github.com/google/cloudprober@v0.11.3/validators/integrity/integrity.go (about)

     1  // Copyright 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  // Package integrity provides data integrity validator for the Cloudprober's
    16  // validator framework.
    17  package integrity
    18  
    19  import (
    20  	"fmt"
    21  
    22  	"github.com/google/cloudprober/logger"
    23  	"github.com/google/cloudprober/probes/probeutils"
    24  	configpb "github.com/google/cloudprober/validators/integrity/proto"
    25  )
    26  
    27  // Validator implements an integrity validator.
    28  type Validator struct {
    29  	pattern         []byte
    30  	patternNumBytes int32
    31  
    32  	l *logger.Logger
    33  }
    34  
    35  // Init initializes the integrity validator.
    36  func (v *Validator) Init(config interface{}, l *logger.Logger) error {
    37  	c, ok := config.(*configpb.Validator)
    38  	if !ok {
    39  		return fmt.Errorf("%v is not a valid integrity validator config", config)
    40  	}
    41  
    42  	switch c.GetPattern().(type) {
    43  	case *configpb.Validator_PatternString:
    44  		v.pattern = []byte(c.GetPatternString())
    45  	case *configpb.Validator_PatternNumBytes:
    46  		v.patternNumBytes = c.GetPatternNumBytes()
    47  	}
    48  
    49  	if len(v.pattern) == 0 && v.patternNumBytes == 0 {
    50  		return fmt.Errorf("bad integrity validator config (%v): one of pattern_string and pattern_num_bytes should be set", c)
    51  	}
    52  
    53  	v.l = l
    54  	return nil
    55  }
    56  
    57  // Validate validates the provided responseBody for data integrity errors, for
    58  // example, data corruption.
    59  func (v *Validator) Validate(responseBody []byte) (bool, error) {
    60  	pattern := v.pattern
    61  	if len(pattern) == 0 {
    62  		if len(responseBody) < int(v.patternNumBytes) {
    63  			return false, fmt.Errorf("response (%s) is smaller than the number of pattern bytes (%d)", responseBody, v.patternNumBytes)
    64  		}
    65  		pattern = responseBody[:v.patternNumBytes]
    66  	}
    67  
    68  	err := probeutils.VerifyPayloadPattern(responseBody, pattern)
    69  
    70  	if err != nil {
    71  		v.l.Error(err.Error())
    72  		return false, nil
    73  	}
    74  
    75  	return true, nil
    76  }
    77  
    78  // PatternNumBytesValidator returns a data integrity validator with number of
    79  /// pattern bytes set to patternNumbBytes.
    80  func PatternNumBytesValidator(patternNumbBytes int32, l *logger.Logger) (*Validator, error) {
    81  	v := &Validator{}
    82  
    83  	vConfig := &configpb.Validator{
    84  		Pattern: &configpb.Validator_PatternNumBytes{
    85  			PatternNumBytes: patternNumbBytes,
    86  		},
    87  	}
    88  
    89  	if err := v.Init(vConfig, l); err != nil {
    90  		return nil, fmt.Errorf("error initializing data integrity validator: %v", err)
    91  	}
    92  
    93  	return v, nil
    94  }