Package multiwatcher provides watchers that watch the entire model.

The package is responsible for creating, feeding, and cleaning up after multiwatchers. The core worker gets an event stream from an AllWatcherBacking, and manages the multiwatcher Store.

The behaviour of the multiwatchers is very much tied to the Store implementation. The store provides a mechanism to get changes over time.



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func Manifold

func Manifold(config ManifoldConfig) dependency.Manifold

Manifold returns a dependency.Manifold that will run a model cache worker. The manifold outputs a *cache.Controller, primarily for the apiserver to depend on and use.

func NewWorkerShim

func NewWorkerShim(config Config) (worker.Worker, error)

NewWorkerShim is a method used for hooking up the specific NewWorker to the manifold NewWorker config arg. This allows other tests to use the NewWorker to get something that acts as a multiwatcher.Factory without having to cast the worker.

func WorkerFactory

func WorkerFactory(in worker.Worker, out interface{}) error

WorkerFactory extracts a Factory from a *Worker.


type Clock

type Clock interface {
	Now() time.Time

Clock describes the time methods used in this package by the worker.

type Collector

type Collector struct {
	// contains filtered or unexported fields

Collector is a prometheus.Collector that collects metrics about multiwatcher worker.

func NewMetricsCollector

func NewMetricsCollector(worker *Worker) *Collector

NewMetricsCollector returns a new Collector.

func (*Collector) Collect

func (c *Collector) Collect(ch chan<- prometheus.Metric)

Collect is part of the prometheus.Collector interface.

func (*Collector) Describe

func (c *Collector) Describe(ch chan<- *prometheus.Desc)

Describe is part of the prometheus.Collector interface.

type Config

type Config struct {
	Clock                Clock
	Logger               Logger
	Backing              state.AllWatcherBacking
	PrometheusRegisterer prometheus.Registerer
	Cleanup              func()

Config is an argument struct used to create a Worker.

func (Config) Validate

func (config Config) Validate() error

Validate validates the worker configuration.

type Logger

type Logger interface {
	IsTraceEnabled() bool
	Tracef(string, ...interface{})
	Errorf(string, ...interface{})
	Criticalf(string, ...interface{})

Logger describes the logging methods used in this package by the worker.

type ManifoldConfig

type ManifoldConfig struct {
	StateName string
	Clock     Clock
	Logger    Logger

	// NOTE: what metrics do we want to expose here?
	// loop restart count for one.
	PrometheusRegisterer prometheus.Registerer

	NewWorker     func(Config) (worker.Worker, error)
	NewAllWatcher func(*state.StatePool) state.AllWatcherBacking

ManifoldConfig holds the information necessary to run a model cache worker in a dependency.Engine.

func (ManifoldConfig) Validate

func (config ManifoldConfig) Validate() error

Validate validates the manifold configuration.

type Watcher

type Watcher struct {
	// contains filtered or unexported fields

Watcher watches any changes to the state.

func (*Watcher) Next

func (w *Watcher) Next() ([]multiwatcher.Delta, error)

Next retrieves all changes that have happened since the last time it was called, blocking until there are some changes available.

The result from the initial call to Next() is different from subsequent calls. The latter will reflect changes that have happened since the last Next() call. In contrast, the initial Next() call will return the deltas that represent the model's complete state at that moment, even when the model is empty. In that empty model case an empty set of deltas is returned.

func (*Watcher) Stop

func (w *Watcher) Stop() error

Stop stops the watcher.

type Worker

type Worker struct {
	// contains filtered or unexported fields

Worker runs the primary goroutine for managing the multiwatchers.

func NewWorker

func NewWorker(config Config) (*Worker, error)

NewWorker creates the worker and starts the loop goroutine.

func (*Worker) Kill

func (w *Worker) Kill()

Kill implements worker.Worker.Kill.

func (*Worker) Report

func (w *Worker) Report() map[string]interface{}

Report is shown up in the engine report of the agent.

func (*Worker) Wait

func (w *Worker) Wait() error

Wait implements worker.Worker.Wait.

func (*Worker) WatchController

func (w *Worker) WatchController() multiwatcher.Watcher

WatchController returns entity delta events for all models in the controller.

func (*Worker) WatchModel

func (w *Worker) WatchModel(modelUUID string) multiwatcher.Watcher

WatchModel returns entity delta events just for the specified model.


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