github.com/juju/juju@v0.0.0-20240327075706-a90865de2538/worker/charmrevision/manifold.go (about)

     1  // Copyright 2015 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package charmrevision
     5  
     6  import (
     7  	"time"
     8  
     9  	"github.com/juju/clock"
    10  	"github.com/juju/errors"
    11  	"github.com/juju/worker/v3"
    12  	"github.com/juju/worker/v3/dependency"
    13  
    14  	"github.com/juju/juju/api/base"
    15  	"github.com/juju/juju/api/controller/charmrevisionupdater"
    16  )
    17  
    18  // ManifoldConfig describes how to create a worker that checks for updates
    19  // available to deployed charms in an environment.
    20  type ManifoldConfig struct {
    21  
    22  	// The named dependencies will be exposed to the start func as resources.
    23  	APICallerName string
    24  	Clock         clock.Clock
    25  
    26  	// The remaining dependencies will be used with the resources to configure
    27  	// and create the worker. The period must be greater than 0; the NewFacade
    28  	// and NewWorker fields must not be nil. charmrevision.NewWorker, and
    29  	// NewAPIFacade, are suitable implementations for most clients.
    30  	Period    time.Duration
    31  	NewFacade func(base.APICaller) (Facade, error)
    32  	NewWorker func(Config) (worker.Worker, error)
    33  	Logger    Logger
    34  }
    35  
    36  // Manifold returns a dependency.Manifold that runs a charm revision worker
    37  // according to the supplied configuration.
    38  func Manifold(config ManifoldConfig) dependency.Manifold {
    39  	return dependency.Manifold{
    40  		Inputs: []string{
    41  			config.APICallerName,
    42  		},
    43  		Start: func(context dependency.Context) (worker.Worker, error) {
    44  			if config.Clock == nil {
    45  				return nil, errors.NotValidf("nil Clock")
    46  			}
    47  			var apiCaller base.APICaller
    48  			if err := context.Get(config.APICallerName, &apiCaller); err != nil {
    49  				return nil, errors.Trace(err)
    50  			}
    51  			facade, err := config.NewFacade(apiCaller)
    52  			if err != nil {
    53  				return nil, errors.Annotatef(err, "cannot create facade")
    54  			}
    55  
    56  			worker, err := config.NewWorker(Config{
    57  				RevisionUpdater: facade,
    58  				Clock:           config.Clock,
    59  				Period:          config.Period,
    60  				Logger:          config.Logger,
    61  			})
    62  			if err != nil {
    63  				return nil, errors.Annotatef(err, "cannot create worker")
    64  			}
    65  			return worker, nil
    66  		},
    67  	}
    68  }
    69  
    70  // NewAPIFacade returns a Facade backed by the supplied APICaller.
    71  var NewAPIFacade = newAPIFacade
    72  
    73  func newAPIFacade(apiCaller base.APICaller) (Facade, error) {
    74  	return charmrevisionupdater.NewClient(apiCaller), nil
    75  }
    76  
    77  // Facade has all the controller methods used by the charm revision worker.
    78  type Facade interface {
    79  	RevisionUpdater
    80  }