Convert arbitrary Golang interface to byte array

Another way to convert interface{} to []bytes is to use a fmt package.

/*
* Convert variable `key` from interface{} to []byte
*/

byteKey := []byte(fmt.Sprintf("%v", key.(interface{})))

fmt.Sprintf converts interface value to string.
[]byte converts string value to byte.

※ Note ※ This method does not work if interface{} value is a pointer. Please find @PassKit's comment below.

Other problems in my code led me away from the gob package earlier, turns out it was the proper way as @nvcnvn suggested. Relevant code on how to solve this issue below:

package bloom

import (
    "encoding/gob"
    "bytes"
)

func GetBytes(key interface{}) ([]byte, error) {
    var buf bytes.Buffer
    enc := gob.NewEncoder(&buf)
    err := enc.Encode(key)
    if err != nil {
        return nil, err
    }
    return buf.Bytes(), nil
}