go-strdur

A highly inefficient implementation of time.Duration based on a string, rather than an int64. It is designed purely soo that hcl configuration files can contain a string representation of a duration for config values, rather than an int64.

Installation

go get -u github.com/dcarbone/go-strdur/v2

Example

package main

import (
    "fmt"
    
    "github.com/dcarbone/go-strdur/v2"
    "github.com/hashicorp/hcl/v2/hclsimple"
)

const exampleConfig = `
duration_value = "24h"
`

type MyConfig struct {
    DurationValue strdur.StringDuration `hcl:"duration_value"`
}

func main() {
    myCnf := new(MyConfig)
    if err := hclsimple.Decode("example.hcl", []byte(exampleConfig), nil, new(MyConfig)); err != nil {
        panic(fmt.Sprintf("Error decoding hcl: %v", err))
    }
    fmt.Println(myCnf.DurationValue.String())
}

Explanation

I created this type specifically because, as of the time of this writing, https://github.com/hashicorp/hcl does not have a great way to handle embedded types.

Given this example:

package main

import (
    "fmt"
    "time"

    "github.com/hashicorp/hcl/v2/hclsimple"
)

const confValue = `
duration_value = "24h"
`

type MyDuration time.Duration

type MyConfig struct {
    DurationValue MyDuration `hcl:"duration_value"`
}

func main() {
    if err := hclsimple.Decode("example.hcl", []byte(confValue), nil, new(MyConfig)); err != nil {
        panic(fmt.Sprintf("Error decoding hcl: %v", err))
    }
}

The above will always fail. Its possible I am missing something in the cty package which can handle this, but I haven't been able to find it.

I offer zero guarantees of performance on this type as it is intended entirely to be used as a value in a config object.