context

README

context  

Provides goroutine-based context state inspired by https://github.com/tylerb/gls and https://github.com/jtolds/gls. It uses the same basic hack as tylerb's library, but adds a stack abstraction that allows nested contexts similar to jtolds' library, but using Enter() and Exit() instead of callback functions.

Documentation

Overview

Package context provides a mechanism for transparently tracking contextual state associated to the current goroutine and even across goroutines.

Index

• type Context
• type Contextual
• type Manager
  • func NewManager() Manager
• type Map
  • func (_m Map) Fill(m Map)

Types

type Context

type Context interface {
	// Enter enters a new level on this Context stack.
	Enter() Context

	// Go starts the given function on a new goroutine.
	Go(fn func())

	// Exit exits the current level on this Context stack.
	Exit()

	// Put puts a key->value pair into the current level of the context stack.
	Put(key string, value interface{}) Context

	// PutIfAbsent puts the given key->value pair into the current level of the
	// context stack if and only if that key is defined nowhere within the context
	// stack (including parent contexts).
	PutIfAbsent(key string, value interface{}) Context

	// PutDynamic puts a key->value pair into the current level of the context
	// stack where the value is generated by a function that gets evaluated at
	// every Read. If the value is a map[string]interface{}, we will unpack the
	// map and set each contained key->value pair independently.
	PutDynamic(key string, valueFN func() interface{}) Context

	// Fill fills the given map with data from this Context
	Fill(m Map)

	// AsMap returns a map containing all values from the supplied obj if it is a
	// Contextual, plus any addition values from along the stack, plus globals if
	// so specified.
	AsMap(obj interface{}, includeGlobals bool) Map

	// Get gets the value at the given key, ascending through the context hierarchy
	// until it finds a value, or returning the global value if none found in contexts.
	Get(key string) (interface{}, bool)
}

Context is a context containing key->value pairs

type Contextual

type Contextual interface {
	// Fill fills the given Map with all of this Contextual's context
	Fill(m Map)
}

Contextual is an interface for anything that maintains its own context.

type Manager

type Manager interface {
	// Enter enters a new level on the current Context stack, creating a new Context
	// if necessary.
	Enter() Context

	// Go starts the given function on a new goroutine but sharing the context of
	// the current goroutine (if it has one).
	Go(func())

	// PutGlobal puts the given key->value pair into the global context.
	PutGlobal(key string, value interface{})

	// PutGlobalDynamic puts a key->value pair into the global context where the
	// value is generated by a function that gets evaluated at every Read. If the
	// value is a map[string]interface{}, we will unpack the map and set each
	// contained key->value pair independently.
	PutGlobalDynamic(key string, valueFN func() interface{})

	// AsMap returns a map containing all values from the supplied obj if it is a
	// Contextual, plus any addition values from along the stack, plus globals if so
	// specified.
	AsMap(obj interface{}, includeGlobals bool) Map

	// Get gets the value at the given key from the current context, ascending through
	// the context hierarchy until it finds a value, or returning the global value if none
	// found in contexts.
	Get(key string) (interface{}, bool)
}

Manager provides the ability to create and access Contexts.

func NewManager

func NewManager() Manager

NewManager creates a new Manager

type Map

type Map map[string]interface{}

Map is a map of key->value pairs.

func (Map) Fill

func (_m Map) Fill(m Map)

Fill implements the method from the Contextual interface.