From 53c60f11ebe707455b861e3c62b2ac88f87e1115 Mon Sep 17 00:00:00 2001
From: "hui.wang" <hui.wang@funplus.com>
Date: Wed, 23 Mar 2022 09:23:14 +0800
Subject: [PATCH] feat: support dump config to yaml through help command

---
 tests/main/main.go |  1 -
 xconf.go           |  2 ++
 xconf_usage.go     | 42 ++++++++++++++++++++++++++++++++++++------
 xutil/util.go      | 15 +++++++++++++++
 4 files changed, 53 insertions(+), 7 deletions(-)

diff --git a/tests/main/main.go b/tests/main/main.go
index 23d9fd6..f70a45d 100644
--- a/tests/main/main.go
+++ b/tests/main/main.go
@@ -15,7 +15,6 @@ func main() {
 		xconf.WithFiles("c1.yaml"),
 		xconf.WithDebug(false),
 		xconf.WithEnvironPrefix("test_prefix_"),
-		xconf.WithOptionUsagePoweredBy(""),
 	)
 	if err := xx.Parse(cc); err != nil {
 		panic(err)
diff --git a/xconf.go b/xconf.go
index d1302f8..3f70174 100644
--- a/xconf.go
+++ b/xconf.go
@@ -34,6 +34,7 @@ type XConf struct {
 	atomicSetFunc       func(interface{})
 	optionUsage         string
 	parseForMerge       bool
+	valPtrForUsageDump  interface{}
 }
 
 // New 构造新的Xconf
@@ -236,6 +237,7 @@ func (x *XConf) parse(valPtr interface{}) (err error) {
 	}
 
 	if x.cc.FlagSet != nil && x.cc.ReplaceFlagSetUsage {
+		x.valPtrForUsageDump = valPtr
 		x.cc.FlagSet.Usage = x.Usage
 	}
 
diff --git a/xconf_usage.go b/xconf_usage.go
index 60b8ae2..34d7aa9 100644
--- a/xconf_usage.go
+++ b/xconf_usage.go
@@ -1,6 +1,7 @@
 package xconf
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -17,24 +18,53 @@ import (
 func (x *XConf) Usage() { x.UsageToWriter(os.Stderr, x.cc.FlagArgs...) }
 
 func (x *XConf) UsageToWriter(w io.Writer, args ...string) {
+	err := x.usageToWriter(w, args...)
+	if err == nil {
+		return
+	}
+	x.cc.LogWarning(fmt.Sprintf("UsageToWriter got error:%s", err.Error()))
+}
+
+func (x *XConf) usageToWriter(w io.Writer, args ...string) (err error) {
 	parsedOptions := xflag.ParseArgsToMapStringString(args)
 	val, got := parsedOptions["help"]
 	if !got {
 		val, got = parsedOptions["h"]
 	}
-	var err error
+	val = xutil.StringTrim(val)
 	if got && strings.EqualFold(xutil.StringTrim(val), "xconf") {
 		// 指定xconf_usage的FlagArgs为空，避免再次触发help逻辑
 		xx := New(WithFlagSet(newFlagSetContinueOnError("xconf_usage")), WithFlagArgs(), WithErrorHandling(ContinueOnError))
 		cc := NewOptions()
 		xutil.PanicErr(xx.Parse(cc))
-		err = xx.usageLinesToWriter(w)
-	} else {
-		err = x.usageLinesToWriter(w)
+		return xx.usageLinesToWriter(w)
 	}
-	if err != nil {
-		x.cc.LogWarning(fmt.Sprintf("UsageToWriter got error:%s", err.Error()))
+	if got && strings.EqualFold(xutil.StringTrim(val), "yaml") {
+		if x.valPtrForUsageDump == nil {
+			return errors.New("usage for yaml got empty config input")
+		}
+		return x.SaveVarToWriterAsYAML(x.valPtrForUsageDump, w)
+	}
+	if got && strings.HasSuffix(val, string(ConfigTypeYAML)) { // 输出到文件
+		defer func() {
+			if err == nil {
+				fmt.Println("\n🍺 save config file as yaml to: ", val)
+			} else {
+				fmt.Println("\n🚫 got error while save config file as yaml, err:", err.Error())
+			}
+			err = nil
+		}()
+		if x.valPtrForUsageDump == nil {
+			return errors.New("usage for yaml file got config input")
+		}
+		bytesBuffer := bytes.NewBuffer([]byte{})
+		err := x.SaveVarToWriterAsYAML(x.valPtrForUsageDump, bytesBuffer)
+		if err != nil {
+			return err
+		}
+		return xutil.FilePutContents(val, bytesBuffer.Bytes())
 	}
+	return x.usageLinesToWriter(w)
 }
 
 // usageLinesToWriter 打印usage信息到io.Writer
diff --git a/xutil/util.go b/xutil/util.go
index bbe84d3..10f8ffc 100644
--- a/xutil/util.go
+++ b/xutil/util.go
@@ -5,6 +5,9 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
 	"regexp"
 	"strings"
 )
@@ -189,3 +192,15 @@ func KVListApplyFunc(f func(k, v string) bool, kv ...string) error {
 	}
 	return nil
 }
+
+func FilePutContents(filename string, content []byte) error {
+	err := os.MkdirAll(filepath.Dir(filename), os.ModePerm)
+	if err != nil {
+		return fmt.Errorf("got error:%s while mkdir:%s", err.Error(), filepath.Dir(filename))
+	}
+	err = ioutil.WriteFile(filename, content, 0644)
+	if err != nil {
+		return fmt.Errorf("got error:%s while write to file:%s", err.Error(), filename)
+	}
+	return nil
+}