github.com/datastax/go-cassandra-native-protocol@v0.0.0-20220706104457-5e8aad05cf90/primitive/reasonmap.go (about)

     1  // Copyright 2020 DataStax
     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 primitive
    16  
    17  import (
    18  	"fmt"
    19  	"io"
    20  	"net"
    21  )
    22  
    23  // <reasonmap> is a map of endpoint to failure reason codes, available from Protocol Version 5 onwards.
    24  // The map is encoded starting with an [int] n followed by n pairs of <endpoint><failurecode> where
    25  // <endpoint> is an [inetaddr] and <failurecode> is a [short].
    26  // Note: a reasonmap is inherently a map, but it is not modeled as a map in Go because [inetaddr]
    27  // is not a valid map key type.
    28  
    29  // FailureReason is a map entry for a <reasonmap>; it contains the endpoint that failed and the corresponding failure
    30  // code.
    31  // +k8s:deepcopy-gen=true
    32  type FailureReason struct {
    33  	Endpoint net.IP
    34  	Code     FailureCode
    35  }
    36  
    37  func ReadReasonMap(source io.Reader) ([]*FailureReason, error) {
    38  	if length, err := ReadInt(source); err != nil {
    39  		return nil, fmt.Errorf("cannot read reason map length: %w", err)
    40  	} else {
    41  		reasonMap := make([]*FailureReason, length)
    42  		for i := 0; i < int(length); i++ {
    43  			if addr, err := ReadInetAddr(source); err != nil {
    44  				return nil, fmt.Errorf("cannot read reason map key for element %d: %w", i, err)
    45  			} else if code, err := ReadShort(source); err != nil {
    46  				return nil, fmt.Errorf("cannot read reason map value for element %d: %w", i, err)
    47  			} else if err := CheckValidFailureCode(FailureCode(code)); err != nil {
    48  				return nil, err
    49  			} else {
    50  				reasonMap[i] = &FailureReason{addr, FailureCode(code)}
    51  			}
    52  		}
    53  		return reasonMap, err
    54  	}
    55  }
    56  
    57  func WriteReasonMap(reasonMap []*FailureReason, dest io.Writer) error {
    58  	if err := WriteInt(int32(len(reasonMap)), dest); err != nil {
    59  		return fmt.Errorf("cannot write reason map length: %w", err)
    60  	}
    61  	for i, reason := range reasonMap {
    62  		if err := WriteInetAddr(reason.Endpoint, dest); err != nil {
    63  			return fmt.Errorf("cannot write reason map key for element %d: %w", i, err)
    64  		} else if err := CheckValidFailureCode(reason.Code); err != nil {
    65  			return err
    66  		} else if err = WriteShort(uint16(reason.Code), dest); err != nil {
    67  			return fmt.Errorf("cannot write reason map value for element %d: %w", i, err)
    68  		}
    69  	}
    70  	return nil
    71  }
    72  
    73  func LengthOfReasonMap(reasonMap []*FailureReason) (int, error) {
    74  	length := LengthOfInt
    75  	for i, reason := range reasonMap {
    76  		if inetAddrLength, err := LengthOfInetAddr(reason.Endpoint); err != nil {
    77  			return -1, fmt.Errorf("cannot compute length of reason map key for element %d: %w", i, err)
    78  		} else {
    79  			length += inetAddrLength + LengthOfShort
    80  		}
    81  	}
    82  	return length, nil
    83  }