hashstructure's Introduction

hashstructure

hashstructure is a Go library for creating a unique hash value for arbitrary values in Go.

This can be used to key values in a hash (for use in a map, set, etc.) that are complex. The most common use case is comparing two values without sending data across the network, caching values locally (de-dup), and so on.

Features

Hash any arbitrary Go value, including complex types.
Tag a struct field to ignore it and not affect the hash value.
Tag a slice type struct field to treat it as a set where ordering doesn't affect the hash code but the field itself is still taken into account to create the hash value.
Optionally specify a custom hash function to optimize for speed, collision avoidance for your data set, etc.
Optionally hash the output of .String() on structs that implement fmt.Stringer, allowing effective hashing of time.Time

Installation

Standard go get:

$ go get github.com/mitchellh/hashstructure

Usage & Example

For usage and examples see the Godoc.

A quick code example is shown below:

type ComplexStruct struct {
    Name     string
    Age      uint
    Metadata map[string]interface{}
}

v := ComplexStruct{
    Name: "mitchellh",
    Age:  64,
    Metadata: map[string]interface{}{
        "car":      true,
        "location": "California",
        "siblings": []string{"Bob", "John"},
    },
}

hash, err := hashstructure.Hash(v, nil)
if err != nil {
    panic(err)
}

fmt.Printf("%d", hash)
// Output:
// 2307517237273902113

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