mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-18 12:20:24 +00:00
284 lines
11 KiB
Go
284 lines
11 KiB
Go
/*
|
|
Copyright 2022 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 library
|
|
|
|
import (
|
|
"math"
|
|
|
|
"github.com/google/cel-go/checker"
|
|
"github.com/google/cel-go/common"
|
|
"github.com/google/cel-go/common/types"
|
|
"github.com/google/cel-go/common/types/ref"
|
|
"github.com/google/cel-go/common/types/traits"
|
|
exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
|
|
)
|
|
|
|
// CostEstimator implements CEL's interpretable.ActualCostEstimator and checker.CostEstimator.
|
|
type CostEstimator struct {
|
|
// SizeEstimator provides a CostEstimator.EstimateSize that this CostEstimator will delegate size estimation
|
|
// calculations to if the size is not well known (i.e. a constant).
|
|
SizeEstimator checker.CostEstimator
|
|
}
|
|
|
|
func (l *CostEstimator) CallCost(function, overloadId string, args []ref.Val, result ref.Val) *uint64 {
|
|
switch function {
|
|
case "check":
|
|
// An authorization check has a fixed cost
|
|
// This cost is set to allow for only two authorization checks per expression
|
|
cost := uint64(350000)
|
|
return &cost
|
|
case "serviceAccount", "path", "group", "resource", "subresource", "namespace", "name", "allowed", "denied", "reason":
|
|
// All authorization builder and accessor functions have a nominal cost
|
|
cost := uint64(1)
|
|
return &cost
|
|
case "isSorted", "sum", "max", "min", "indexOf", "lastIndexOf":
|
|
var cost uint64
|
|
if len(args) > 0 {
|
|
cost += traversalCost(args[0]) // these O(n) operations all cost roughly the cost of a single traversal
|
|
}
|
|
return &cost
|
|
case "url", "lowerAscii", "upperAscii", "substring", "trim":
|
|
if len(args) >= 1 {
|
|
cost := uint64(math.Ceil(float64(actualSize(args[0])) * common.StringTraversalCostFactor))
|
|
return &cost
|
|
}
|
|
case "replace", "split":
|
|
if len(args) >= 1 {
|
|
// cost is the traversal plus the construction of the result
|
|
cost := uint64(math.Ceil(float64(actualSize(args[0])) * 2 * common.StringTraversalCostFactor))
|
|
return &cost
|
|
}
|
|
case "join":
|
|
if len(args) >= 1 {
|
|
cost := uint64(math.Ceil(float64(actualSize(result)) * 2 * common.StringTraversalCostFactor))
|
|
return &cost
|
|
}
|
|
case "find", "findAll":
|
|
if len(args) >= 2 {
|
|
strCost := uint64(math.Ceil((1.0 + float64(actualSize(args[0]))) * common.StringTraversalCostFactor))
|
|
// We don't know how many expressions are in the regex, just the string length (a huge
|
|
// improvement here would be to somehow get a count the number of expressions in the regex or
|
|
// how many states are in the regex state machine and use that to measure regex cost).
|
|
// For now, we're making a guess that each expression in a regex is typically at least 4 chars
|
|
// in length.
|
|
regexCost := uint64(math.Ceil(float64(actualSize(args[1])) * common.RegexStringLengthCostFactor))
|
|
cost := strCost * regexCost
|
|
return &cost
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (l *CostEstimator) EstimateCallCost(function, overloadId string, target *checker.AstNode, args []checker.AstNode) *checker.CallEstimate {
|
|
// WARNING: Any changes to this code impact API compatibility! The estimated cost is used to determine which CEL rules may be written to a
|
|
// CRD and any change (cost increases and cost decreases) are breaking.
|
|
switch function {
|
|
case "check":
|
|
// An authorization check has a fixed cost
|
|
// This cost is set to allow for only two authorization checks per expression
|
|
return &checker.CallEstimate{CostEstimate: checker.CostEstimate{Min: 350000, Max: 350000}}
|
|
case "serviceAccount", "path", "group", "resource", "subresource", "namespace", "name", "allowed", "denied", "reason":
|
|
// All authorization builder and accessor functions have a nominal cost
|
|
return &checker.CallEstimate{CostEstimate: checker.CostEstimate{Min: 1, Max: 1}}
|
|
case "isSorted", "sum", "max", "min", "indexOf", "lastIndexOf":
|
|
if target != nil {
|
|
// Charge 1 cost for comparing each element in the list
|
|
elCost := checker.CostEstimate{Min: 1, Max: 1}
|
|
// If the list contains strings or bytes, add the cost of traversing all the strings/bytes as a way
|
|
// of estimating the additional comparison cost.
|
|
if elNode := l.listElementNode(*target); elNode != nil {
|
|
t := elNode.Type().GetPrimitive()
|
|
if t == exprpb.Type_STRING || t == exprpb.Type_BYTES {
|
|
sz := l.sizeEstimate(elNode)
|
|
elCost = elCost.Add(sz.MultiplyByCostFactor(common.StringTraversalCostFactor))
|
|
}
|
|
return &checker.CallEstimate{CostEstimate: l.sizeEstimate(*target).MultiplyByCost(elCost)}
|
|
} else { // the target is a string, which is supported by indexOf and lastIndexOf
|
|
return &checker.CallEstimate{CostEstimate: l.sizeEstimate(*target).MultiplyByCostFactor(common.StringTraversalCostFactor)}
|
|
}
|
|
}
|
|
case "url":
|
|
if len(args) == 1 {
|
|
sz := l.sizeEstimate(args[0])
|
|
return &checker.CallEstimate{CostEstimate: sz.MultiplyByCostFactor(common.StringTraversalCostFactor)}
|
|
}
|
|
case "lowerAscii", "upperAscii", "substring", "trim":
|
|
if target != nil {
|
|
sz := l.sizeEstimate(*target)
|
|
return &checker.CallEstimate{CostEstimate: sz.MultiplyByCostFactor(common.StringTraversalCostFactor), ResultSize: &sz}
|
|
}
|
|
case "replace":
|
|
if target != nil && len(args) >= 2 {
|
|
sz := l.sizeEstimate(*target)
|
|
toReplaceSz := l.sizeEstimate(args[0])
|
|
replaceWithSz := l.sizeEstimate(args[1])
|
|
// smallest possible result: smallest input size composed of the largest possible substrings being replaced by smallest possible replacement
|
|
minSz := uint64(math.Ceil(float64(sz.Min)/float64(toReplaceSz.Max))) * replaceWithSz.Min
|
|
// largest possible result: largest input size composed of the smallest possible substrings being replaced by largest possible replacement
|
|
maxSz := uint64(math.Ceil(float64(sz.Max)/float64(toReplaceSz.Min))) * replaceWithSz.Max
|
|
|
|
// cost is the traversal plus the construction of the result
|
|
return &checker.CallEstimate{CostEstimate: sz.MultiplyByCostFactor(2 * common.StringTraversalCostFactor), ResultSize: &checker.SizeEstimate{Min: minSz, Max: maxSz}}
|
|
}
|
|
case "split":
|
|
if target != nil {
|
|
sz := l.sizeEstimate(*target)
|
|
|
|
// Worst case size is where is that a separator of "" is used, and each char is returned as a list element.
|
|
max := sz.Max
|
|
if len(args) > 1 {
|
|
if c := args[1].Expr().GetConstExpr(); c != nil {
|
|
max = uint64(c.GetInt64Value())
|
|
}
|
|
}
|
|
// Cost is the traversal plus the construction of the result.
|
|
return &checker.CallEstimate{CostEstimate: sz.MultiplyByCostFactor(2 * common.StringTraversalCostFactor), ResultSize: &checker.SizeEstimate{Min: 0, Max: max}}
|
|
}
|
|
case "join":
|
|
if target != nil {
|
|
var sz checker.SizeEstimate
|
|
listSize := l.sizeEstimate(*target)
|
|
if elNode := l.listElementNode(*target); elNode != nil {
|
|
elemSize := l.sizeEstimate(elNode)
|
|
sz = listSize.Multiply(elemSize)
|
|
}
|
|
|
|
if len(args) > 0 {
|
|
sepSize := l.sizeEstimate(args[0])
|
|
minSeparators := uint64(0)
|
|
maxSeparators := uint64(0)
|
|
if listSize.Min > 0 {
|
|
minSeparators = listSize.Min - 1
|
|
}
|
|
if listSize.Max > 0 {
|
|
maxSeparators = listSize.Max - 1
|
|
}
|
|
sz = sz.Add(sepSize.Multiply(checker.SizeEstimate{Min: minSeparators, Max: maxSeparators}))
|
|
}
|
|
|
|
return &checker.CallEstimate{CostEstimate: sz.MultiplyByCostFactor(common.StringTraversalCostFactor), ResultSize: &sz}
|
|
}
|
|
case "find", "findAll":
|
|
if target != nil && len(args) >= 1 {
|
|
sz := l.sizeEstimate(*target)
|
|
// Add one to string length for purposes of cost calculation to prevent product of string and regex to be 0
|
|
// in case where string is empty but regex is still expensive.
|
|
strCost := sz.Add(checker.SizeEstimate{Min: 1, Max: 1}).MultiplyByCostFactor(common.StringTraversalCostFactor)
|
|
// We don't know how many expressions are in the regex, just the string length (a huge
|
|
// improvement here would be to somehow get a count the number of expressions in the regex or
|
|
// how many states are in the regex state machine and use that to measure regex cost).
|
|
// For now, we're making a guess that each expression in a regex is typically at least 4 chars
|
|
// in length.
|
|
regexCost := l.sizeEstimate(args[0]).MultiplyByCostFactor(common.RegexStringLengthCostFactor)
|
|
// worst case size of result is that every char is returned as separate find result.
|
|
return &checker.CallEstimate{CostEstimate: strCost.Multiply(regexCost), ResultSize: &checker.SizeEstimate{Min: 0, Max: sz.Max}}
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func actualSize(value ref.Val) uint64 {
|
|
if sz, ok := value.(traits.Sizer); ok {
|
|
return uint64(sz.Size().(types.Int))
|
|
}
|
|
return 1
|
|
}
|
|
|
|
func (l *CostEstimator) sizeEstimate(t checker.AstNode) checker.SizeEstimate {
|
|
if sz := t.ComputedSize(); sz != nil {
|
|
return *sz
|
|
}
|
|
if sz := l.EstimateSize(t); sz != nil {
|
|
return *sz
|
|
}
|
|
return checker.SizeEstimate{Min: 0, Max: math.MaxUint64}
|
|
}
|
|
|
|
func (l *CostEstimator) listElementNode(list checker.AstNode) checker.AstNode {
|
|
if lt := list.Type().GetListType(); lt != nil {
|
|
nodePath := list.Path()
|
|
if nodePath != nil {
|
|
// Provide path if we have it so that a OpenAPIv3 maxLength validation can be looked up, if it exists
|
|
// for this node.
|
|
path := make([]string, len(nodePath)+1)
|
|
copy(path, nodePath)
|
|
path[len(nodePath)] = "@items"
|
|
return &itemsNode{path: path, t: lt.GetElemType(), expr: nil}
|
|
} else {
|
|
// Provide just the type if no path is available so that worst case size can be looked up based on type.
|
|
return &itemsNode{t: lt.GetElemType(), expr: nil}
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (l *CostEstimator) EstimateSize(element checker.AstNode) *checker.SizeEstimate {
|
|
if l.SizeEstimator != nil {
|
|
return l.SizeEstimator.EstimateSize(element)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
type itemsNode struct {
|
|
path []string
|
|
t *exprpb.Type
|
|
expr *exprpb.Expr
|
|
}
|
|
|
|
func (i *itemsNode) Path() []string {
|
|
return i.path
|
|
}
|
|
|
|
func (i *itemsNode) Type() *exprpb.Type {
|
|
return i.t
|
|
}
|
|
|
|
func (i *itemsNode) Expr() *exprpb.Expr {
|
|
return i.expr
|
|
}
|
|
|
|
func (i *itemsNode) ComputedSize() *checker.SizeEstimate {
|
|
return nil
|
|
}
|
|
|
|
// traversalCost computes the cost of traversing a ref.Val as a data tree.
|
|
func traversalCost(v ref.Val) uint64 {
|
|
// TODO: This could potentially be optimized by sampling maps and lists instead of traversing.
|
|
switch vt := v.(type) {
|
|
case types.String:
|
|
return uint64(float64(len(string(vt))) * common.StringTraversalCostFactor)
|
|
case types.Bytes:
|
|
return uint64(float64(len([]byte(vt))) * common.StringTraversalCostFactor)
|
|
case traits.Lister:
|
|
cost := uint64(0)
|
|
for it := vt.Iterator(); it.HasNext() == types.True; {
|
|
i := it.Next()
|
|
cost += traversalCost(i)
|
|
}
|
|
return cost
|
|
case traits.Mapper: // maps and objects
|
|
cost := uint64(0)
|
|
for it := vt.Iterator(); it.HasNext() == types.True; {
|
|
k := it.Next()
|
|
cost += traversalCost(k) + traversalCost(vt.Get(k))
|
|
}
|
|
return cost
|
|
default:
|
|
return 1
|
|
}
|
|
}
|