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requestmatch.go
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requestmatch.go
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/*
* Copyright (c) 2017, MegaEase
* All rights reserved.
*
* 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 proxies
import (
"fmt"
"hash/fnv"
"math/rand"
"github.com/megaease/easegress/v2/pkg/logger"
"github.com/megaease/easegress/v2/pkg/protocols"
"github.com/megaease/easegress/v2/pkg/util/stringtool"
)
// RequestMatcher is the interface to match requests.
type RequestMatcher interface {
Match(req protocols.Request) bool
}
// RequestMatcherBaseSpec describe RequestMatcher
type RequestMatcherBaseSpec struct {
Policy string `json:"policy" jsonschema:"omitempty,enum=,enum=general,enum=ipHash,enum=headerHash,enum=random"`
MatchAllHeaders bool `json:"matchAllHeaders" jsonschema:"omitempty"`
Headers map[string]*stringtool.StringMatcher `json:"headers" jsonschema:"omitempty"`
Permil uint32 `json:"permil" jsonschema:"omitempty,minimum=0,maximum=1000"`
HeaderHashKey string `json:"headerHashKey" jsonschema:"omitempty"`
}
// Validate validates the RequestMatcherBaseSpec.
func (s *RequestMatcherBaseSpec) Validate() error {
if s.Policy == "general" || s.Policy == "" {
if len(s.Headers) == 0 {
return fmt.Errorf("headers is not specified")
}
} else if s.Permil == 0 {
return fmt.Errorf("permil is not specified")
}
for _, v := range s.Headers {
if err := v.Validate(); err != nil {
return err
}
}
if s.Policy == "headerHash" && s.HeaderHashKey == "" {
return fmt.Errorf("headerHash needs to specify headerHashKey")
}
return nil
}
// NewRequestMatcher creates a new traffic matcher according to spec.
func NewRequestMatcher(spec *RequestMatcherBaseSpec) RequestMatcher {
switch spec.Policy {
case "ipHash":
return &ipHashMatcher{permill: spec.Permil}
case "headerHash":
return &headerHashMatcher{
permill: spec.Permil,
headerHashKey: spec.HeaderHashKey,
}
case "random":
return &randomMatcher{permill: spec.Permil}
}
logger.Errorf("BUG: unsupported probability policy: %s", spec.Policy)
return &ipHashMatcher{permill: spec.Permil}
}
// randomMatcher implements random request matcher.
type randomMatcher struct {
permill uint32
}
// Match implements protocols.Matcher.
func (rm randomMatcher) Match(req protocols.Request) bool {
return rand.Uint32()%1000 < rm.permill
}
// headerHashMatcher implements header hash request matcher.
type headerHashMatcher struct {
permill uint32
headerHashKey string
}
// Match implements protocols.Matcher.
func (hhm headerHashMatcher) Match(req protocols.Request) bool {
v := req.Header().Get(hhm.headerHashKey).(string)
hash := fnv.New32()
hash.Write([]byte(v))
return hash.Sum32()%1000 < hhm.permill
}
// ipHashMatcher implements IP address hash matcher.
type ipHashMatcher struct {
permill uint32
}
// Match implements protocols.Matcher.
func (iphm ipHashMatcher) Match(req protocols.Request) bool {
ip := req.RealIP()
hash := fnv.New32()
hash.Write([]byte(ip))
return hash.Sum32()%1000 < iphm.permill
}