Update server dependencies
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Godeps/_workspace/src/github.com/spf13/viper/README.md
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Godeps/_workspace/src/github.com/spf13/viper/README.md
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@ -1,47 +1,48 @@
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viper [](https://travis-ci.org/spf13/viper)
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=====
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[](https://gitter.im/spf13/viper?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
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Go configuration with fangs!
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[](https://travis-ci.org/spf13/viper) [](https://gitter.im/spf13/viper?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
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Go configuration with fangs
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## What is Viper?
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Viper is a complete configuration solution for go applications. It has
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been designed to work within an application to handle all types of
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configuration. It supports
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Viper is a complete configuration solution for go applications including 12 factor apps. It is designed
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to work within an application, and can handle all types of configuration needs
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and formats. It supports:
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* setting defaults
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* reading from json, toml and yaml config files
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* reading from JSON, TOML, YAML and HCL config files
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* live watching and re-reading of config files (optional)
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* reading from environment variables
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* reading from remote config systems (Etcd or Consul), watching changes
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* reading from remote config systems (etcd or Consul), and watching changes
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* reading from command line flags
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* reading from buffer
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* setting explicit values
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It can be thought of as a registry for all of your applications
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Viper can be thought of as a registry for all of your applications
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configuration needs.
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## Why Viper?
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When building a modern application, you don’t want to have to worry about
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When building a modern application, you don’t want to worry about
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configuration file formats; you want to focus on building awesome software.
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Viper is here to help with that.
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Viper does the following for you:
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1. Find, load and marshal a configuration file in JSON, TOML or YAML.
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1. Find, load, and unmarshal a configuration file in JSON, TOML, YAML or HCL.
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2. Provide a mechanism to set default values for your different
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configuration options.
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3. Provide a mechanism to set override values for options specified
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through command line flags.
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4. Provide an alias system to easily rename parameters without breaking
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existing code.
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5. Make it easy to tell the difference between when a user has provided
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a command line or config file which is the same as the default.
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3. Provide a mechanism to set override values for options specified through
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command line flags.
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4. Provide an alias system to easily rename parameters without breaking existing
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code.
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5. Make it easy to tell the difference between when a user has provided a
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command line or config file which is the same as the default.
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Viper uses the following precedence order. Each item takes precedence
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over the item below it:
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Viper uses the following precedence order. Each item takes precedence over the
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item below it:
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* explicit call to Set
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* flag
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@ -56,42 +57,71 @@ Viper configuration keys are case insensitive.
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### Establishing Defaults
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A good configuration system will support default values. A default value
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is not required for a key, but can establish a default to be used in the
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event that the key hasn’t be set via config file, environment variable,
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remote configuration or flag.
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A good configuration system will support default values. A default value is not
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required for a key, but it's useful in the event that a key hasn’t been set via
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config file, environment variable, remote configuration or flag.
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Examples:
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viper.SetDefault("ContentDir", "content")
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viper.SetDefault("LayoutDir", "layouts")
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viper.SetDefault("Taxonomies", map[string]string{"tag": "tags", "category": "categories"})
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```go
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viper.SetDefault("ContentDir", "content")
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viper.SetDefault("LayoutDir", "layouts")
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viper.SetDefault("Taxonomies", map[string]string{"tag": "tags", "category": "categories"})
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```
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### Reading Config Files
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If you want to support a config file, Viper requires a minimal
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configuration so it knows where to look for the config file. Viper
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supports json, toml and yaml files. Viper can search multiple paths, but
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currently a single viper only supports a single config file.
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Viper requires minimal configuration so it knows where to look for config files.
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Viper supports JSON, TOML, YAML and HCL files. Viper can search multiple paths, but
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currently a single Viper instance only supports a single configuration file.
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Viper does not default to any configuration search paths leaving defaults decision
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to an application.
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viper.SetConfigName("config") // name of config file (without extension)
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viper.AddConfigPath("/etc/appname/") // path to look for the config file in
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viper.AddConfigPath("$HOME/.appname") // call multiple times to add many search paths
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err := viper.ReadInConfig() // Find and read the config file
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if err != nil { // Handle errors reading the config file
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panic(fmt.Errorf("Fatal error config file: %s \n", err))
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}
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Here is an example of how to use Viper to search for and read a configuration file.
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None of the specific paths are required, but at least one path should be provided
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where a configuration file is expected.
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```go
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viper.SetConfigName("config") // name of config file (without extension)
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viper.AddConfigPath("/etc/appname/") // path to look for the config file in
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viper.AddConfigPath("$HOME/.appname") // call multiple times to add many search paths
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viper.AddConfigPath(".") // optionally look for config in the working directory
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err := viper.ReadInConfig() // Find and read the config file
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if err != nil { // Handle errors reading the config file
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panic(fmt.Errorf("Fatal error config file: %s \n", err))
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}
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```
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### Watching and re-reading config files
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Viper supports the ability to have your application live read a config file while running.
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Gone are the days of needing to restart a server to have a config take effect,
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viper powered applications can read an update to a config file while running and
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not miss a beat.
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Simply tell the viper instance to watchConfig.
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Optionally you can provide a function for Viper to run each time a change occurs.
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**Make sure you add all of the configPaths prior to calling `WatchConfig()`**
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```go
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viper.WatchConfig()
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viper.OnConfigChange(func(e fsnotify.Event) {
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fmt.Println("Config file changed:", e.Name)
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})
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```
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### Reading Config from io.Reader
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Viper predefined many configuration sources, such as files, environment variables, flags and
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remote K/V store. But you are not bound to them. You can also implement your own way to
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require configuration and feed it to viper.
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Viper predefines many configuration sources such as files, environment
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variables, flags, and remote K/V store, but you are not bound to them. You can
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also implement your own required configuration source and feed it to viper.
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````go
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```go
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viper.SetConfigType("yaml") // or viper.SetConfigType("YAML")
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// any approach to require this configuration into your program.
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// any approach to require this configuration into your program.
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var yamlExample = []byte(`
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Hacker: true
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name: steve
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@ -110,202 +140,289 @@ beard: true
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viper.ReadConfig(bytes.NewBuffer(yamlExample))
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viper.Get("name") // this would be "steve"
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````
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```
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### Setting Overrides
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These could be from a command line flag, or from your own application logic.
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viper.Set("Verbose", true)
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viper.Set("LogFile", LogFile)
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```go
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viper.Set("Verbose", true)
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viper.Set("LogFile", LogFile)
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```
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### Registering and Using Aliases
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Aliases permit a single value to be referenced by multiple keys
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viper.RegisterAlias("loud", "Verbose")
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```go
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viper.RegisterAlias("loud", "Verbose")
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viper.Set("verbose", true) // same result as next line
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viper.Set("loud", true) // same result as prior line
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viper.Set("verbose", true) // same result as next line
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viper.Set("loud", true) // same result as prior line
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viper.GetBool("loud") // true
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viper.GetBool("verbose") // true
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viper.GetBool("loud") // true
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viper.GetBool("verbose") // true
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```
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### Working with Environment Variables
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Viper has full support for environment variables. This enables 12 factor
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applications out of the box. There are four methods that exist to aid
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with working with ENV:
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applications out of the box. There are four methods that exist to aid working
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with ENV:
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* AutomaticEnv()
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* BindEnv(string...) : error
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* SetEnvPrefix(string)
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* SetEnvReplacer(string...) *strings.Replacer
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* `AutomaticEnv()`
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* `BindEnv(string...) : error`
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* `SetEnvPrefix(string)`
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* `SetEnvReplacer(string...) *strings.Replacer`
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_When working with ENV variables, it’s important to recognize that Viper
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treats ENV variables as case sensitive._
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Viper provides a mechanism to try to ensure that ENV variables are
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unique. By using SetEnvPrefix, you can tell Viper to use add a prefix
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while reading from the environment variables. Both BindEnv and
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AutomaticEnv will use this prefix.
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Viper provides a mechanism to try to ensure that ENV variables are unique. By
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using `SetEnvPrefix`, you can tell Viper to use add a prefix while reading from
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the environment variables. Both `BindEnv` and `AutomaticEnv` will use this
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prefix.
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BindEnv takes one or two parameters. The first parameter is the key
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name, the second is the name of the environment variable. The name of
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the environment variable is case sensitive. If the ENV variable name is
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not provided, then Viper will automatically assume that the key name
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matches the ENV variable name but the ENV variable is IN ALL CAPS. When
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you explicitly provide the ENV variable name, it **does not**
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automatically add the prefix.
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`BindEnv` takes one or two parameters. The first parameter is the key name, the
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second is the name of the environment variable. The name of the environment
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variable is case sensitive. If the ENV variable name is not provided, then
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Viper will automatically assume that the key name matches the ENV variable name,
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but the ENV variable is IN ALL CAPS. When you explicitly provide the ENV
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variable name, it **does not** automatically add the prefix.
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One important thing to recognize when working with ENV variables is that
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the value will be read each time it is accessed. It does not fix the
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value when the BindEnv is called.
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One important thing to recognize when working with ENV variables is that the
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value will be read each time it is accessed. Viper does not fix the value when
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the `BindEnv` is called.
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AutomaticEnv is a powerful helper especially when combined with
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SetEnvPrefix. When called, Viper will check for an environment variable
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any time a viper.Get request is made. It will apply the following rules.
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It will check for a environment variable with a name matching the key
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uppercased and prefixed with the EnvPrefix if set.
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`AutomaticEnv` is a powerful helper especially when combined with
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`SetEnvPrefix`. When called, Viper will check for an environment variable any
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time a `viper.Get` request is made. It will apply the following rules. It will
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check for a environment variable with a name matching the key uppercased and
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prefixed with the `EnvPrefix` if set.
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SetEnvReplacer allows you to use a `strings.Replacer` object to rewrite Env keys
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to an extent. This is useful if you want to use `-` or something in your Get()
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calls, but want your environmental variables to use `_` delimiters. An example
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of using it can be found in `viper_test.go`.
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`SetEnvReplacer` allows you to use a `strings.Replacer` object to rewrite Env
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keys to an extent. This is useful if you want to use `-` or something in your
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`Get()` calls, but want your environmental variables to use `_` delimiters. An
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example of using it can be found in `viper_test.go`.
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#### Env example
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SetEnvPrefix("spf") // will be uppercased automatically
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BindEnv("id")
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```go
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SetEnvPrefix("spf") // will be uppercased automatically
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BindEnv("id")
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os.Setenv("SPF_ID", "13") // typically done outside of the app
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id := Get("id") // 13
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os.Setenv("SPF_ID", "13") // typically done outside of the app
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id := Get("id") // 13
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```
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### Working with Flags
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Viper has the ability to bind to flags. Specifically, Viper supports
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Pflags as used in the [Cobra](https://github.com/spf13/cobra) library.
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Viper has the ability to bind to flags. Specifically, Viper supports `Pflags`
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as used in the [Cobra](https://github.com/spf13/cobra) library.
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Like BindEnv, the value is not set when the binding method is called, but
|
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when it is accessed. This means you can bind as early as you want, even
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in an init() function.
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Like `BindEnv`, the value is not set when the binding method is called, but when
|
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it is accessed. This means you can bind as early as you want, even in an
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`init()` function.
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The BindPFlag() method provides this functionality.
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The `BindPFlag()` method provides this functionality.
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Example:
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serverCmd.Flags().Int("port", 1138, "Port to run Application server on")
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viper.BindPFlag("port", serverCmd.Flags().Lookup("port"))
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```go
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serverCmd.Flags().Int("port", 1138, "Port to run Application server on")
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viper.BindPFlag("port", serverCmd.Flags().Lookup("port"))
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```
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The use of [pflag](https://github.com/spf13/pflag/) in Viper does not preclude
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the use of other packages that use the [flag](https://golang.org/pkg/flag/)
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package from the standard library. The pflag package can handle the flags
|
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defined for the flag package by importing these flags. This is accomplished
|
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by a calling a convenience function provided by the pflag package called
|
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AddGoFlagSet().
|
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|
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Example:
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|
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```go
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package main
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import (
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"flag"
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"github.com/spf13/pflag"
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)
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func main() {
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pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
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pflag.Parse()
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...
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}
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```
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#### Flag interfaces
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Viper provides two Go interfaces to bind other flag systems if you don't use `Pflags`.
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`FlagValue` represents a single flag. This is a very simple example on how to implement this interface:
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```go
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type myFlag struct {}
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func (f myFlag) IsChanged() { return false }
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func (f myFlag) Name() { return "my-flag-name" }
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func (f myFlag) ValueString() { return "my-flag-value" }
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func (f myFlag) ValueType() { return "string" }
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```
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Once your flag implements this interface, you can simply tell Viper to bind it:
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```go
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viper.BindFlagValue("my-flag-name", myFlag{})
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```
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`FlagValueSet` represents a group of flags. This is a very simple example on how to implement this interface:
|
||||
|
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```go
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type myFlagSet struct {
|
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flags []myFlag
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}
|
||||
|
||||
func (f myFlagSet) VisitAll(fn func(FlagValue)) {
|
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for _, flag := range flags {
|
||||
fn(flag)
|
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}
|
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}
|
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```
|
||||
|
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Once your flag set implements this interface, you can simply tell Viper to bind it:
|
||||
|
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```go
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fSet := myFlagSet{
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flags: []myFlag{myFlag{}, myFlag{}},
|
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}
|
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viper.BindFlagValues("my-flags", fSet)
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```
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### Remote Key/Value Store Support
|
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Viper will read a config string (as JSON, TOML, or YAML) retrieved from a
|
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path in a Key/Value store such as Etcd or Consul. These values take precedence
|
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over default values, but are overriden by configuration values retrieved from disk,
|
||||
|
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To enable remote support in Viper, do a blank import of the `viper/remote`
|
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package:
|
||||
|
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`import _ "github.com/spf13/viper/remote"`
|
||||
|
||||
Viper will read a config string (as JSON, TOML, YAML or HCL) retrieved from a path
|
||||
in a Key/Value store such as etcd or Consul. These values take precedence over
|
||||
default values, but are overridden by configuration values retrieved from disk,
|
||||
flags, or environment variables.
|
||||
|
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Viper uses [crypt](https://github.com/xordataexchange/crypt) to retrieve configuration
|
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from the K/V store, which means that you can store your configuration values
|
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encrypted and have them automatically decrypted if you have the correct
|
||||
gpg keyring. Encryption is optional.
|
||||
Viper uses [crypt](https://github.com/xordataexchange/crypt) to retrieve
|
||||
configuration from the K/V store, which means that you can store your
|
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configuration values encrypted and have them automatically decrypted if you have
|
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the correct gpg keyring. Encryption is optional.
|
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|
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You can use remote configuration in conjunction with local configuration, or
|
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independently of it.
|
||||
|
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`crypt` has a command-line helper that you can use to put configurations
|
||||
in your K/V store. `crypt` defaults to etcd on http://127.0.0.1:4001.
|
||||
`crypt` has a command-line helper that you can use to put configurations in your
|
||||
K/V store. `crypt` defaults to etcd on http://127.0.0.1:4001.
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||||
|
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go get github.com/xordataexchange/crypt/bin/crypt
|
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crypt set -plaintext /config/hugo.json /Users/hugo/settings/config.json
|
||||
```bash
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$ go get github.com/xordataexchange/crypt/bin/crypt
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||||
$ crypt set -plaintext /config/hugo.json /Users/hugo/settings/config.json
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||||
```
|
||||
|
||||
Confirm that your value was set:
|
||||
|
||||
crypt get -plaintext /config/hugo.json
|
||||
```bash
|
||||
$ crypt get -plaintext /config/hugo.json
|
||||
```
|
||||
|
||||
See the `crypt` documentation for examples of how to set encrypted values, or how
|
||||
to use Consul.
|
||||
See the `crypt` documentation for examples of how to set encrypted values, or
|
||||
how to use Consul.
|
||||
|
||||
### Remote Key/Value Store Example - Unencrypted
|
||||
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viper.AddRemoteProvider("etcd", "http://127.0.0.1:4001","/config/hugo.json")
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||||
viper.SetConfigType("json") // because there is no file extension in a stream of bytes
|
||||
err := viper.ReadRemoteConfig()
|
||||
```go
|
||||
viper.AddRemoteProvider("etcd", "http://127.0.0.1:4001","/config/hugo.json")
|
||||
viper.SetConfigType("json") // because there is no file extension in a stream of bytes
|
||||
err := viper.ReadRemoteConfig()
|
||||
```
|
||||
|
||||
### Remote Key/Value Store Example - Encrypted
|
||||
|
||||
viper.AddSecureRemoteProvider("etcd","http://127.0.0.1:4001","/config/hugo.json","/etc/secrets/mykeyring.gpg")
|
||||
viper.SetConfigType("json") // because there is no file extension in a stream of bytes
|
||||
err := viper.ReadRemoteConfig()
|
||||
```go
|
||||
viper.AddSecureRemoteProvider("etcd","http://127.0.0.1:4001","/config/hugo.json","/etc/secrets/mykeyring.gpg")
|
||||
viper.SetConfigType("json") // because there is no file extension in a stream of bytes
|
||||
err := viper.ReadRemoteConfig()
|
||||
```
|
||||
|
||||
### Watching Changes in Etcd - Unencrypted
|
||||
### Watching Changes in etcd - Unencrypted
|
||||
|
||||
// alternatively, you can create a new viper instance.
|
||||
var runtime_viper = viper.New()
|
||||
```go
|
||||
// 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") // because there is no file extension in a stream of bytes
|
||||
runtime_viper.AddRemoteProvider("etcd", "http://127.0.0.1:4001", "/config/hugo.yml")
|
||||
runtime_viper.SetConfigType("yaml") // because there is no file extension in a stream of bytes
|
||||
|
||||
// read from remote config the first time.
|
||||
err := runtime_viper.ReadRemoteConfig()
|
||||
// read from remote config the first time.
|
||||
err := runtime_viper.ReadRemoteConfig()
|
||||
|
||||
// marshal config
|
||||
runtime_viper.Marshal(&runtime_conf)
|
||||
// unmarshal config
|
||||
runtime_viper.Unmarshal(&runtime_conf)
|
||||
|
||||
// open a goroutine to wath remote changes forever
|
||||
go func(){
|
||||
for {
|
||||
time.Sleep(time.Second * 5) // delay after each request
|
||||
// open a goroutine to watch remote changes forever
|
||||
go func(){
|
||||
for {
|
||||
time.Sleep(time.Second * 5) // delay after each request
|
||||
|
||||
// currenlty, only tested with etcd support
|
||||
err := runtime_viper.WatchRemoteConfig()
|
||||
if err != nil {
|
||||
log.Errorf("unable to read remote config: %v", err)
|
||||
continue
|
||||
}
|
||||
|
||||
// marshal 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.Marshal(&runtime_conf)
|
||||
}
|
||||
}()
|
||||
// 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)
|
||||
}
|
||||
}()
|
||||
```
|
||||
|
||||
## Getting Values From Viper
|
||||
|
||||
In Viper, there are a few ways to get a value depending on what type of value you want to retrieved.
|
||||
In Viper, there are a few ways to get a value depending on the value's type.
|
||||
The following functions and methods exist:
|
||||
|
||||
* 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
|
||||
* `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`
|
||||
|
||||
One important thing to recognize is that each Get function will return
|
||||
its zero value if it’s not found. To check if a given key exists, the IsSet()
|
||||
method has been provided.
|
||||
One important thing to recognize is that each Get function will return a zero
|
||||
value if it’s not found. To check if a given key exists, the `IsSet()` method
|
||||
has been provided.
|
||||
|
||||
Example:
|
||||
|
||||
viper.GetString("logfile") // case-insensitive Setting & Getting
|
||||
if viper.GetBool("verbose") {
|
||||
fmt.Println("verbose enabled")
|
||||
}
|
||||
|
||||
```go
|
||||
viper.GetString("logfile") // case-insensitive Setting & Getting
|
||||
if viper.GetBool("verbose") {
|
||||
fmt.Println("verbose enabled")
|
||||
}
|
||||
```
|
||||
### Accessing nested keys
|
||||
|
||||
The accessor methods also accept formatted paths to deeply nested keys.
|
||||
For example, if the following JSON file is loaded:
|
||||
The accessor methods also accept formatted paths to deeply nested keys. For
|
||||
example, if the following JSON file is loaded:
|
||||
|
||||
```
|
||||
```json
|
||||
{
|
||||
"host": {
|
||||
"address": "localhost",
|
||||
|
|
@ -326,24 +443,26 @@ For example, if the following JSON file is loaded:
|
|||
```
|
||||
|
||||
Viper can access a nested field by passing a `.` delimited path of keys:
|
||||
```
|
||||
|
||||
```go
|
||||
GetString("datastore.metric.host") // (returns "127.0.0.1")
|
||||
```
|
||||
|
||||
This obeys the precendense rules established above; the search for the root key
|
||||
(in this examole, `datastore`) will cascade through the remaining configuration registries
|
||||
until found. The search for the subkeys (`metric` and `host`), however, will not.
|
||||
This obeys the precedence rules established above; the search for the root key
|
||||
(in this example, `datastore`) will cascade through the remaining configuration
|
||||
registries until found. The search for the sub-keys (`metric` and `host`),
|
||||
however, will not.
|
||||
|
||||
For example, if the `metric` key was not defined in the configuration loaded
|
||||
from file, but was defined in the defaults, Viper would return the zero value.
|
||||
|
||||
On the other hand, if the primary key was not defined, Viper would go through the
|
||||
remaining registries looking for it.
|
||||
On the other hand, if the primary key was not defined, Viper would go through
|
||||
the remaining registries looking for it.
|
||||
|
||||
Lastly, if there exists a key that matches the delimited key path, its value will
|
||||
be returned instead. E.g.
|
||||
Lastly, if there exists a key that matches the delimited key path, its value
|
||||
will be returned instead. E.g.
|
||||
|
||||
```
|
||||
```json
|
||||
{
|
||||
"datastore.metric.host": "0.0.0.0",
|
||||
"host": {
|
||||
|
|
@ -365,59 +484,110 @@ be returned instead. E.g.
|
|||
GetString("datastore.metric.host") //returns "0.0.0.0"
|
||||
```
|
||||
|
||||
### Marshaling
|
||||
### Extract sub-tree
|
||||
|
||||
You also have the option of Marshaling all or a specific value to a struct, map, etc.
|
||||
Extract sub-tree from Viper.
|
||||
|
||||
For example, `viper` represents:
|
||||
|
||||
```json
|
||||
app:
|
||||
cache1:
|
||||
max-items: 100
|
||||
item-size: 64
|
||||
cache2:
|
||||
max-items: 200
|
||||
item-size: 80
|
||||
```
|
||||
|
||||
After executing:
|
||||
|
||||
```go
|
||||
subv := viper.Sub("app.cache1")
|
||||
```
|
||||
|
||||
`subv` represents:
|
||||
|
||||
```json
|
||||
max-items: 100
|
||||
item-size: 64
|
||||
```
|
||||
|
||||
Suppose we have:
|
||||
|
||||
```go
|
||||
func NewCache(cfg *Viper) *Cache {...}
|
||||
```
|
||||
|
||||
which creates a cache based on config information formatted as `subv`.
|
||||
Now it's easy to create these 2 caches separately as:
|
||||
|
||||
```go
|
||||
cfg1 := viper.Sub("app.cache1")
|
||||
cache1 := NewCache(cfg1)
|
||||
|
||||
cfg2 := viper.Sub("app.cache2")
|
||||
cache2 := NewCache(cfg2)
|
||||
```
|
||||
|
||||
### Unmarshaling
|
||||
|
||||
You also have the option of Unmarshaling all or a specific value to a struct, map,
|
||||
etc.
|
||||
|
||||
There are two methods to do this:
|
||||
|
||||
* Marshal(rawVal interface{}) : error
|
||||
* MarshalKey(key string, rawVal interface{}) : error
|
||||
* `Unmarshal(rawVal interface{}) : error`
|
||||
* `UnmarshalKey(key string, rawVal interface{}) : error`
|
||||
|
||||
Example:
|
||||
|
||||
type config struct {
|
||||
Port int
|
||||
Name string
|
||||
}
|
||||
```go
|
||||
type config struct {
|
||||
Port int
|
||||
Name string
|
||||
PathMap string `mapstructure:"path_map"`
|
||||
}
|
||||
|
||||
var C config
|
||||
|
||||
err := Marshal(&C)
|
||||
if err != nil {
|
||||
t.Fatalf("unable to decode into struct, %v", err)
|
||||
}
|
||||
var C config
|
||||
|
||||
err := Unmarshal(&C)
|
||||
if err != nil {
|
||||
t.Fatalf("unable to decode into struct, %v", err)
|
||||
}
|
||||
```
|
||||
|
||||
## Viper or Vipers?
|
||||
|
||||
Viper comes ready to use out of the box. There is no configuration or
|
||||
initialization needed to begin using Viper. Since most applications will
|
||||
want to use a single central repository for their configuration, the
|
||||
viper package provides this. It is similar to a singleton.
|
||||
initialization needed to begin using Viper. Since most applications will want
|
||||
to use a single central repository for their configuration, the viper package
|
||||
provides this. It is similar to a singleton.
|
||||
|
||||
In all of the examples above, they demonstrate using viper in its
|
||||
singleton style approach.
|
||||
In all of the examples above, they demonstrate using viper in it's singleton
|
||||
style approach.
|
||||
|
||||
### Working with multiple vipers
|
||||
|
||||
You can also create many different vipers for use in your application.
|
||||
Each will have it’s own unique set of configurations and values. Each
|
||||
can read from a different config file, key value store, etc. All of the
|
||||
functions that viper package supports are mirrored as methods on a viper.
|
||||
You can also create many different vipers for use in your application. Each will
|
||||
have it’s own unique set of configurations and values. Each can read from a
|
||||
different config file, key value store, etc. All of the functions that viper
|
||||
package supports are mirrored as methods on a viper.
|
||||
|
||||
Example:
|
||||
|
||||
x := viper.New()
|
||||
y := viper.New()
|
||||
```go
|
||||
x := viper.New()
|
||||
y := viper.New()
|
||||
|
||||
x.SetDefault("ContentDir", "content")
|
||||
y.SetDefault("ContentDir", "foobar")
|
||||
x.SetDefault("ContentDir", "content")
|
||||
y.SetDefault("ContentDir", "foobar")
|
||||
|
||||
...
|
||||
//...
|
||||
```
|
||||
|
||||
When working with multiple vipers, it is up to the user to keep track of
|
||||
the different vipers.
|
||||
When working with multiple vipers, it is up to the user to keep track of the
|
||||
different vipers.
|
||||
|
||||
## Q & A
|
||||
|
||||
|
|
@ -425,13 +595,13 @@ Q: Why not INI files?
|
|||
|
||||
A: Ini files are pretty awful. There’s no standard format, and they are hard to
|
||||
validate. Viper is designed to work with JSON, TOML or YAML files. If someone
|
||||
really wants to add this feature, I’d be happy to merge it. It’s easy to
|
||||
specify which formats your application will permit.
|
||||
really wants to add this feature, I’d be happy to merge it. It’s easy to specify
|
||||
which formats your application will permit.
|
||||
|
||||
Q: Why is it called “Viper”?
|
||||
|
||||
A: Viper is designed to be a [companion](http://en.wikipedia.org/wiki/Viper_(G.I._Joe)) to
|
||||
[Cobra](https://github.com/spf13/cobra). While both can operate completely
|
||||
A: Viper is designed to be a [companion](http://en.wikipedia.org/wiki/Viper_(G.I._Joe))
|
||||
to [Cobra](https://github.com/spf13/cobra). While both can operate completely
|
||||
independently, together they make a powerful pair to handle much of your
|
||||
application foundation needs.
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue