sigs.k8s.io/cluster-api@v1.6.3/internal/util/hash/hash.go (about)

     1  /*
     2  Copyright 2023 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  // Package hash provides utils to calculate hashes.
    18  package hash
    19  
    20  import (
    21  	"fmt"
    22  	"hash/fnv"
    23  
    24  	"github.com/davecgh/go-spew/spew"
    25  )
    26  
    27  // Compute computes the hash of an object using the spew library.
    28  // Note: spew follows pointers and prints actual values of the nested objects
    29  // ensuring the hash does not change when a pointer changes.
    30  func Compute(obj interface{}) (uint32, error) {
    31  	hasher := fnv.New32a()
    32  
    33  	printer := spew.ConfigState{
    34  		Indent:         " ",
    35  		SortKeys:       true,
    36  		DisableMethods: true,
    37  		SpewKeys:       true,
    38  	}
    39  
    40  	if _, err := printer.Fprintf(hasher, "%#v", obj); err != nil {
    41  		return 0, fmt.Errorf("failed to calculate hash")
    42  	}
    43  
    44  	return hasher.Sum32(), nil
    45  }