viper

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Published: Oct 24, 2016 License: MIT Imports: 25 Imported by: 6

README

viper logo

Go configuration with fangs!

Many Go projects are built using Viper including:

Build Status GoDoc

What is Viper (aka: cfg)?

Viper is a complete configuration solution for go applications including 12 factor apps. It is designed to work within an application, and can handle all types of configuration needs and formats. It supports:

  • setting defaults
  • reading from JSON, TOML, YAML, HCL, and Java properties config files
  • live watching and re-reading of config files (optional)
  • reading from environment variables
  • reading from remote config systems (etcd or Consul), and watching changes
  • reading from command line flags
  • reading from buffer
  • setting explicit values

Viper can be thought of as a registry for all of your applications configuration needs.

Why Use This?

When building a modern application, you don’t want to worry about configuration file formats; you want to focus on building awesome software. This package is here to help with that.

It does the following for you:

  1. Find, load, and unmarshal a configuration file in JSON, TOML, YAML, HCL, or Java properties formats.
  2. Provide a mechanism to set default values for your different configuration options.
  3. Provide a mechanism to set override values for options specified through command line flags.
  4. Provide an alias system to easily rename parameters without breaking existing code.
  5. Make it easy to tell the difference between when a user has provided a command line or config file which is the same as the default.

Viper uses the following precedence order. Each item takes precedence over the item below it:

  • explicit call to Set
  • flag
  • env
  • config
  • key/value store
  • default

Note that configuration "keys" are case insensitive.

Putting Values into the system (aka: viper)

Establishing Defaults

A good configuration system will support default values. A default value is not required for a key, but it's useful in the event that a key hasn’t been set via config file, environment variable, remote configuration or flag.

Examples:

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

Reading Config Files

Viper requires minimal configuration so it knows where to look for config files. Viper supports JSON, TOML, YAML, HCL, and Java Properties files. Viper can search multiple paths, but currently a single Viper instance only supports a single configuration file. Viper does not default to any configuration search paths leaving defaults decision to an application.

Here is an example of how to use Viper to search for and read a configuration file. None of the specific paths are required, but at least one path should be provided where a configuration file is expected.

viper.SetConfigName("config") // name of config file (without extension)
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(".")               // optionally look for config in the working directory
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))
}

Watching and re-reading config files

Viper supports the ability to have your application live read a config file while running.

Gone are the days of needing to restart a server to have a config take effect, viper powered applications can read an update to a config file while running and not miss a beat.

Simply tell the viper instance to watchConfig. Optionally you can provide a function for Viper to run each time a change occurs.

Make sure you add all of the configPaths prior to calling WatchConfig()

		viper.WatchConfig()
		viper.OnConfigChange(func(e fsnotify.Event) {
			fmt.Println("Config file changed:", e.Name)
		})

Reading Config from io.Reader

Viper predefines many configuration sources such as files, environment variables, flags, and remote K/V store, but you are not bound to them. You can also implement your own required configuration source and feed it to viper.

viper.SetConfigType("yaml") // or viper.SetConfigType("YAML")

// any approach to require this configuration into your program.
var yamlExample = []byte(`
Hacker: true
name: steve
hobbies:
- skateboarding
- snowboarding
- go
clothing:
  jacket: leather
  trousers: denim
age: 35
eyes : brown
beard: true
`)

viper.ReadConfig(bytes.NewBuffer(yamlExample))

viper.Get("name") // this would be "steve"

Setting Overrides

These could be from a command line flag, or from your own application logic.

viper.Set("Verbose", true)
viper.Set("LogFile", LogFile)

Registering and Using Aliases

Aliases permit a single value to be referenced by multiple keys

viper.RegisterAlias("loud", "Verbose")

viper.Set("verbose", true) // same result as next line
viper.Set("loud", true)   // same result as prior line

viper.GetBool("loud") // true
viper.GetBool("verbose") // true

Working with Environment Variables

Viper has full support for environment variables. This enables 12 factor applications out of the box. There are four methods that exist to aid working with ENV:

  • AutomaticEnv()
  • BindEnv(string...) : error
  • SetEnvPrefix(string)
  • SetEnvReplacer(string...) *strings.Replacer

When working with ENV variables, it’s important to recognize that Viper treats ENV variables as case sensitive.

Viper provides a mechanism to try to ensure that ENV variables are unique. By using SetEnvPrefix, you can tell Viper to use add a prefix while reading from the environment variables. Both BindEnv and AutomaticEnv will use this prefix.

BindEnv takes one or two parameters. The first parameter is the key name, the second is the name of the environment variable. The name of the environment variable is case sensitive. If the ENV variable name is not provided, then Viper will automatically assume that the key name matches the ENV variable name, but the ENV variable is IN ALL CAPS. When you explicitly provide the ENV variable name, it does not automatically add the prefix.

One important thing to recognize when working with ENV variables is that the value will be read each time it is accessed. Viper does not fix the value when the BindEnv is called.

AutomaticEnv is a powerful helper especially when combined with SetEnvPrefix. When called, Viper will check for an environment variable any time a viper.Get request is made. It will apply the following rules. It will check for a environment variable with a name matching the key uppercased and prefixed with the EnvPrefix if set.

SetEnvReplacer allows you to use a strings.Replacer object to rewrite Env keys to an extent. This is useful if you want to use - or something in your Get() calls, but want your environmental variables to use _ delimiters. An example of using it can be found in viper_test.go.

Env example
SetEnvPrefix("spf") // will be uppercased automatically
BindEnv("id")

os.Setenv("SPF_ID", "13") // typically done outside of the app

id := Get("id") // 13

Working with Flags

Viper has the ability to bind to flags. Specifically, Viper supports Pflags as used in the Cobra library.

Like BindEnv, the value is not set when the binding method is called, but when it is accessed. This means you can bind as early as you want, even in an init() function.

The BindPFlag() method provides this functionality.

Example:

serverCmd.Flags().Int("port", 1138, "Port to run Application server on")
viper.BindPFlag("port", serverCmd.Flags().Lookup("port"))

The use of pflag in Viper does not preclude the use of other packages that use the flag package from the standard library. The pflag package can handle the flags defined for the flag package by importing these flags. This is accomplished by a calling a convenience function provided by the pflag package called AddGoFlagSet().

Example:

package main

import (
	"flag"
	"github.com/spf13/pflag"
)

func main() {
	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
	pflag.Parse()
    ...
}
Flag interfaces

Viper provides two Go interfaces to bind other flag systems if you don't use Pflags.

FlagValue represents a single flag. This is a very simple example on how to implement this interface:

type myFlag struct {}
func (f myFlag) HasChanged() bool { return false }
func (f myFlag) Name() string { return "my-flag-name" }
func (f myFlag) ValueString() string { return "my-flag-value" }
func (f myFlag) ValueType() string { return "string" }

Once your flag implements this interface, you can simply tell Viper to bind it:

viper.BindFlagValue("my-flag-name", myFlag{})

FlagValueSet represents a group of flags. This is a very simple example on how to implement this interface:

type myFlagSet struct {
	flags []myFlag
}

func (f myFlagSet) VisitAll(fn func(FlagValue)) {
	for _, flag := range flags {
		fn(flag)
	}
}

Once your flag set implements this interface, you can simply tell Viper to bind it:

fSet := myFlagSet{
	flags: []myFlag{myFlag{}, myFlag{}},
}
viper.BindFlagValues("my-flags", fSet)

Remote Key/Value Store Support

To enable remote support in Viper, do a blank import of the viper/remote package:

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.

Viper uses crypt to retrieve configuration from the K/V store, which means that you can store your configuration values encrypted and have them automatically decrypted if you have the correct gpg keyring. Encryption is optional.

You can use remote configuration in conjunction with local configuration, or independently of it.

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.

$ go get github.com/xordataexchange/crypt/bin/crypt
$ crypt set -plaintext /config/hugo.json /Users/hugo/settings/config.json

Confirm that your value was set:

$ crypt get -plaintext /config/hugo.json

See the crypt documentation for examples of how to set encrypted values, or how to use Consul.

Remote Key/Value Store Example - Unencrypted

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, supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop"
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,  supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop"
err := viper.ReadRemoteConfig()

Watching Changes in etcd - Unencrypted

// 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, supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop"

// read from remote config the first time.
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)
	}
}()

Getting Values From Viper

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

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")
}

Accessing nested keys

The accessor methods also accept formatted paths to deeply nested keys. For example, if the following JSON file is loaded:

{
    "host": {
        "address": "localhost",
        "port": 5799
    },
    "datastore": {
        "metric": {
            "host": "127.0.0.1",
            "port": 3099
        },
        "warehouse": {
            "host": "198.0.0.1",
            "port": 2112
        }
    }
}

Viper can access a nested field by passing a . delimited path of keys:

GetString("datastore.metric.host") // (returns "127.0.0.1")

This obeys the precedence rules established above; the search for the path will cascade through the remaining configuration registries until found.

For example, given this configuration file, both datastore.metric.host and datastore.metric.port are already defined (and may be overridden). If in addition datastore.metric.protocol was defined in the defaults, Viper would also find it.

However, if datastore.metric was overridden (by a flag, an environment variable, the Set() method, …) with an immediate value, then all sub-keys of datastore.metric become undefined, they are “shadowed” by the higher-priority configuration level.

Lastly, if there exists a key that matches the delimited key path, its value will be returned instead. E.g.

{
    "datastore.metric.host": "0.0.0.0",
    "host": {
        "address": "localhost",
        "port": 5799
    },
    "datastore": {
        "metric": {
            "host": "127.0.0.1",
            "port": 3099
        },
        "warehouse": {
            "host": "198.0.0.1",
            "port": 2112
        }
    }
}

GetString("datastore.metric.host") // returns "0.0.0.0"

Extract sub-tree

Extract sub-tree from Viper.

For example, viper represents:

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

After executing:

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

subv represents:

max-items: 100
item-size: 64

Suppose we have:

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:

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:

  • Unmarshal(rawVal interface{}) : error
  • UnmarshalKey(key string, rawVal interface{}) : error

Example:

type config struct {
	Port int
	Name string
	PathMap string `mapstructure:"path_map"`
}

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.

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.

Example:

x := viper.New()
y := viper.New()

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.

Q & A

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.

Q: Why is it called “Viper”?

A: Viper is designed to be a companion to Cobra. While both can operate completely independently, together they make a powerful pair to handle much of your application foundation needs.

Q: Why is it called “Cobra”?

A: Is there a better name for a commander?

Documentation

Index

Constants

View Source
const (
	AvailCLI            = 1 << iota // global has a related CLI option available
	AvailEnv                        // global can be set in DVLN_<GLOB>
	AvailCfgFile                    // global can be set in dvln cfg file
	AvailRemote                     // global can be set in remote cfg mechanism
	AvailVCSPkg                     // global can be set on VCS pkg
	AvailVCSMPkg                    // global can be set on VCS multi-pkg pkg
	AvailVCSCodeBasePkg             // global can be set on VCS codebase pkg
	AvailVCSHookPkg                 // global can be set on VCS hook pkg
	AvailVCSPluginPkg               // global can be set on VCS plugin pkg
	AvailDefault                    // global value is coming from default setting

	ConstGlobal      = AvailDefault
	InternalGlobal   = AvailDefault
	BasicGlobal      = AvailEnv | AvailCfgFile | AvailDefault
	CLIGlobal        = AvailCLI | BasicGlobal
	CLIOnlyGlobal    = AvailCLI | AvailDefault
	VCSGlobal        = AvailVCSPkg | AvailVCSMPkg | AvailVCSCodeBasePkg | AvailVCSHookPkg | AvailVCSPluginPkg | AvailDefault
	BasicVCSGlobal   = BasicGlobal | VCSGlobal
	FullVCSGlobal    = CLIGlobal | VCSGlobal
	BasicVCSCBGlobal = BasicGlobal | AvailVCSCodeBasePkg
	FullVCSCBGlobal  = CLIGlobal | AvailVCSCodeBasePkg
)

These fields describe where one can configure a given 'key' (glob variable) from so that the calling tool can control which settings are honored. Of course CLI use/setting of a given variable/key must be configured elsewhere such as via 'cobra' (the 'cli' commander pkg). For 'dvln' needs I've updated the table to also include other ways that variables/keys can be set so if you use this in your own library you can ignore those levels or trim them out. The order of evaluation for config levels is:

Overrides (set via this packages Set() method used after CLI processed)
CLI (option given to the command line tool pushed into here via Set())
Env (in the users env)
Local Config File (in the users tool config file)
Remote Key/Val (via a remote key/value store or config)
Pkg Singleton Settings (dvln: on an individual "leaf" VCS package)
Multi-Package (MPkg) Settings (dvln: on a multi-pkg VCS package)
CodeBase Settings (dvln: on a codebase definition VCS package)
Default Settings (viper: set via SetDefault(...)

Note that if keys (globals/variables) have augmented description data added such as where they can be set, at which level(s), then settings at that level for that variable should not be honored (only valid levels honored). This is not fully implemented except for the 'dvln:' focused levels above.

Feature: the VCS Pkg/Codebase related settings in terms of where keys (globs)

can be set from, but the builtin 'viper' options don't yet honor
these and could be modified to honor them coming up (ie: this way
one can use this as a "globals" mechanism and avoid chances of clients
overriding some settings via env or config file settings)

Variables

View Source
var APIVersionName = "apiver"

APIVersionName is needed for JSON output of the *Viper structure, if no api version is set then the JSON is bogus (defaults to "apiver" as the name of the key being looked for)

View Source
var LookName = "look"

LookName is used for the String() method to dump a viper's user focused info (relating to what the DE can set in the env or in a config file) and will be a string set to either "json" or "text" (ie: String() will examine viper settings and get whatever "look" is set to and use that as the look)

View Source
var RemoteConfig remoteConfigFactory

RemoteConfig is optional, see the remote package

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

SupportedExts are universally supported extensions.

View Source
var SupportedRemoteProviders = []string{"etcd", "consul"}

SupportedRemoteProviders are universally supported remote providers.

View Source
var TerseName = "terse"

TerseName is used to dump brief information about the viper cfg|env, so if "terse" is set as a key and is true then a reduced amount of data will be dumped (note that VerboseName's setting, if set, overrides this)

View Source
var UserCfgTypeName = "globs"

UserCfgTypeName is the viper config key that will be a string of either 'cfg' or 'env' to control the String() method returning data about what keys can be set in the config file or what env vars can be used by the user

View Source
var VerboseName = "verbose"

VerboseName is used to decide to dump the information verbosely or not, so if "verbose" is set to 'true' (as a viper key) then verbose output is on

Functions

func AddConfigPath

func AddConfigPath(in string)

AddConfigPath adds a path for Viper to search for the config file in. Can be called multiple times to define multiple search paths.

func AddRemoteProvider

func AddRemoteProvider(provider, endpoint, path string) error

AddRemoteProvider adds a remote configuration source. Remote Providers are searched in the order they are added. provider is a string value, "etcd" or "consul" are currently supported. endpoint is the url. etcd requires http://ip:port consul requires ip:port path is the path in the k/v store to retrieve configuration To retrieve a config file called myapp.json from /configs/myapp.json you should set path to /configs and set config name (SetConfigName()) to "myapp"

func AddSecureRemoteProvider

func AddSecureRemoteProvider(provider, endpoint, path, secretkeyring string) error

AddSecureRemoteProvider adds a remote configuration source. Secure Remote Providers are searched in the order they are added. provider is a string value, "etcd" or "consul" are currently supported. endpoint is the url. etcd requires http://ip:port consul requires ip:port secretkeyring is the filepath to your openpgp secret keyring. e.g. /etc/secrets/myring.gpg path is the path in the k/v store to retrieve configuration To retrieve a config file called myapp.json from /configs/myapp.json you should set path to /configs and set config name (SetConfigName()) to "myapp" Secure Remote Providers are implemented with github.com/xordataexchange/crypt

func AllKeys

func AllKeys() []string

AllKeys returns all keys holding a value, regardless of where they are set. Nested keys are returned with a v.keyDelim (= ".") separator

func AllSettings

func AllSettings() map[string]interface{}

AllSettings merges all settings and returns them as a map[string]interface{}.

func AutomaticEnv

func AutomaticEnv()

AutomaticEnv has Viper check ENV variables for all.

func BindEnv

func BindEnv(input ...string) error

BindEnv binds a Viper key to a ENV variable. ENV variables are case sensitive. If only a key is provided, it will use the env key matching the key, uppercased. EnvPrefix will be used when set when env name is not provided.

func BindFlagValue

func BindFlagValue(key string, flag FlagValue) error

BindFlagValue binds a specific key to a FlagValue. Example(where serverCmd is a Cobra instance):

serverCmd.Flags().Int("port", 1138, "Port to run Application server on")
Viper.BindFlagValue("port", serverCmd.Flags().Lookup("port"))

func BindFlagValues

func BindFlagValues(flags FlagValueSet) error

BindFlagValues binds a full FlagValue set to the configuration, using each flag's long name as the config key.

func BindPFlag

func BindPFlag(key string, flag *pflag.Flag) error

BindPFlag binds a specific key to a pflag (as used by cobra). Example (where serverCmd is a Cobra instance):

func BindPFlags

func BindPFlags(flags *pflag.FlagSet) error

BindPFlags binds a full flag set to the configuration, using each flag's long name as the config key.

func ClearConfigSettings

func ClearConfigSettings()

ClearConfigSettings clears out any previously added config file paths and names from previous runs (if run under, say, a test hardness) and allows the next run to cleanly re-determine what config file to read in

func ClearPFlag

func ClearPFlag(key string)

ClearPFlag is a bit of a hack, used to be replace but was having issues so now it's a simple mechanism to clear viper's knowledge of a command line flag so that an override can override a command line setting (the way viper works is that if pflags has a flag set and a Set() has been called it'll actually prefer the pflag setting, not the override setting). If you want it to prefer the Set() override setting you can use this, typically only used if one is using SetPflags() above.

func ConfigFileUsed

func ConfigFileUsed() string

ConfigFileUsed returns the file used to populate the config registry

func Debug

func Debug()

Debug prints all configuration registries for debugging purposes.

func Filesys

func Filesys() afero.Fs

Filesys returns current filesystem used for message writing, can be nil if it hasn't been set yet

func Get

func Get(key string) interface{}

Get can retrieve any value given the key to use. Get has the behavior of returning the value associated with the first place from where it is set. Viper will check in the following order: override, flag, env, config file, key/value store, default

Get returns an interface. For a specific value use one of the Get____ methods.

func GetBool

func GetBool(key string) bool

GetBool returns the value associated with the key as a boolean.

func GetDuration

func GetDuration(key string) time.Duration

GetDuration returns the value associated with the key as a duration.

func GetFloat64

func GetFloat64(key string) float64

GetFloat64 returns the value associated with the key as a float64.

func GetInt

func GetInt(key string) int

GetInt returns the value associated with the key as an integer.

func GetInt64

func GetInt64(key string) int64

GetInt64 returns the value associated with the key as an integer.

func GetSizeInBytes

func GetSizeInBytes(key string) uint

GetSizeInBytes returns the size of the value associated with the given key in bytes.

func GetString

func GetString(key string) string

GetString returns the value associated with the key as a string.

func GetStringMap

func GetStringMap(key string) map[string]interface{}

GetStringMap returns the value associated with the key as a map of interfaces.

func GetStringMapString

func GetStringMapString(key string) map[string]string

GetStringMapString returns the value associated with the key as a map of strings.

func GetStringMapStringSlice

func GetStringMapStringSlice(key string) map[string][]string

GetStringMapStringSlice returns the value associated with the key as a map to a slice of strings.

func GetStringSlice

func GetStringSlice(key string) []string

GetStringSlice returns the value associated with the key as a slice of strings.

func GetTime

func GetTime(key string) time.Time

GetTime returns the value associated with the key as time.

func InConfig

func InConfig(key string) bool

InConfig checks to see if the given key (or an alias) is in the config file.

func IsSet

func IsSet(key string) bool

IsSet checks to see if the key has been set in any of the data locations.

func MergeConfig

func MergeConfig(in io.Reader) error

MergeConfig merges a new configuration with an existing config.

func MergeInConfig

func MergeInConfig() error

MergeInConfig merges a new configuration with an existing config.

func OnConfigChange

func OnConfigChange(run func(in fsnotify.Event))

func ReadConfig

func ReadConfig(in io.Reader) error

ReadConfig will read a configuration file, setting existing keys to nil if the key does not exist in the file.

func ReadInConfig

func ReadInConfig() error

ReadInConfig will discover and load the configuration file from disk and key/value stores, searching in one of the defined paths.

func ReadRemoteConfig

func ReadRemoteConfig() error

ReadRemoteConfig attempts to get configuration from a remote source and read it in the remote configuration registry.

func RegisterAlias

func RegisterAlias(alias string, key string)

RegisterAlias is a way to provide another accessor for the same key. This enables one to change a name without breaking the application

func Reset

func Reset()

Reset is intended for testing, will reset all to default settings. In the public interface for the viper package so applications can use it in their testing as well.

func Set

func Set(key string, value interface{})

Set sets the value for the key in the override regiser. Will be used instead of values obtained via flags, config file, ENV, default, or key/value store.

func SetConfigFile

func SetConfigFile(in string)

SetConfigFile explicitly defines the path, name and extension of the config file Viper will use this and not check any of the config paths

func SetConfigName

func SetConfigName(in string)

SetConfigName sets name for the config file. Does not include extension.

func SetConfigType

func SetConfigType(in string)

SetConfigType sets the type of the configuration returned by the remote source, e.g. "json".

func SetDefault

func SetDefault(key string, value interface{})

SetDefault sets the default value for this key. Default only used when no value is provided by the user via flag, config or ENV.

func SetDesc

func SetDesc(key string, desc string, useLevel UseLevel, useScope int)

SetDesc sets the optional description for this key.

func SetEnvKeyReplacer

func SetEnvKeyReplacer(r *strings.Replacer)

SetEnvKeyReplacer sets the strings.Replacer on the viper object Useful for mapping an environmental variable to a key that does not match it.

func SetEnvPrefix

func SetEnvPrefix(in string)

SetEnvPrefix defines a prefix that ENVIRONMENT variables will use. E.g. if your prefix is "spf", the env registry will look for env. variables that start with "SPF_"

func SetFilesys

func SetFilesys(fs afero.Fs)

SetFilesys will set the filesystem wrapper up to write to the real filesystem or a virtual filesystem if preferred (see afero). If the filesys that is passed in is 'nil' it causes it to "bootstrap" the OS filesystem if none has yet been set, if one is set it ignores nil calls.

func SetFs

func SetFs(fs afero.Fs)

SetFs sets the filesystem to use to read configuration.

func SetPFlags

func SetPFlags(flags *pflag.FlagSet) (err error)

SetPFlags informs viper about CLI flags so it knows what key settings come from the command line. It can be used when viper/cobra/pflags are being used in concert *AND* when one wishes to pre-set all defaults manually (if you do not wish to do that instead use BindPFlags and not SetPFlags). The difference is that this visits all flags and *only* if they are "Changed" (from the CLI) does it identify them as "active" pflags (vs BindPFlags which sets every flag in existence into v.pflags[] and uses SetDefault() so vipers default value comes from the flags default value setting... to use SetPFlags you should have manually set the starting default value for each flag). So here we only put the used CLI's in v.pflags[] and we only use v.Set() to push CLI used args in at the v.override[] level (avoids having the app do these Set's). Goal: this can tie in later w/support for no args to strings/ints/bools where the default would be to take the *options* defined default (thereby putting it into play) over the already pre-set default (if/when desired only)

func SetTypeByDefaultValue

func SetTypeByDefaultValue(enable bool)

SetTypeByDefaultValue enables or disables the inference of a key value's type when the Get function is used based upon a key's default value as opposed to the value returned based on the normal fetch logic.

For example, if a key has a default value of []string{} and the same key is set via an environment variable to "a b c", a call to the Get function would return a string slice for the key if the key's type is inferred by the default value and the Get function would return:

[]string {"a", "b", "c"}

Otherwise the Get function would return:

"a b c"

func Unmarshal

func Unmarshal(rawVal interface{}) error

Unmarshal unmarshals the config into a Struct. Make sure that the tags on the fields of the structure are properly set.

func UnmarshalKey

func UnmarshalKey(key string, rawVal interface{}) error

UnmarshalKey takes a single key and unmarshals it into a Struct.

func WatchConfig

func WatchConfig()

WatchConfig monitors your config file for changes, if any seen then it is re-read. Note that this capability uses fsnotify and is not compatible with the afero filesystem mechanism at this point (so beware).

func WatchRemoteConfig

func WatchRemoteConfig() error

Types

type ConfigFileNotFoundError

type ConfigFileNotFoundError struct {
	// contains filtered or unexported fields
}

ConfigFileNotFoundError denotes failing to find configuration file.

func (ConfigFileNotFoundError) Error

func (fnfe ConfigFileNotFoundError) Error() string

Error returns the formatted configuration error.

type ConfigParseError

type ConfigParseError struct {
	// contains filtered or unexported fields
}

ConfigParseError denotes failing to parse configuration file.

func (ConfigParseError) Error

func (pe ConfigParseError) Error() string

Error returns the formatted configuration error.

type FlagValue

type FlagValue interface {
	HasChanged() bool
	Name() string
	ValueString() string
	ValueType() string
}

FlagValue is an interface that users can implement to bind different flags to viper.

type FlagValueSet

type FlagValueSet interface {
	VisitAll(fn func(FlagValue))
}

FlagValueSet is an interface that users can implement to bind a set of flags to viper.

type RemoteConfigError

type RemoteConfigError string

RemoteConfigError denotes encountering an error while trying to pull the configuration from the remote provider.

func (RemoteConfigError) Error

func (rce RemoteConfigError) Error() string

Error returns the formatted remote provider error

type RemoteProvider

type RemoteProvider interface {
	Provider() string
	Endpoint() string
	Path() string
	SecretKeyring() string
}

RemoteProvider stores the configuration necessary to connect to a remote key/value store. Optional secretKeyring to unencrypt encrypted values can be provided.

type UnsupportedConfigError

type UnsupportedConfigError string

UnsupportedConfigError denotes encountering an unsupported configuration filetype.

func (UnsupportedConfigError) Error

func (str UnsupportedConfigError) Error() string

Error returns the formatted configuration error.

type UnsupportedRemoteProviderError

type UnsupportedRemoteProviderError string

UnsupportedRemoteProviderError denotes encountering an unsupported remote provider. Currently only etcd and Consul are supported.

func (UnsupportedRemoteProviderError) Error

Error returns the formatted remote provider error.

type UseLevel

type UseLevel int

UseLevel is a type that indicates the level of user should be "at" to use a given config key (variable)... meaning they likely don't want to be setting or playing with it until they reach a given level (or maybe never at all if it is an internal use key/variable setting)

const (
	NoviceUser      UseLevel = iota // for novice level users
	StandardUser                    // for "normal" level users
	ExpertUser                      // for expert level users
	AdminUser                       // for admin level users
	InternalUse                     // for internal use primarily, hides it
	RestrictedUse                   // for any (future) restricted global
	UnknownUseLevel                 // in case we have no setting
)

UseLevels available, just integers at this point

func Desc

func Desc(key string) (string, UseLevel, int)

Desc returns the description, if any, for the given key, if no desc then "" for the description, UnknownUseLevel for UseLevel and 0 for where it can be set from (ie: nowhere)

func UseLevelString2UseLevel

func UseLevelString2UseLevel(s string) UseLevel

UseLevelString2UseLevel takes the string representation of a user/use level and returns the UseLevel (Go type) that maps to that string, if mapping fails the unknown use level comes back for now

func (UseLevel) String

func (ul UseLevel) String() string

String implements a stringer for the UseLevel type so we can print out a string representations for the user use level setting

type Viper

type Viper struct {
	// contains filtered or unexported fields
}

Viper is a prioritized configuration registry. It maintains a set of configuration sources, fetches values to populate those, and provides them according to the source's priority. The priority of the sources is the following: 1. overrides 2. flags 3. env. variables 4. config file 5. key/value store 5 1/2. the dvln codebase and pkg settings fall into this area 6. defaults

For example, if values from the following sources were loaded:

Defaults : {
	"secret": "",
	"user": "default",
	"endpoint": "https://localhost"
}
Config : {
	"user": "root"
	"secret": "defaultsecret"
}
Env : {
	"secret": "somesecretkey"
}

The resulting config will have the following values:

{
	"secret": "somesecretkey",
	"user": "root",
	"endpoint": "https://localhost"
}

func GetSingleton

func GetSingleton() *Viper

GetSingleton allows one to grab the package global viper instance

func GetViper

func GetViper() *Viper

GetViper gets the global Viper instance.

func New

func New() *Viper

New returns an initialized Viper instance.

func Sub

func Sub(key string) *Viper

Sub returns new Viper instance representing a sub tree of this instance.

func (*Viper) AddConfigPath

func (v *Viper) AddConfigPath(in string)

AddConfigPath is same as like named singleton (but drives off given *Viper)

func (*Viper) AddRemoteProvider

func (v *Viper) AddRemoteProvider(provider, endpoint, path string) error

AddRemoteProvider same as like named singleton (but drives off given *Viper)

func (*Viper) AddSecureRemoteProvider

func (v *Viper) AddSecureRemoteProvider(provider, endpoint, path, secretkeyring string) error

AddSecureRemoteProvider is same as like named singleton (but drives off given *Viper)

func (*Viper) AllKeys

func (v *Viper) AllKeys() []string

AllKeys is same as like named singleton (but drives off given *Viper)

func (*Viper) AllSettings

func (v *Viper) AllSettings() map[string]interface{}

AllSettings is same as like named singleton (but drives off given *Viper)

func (*Viper) AutomaticEnv

func (v *Viper) AutomaticEnv()

AutomaticEnv is same as like named singleton (but drives off given *Viper)

func (*Viper) BindEnv

func (v *Viper) BindEnv(input ...string) error

BindEnv is same as like named singleton (but drives off given *Viper)

func (*Viper) BindFlagValue

func (v *Viper) BindFlagValue(key string, flag FlagValue) error

func (*Viper) BindFlagValues

func (v *Viper) BindFlagValues(flags FlagValueSet) (err error)

func (*Viper) BindPFlag

func (v *Viper) BindPFlag(key string, flag *pflag.Flag) error

BindPFlag is same as like named singleton (but drives off given *Viper)

func (*Viper) BindPFlags

func (v *Viper) BindPFlags(flags *pflag.FlagSet) error

BindPFlags is same as like named singleton (but drives off given *Viper)

func (*Viper) ClearConfigSettings

func (v *Viper) ClearConfigSettings()

ClearConfigSettings is same as like named singleton (but drives off given *Viper)

func (*Viper) ClearPFlag

func (v *Viper) ClearPFlag(key string)

ClearPFlag is same as like named singleton (but drives off given *Viper)

func (*Viper) ConfigFileUsed

func (v *Viper) ConfigFileUsed() string

func (*Viper) Debug

func (v *Viper) Debug()

Debug is same as like named singleton (but drives off given *Viper)

func (*Viper) Desc

func (v *Viper) Desc(key string) (string, UseLevel, int)

Desc is same as like named singleton (but drives off given *Viper)

func (*Viper) Get

func (v *Viper) Get(key string) interface{}

Get is same as like named singleton (but drives off given *Viper)

func (*Viper) GetBool

func (v *Viper) GetBool(key string) bool

GetBool is same as like named singleton (but drives off given *Viper)

func (*Viper) GetDuration

func (v *Viper) GetDuration(key string) time.Duration

GetDuration is same as like named singleton (but drives off given *Viper)

func (*Viper) GetFloat64

func (v *Viper) GetFloat64(key string) float64

GetFloat64 is same as like named singleton (but drives off given *Viper)

func (*Viper) GetInt

func (v *Viper) GetInt(key string) int

GetInt is same as like named singleton (but drives off given *Viper)

func (*Viper) GetInt64

func (v *Viper) GetInt64(key string) int64

func (*Viper) GetSizeInBytes

func (v *Viper) GetSizeInBytes(key string) uint

GetSizeInBytes is same as like named singleton (but drives off given *Viper)

func (*Viper) GetString

func (v *Viper) GetString(key string) string

GetString is same as like named singleton (but drives off given *Viper)

func (*Viper) GetStringMap

func (v *Viper) GetStringMap(key string) map[string]interface{}

GetStringMap is same as like named singleton (but drives off given *Viper)

func (*Viper) GetStringMapString

func (v *Viper) GetStringMapString(key string) map[string]string

GetStringMapString is same as like named singleton (but drives off given *Viper)

func (*Viper) GetStringMapStringSlice

func (v *Viper) GetStringMapStringSlice(key string) map[string][]string

func (*Viper) GetStringSlice

func (v *Viper) GetStringSlice(key string) []string

GetStringSlice is same as like named singleton (but drives off given *Viper)

func (*Viper) GetTime

func (v *Viper) GetTime(key string) time.Time

GetTime is same as like named singleton (but drives off given *Viper)

func (*Viper) InConfig

func (v *Viper) InConfig(key string) bool

InConfig is same as like named singleton (but drives off given *Viper)

func (*Viper) IsSet

func (v *Viper) IsSet(key string) bool

IsSet is same as like named singleton (but drives off given *Viper)

func (*Viper) MergeConfig

func (v *Viper) MergeConfig(in io.Reader) error

func (*Viper) MergeInConfig

func (v *Viper) MergeInConfig() error

func (*Viper) OnConfigChange

func (v *Viper) OnConfigChange(run func(in fsnotify.Event))

func (*Viper) ReadConfig

func (v *Viper) ReadConfig(in io.Reader) error

func (*Viper) ReadInConfig

func (v *Viper) ReadInConfig() error

ReadInConfig is same as like named singleton (but drives off given *Viper)

func (*Viper) ReadRemoteConfig

func (v *Viper) ReadRemoteConfig() error

ReadRemoteConfig is same as like named singleton (but drives off given *Viper)

func (*Viper) RegisterAlias

func (v *Viper) RegisterAlias(alias string, key string)

RegisterAlias is same as like named singleton (but drives off given *Viper)

func (*Viper) Set

func (v *Viper) Set(key string, value interface{})

Set is same as like named singleton (but drives off given *Viper)

func (*Viper) SetConfigFile

func (v *Viper) SetConfigFile(in string)

SetConfigFile is same as like named singleton (but drives off given *Viper)

func (*Viper) SetConfigName

func (v *Viper) SetConfigName(in string)

SetConfigName is same as like named singleton (but drives off given *Viper)

func (*Viper) SetConfigType

func (v *Viper) SetConfigType(in string)

SetConfigType is same as like named singleton (but drives off given *Viper)

func (*Viper) SetDefault

func (v *Viper) SetDefault(key string, value interface{})

SetDefault is same as like named singleton (but drives off given *Viper)

func (*Viper) SetDesc

func (v *Viper) SetDesc(key string, desc string, useLevel UseLevel, useScope int)

SetDesc is same as like named singleton (but drives off given *Viper)

func (*Viper) SetEnvKeyReplacer

func (v *Viper) SetEnvKeyReplacer(r *strings.Replacer)

SetEnvKeyReplacer is same as like named singleton (but drives off given *Viper)

func (*Viper) SetEnvPrefix

func (v *Viper) SetEnvPrefix(in string)

SetEnvPrefix is same as like named singleton method (drives off given *Viper)

func (*Viper) SetFs

func (v *Viper) SetFs(fs afero.Fs)

func (*Viper) SetPFlags

func (v *Viper) SetPFlags(flags *pflag.FlagSet) (err error)

SetPFlags is same as like named singleton (but drives off given *Viper)

func (*Viper) SetTypeByDefaultValue

func (v *Viper) SetTypeByDefaultValue(enable bool)

func (*Viper) String

func (v *Viper) String() string

String will return a string with available config settings through either the env or via the config file so the user can see: - what settings are available, what is their current val (at least) - optionally show description and a user expertise level recommended This method leverages viper itself to decide what the look/format of the string is (text or json) and how to determine if verbose or terse mode is active via the exported package globs: - LookName defaults to "look" as the key to look for "text|json" - TerseName defaults to "terse" as the key, if true then terse - VerboseName defaults to "verbose" as the key, if true then verbose (overrides terse) - APIVersionName defaults to "apiver" and is required for JSON formatted output

func (*Viper) Sub

func (v *Viper) Sub(key string) *Viper

func (*Viper) Unmarshal

func (v *Viper) Unmarshal(rawVal interface{}) error

func (*Viper) UnmarshalExact

func (v *Viper) UnmarshalExact(rawVal interface{}) error

UnmarshalExact unmarshals the config into a Struct, erroring if a field is nonexistent in the destination struct.

func (*Viper) UnmarshalKey

func (v *Viper) UnmarshalKey(key string, rawVal interface{}) error

func (*Viper) WatchConfig

func (v *Viper) WatchConfig()

func (*Viper) WatchRemoteConfig

func (v *Viper) WatchRemoteConfig() error

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