doc(fxconfig): Provided documentation (#58)

docs/modules/fxconfig.md

@@ -0,0 +1,149 @@
+# Config Module
+
+[![ci](https://github.com/ankorstore/yokai/actions/workflows/fxconfig-ci.yml/badge.svg)](https://github.com/ankorstore/yokai/actions/workflows/fxconfig-ci.yml)
+[![go report](https://goreportcard.com/badge/github.com/ankorstore/yokai/fxconfig)](https://goreportcard.com/report/github.com/ankorstore/yokai/fxconfig)
+[![codecov](https://codecov.io/gh/ankorstore/yokai/graph/badge.svg?token=ghUBlFsjhR&flag=fxconfig)](https://app.codecov.io/gh/ankorstore/yokai/tree/main/fxconfig)
+[![Deps](https://img.shields.io/badge/osi-deps-blue)](https://deps.dev/go/github.com%2Fankorstore%2Fyokai%2Ffxconfig)
+[![PkgGoDev](https://pkg.go.dev/badge/github.com/ankorstore/yokai/fxconfig)](https://pkg.go.dev/github.com/ankorstore/yokai/fxconfig)
+
+## Installation
+
+The [fxconfig](https://github.com/ankorstore/yokai/tree/main/fxconfig) module is automatically loaded by
+the [fxcore](https://github.com/ankorstore/yokai/tree/main/fxcore).
+
+You have nothing to install, it's ready to use
+
+## Documentation
+
+### Configuration files
+
+By default, the module expects the configuration files:
+
+- to be present in the `./configs` directory of your project
+- to be named `config.{format}` (ex: `config.yaml`, `config.json`, etc.)
+- to offer env overrides files named `config.{env}.{format}` based on the env var `APP_ENV` (ex: `config.test.yaml` if
+  env var `APP_ENV=test`)
+
+The following configuration files format are supported: JSON, TOML, YAML, HCL, INI, and env file.
+
+### Configuration usage
+
+For the following examples, we will be considering those configuration files:
+
+```yaml title="configs/config.yaml"
+app:
+  name: app
+  env: dev
+  version: 0.1.0
+  debug: false
+config:
+  values:
+    string_value: default
+    int_value: 0
+  placeholder: foo-${BAR}-baz
+  substitution: foo
+```
+
+and
+
+```yaml title="configs/config.test.yaml"
+app:
+  env: test
+  debug: true
+config:
+  values:
+    string_value: test
+```
+
+#### Configuration access
+
+This module makes available the [*config.Config](https://github.com/ankorstore/yokai/blob/main/config/config.go) in
+Yokai dependency injection system.
+
+To access it, you just need to inject it where needed, for example:
+
+```go title="internal/service/example.go"
+package service
+
+import (
+	"fmt"
+
+	"github.com/ankorstore/yokai/config"
+)
+
+type ExampleService struct {
+	config *config.Config
+}
+
+func NewExampleService(config *config.Config) *ExampleService {
+	return &ExampleService{
+		config: config,
+	}
+}
+
+func (s *ExampleService) PrintConfig() {
+	// helpers
+	fmt.Printf("name: %s", s.config.AppName())       // name: app
+	fmt.Printf("env: %s", s.config.AppEnv())         // env: dev
+	fmt.Printf("version: %s", s.config.AppVersion()) // version: 0.1.0
+	fmt.Printf("debug: %v", s.config.AppDebug())     // debug: false
+
+	// others
+	fmt.Printf("string_value: %s", s.config.GetString("config.values.string_value")) // string_value: default
+	fmt.Printf("int_value: %s", s.config.GetInt("config.values.int_value"))          // int_value: 0
+}
+```
+
+#### Configuration dynamic env overrides
+
+This module offers the possibility to override dynamically (by merging) configuration files depending on the env
+var `APP_ENV` value.
+
+For example, if `APP_ENV=test`, the module will use `config.yaml` values and merge / override them
+with `config.test.yaml` values.
+
+If you run your application in `test` mode:
+
+```go title="internal/service/example.go"
+// helpers
+fmt.Printf("var: %s", s.config.GetEnvVar("APP_ENV")) // var: test
+
+fmt.Printf("name: %s", s.config.AppName())           // name: app
+fmt.Printf("env: %s", s.config.AppEnv())             // env: test
+fmt.Printf("version: %s", s.config.AppVersion())     // version: 0.1.0
+fmt.Printf("debug: %v", s.config.AppDebug())         // debug: true
+
+// others
+fmt.Printf("string_value: %s", s.config.GetString("config.values.string_value")) // string_value: test
+fmt.Printf("int_value: %s", s.config.GetInt("config.values.int_value"))          // int_value: 0
+```
+
+You can use any value for `APP_ENV` (to allow you to reflect your own envs): for example if `APP_ENV=custom`, the module
+will use `config.yaml` values and override them with `config.custom.yaml` values (you just need to ensure
+that `config.custom.yaml` exists).
+
+#### Configuration env var placeholders
+
+This module offers the possibility to use placeholders in the config files to reference an env var value, that will be
+resolved at runtime.
+
+Placeholder pattern: `${ENV_VAR_NAME}`.
+
+For example, with the env var `BAR=bar`:
+
+```go title="internal/service/example.go"
+// placeholder: foo-bar-baz
+fmt.Printf("placeholder: %s", s.config.GetString("config.placeholder"))
+```
+
+#### Configuration env var substitution
+
+This module offers the possibility to perform configuration files values substitution from env var values.
+
+For example, if you have a configuration key `config.substitution=foo`, providing the env var `CONFIG_SUBSTITUTION=bar`
+will override the value from `foo` to `bar`.
+
+```go title="internal/service/example.go"
+// substitution: bar
+fmt.Printf("substitution: %s", cfg.GetString("config.substitution")) 
+```

mkdocs.yml

@@ -56,4 +56,6 @@ markdown_extensions:
 
 # Pages tree
 nav:
-  - 'Home': 'index.md'
+  - "Home": 'index.md'
+  - "Modules":
+      - "Config": modules/fxconfig.md