Viper - Go应用程序的完整配置解决方案

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viper.SetDefault("ContentDir", "content")
viper.SetDefault("LayoutDir", "layouts")
viper.SetDefault("Taxonomies", map[string]string{"tag": "tags", "category": "categories"})

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var SupportedExts = []string{"json", "toml", "yaml", "yml", "properties", "props", "prop", "hcl"}

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viper.Set("name", "clark")
viper.Set("age", 31)
fmt.Printf("name:%+v, age:%d\n", viper.Get("name"), viper.GetInt("age"))

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// 通过注册loud别名，当修改verbose时，loud也将改变，反之亦然
viper.RegisterAlias("loud", "Verbose")

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// 指定了config配置名称，后缀从支持扩展名中选择
viper.SetConfigName("config") // name of config file (without extension)

// 指定配置搜索路径
viper.AddConfigPath("/etc/appname/")   // path to look for the config file in
viper.AddConfigPath("$HOME/.appname")  // call multiple times to add many search paths
viper.AddConfigPath("./testdata/config/")  // call multiple times to add many search paths
viper.AddConfigPath(".")               // optionally look for config in the working directory

// 从搜索路径中，寻找最新的配置，读入到viper.config中（解析配置文件，读入到配置）
err := viper.ReadInConfig() // Find and read the config file
if err != nil { // Handle errors reading the config file
    panic(fmt.Errorf("Fatal error config file: %s \n", err))
}

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// 写入成功，按配置文件最新寻找到的配置文件，覆盖写
err = viper.WriteConfig() // writes current config to predefined path set by 'viper.AddConfigPath()' and 'viper.SetConfigName'
if err != nil {
    fmt.Printf("1. write config file err: %s\n", err)
}

// 写入失败，文件存在，不会覆盖已有配置写入
err = viper.SafeWriteConfig()
if err != nil {
    fmt.Printf("2. write config file err: %s\n", err)
}

// 写入成功，文件不存在，创建文件，写入
err = viper.WriteConfigAs("./testdata/temp/config.yml")
if err != nil {
    fmt.Printf("3. write config file err: %s\n", err)
}

// 写入失败，文件存在，不会覆盖已有配置写入
err = viper.SafeWriteConfigAs("./testdata/temp/config.yml") // will error since it has already been written
if err != nil {
    fmt.Printf("4. write config file err: %s\n", err)
}

err = viper.SafeWriteConfigAs("./testdata/temp/other_config.yml")
if err != nil {
    fmt.Printf("5. write config file err: %s\n", err)
}

--- // 输出
2. write config file err: File: /data/go/proj/go-example/testdata/config/config.yml exists. Use WriteConfig to overwrite.
4. write config file err: File: ./testdata/temp/config.yml exists. Use WriteConfig to overwrite.
5. write config file err: open ./testdata/temp/other_config.yml: no such file or directory

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// 配置监听，在修改配置时候，会自动检查并做对应的回调事件处理
viper.WatchConfig()
viper.OnConfigChange(func(e fsnotify.Event) {
    fmt.Println("Config file changed:", e.Name)
})
<-make(chan struct{})

--- // 输出
Config file changed: /data/go/proj/go-example/testdata/config/config.yml
Config file changed: /data/go/proj/go-example/testdata/config/config.yml
Config file changed: /data/go/proj/go-example/testdata/config/config.yml

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// 基于IO读取配置信息
viper.SetConfigType("yaml") // or viper.SetConfigType("YAML")

// Yaml字面量配置
var yamlExample = []byte(`
Hacker: true
name: steve
hobbies:
- skateboarding
- snowboarding
- GOLANG
clothing:
  jacket: leather
  trousers: denim
age: 35
eyes : brown
beard: true
company:
  inner:
    - alibaba
    - tencent
  outer:
    - google
    - aws
    - netflix
`)

// 基于io.Reader接口读取
err = viper.ReadConfig(bytes.NewBuffer(yamlExample))
if err != nil {
    fmt.Printf("read config err: %s\n", err)
}
fmt.Printf("%+v\n", viper.Get("name"))
fmt.Printf("%+v\n", viper.GetBool("beard"))
fmt.Printf("%+v\n", viper.GetInt("age"))
fmt.Printf("%+v\n", viper.GetStringSlice("hobbies"))
fmt.Printf("%+v\n", viper.GetStringMap("clothing"))
fmt.Printf("%+v\n", viper.GetStringMapStringSlice("company"))
fmt.Printf("outer company => %+v\n", viper.GetStringSlice("company.outer"))
fmt.Printf("clothing.trousers=>%s\n", viper.Get("clothing.trousers"))

--- //输出
steve
true
35
[skateboarding snowboarding go]
map[jacket:leather trousers:denim]
map[inner:[alibaba tencent] outer:[google aws netflix]]
outer company => [google aws netflix]
clothing.trousers=>denim

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// 环境变量读取
os.Setenv("SPF_ID", "13") // typically done outside of the app
os.Setenv("THIS_YEAR", "2019")

// 设置前缀
viper.SetEnvPrefix("spf") // will be uppercased automatically
// 绑定单个值，则拼接SPF前缀
viper.BindEnv("id")
// 绑定两个值，则第二个值为指定的环境变量全名
viper.BindEnv("year", "THIS_YEAR")
fmt.Printf("id=%s, this year is %s\n", viper.Get("id"), viper.Get("year"))

--- // 输出
id=13, this year is 2019

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// Flag变量读取
pflag.Int("port", 1234, "Port to run Application server on")
pflag.Parse()
viper.BindPFlags(pflag.CommandLine)
fmt.Printf("Flag port: %d\n", viper.Get("port"))

--- // 输出
Flag port: 1234

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// 添加远端Provider提供者etcd
viper.AddRemoteProvider("etcd", "http://127.0.0.1:4001","/config/hugo.json")

// 指定加密传输
// viper.AddSecureRemoteProvider("etcd","http://127.0.0.1:4001","/config/hugo.json","/etc/secrets/mykeyring.gpg")

// 远端读取需要指定配置类型，支持 "json", "toml", "yaml", "yml", "properties", "props", "prop"
viper.SetConfigType("json") 

// 解析读入远程配置
err := viper.ReadRemoteConfig()

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viper.AddRemoteProvider("consul", "localhost:8500", "MY_CONSUL_KEY")
viper.SetConfigType("json") // Need to explicitly set this to json
err := viper.ReadRemoteConfig()

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// alternatively, you can create a new viper instance.
var runtime_viper = viper.New()
runtime_viper.AddRemoteProvider("etcd", "http://127.0.0.1:4001", "/config/hugo.yml")
runtime_viper.SetConfigType("yaml") 
err := runtime_viper.ReadRemoteConfig()

// unmarshal config
runtime_viper.Unmarshal(&runtime_conf)

// open a goroutine to watch remote changes forever
go func(){
    for {
        time.Sleep(time.Second * 5) // delay after each request

        // currently, only tested with etcd support
        err := runtime_viper.WatchRemoteConfig()
        if err != nil {
            log.Errorf("unable to read remote config: %v", err)
            continue
        }

        // unmarshal new config into our runtime config struct. you can also use channel
        // to implement a signal to notify the system of the changes
        runtime_viper.Unmarshal(&runtime_conf)
    }
}()

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Get(key string) : interface{}
GetBool(key string) : bool
GetFloat64(key string) : float64
GetInt(key string) : int
GetString(key string) : string
GetStringMap(key string) : map[string]interface{}
GetStringMapString(key string) : map[string]string
GetStringSlice(key string) : []string
GetTime(key string) : time.Time
GetDuration(key string) : time.Duration
IsSet(key string) : bool
AllSettings() : map[string]interface{}

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viper.GetString("datastore.metric.host)

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app:
  cache1:
    max-items: 100
    item-size: 64
  cache2:
    max-items: 200
    item-size: 80

// 获取cache1
subv := viper.Sub("app.cache1")

// subv
max-items: 100
item-size: 64

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// 类似于JSON的解析，可以解析到指定的结构体上面
type config struct {
    Port int
    Name string
    PathMap string `mapstructure:"path_map"`
}

var C config
if err := viper.Unmarshal(&C); err != nil {
    t.Fatalf("unable to decode into struct, %v", err)
}

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// Marshalling to string
c := viper.AllSettings()
bs, err := yaml.Marshal(c)
if err != nil {
    log.Fatalf("unable to marshal config to YAML: %v", err)
}
fmt.Printf("----\n%s\n", bs)