github.com/niedbalski/juju@v0.0.0-20190215020005-8ff100488e47/worker/remoterelations/manifold.go (about)

     1  // Copyright 2016 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package remoterelations
     5  
     6  import (
     7  	"github.com/juju/clock"
     8  	"github.com/juju/errors"
     9  	"gopkg.in/juju/worker.v1"
    10  	"gopkg.in/juju/worker.v1/dependency"
    11  
    12  	"github.com/juju/juju/agent"
    13  	"github.com/juju/juju/api"
    14  	"github.com/juju/juju/api/base"
    15  	"github.com/juju/juju/worker/apicaller"
    16  )
    17  
    18  // ManifoldConfig defines the names of the manifolds on which a
    19  // Worker manifold will depend.
    20  type ManifoldConfig struct {
    21  	AgentName     string
    22  	APICallerName string
    23  
    24  	NewControllerConnection  apicaller.NewExternalControllerConnectionFunc
    25  	NewRemoteRelationsFacade func(base.APICaller) (RemoteRelationsFacade, error)
    26  	NewWorker                func(Config) (worker.Worker, error)
    27  }
    28  
    29  // Validate is called by start to check for bad configuration.
    30  func (config ManifoldConfig) Validate() error {
    31  	if config.AgentName == "" {
    32  		return errors.NotValidf("empty AgentName")
    33  	}
    34  	if config.APICallerName == "" {
    35  		return errors.NotValidf("empty APICallerName")
    36  	}
    37  	if config.NewControllerConnection == nil {
    38  		return errors.NotValidf("nil NewControllerConnection")
    39  	}
    40  	if config.NewRemoteRelationsFacade == nil {
    41  		return errors.NotValidf("nil NewRemoteRelationsFacade")
    42  	}
    43  	if config.NewWorker == nil {
    44  		return errors.NotValidf("nil NewWorker")
    45  	}
    46  	return nil
    47  }
    48  
    49  // start is a StartFunc for a Worker manifold.
    50  func (config ManifoldConfig) start(context dependency.Context) (worker.Worker, error) {
    51  	if err := config.Validate(); err != nil {
    52  		return nil, errors.Trace(err)
    53  	}
    54  
    55  	var agent agent.Agent
    56  	if err := context.Get(config.AgentName, &agent); err != nil {
    57  		return nil, errors.Trace(err)
    58  	}
    59  	var apiConn api.Connection
    60  	if err := context.Get(config.APICallerName, &apiConn); err != nil {
    61  		return nil, errors.Trace(err)
    62  	}
    63  	facade, err := config.NewRemoteRelationsFacade(apiConn)
    64  	if err != nil {
    65  		return nil, errors.Trace(err)
    66  	}
    67  
    68  	w, err := config.NewWorker(Config{
    69  		ModelUUID:                agent.CurrentConfig().Model().Id(),
    70  		RelationsFacade:          facade,
    71  		NewRemoteModelFacadeFunc: remoteRelationsFacadeForModelFunc(config.NewControllerConnection),
    72  		Clock:                    clock.WallClock,
    73  	})
    74  	if err != nil {
    75  		return nil, errors.Trace(err)
    76  	}
    77  	return w, nil
    78  }
    79  
    80  // Manifold packages a Worker for use in a dependency.Engine.
    81  func Manifold(config ManifoldConfig) dependency.Manifold {
    82  	return dependency.Manifold{
    83  		Inputs: []string{
    84  			config.AgentName,
    85  			config.APICallerName,
    86  		},
    87  		Start: config.start,
    88  	}
    89  }