vendor: revendor metrics-server, custom-metrics-apiserver

vendor/k8s.io/apiserver/pkg/audit/context.go

@@ -0,0 +1,84 @@
+/*
+Copyright 2020 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 audit
+
+import (
+	"context"
+
+	genericapirequest "k8s.io/apiserver/pkg/endpoints/request"
+)
+
+// The key type is unexported to prevent collisions
+type key int
+
+const (
+	// auditAnnotationsKey is the context key for the audit annotations.
+	auditAnnotationsKey key = iota
+)
+
+// annotations = *[]annotation instead of a map to preserve order of insertions
+type annotation struct {
+	key, value string
+}
+
+// WithAuditAnnotations returns a new context that can store audit annotations
+// via the AddAuditAnnotation function.  This function is meant to be called from
+// an early request handler to allow all later layers to set audit annotations.
+// This is required to support flows where handlers that come before WithAudit
+// (such as WithAuthentication) wish to set audit annotations.
+func WithAuditAnnotations(parent context.Context) context.Context {
+	// this should never really happen, but prevent double registration of this slice
+	if _, ok := parent.Value(auditAnnotationsKey).(*[]annotation); ok {
+		return parent
+	}
+
+	var annotations []annotation // avoid allocations until we actually need it
+	return genericapirequest.WithValue(parent, auditAnnotationsKey, &annotations)
+}
+
+// AddAuditAnnotation sets the audit annotation for the given key, value pair.
+// It is safe to call at most parts of request flow that come after WithAuditAnnotations.
+// The notable exception being that this function must not be called via a
+// defer statement (i.e. after ServeHTTP) in a handler that runs before WithAudit
+// as at that point the audit event has already been sent to the audit sink.
+// Handlers that are unaware of their position in the overall request flow should
+// prefer AddAuditAnnotation over LogAnnotation to avoid dropping annotations.
+func AddAuditAnnotation(ctx context.Context, key, value string) {
+	// use the audit event directly if we have it
+	if ae := genericapirequest.AuditEventFrom(ctx); ae != nil {
+		LogAnnotation(ae, key, value)
+		return
+	}
+
+	annotations, ok := ctx.Value(auditAnnotationsKey).(*[]annotation)
+	if !ok {
+		return // adding audit annotation is not supported at this call site
+	}
+
+	*annotations = append(*annotations, annotation{key: key, value: value})
+}
+
+// This is private to prevent reads/write to the slice from outside of this package.
+// The audit event should be directly read to get access to the annotations.
+func auditAnnotationsFrom(ctx context.Context) []annotation {
+	annotations, ok := ctx.Value(auditAnnotationsKey).(*[]annotation)
+	if !ok {
+		return nil // adding audit annotation is not supported at this call site
+	}
+
+	return *annotations
+}