/
regexpfilterset.go
96 lines (82 loc) · 2.67 KB
/
regexpfilterset.go
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// Copyright The OpenTelemetry 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 regexp // import "github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal/processor/filterset/regexp"
import (
"regexp"
"github.com/golang/groupcache/lru"
)
// FilterSet encapsulates a set of filters and caches match results.
// Filters are re2 regex strings.
// FilterSet is exported for convenience, but has unexported fields and should be constructed through NewFilterSet.
//
// FilterSet satisfies the FilterSet interface from
// "go.opentelemetry.io/collector/internal/processor/filterset"
type FilterSet struct {
regexes []*regexp.Regexp
cacheEnabled bool
cache *lru.Cache
}
// NewFilterSet constructs a FilterSet of re2 regex strings.
// If any of the given filters fail to compile into re2, an error is returned.
func NewFilterSet(filters []string, cfg *Config) (*FilterSet, error) {
fs := &FilterSet{
regexes: make([]*regexp.Regexp, 0, len(filters)),
}
if cfg != nil && cfg.CacheEnabled {
fs.cacheEnabled = true
fs.cache = lru.New(cfg.CacheMaxNumEntries)
}
if err := fs.addFilters(filters); err != nil {
return nil, err
}
return fs, nil
}
// Matches returns true if the given string matches any of the FilterSet's filters.
// The given string must be fully matched by at least one filter's re2 regex.
func (rfs *FilterSet) Matches(toMatch string) bool {
if rfs.cacheEnabled {
if v, ok := rfs.cache.Get(toMatch); ok {
return v.(bool)
}
}
for _, r := range rfs.regexes {
if r.MatchString(toMatch) {
if rfs.cacheEnabled {
rfs.cache.Add(toMatch, true)
}
return true
}
}
if rfs.cacheEnabled {
rfs.cache.Add(toMatch, false)
}
return false
}
// addFilters compiles all the given filters and stores them as regexes.
// All regexes are automatically anchored to enforce full string matches.
func (rfs *FilterSet) addFilters(filters []string) error {
dedup := make(map[string]struct{}, len(filters))
for _, f := range filters {
if _, ok := dedup[f]; ok {
continue
}
re, err := regexp.Compile(f)
if err != nil {
return err
}
rfs.regexes = append(rfs.regexes, re)
dedup[f] = struct{}{}
}
return nil
}