From 2e16b70e4a3534a67725e25148a70dbb0936640d Mon Sep 17 00:00:00 2001
From: timest <timest.lyy@gmail.com>
Date: Tue, 10 Jul 2018 21:00:31 +0800
Subject: [PATCH] init commit

---
 .gitignore |  15 ++++++
 env.go     | 150 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 165 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 env.go

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b66cec6
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,15 @@
+# Created by .ignore support plugin (hsz.mobi)
+### Go template
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, build with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
diff --git a/env.go b/env.go
new file mode 100644
index 0000000..f601188
--- /dev/null
+++ b/env.go
@@ -0,0 +1,150 @@
+package env
+
+import (
+	"reflect"
+	"strings"
+	"log"
+	"strconv"
+	"os"
+	"fmt"
+	"time"
+)
+
+var (
+	DEFAULT_SEPARATOR = "_"
+)
+
+func upper(v string) string {
+	return strings.ToUpper(v)
+}
+
+func Fill(v interface{}) error {
+	if reflect.ValueOf(v).Kind() != reflect.Ptr {
+		return fmt.Errorf("Fill只接受指针类型的值")
+	}
+	//for _, v := range os.Environ() {
+	//	if strings.HasPrefix(v, "CONFIG") {
+	//		log.Print(v)
+	//	}
+	//}
+	ind := reflect.Indirect(reflect.ValueOf(v))
+	prefix := upper(ind.Type().Name())
+	err := fill(prefix, ind)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func combine(p, n string, v string, ok bool) string{
+	if !ok {
+		return p + DEFAULT_SEPARATOR + n
+	}
+	return p + v + n
+}
+
+func parseBool(v string) (bool, error) {
+	if v == "" {
+		return false, nil
+	}
+	return strconv.ParseBool(v)
+}
+
+func fill(pf string, ind reflect.Value) error{
+	for i := 0; i < ind.NumField(); i++ {
+		f := ind.Type().Field(i)
+		name := f.Name
+		envName, exist := f.Tag.Lookup("env")
+		if exist {
+			name = envName
+		}
+		s, exist := f.Tag.Lookup("sep")
+		p := combine(pf, upper(name), s, exist)
+		switch ind.Field(i).Kind() {
+		case reflect.Struct:
+			err := fill(p, ind.Field(i))
+			if err != nil {
+				return err
+			}
+		default:
+			err := parse(p, ind.Field(i), f)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func parse(prefix string, f reflect.Value, sf reflect.StructField) error {
+	log.Print("parse:", prefix, f.String(), f.Type().String(), f.Kind().String())
+	df := sf.Tag.Get("default")
+	isRequire, err := parseBool(sf.Tag.Get("require"))
+	if err != nil {
+		return fmt.Errorf("字段:%s require不是合法的布尔值，支持: 1 t T true TRUE True.", prefix)
+	}
+	ev, exist := os.LookupEnv(prefix)
+
+	if !exist && isRequire {
+		return fmt.Errorf("%s 是必须的变量，但没有被设置", prefix)
+	}
+	if !exist && df != "" {
+		ev = df
+	}
+	log.Print("ev:", ev)
+	switch f.Kind() {
+	case reflect.String:
+		f.SetString(df)
+	case reflect.Int:
+		iv, err := strconv.ParseInt(ev, 10, 32)
+		if err != nil {
+			return err
+		}
+		f.SetInt(iv)
+	case reflect.Int64:
+		if f.Type().String() == "time.Duration" {
+			t, err := time.ParseDuration(ev)
+			if err != nil {
+				return err
+			}
+			f.Set(reflect.ValueOf(t))
+		} else {
+			iv, err := strconv.ParseInt(ev, 10, 64)
+			if err != nil {
+				return err
+			}
+			f.SetInt(iv)
+		}
+	case reflect.Uint:
+		uiv, err := strconv.ParseUint(ev, 10, 32)
+		if err != nil {
+			return err
+		}
+		f.SetUint(uiv)
+	case reflect.Uint64:
+		uiv, err := strconv.ParseUint(ev, 10, 64)
+		if err != nil {
+			return err
+		}
+		f.SetUint(uiv)
+	case reflect.Float32:
+		f32, err := strconv.ParseFloat(ev,  32)
+		if err != nil {
+			return err
+		}
+		f.SetFloat(f32)
+	case reflect.Float64:
+		f64, err := strconv.ParseFloat(ev,  64)
+		if err != nil {
+			return err
+		}
+		f.SetFloat(f64)
+	case reflect.Bool:
+		b, err := parseBool(ev)
+		if err != nil {
+			return err
+		}
+		f.SetBool(b)
+	}
+	return nil
+}
\ No newline at end of file