Golang Connection.MetadataUpdater方法代码示例

// startAPIWorkers is called to start workers which rely on the
// machine agent's API connection (via the apiworkers manifold). It
// returns a Runner with a number of workers attached to it.
//
// The workers started here need to be converted to run under the
// dependency engine. Once they have all been converted, this method -
// and the apiworkers manifold - can be removed.
func (a *MachineAgent) startAPIWorkers(apiConn api.Connection) (_ worker.Worker, outErr error) {
	agentConfig := a.CurrentConfig()

	entity, err := apiagent.NewState(apiConn).Entity(a.Tag())
	if err != nil {
		return nil, errors.Trace(err)
	}

	var isModelManager bool
	for _, job := range entity.Jobs() {
		switch job {
		case multiwatcher.JobManageModel:
			isModelManager = true
		default:
			// TODO(dimitern): Once all workers moved over to using
			// the API, report "unknown job type" here.
		}
	}

	runner := newConnRunner(apiConn)
	defer func() {
		// If startAPIWorkers exits early with an error, stop the
		// runner so that any already started runners aren't leaked.
		if outErr != nil {
			worker.Stop(runner)
		}
	}()

	modelConfig, err := apiagent.NewState(apiConn).ModelConfig()
	if err != nil {
		return nil, fmt.Errorf("cannot read model config: %v", err)
	}

	// Perform the operations needed to set up hosting for containers.
	if err := a.setupContainerSupport(runner, apiConn, agentConfig); err != nil {
		cause := errors.Cause(err)
		if params.IsCodeDead(cause) || cause == worker.ErrTerminateAgent {
			return nil, worker.ErrTerminateAgent
		}
		return nil, fmt.Errorf("setting up container support: %v", err)
	}

	if isModelManager {

		// Published image metadata for some providers are in simple streams.
		// Providers that do not depend on simple streams do not need this worker.
		env, err := newEnvirons(modelConfig)
		if err != nil {
			return nil, errors.Annotate(err, "getting environ")
		}
		if _, ok := env.(simplestreams.HasRegion); ok {
			// Start worker that stores published image metadata in state.
			runner.StartWorker("imagemetadata", func() (worker.Worker, error) {
				return newMetadataUpdater(apiConn.MetadataUpdater()), nil
			})
		}

		// We don't have instance info set and the network config for the
		// bootstrap machine only, so update it now. All the other machines will
		// have instance info including network config set at provisioning time.
		if err := a.setControllerNetworkConfig(apiConn); err != nil {
			return nil, errors.Annotate(err, "setting controller network config")
		}
	} else {
		runner.StartWorker("stateconverter", func() (worker.Worker, error) {
			// TODO(fwereade): this worker needs its own facade.
			facade := apimachiner.NewState(apiConn)
			handler := conv2state.New(facade, a)
			w, err := watcher.NewNotifyWorker(watcher.NotifyConfig{
				Handler: handler,
			})
			if err != nil {
				return nil, errors.Annotate(err, "cannot start controller promoter worker")
			}
			return w, nil
		})
	}
	return runner, nil
}