github.com/google/cloudprober@v0.11.3/rds/server/filter/filter.go (about)

     1  // Copyright 2017-2018 The Cloudprober Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  /*
    16  Package filter implements common filters for the RDS (resource discovery
    17  service) providers.
    18  */
    19  package filter
    20  
    21  import (
    22  	"regexp"
    23  	"time"
    24  
    25  	"github.com/google/cloudprober/logger"
    26  )
    27  
    28  // RegexFilter implements a regex based filter.
    29  type RegexFilter struct {
    30  	re *regexp.Regexp
    31  }
    32  
    33  // NewRegexFilter returns a new regex filter.
    34  func NewRegexFilter(regexStr string) (*RegexFilter, error) {
    35  	re, err := regexp.Compile(regexStr)
    36  	if err != nil {
    37  		return nil, err
    38  	}
    39  
    40  	return &RegexFilter{re}, nil
    41  }
    42  
    43  // Match returns true if provided string matches the regex of the filter.
    44  // Otherwise, false is returned.
    45  func (rf *RegexFilter) Match(name string, l *logger.Logger) bool {
    46  	return rf.re.MatchString(name)
    47  }
    48  
    49  // LabelsFilter implements a filter on resource's labels.
    50  type LabelsFilter struct {
    51  	labels map[string]*regexp.Regexp
    52  }
    53  
    54  // NewLabelsFilter builds LabelsFilter from a key:regexp map.
    55  func NewLabelsFilter(labelsFilter map[string]string) (*LabelsFilter, error) {
    56  	labels := make(map[string]*regexp.Regexp)
    57  
    58  	for key, regexStr := range labelsFilter {
    59  		re, err := regexp.Compile(regexStr)
    60  		if err != nil {
    61  			return nil, err
    62  		}
    63  		labels[key] = re
    64  	}
    65  
    66  	return &LabelsFilter{labels: labels}, nil
    67  }
    68  
    69  // Match returns true if provided string matches the regex of the filter.
    70  // Otherwise, false is returned.
    71  func (lf *LabelsFilter) Match(inputLabels map[string]string, l *logger.Logger) bool {
    72  	for k, re := range lf.labels {
    73  		// If input labels don't have the requisite key or key's value doesn't match
    74  		// the given regex, return false.
    75  		if v, ok := inputLabels[k]; !ok || !re.MatchString(v) {
    76  			return false
    77  		}
    78  	}
    79  	return true
    80  }
    81  
    82  // FreshnessFilter implements a filter that succeeds only if the given time
    83  // is within a pre-defined duration.
    84  type FreshnessFilter struct {
    85  	d time.Duration
    86  }
    87  
    88  // NewFreshnessFilter returns a new freshness filter.
    89  func NewFreshnessFilter(dStr string) (*FreshnessFilter, error) {
    90  	d, err := time.ParseDuration(dStr)
    91  	return &FreshnessFilter{d}, err
    92  }
    93  
    94  // Match returns true if the given time is within a pre-defined duration.
    95  func (ff *FreshnessFilter) Match(t time.Time, l *logger.Logger) bool {
    96  	return time.Since(t) < ff.d
    97  }