Init.

README.md

@@ -1,2 +1,27 @@
 # yaconf
 Golang yaml config reader
+
+```golang
+package main
+
+import (
+    "log"
+
+    "github.com/onrik/yaconf"
+)
+
+type Config struct {
+    LogFile string `yaml:"log_file" yaconf:"required"`
+}
+
+func main() {
+	config := Config{}
+	err := yaconf.Read("config.yml", &config)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+    log.Printf("%+v\n", config)
+}
+```

go.mod

@@ -0,0 +1,5 @@
+module github.com/onrik/yaconf
+
+go 1.19
+
+require gopkg.in/yaml.v3 v3.0.1

go.sum

@@ -0,0 +1,4 @@
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

yaconf.go

@@ -0,0 +1,85 @@
+package yaconf
+
+import (
+	"fmt"
+	"os"
+	"reflect"
+	"strings"
+
+	"gopkg.in/yaml.v3"
+)
+
+type validator interface {
+	Validate() error
+}
+
+func addPrefix(prefix, name string) string {
+	if prefix == "" {
+		return name
+	}
+
+	return fmt.Sprintf("%s.%s", prefix, name)
+}
+
+func validate(config interface{}, prefix string) []string {
+	t := reflect.TypeOf(config)
+	v := reflect.ValueOf(config)
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+		v = v.Elem()
+	}
+
+	errors := []string{}
+	for i := 0; i < t.NumField(); i++ {
+		f := t.Field(i)
+		name := f.Tag.Get("yaml")
+		if name == "" {
+			name = f.Name
+		}
+
+		if f.Tag.Get("yaconf") == "required" && v.Field(i).IsZero() {
+			errors = append(errors, fmt.Sprintf("%s is required", addPrefix(prefix, name)))
+			continue
+		}
+
+		if f.Type.Kind() == reflect.Struct {
+			errors = append(errors, validate(v.Field(i).Interface(), addPrefix(prefix, name))...)
+			continue
+		}
+
+		if f.Type.Kind() == reflect.Ptr {
+			if f.Type.Elem().Kind() == reflect.Struct {
+				if v.Field(i).IsNil() {
+					v.Field(i).Set(reflect.New(f.Type.Elem()))
+				}
+				errors = append(errors, validate(v.Field(i).Elem().Interface(), addPrefix(prefix, name))...)
+			}
+		}
+
+	}
+	return errors
+}
+
+// Read config from file
+func Read(filename string, config interface{}) error {
+	data, err := os.ReadFile(filename)
+	if err != nil {
+		return err
+	}
+
+	err = yaml.Unmarshal(data, config)
+	if err != nil {
+		return err
+	}
+
+	errors := validate(config, "")
+	if len(errors) > 0 {
+		return fmt.Errorf(strings.Join(errors, ", "))
+	}
+
+	if v, ok := config.(validator); ok {
+		return v.Validate()
+	}
+
+	return nil
+}