chu

Configuration library to load from multiple sources.

go get github.com/rakunlabs/chu

Usage

Define a struct to hold the configuration.

type Config struct {
    Name string   `cfg:"name"`
    Age  int      `cfg:"age"`
    Secret string `cfg:"secret" log:"-"` // skip this field in chu.MarshalMap
}

And load the configuration.

cfg := Config{}

if err := chu.Load(ctx, "test", &cfg); err != nil {
    return fmt.Errorf("failed to load config: %w", err)
}

slog.Info("loaded configuration", "config", chu.MarshalMap(ctx, cfg))

The configuration will be loaded from the following sources in order:
- Default
- File
- Http
- Environment

chu.MarshalMap or chu.MarshalJSON print the configuration, skipping the fields log:"false" tag and value unless 1, t, T, TRUE, true, True makes false.
String func use fmt.Stringer interface checks to print the configuration.

CONFIG_NAME_PREFIX env value can be used to set the prefix for the configuration.

Loaders

Check example folder to see how to use loaders with different kind of configuration.

Default

Default loader is used to set default values from tag default.

type Config struct {
    Name string `cfg:"name" default:"John"`
    Age  int    `cfg:"age"  default:"30"`
}

Default supports numbers, string, bool, time.Duration and pointer of that types.

Http

HTTP loader is used to load configuration from HTTP server.

Env Value	Description	Default
CONFIG_HTTP_ADDR	HTTP server address, not exist than skips loader	-
CONFIG_HTTP_PREFIX	Prefix for the configuration	-

It send GET request to the server with CONFIG_HTTP_ADDR env value with appending the name as path.
204 or 404 response code will skip the loader, only accept 200 response code.

File

File loader is used to load configuration from file.

First checking CONFIG_FILE env value and try current location to find in order of .toml, .yaml, .yml, .json extension with using given name.

Environment

Environment loader is used to load configuration from environment variables.

env or cfg tag can usable for environment loader.
If you have .env, .env.local file in the current directory, it will be loaded automatically.
Add extra env file using CONFIG_ENV_FILE env value.

export NAME=John
export AGE=30

type Config struct {
    Name string `cfg:"name"`
    Age  int    `cfg:"age"`
}

When loading configuration, usable to change env loader's options.

err := chu.Load(ctx, "my-app", &cfg,
    // now you need to set prefix "MY_APP_" for env variables
    chu.WithLoaderOption(loaderenv.New(
        loaderenv.WithPrefix("MY_APP_"),
    )),
)

Use the noprefix tag option on fields that should also check unprefixed env vars as a fallback.
The prefixed value takes priority when both exist.

type Config struct {
    AppName  string `cfg:"app_name"`              // only MY_APP_APP_NAME
    LogLevel string `cfg:"log_level,noprefix"`    // MY_APP_LOG_LEVEL, falls back to LOG_LEVEL
}

Other Loaders

This loaders not enabled by default. Import the package to enable it.
Use chu.WithLoaderOption to set the loader options.
Or use chu.WithLoader to set the loaders manually.

#### Vault

Vault loader is used to load configuration from HashiCorp Vault.
This is not enabled by default.

Enable Vault loader importing the package.

import (
    _ "github.com/rakunlabs/chu/loader/external/loadervault"
)

Env Value	Description	Default
VAULT_SECRET_BASE_PATH	Prefix for the configuration, must given base	-
VAULT_ADDR VAULT_AGENT_ADDR	Vault server address, not exist than skips loader	-
VAULT_ROLE_ID	Role ID for AppRole authentication, for role login	-
VAULT_SECRET_ID	Secret ID for AppRole authentication, for role login	-
VAULT_APPROLE_BASE_PATH	Base path for AppRole authentication, for role login	auth/approle/login

#### Consul

Consul loader is used to load configuration from HashiCorp Consul.
This is not enabled by default.

Enable Consul loader importing the package.

import (
    _ "github.com/rakunlabs/chu/loader/external/loaderconsul"
)

Env Value	Description	Default
CONSUL_CONFIG_PATH_PREFIX	Prefix for the configuration	-
CONSUL_HTTP_ADDR	Consul server address, not exist than skips loader	-