 | + return w |
| 186 | + } |
| 187 | + return nil |
| 188 | +} |
| 189 | + |
| 190 | +// registerValidatingWebhook registers a validating webhook if necessary. |
| 191 | +func (blder *WebhookBuilder) registerValidatingWebhook() { |
| 192 | + vwh := blder.getValidatingWebhook() |
| 193 | + if vwh != nil { |
| 194 | + vwh.LogConstructor = blder.logConstructor |
| 195 | + path := generateValidatePath(blder.gvk) |
| 196 | + |
| 197 | + // Checking if the path is already registered. |
| 198 | + // If so, just skip it. |
| 199 | + if !blder.isAlreadyHandled(path) { |
| 200 | + log := blder.mgr.GetLogger() |
| 201 | + log.Info("Registering a validating webhook", |
| 202 | + "GVK", blder.gvk, |
| 203 | + "path", path) |
| 204 | + blder.mgr.GetWebhookServer().Register(path, vwh) |
| 205 | + } |
| 206 | + } |
| 207 | +} |
| 208 | + |
| 209 | +func (blder *WebhookBuilder) getValidatingWebhook() *admission.Webhook { |
| 210 | + if validator := blder.customValidator; validator != nil { |
| 211 | + w := admission.WithCustomValidator(blder.mgr.GetScheme(), blder.apiType, validator) |
| 212 | + if blder.recoverPanic != nil { |
| 213 | + w = w.WithRecoverPanic(*blder.recoverPanic) |
| 214 | + } |
| 215 | + return w |
| 216 | + } |
| 217 | + return nil |
| 218 | +} |
| 219 | + |
| 220 | +func (blder *WebhookBuilder) registerConversionWebhook() error { |
| 221 | + log := blder.mgr.GetLogger() |
| 222 | + ok, err := conversion.IsConvertible(blder.mgr.GetScheme(), blder.apiType) |
| 223 | + if err != nil { |
| 224 | + log.Error(err, "conversion check failed", "GVK", blder.gvk) |
| 225 | + return err |
| 226 | + } |
| 227 | + if ok { |
| 228 | + if !blder.isAlreadyHandled("/convert") { |
| 229 | + blder.mgr.GetWebhookServer().Register("/convert", conversion.NewWebhookHandler(blder.mgr.GetScheme())) |
| 230 | + } |
| 231 | + log.Info("Conversion webhook enabled", "GVK", blder.gvk) |
| 232 | + } |
| 233 | + |
| 234 | + return nil |
| 235 | +} |
| 236 | + |
| 237 | +func (blder *WebhookBuilder) getType() (runtime.Object, error) { |
| 238 | + if blder.apiType != nil { |
| 239 | + return blder.apiType, nil |
| 240 | + } |
| 241 | + return nil, errors.New("For() must be called with a valid object") |
| 242 | +} |
| 243 | + |
| 244 | +func (blder *WebhookBuilder) isAlreadyHandled(path string) bool { |
| 245 | + if blder.mgr.GetWebhookServer().WebhookMux() == nil { |
| 246 | + return false |
| 247 | + } |
| 248 | + h, p := blder.mgr.GetWebhookServer().WebhookMux().Handler(&http.Request{URL: &url.URL{Path: path}}) |
| 249 | + if p == path && h != nil { |
| 250 | + return true |
| 251 | + } |
| 252 | + return false |
| 253 | +} |
| 254 | + |
| 255 | +func generateMutatePath(gvk schema.GroupVersionKind) string { |
| 256 | + return "/mutate-" + strings.ReplaceAll(gvk.Group, ".", "-") + "-" + |
| 257 | + gvk.Version + "-" + strings.ToLower(gvk.Kind) |
| 258 | +} |
| 259 | + |
| 260 | +func generateValidatePath(gvk schema.GroupVersionKind) string { |
| 261 | + return "/validate-" + strings.ReplaceAll(gvk.Group, ".", "-") + "-" + |
| 262 | + gvk.Version + "-" + strings.ToLower(gvk.Kind) |
| 263 | +} |
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