Go: Calculating the MD5 hash of a struct

In some scenarios, calculating the hash of a piece of data is useful, for instance when you only need to know that something in the dataset has changed, no matter what.

Calculating a hash is moderately computing consuming but has some advantadges:

Avoids checking the changes field by field of the dataset
Allows storing only the data hash instead of the whole dataset

In Golang, calculating MD5 hashes of structs can be achieved by using a code piece as this:

import (
  "bytes"
  "crypto/md5"
  "encoding/gob"
  "encoding/hex"
  "fmt"
)

// Random struct, just for demo purposes
type MySubStruct struct {
  Zaz *bool
}
type MyStruct struct {
  Foo int
  Bar []string
  Baz MySubStruct
}

func main() {
  // Hasheable struct
  myBool := false
  myStruct := MyStruct{
    Foo: 67372388,
    Bar: []string{"b", "ar", ""},
    Baz: MySubStruct{
      Zaz: &myBool,
    },
  }

  // Create a gob encoder 
  // and a buffer for storing the encoded struct
  var buffer bytes.Buffer
  encoder := gob.NewEncoder(&buffer)
  encoder.Encode(myStruct)

  // Calculate the MD5 hash of the buffered data
  md5Hash := md5.Sum(buffer.Bytes())
    
  // Print the hash as hex string
  hexedMD5Hash := hex.EncodeToString(md5Hash[:])
  fmt.Println(hexedMD5Hash)
}

You can try the above example in the Go playground

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