gonfig's Introduction

gonfig

A simple tool to help with Go (web) service configs.

gonfig reads a given JSON file containing an arbitrary set of configuration settings and produces Go code that exposes these settings as variables. The name of the package where the variables are defined is configurable.

For example, given the following JSON:

{
    "api_endpoint": "https://us-3.rightscale.com",
    "port": 8000,
    "worker": {
        "enabled": true,
        "concurrency": 20
    }
}

Running:

gonfig config.json

generates a config.go file which includes the following snippet:

var (
        ApiEndpoint string
        Port int64
        Worker *WorkerCfg
)

type WorkerCfg struct {
        Concurrency int64 `json:"concurrency"`
        Enabled     bool  `json:"enabled"`
}

The file also contains a Load function:

func Load(path string) error

As you'd expect that function initializes the variables with the values read from the JSON. Client code can then consume the configuration file with something like:

package main

func main() {
        err := Load("config.json")
        if err != nil {
                panic("Invalid configuration: " + err.Error())
        }
        // Now use ApiEndpoint, Port and Worker variables
}

If you'd rather not pollute the main package with config stuff then gonfig can be told to use a different package and output file:

gonfig -o config/config.go -p cfg

The above Generates the file config.go in the config directory (creating it if necessary). The generated code defines the cfg package so the client code would look like:

func main() {
        err := cfg.Load("config.json")
        // Check err and use cfg.ApiEndpint, cfg.Port etc.
}

Usage

gonfig --help
usage: gonfig [<flags>]

Flags:
  --help               Show help.
  -c, --config=CONFIG  path to JSON configuration, defaults to "config.json"
  -o, --out=OUT        path to output file, defaults to "config.go"
  -p, --package="main"  
                       name of go package containing config code

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