config

Documentation

Overview

Package config provides configuration loading logic. Similar to how engines and plugins work each sub-package of implements a TransformationProvider interface, which provides a method to transform configuration values.

The top-level config file for taskcluster-worker has the following form:

transforms:
 - packet
 - env
 - secrets
config:
 ... // options to be transformed

In the example above configuration options from `config` will be transformed by the packet, env, and secrets TransformationProviders, in the order given.

After all configured TransformationProviders have run the configuration object constructed will be validated against the config schema required by the 'worker' package.

A TransformationProvider gets the configuration object and can do any transformations it desires. For example the "env" transformation will replace any object on the form {$env: VAR} with the value of the environment variable VAR.

Index

• func Load(data []byte, monitor runtime.Monitor) (map[string]interface{}, error)
• func LoadFromFile(filename string, monitor runtime.Monitor) (interface{}, error)
• func Providers() map[string]TransformationProvider
• func Register(name string, provider TransformationProvider)
• func ReplaceObjects(config map[string]interface{}, key string, ...) error
• func Schema() schematypes.Object
• type TransformationProvider

Functions

func Load

func Load(data []byte, monitor runtime.Monitor) (map[string]interface{}, error)

Load configuration from YAML config object.

func LoadFromFile

func LoadFromFile(filename string, monitor runtime.Monitor) (interface{}, error)

LoadFromFile will load configuration options from a YAML file and validate against the config file schema, returning an error message explaining what went wrong if unsuccessful.

func Providers

func Providers() map[string]TransformationProvider

Providers returns a map of the registered TransformationProvider.

func Register

func Register(name string, provider TransformationProvider)

Register will register a TransformationProvider. This is intended to be called at static initialization time (in func init()), and will thus panic if the given name already is in use.

func ReplaceObjects

func ReplaceObjects(
	config map[string]interface{},
	key string,
	replacement func(obj map[string]interface{}) (interface{}, error),
) error

ReplaceObjects will traverse through the config object and replace all objects that has a the given '$' + key property with the value returned from replacement(obj).

This is useful when implementing TransformationProviders.

func Schema

func Schema() schematypes.Object

Schema returns the configuration file schema

Types

type TransformationProvider

type TransformationProvider interface {
	Transform(config map[string]interface{}, monitor runtime.Monitor) error
}

A TransformationProvider provides a method Transform(config) that knows how to transform the configuration object. Typically, by replacing objects matching a specific pattern or overwriting specific values.

The config object is a simple JSON compatible structure, and Transform() should maintain this property. That means it consists of the following types:

• map[string]interface{}
• []interface{}
• string
• float64
• bool
• nil