instancemgmt

Documentation

Overview

Package instancemgmt provides utilities for managing plugin instances.

Index

• type CachedInstance
• type Instance
• type InstanceCallbackFunc
• type InstanceDisposer
• type InstanceManager
  • func New(provider InstanceProvider) InstanceManager
• type InstanceProvider

Types

type CachedInstance

type CachedInstance struct {
	PluginContext backend.PluginContext
	// contains filtered or unexported fields
}

CachedInstance a cached Instance.

type Instance

type Instance interface{}

Instance is a marker interface for an instance.

type InstanceCallbackFunc

type InstanceCallbackFunc interface{}

InstanceCallbackFunc defines the callback function of the InstanceManager.Do method. The argument provided will of type Instance.

type InstanceDisposer

type InstanceDisposer interface {
	Dispose()
}

InstanceDisposer is implemented by an Instance that has a Dispose method, which defines that the instance is disposable.

InstanceManager will call the Dispose method before an Instance is replaced with a new Instance. This allows an Instance to clean up resources in use, if any.

type InstanceManager

type InstanceManager interface {
	// Get returns an Instance.
	//
	// If Instance is cached and not updated it's returned. If Instance is not cached or
	// updated, a new Instance is created and cached before returned.
	Get(ctx context.Context, pluginContext backend.PluginContext) (Instance, error)

	// Do provides an Instance as argument to fn.
	//
	// If Instance is cached and not updated provides as argument to fn. If Instance is not cached or
	// updated, a new Instance is created and cached before provided as argument to fn.
	Do(ctx context.Context, pluginContext backend.PluginContext, fn InstanceCallbackFunc) error
}

InstanceManager manages the lifecycle of instances.

func New

func New(provider InstanceProvider) InstanceManager

New create a new instance manager.

type InstanceProvider

type InstanceProvider interface {
	// GetKey returns a cache key to be used for caching an Instance.
	GetKey(ctx context.Context, pluginContext backend.PluginContext) (interface{}, error)

	// NeedsUpdate returns whether a cached Instance have been updated.
	NeedsUpdate(ctx context.Context, pluginContext backend.PluginContext, cachedInstance CachedInstance) bool

	// NewInstance creates a new Instance.
	NewInstance(ctx context.Context, pluginContext backend.PluginContext) (Instance, error)
}

InstanceProvider defines an instance provider, providing instances.