configreader

configreader — layered configuration parser

import "github.com/downsized-devs/sdk-go/configreader"

Stability: Stable — see STABILITY.md

Reads JSON/YAML config files via viper, with JSON-reference resolution and custom time.Duration decoding. Pairs with configbuilder.

Features

• ReadConfig(target any) — unmarshal into your struct
• AllSettings() — flat view of every key
• JSON reference resolution ($ref) for shared fragments
• Built-in time.Duration and string-to-slice decode hooks

Installation

go get github.com/downsized-devs/sdk-go/configreader

Quick Start

type AppConfig struct {
    Redis struct {
        Address    string
        DefaultTTL time.Duration
    }
    Logger struct{ Level string }
}

r := configreader.Init(configreader.Options{
    ConfigFile: "config/runtime.json",
})
var cfg AppConfig
if err := r.ReadConfig(&cfg); err != nil {
    log.Fatal(err)
}

API Reference

Examples

Layer defaults + environment overrides

r := configreader.Init(configreader.Options{
    ConfigFile: "config/defaults.json",
    AdditionalConfigOptions: []configreader.AdditionalConfigOptions{
        { ConfigFile: fmt.Sprintf("config/%s.json", os.Getenv("ENV")), Type: "json" },
    },
})

Use with Duration fields

type Cfg struct {
    Timeout time.Duration // "5s", "1m30s" both decoded
}

Error Handling

ReadConfig returns descriptive errors for missing files, type mismatches, and unresolved $ref pointers. Don't continue on error — config-load failure should be fatal.

Dependencies

• Internal: files
• External: github.com/mitchellh/mapstructure, github.com/spf13/viper

Testing

go test ./configreader/...

Contributing

See CONTRIBUTING.md.

Related Packages

• configbuilder — write side; produces the files this package reads.
• files — path-existence checks.