env

Documentation

Overview

Built-in mechanism for loading configurations(properties) from various source.

ConfigLoader

You can use "DefaultLoader" to load configuration by default.

evn := DefaultLoader.New().
  ParseFlags().
  Load()

Documentation: https://github.com/mikelue/go-misc/blob/master/ioc/frangipani/README.md

ConfigBuilder

You can use this object to customized the behavior of loading configurations.

env := NewConfigBuilder().
  Priority(CL_ENVVAR, CL_ARGS, CL_CONFIG_FILE, CL_PWD).
  Prefix("dog").
  Build().
  ParseFlags().Load()

Index

• Constants
• type ConfigBuilder
  • func NewConfigBuilder() *ConfigBuilder
  • func (self *ConfigBuilder) Build() ConfigLoader
  • func (self *ConfigBuilder) DefaultWithMap(properties map[string]interface{}) *ConfigBuilder
  • func (self *ConfigBuilder) DefaultWithViper(viper *viper.Viper) *ConfigBuilder
  • func (self *ConfigBuilder) Pflags(newFlags *pflag.FlagSet) *ConfigBuilder
  • func (self *ConfigBuilder) Prefix(prefix string) *ConfigBuilder
  • func (self *ConfigBuilder) Priority(sources ...ConfigSource) *ConfigBuilder
• type ConfigLoader
• type ConfigSource
• type IDefaultLoader
  • func (self *IDefaultLoader) New() ConfigLoader
  • func (*IDefaultLoader) WithMap(properties map[string]interface{}) ConfigLoader
  • func (*IDefaultLoader) WithViper(viper *viper.Viper) ConfigLoader

Examples

• ConfigBuilder
• IDefaultLoader.New
• IDefaultLoader.WithMap
• IDefaultLoader.WithViper

Constants

const (
	// Properties packed as JSON format
	FLAG_CONFIG_JSON = ".config.json"
	// Properties packed as YAML format
	FLAG_CONFIG_YAML = ".config.yaml"
	// Properties from external file
	FLAG_CONFIG_FILES = PROP_CONFIG_FILES
	// For activated profiles(see frangipani)
	FLAG_ACITVE_PROFILES = PROP_PROFILES_ACTIVE
)

const (
	// Name of environment variable for packed properties as JSON format
	ENVVAR_JSON = "_CONFIG_JSON"
	// Name of environment variable for packed properties as YAML format
	ENVVAR_YAML = "_CONFIG_YAML"
	// Name of environment variable for external file
	ENVVAR_FILE = "_CONFIG_FILES"
	// Name of environment variable for activated profiles(see frangipani)
	ENVVAR_PROFILES_ACTIVE = "_PROFILES_ACTIVE"
)

const (
	// Default prefix of loading mechanism
	DEFAULT_PREFIX = "fgapp"

	// Default name of logger
	//
	// See: https://github.com/go-eden/slf4go-logrus
	LOGGER_NAME_CONFIG = "fgapp.config"

	// The configuration file
	PROP_CONFIG_FILES = ".config.files"
	// The profiles to be activated
	PROP_PROFILES_ACTIVE = ".profiles.active"
)

Types

type ConfigBuilder

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

This object is the center of customizing loading mechanisms of configurations.

Example

oldOsArgs := os.Args

defer func() {
	os.Args = oldOsArgs
}()

// This is just to make testing re-runnable
pflag.CommandLine = pflag.NewFlagSet("ExampleIDefaultLoader_New", pflag.ExitOnError)

os.Args = []string{
	`--guava.config.yaml={ db.host: apple-linux, db.port: 8871 }`,
}
os.Setenv(
	"GUAVA_CONFIG_YAML",
	`{ db.host: guava-linux }`,
)

// Makes the source of environment variables having higher priority than arguments
typedProperties := NewConfigBuilder().
	Prefix("guava").
	Priority(CL_ENVVAR, CL_ARGS).
	Build().
	ParseFlags().Load().
	Typed()

fmt.Printf("%s:%d", typedProperties.GetString("db.host"), typedProperties.GetInt("db.port"))

Output:

guava-linux:8871

func NewConfigBuilder

func NewConfigBuilder() *ConfigBuilder

Consturcts a new builder so that you can custoimze the loading of configurations.

func (*ConfigBuilder) Build

func (self *ConfigBuilder) Build() ConfigLoader

Builds the "ConfigLoader", which is used to load an instance of "Environment".

func (*ConfigBuilder) DefaultWithMap

func (self *ConfigBuilder) DefaultWithMap(properties map[string]interface{}) *ConfigBuilder

Sets up the default properties, this has the lowest priority set by "Priority".

func (*ConfigBuilder) DefaultWithViper

func (self *ConfigBuilder) DefaultWithViper(viper *viper.Viper) *ConfigBuilder

Sets up the default properties(by viper), this has the lowest priority set by "Priority".

See spf13/Viper: https://github.com/spf13/viper

func (*ConfigBuilder) Pflags

func (self *ConfigBuilder) Pflags(newFlags *pflag.FlagSet) *ConfigBuilder

Sets-up customized flags for parsing of arguments

func (*ConfigBuilder) Prefix

func (self *ConfigBuilder) Prefix(prefix string) *ConfigBuilder

Sets the prefix of loading.

This can affect naming of various sources.

See detail: https://github.com/mikelue/go-misc/blob/master/ioc/frangipani/README.md

func (*ConfigBuilder) Priority

func (self *ConfigBuilder) Priority(sources ...ConfigSource) *ConfigBuilder

Sets the priority of supported sources.

The higher priority of sources should be put in front of others.

See: ConfigSource

type ConfigLoader

type ConfigLoader interface {
	// Loads the environment object
	Load() fg.Environment
	// Parse the flags
	ParseFlags() ConfigLoader
}

To load a bunch of sources as "Environment".

type ConfigSource

type ConfigSource int

CL - stands for [C]onfiguration [L]oading

const (
	// The source comes from default names of files in $XDG_CONFIG_HOME
	CL_XDG ConfigSource = 1
	// The source comes from arguments:
	//   --fgapp.config.yaml
	//   --fgapp.config.json
	//   --fgapp.config.config.files
	//   --fgapp.config.files
	//   --fgapp.profiles.active
	CL_ARGS ConfigSource = 2
	// The source comes from environment variables:
	//   $FGAPP_CONFIG_YAML
	//   $FGAPP_CONFIG_JSON
	//   $FGAPP_CONFIG_FILES
	//   $FGAPP_PROFILES_ACTIVE
	CL_ENVVAR ConfigSource = 3
	// The source comes from provided file name
	CL_CONFIG_FILE ConfigSource = 4
	// The source comes default names of files in working directory
	//
	// See: os.Getwd()
	CL_PWD ConfigSource = 5
	// The source comes default names of files in directory of command
	//
	// See: os.Args[0]
	CL_CMDDIR ConfigSource = 6
)

type IDefaultLoader

type IDefaultLoader int

var DefaultLoader IDefaultLoader

Method space used to construct new instance of "ConfigLoader"

func (*IDefaultLoader) New

func (self *IDefaultLoader) New() ConfigLoader

With default setting for loading configurations

Example

// This is just to make testing re-runnable
pflag.CommandLine = pflag.NewFlagSet("ExampleIDefaultLoader_New", pflag.ExitOnError)

os.Setenv(
	"FGAPP_CONFIG_YAML",
	`{ db.host: dev-linux, db.port: 1980 }`,
)

typedProperties := DefaultLoader.New().
	ParseFlags().Load().
	Typed()

fmt.Printf("%s:%d",
	typedProperties.GetString("db.host"),
	typedProperties.GetInt("db.port"),
)

Output:

dev-linux:1980

func (*IDefaultLoader) WithMap

func (*IDefaultLoader) WithMap(properties map[string]interface{}) ConfigLoader

With some default values(as map) and settings for loading configurations

Example

// This is just to make testing re-runnable
pflag.CommandLine = pflag.NewFlagSet("ExampleIDefaultLoader_New", pflag.ExitOnError)

os.Setenv(
	"FGAPP_CONFIG_YAML",
	`{ db.host: dev-linux }`,
)

typedProperties := DefaultLoader.
	WithMap(map[string]interface{}{
		"db.port": 87,
	}).
	ParseFlags().Load().
	Typed()

fmt.Printf("%s:%d",
	typedProperties.GetString("db.host"),
	typedProperties.GetInt("db.port"),
)

Output:

dev-linux:87

func (*IDefaultLoader) WithViper

func (*IDefaultLoader) WithViper(viper *viper.Viper) ConfigLoader

With some default values(as "*viper.Viper") and settings for loading configurations

Example

// This is just to make testing re-runnable
pflag.CommandLine = pflag.NewFlagSet("ExampleIDefaultLoader_New", pflag.ExitOnError)

os.Setenv(
	"FGAPP_CONFIG_YAML",
	`{ db.host: dev-linux }`,
)

viper := viper.New()
viper.Set("db.port", 998)

typedProperties := DefaultLoader.
	WithViper(viper).
	ParseFlags().Load().
	Typed()

fmt.Printf("%s:%d",
	typedProperties.GetString("db.host"),
	typedProperties.GetInt("db.port"),
)

Output:

dev-linux:998