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matcher.go
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/
matcher.go
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/*
*
* Copyright 2020 gRPC 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 resolver
import (
"fmt"
"regexp"
"strings"
"google.golang.org/grpc/internal/grpcrand"
"google.golang.org/grpc/internal/grpcutil"
iresolver "google.golang.org/grpc/internal/resolver"
"google.golang.org/grpc/metadata"
xdsclient "google.golang.org/grpc/xds/internal/client"
)
func routeToMatcher(r *xdsclient.Route) (*compositeMatcher, error) {
var pathMatcher pathMatcherInterface
switch {
case r.Regex != nil:
re, err := regexp.Compile(*r.Regex)
if err != nil {
return nil, fmt.Errorf("failed to compile regex %q", *r.Regex)
}
pathMatcher = newPathRegexMatcher(re)
case r.Path != nil:
pathMatcher = newPathExactMatcher(*r.Path, r.CaseInsensitive)
case r.Prefix != nil:
pathMatcher = newPathPrefixMatcher(*r.Prefix, r.CaseInsensitive)
default:
return nil, fmt.Errorf("illegal route: missing path_matcher")
}
var headerMatchers []headerMatcherInterface
for _, h := range r.Headers {
var matcherT headerMatcherInterface
switch {
case h.ExactMatch != nil && *h.ExactMatch != "":
matcherT = newHeaderExactMatcher(h.Name, *h.ExactMatch)
case h.RegexMatch != nil && *h.RegexMatch != "":
re, err := regexp.Compile(*h.RegexMatch)
if err != nil {
return nil, fmt.Errorf("failed to compile regex %q, skipping this matcher", *h.RegexMatch)
}
matcherT = newHeaderRegexMatcher(h.Name, re)
case h.PrefixMatch != nil && *h.PrefixMatch != "":
matcherT = newHeaderPrefixMatcher(h.Name, *h.PrefixMatch)
case h.SuffixMatch != nil && *h.SuffixMatch != "":
matcherT = newHeaderSuffixMatcher(h.Name, *h.SuffixMatch)
case h.RangeMatch != nil:
matcherT = newHeaderRangeMatcher(h.Name, h.RangeMatch.Start, h.RangeMatch.End)
case h.PresentMatch != nil:
matcherT = newHeaderPresentMatcher(h.Name, *h.PresentMatch)
default:
return nil, fmt.Errorf("illegal route: missing header_match_specifier")
}
if h.InvertMatch != nil && *h.InvertMatch {
matcherT = newInvertMatcher(matcherT)
}
headerMatchers = append(headerMatchers, matcherT)
}
var fractionMatcher *fractionMatcher
if r.Fraction != nil {
fractionMatcher = newFractionMatcher(*r.Fraction)
}
return newCompositeMatcher(pathMatcher, headerMatchers, fractionMatcher), nil
}
// compositeMatcher.match returns true if all matchers return true.
type compositeMatcher struct {
pm pathMatcherInterface
hms []headerMatcherInterface
fm *fractionMatcher
}
func newCompositeMatcher(pm pathMatcherInterface, hms []headerMatcherInterface, fm *fractionMatcher) *compositeMatcher {
return &compositeMatcher{pm: pm, hms: hms, fm: fm}
}
func (a *compositeMatcher) match(info iresolver.RPCInfo) bool {
if a.pm != nil && !a.pm.match(info.Method) {
return false
}
// Call headerMatchers even if md is nil, because routes may match
// non-presence of some headers.
var md metadata.MD
if info.Context != nil {
md, _ = metadata.FromOutgoingContext(info.Context)
if extraMD, ok := grpcutil.ExtraMetadata(info.Context); ok {
md = metadata.Join(md, extraMD)
// Remove all binary headers. They are hard to match with. May need
// to add back if asked by users.
for k := range md {
if strings.HasSuffix(k, "-bin") {
delete(md, k)
}
}
}
}
for _, m := range a.hms {
if !m.match(md) {
return false
}
}
if a.fm != nil && !a.fm.match() {
return false
}
return true
}
func (a *compositeMatcher) String() string {
var ret string
if a.pm != nil {
ret += a.pm.String()
}
for _, m := range a.hms {
ret += m.String()
}
if a.fm != nil {
ret += a.fm.String()
}
return ret
}
type fractionMatcher struct {
fraction int64 // real fraction is fraction/1,000,000.
}
func newFractionMatcher(fraction uint32) *fractionMatcher {
return &fractionMatcher{fraction: int64(fraction)}
}
var grpcrandInt63n = grpcrand.Int63n
func (fm *fractionMatcher) match() bool {
t := grpcrandInt63n(1000000)
return t <= fm.fraction
}
func (fm *fractionMatcher) String() string {
return fmt.Sprintf("fraction:%v", fm.fraction)
}