以一个简单的例子说明一下go中比较有用的小工具
1. 小工具
1.1 生成一个main.go脚本
jeffreyguan@localhost ~$ cat > main.go
package main
import "fmt"
func main() { fmt.Println("Hello, Jeffrey Guan") }
jeffreyguan@localhost ~$ cat main.go 130 ↵
package main
import "fmt"
func main() { fmt.Println("Hello, Jeffrey Guan") }
1.2. gofmt main.go
jeffreyguan@localhost ~$ gofmt main.go
package main
import "fmt"
func main() { fmt.Println("Hello, Jeffrey Guan") }
1.3. gofmt -d main.go
jeffreyguan@localhost ~$ gofmt -d main.go
diff -u main.go.orig main.go
--- main.go.orig 2019-08-17 21:42:13.000000000 +0800
+++ main.go 2019-08-17 21:42:13.000000000 +0800
@@ -1,5 +1,5 @@
package main
-import "fmt"
-func main() { fmt.Println("Hello, Jeffrey Guan") }
+import "fmt"
+func main() { fmt.Println("Hello, Jeffrey Guan") }
1.4. gofmt -w main.go
jeffreyguan@localhost ~$ gofmt -w main.go
jeffreyguan@localhost ~$ cat main.go
package main
import "fmt"
func main() { fmt.Println("Hello, Jeffrey Guan") }
1.5. go build
go build flags:
https://lukeeckley.com/post/useful-go-build-flags/
debug与release版本
https://dave.cheney.net/2014/09/28/using-build-to-switch-between-debug-and-release
jeffreyguan@localhost ~$ go build main.go
jeffreyguan@localhost ~$ file main
main: Mach-O 64-bit executable x86_64
按平台生成可执行文件
jeffreyguan@localhost ~$ GOOS=windows go build main.go
jeffreyguan@localhost ~$ file main.exe
main.exe: PE32+ executable (console) x86-64 (stripped to external PDB), for MS Windows
是否开启debug log和release log打印
main.go
package main
func main() {
Debug("It's expensive")
}
log_debug.go
//+build debug
package main
import "fmt"
func Debug(a ...interface{}) {
fmt.Println(a...)
}
log_release.go
//+build !debug
package main
func Debug(a ...interface{}) {}
开启debuglog
go build -tags "debug"
不开启
go build
1.6. go get
go get github.com/golang/example/hello
1.7. go list
jeffreyguan@localhost ~/lanjie$ cat main.go
// demo is also demo
package main
import "fmt"
func main() { fmt.Println("Hello, Jeffrey Guan") }
jeffreyguan@localhost ~/lanjie$ go list -f '{{ .Name }}'
main
jeffreyguan@localhost ~/lanjie$ go list -f '{{ .Name }}: {{ .Doc}}'
main: demo is also demo
jeffreyguan@localhost ~/lanjie$ go list -f '{{ .Name }}: {{ .Doc}}'
main: demo is also demo
jeffreyguan@localhost ~/lanjie$ go list -f '{{ .Imports }}'
[fmt]
jeffreyguan@localhost ~/lanjie$ go list -f '{{ join .Imports "\n"}}' fmt
errors
internal/fmtsort
io
math
os
reflect
strconv
sync
unicode/utf8
jeffreyguan@localhost ~/lanjie$ go list -f '{{ .Doc }}' fmt
Package fmt implements formatted I/O with functions analogous to C's printf and scanf.
1.8. do doc
jeffreyguan@localhost ~/lanjie$ go doc fmt
jeffreyguan@localhost ~/lanjie$ go doc fmt Println
func Println(a ...interface{}) (n int, err error)
Println formats using the default formats for its operands and writes to
standard output. Spaces are always added between operands and a newline is
appended. It returns the number of bytes written and any write error
encountered.
# 在本地启动go doc
jeffreyguan@localhost ~/lanjie$ godoc -http=localhost:6060
1.9 errcheck
1.10 go vet
1.11 go-wrk
1.12 go tool pprof
https://segmentfault.com/a/1190000016412013
https://www.infoq.cn/article/f69uvzJUOmq276HBp1Qb
1.13 go-torch
1.14 go tool trace
https://segmentfault.com/a/1190000019736288
2. 通过go启动web服务
3. golang中常用的库
3.1 mapstructure： 解析未知结构的yaml、json
示例
package main
import (
"encoding/json"
"fmt"
"github.com/mitchellh/mapstructure"
"gopkg.in/yaml.v2"
)
const (
test_yaml = `
extraImageList:
- registry: repository_xx
name: image_name_xx
tag: image_tag_xx
- registry: repository_yy
name: image_name_yy
tag: image_tag_yy
image:
registry: registry_zz
name: name_zz
tag: tag_zz`
test_json = `
{
"extraImageList": [
{
"registry": "xxxx",
"name": "fuck",
"tag": "aaaa"
},
{
"registry": "yyy",
"name": "fuck2",
"tag": "bbbb"
}
],
"image": {
"registry": "abab",
"name": "cdcd",
"tag": 1
}
}
`
)
type MyImage struct {
ExtraImageList []Image `yaml:"extraImageList" json:"extraImageList" mapstructure:"extraImageList"`
Image Image `yaml:"image" json:"image" mapstructure:"image"`
}
type Image struct {
Registry string `yaml:"registry" json:"registry" mapstructure:"registry"`
Name string `yaml:"name" json:"name" mapstructure:"name"`
Tag string `yaml:"tag" json:"tag" mapstructure:"tag"`
Repository string `mapstructure:"repository"`
}
type NewMyImage struct {
ExtraImageList []Image `yaml:"extraImageList" json:"extraImageList" mapstructure:"extraImageList"`
Image Image `yaml:"image" json:"image" mapstructure:"image"`
TestImage string `mapstructure:"testimage"`
ImageList []Image `mapstructure:"imagelist"`
}
func main() {
// yaml解析
tempExtra := MyImage{}
//cont, _ := ioutil.ReadFile("test.yaml")
//yaml.Unmarshal(cont, &tempExtra)
cont := test_yaml
yaml.Unmarshal([]byte(cont), &tempExtra)
fmt.Printf("yaml: %s\n", tempExtra.ExtraImageList[0].Tag)
// 打印json字符串
result, err := json.Marshal(tempExtra)
if err != nil {
panic(err)
}
fmt.Printf("json: %s\n", result)
// mapstructure解析
var myImage NewMyImage
var tempImage2 map[string]interface{}
//newCont2, _ := ioutil.ReadFile("test.json")
//json.Unmarshal(newCont2,&tempImage2)
newCont2 := test_json
json.Unmarshal([]byte(newCont2),&tempImage2)
if err := mapstructure.WeakDecode(tempImage2, &myImage); err != nil {
panic(err)
}
fmt.Printf("mapstructure: %#v", myImage.Image)
}