github.com/wallyworld/juju@v0.0.0-20161013125918-6cf1bc9d917a/worker/migrationmaster/manifold.go (about)

     1  // Copyright 2016 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package migrationmaster
     5  
     6  import (
     7  	"github.com/juju/errors"
     8  	"github.com/juju/utils/clock"
     9  
    10  	"github.com/juju/juju/agent"
    11  	"github.com/juju/juju/api"
    12  	"github.com/juju/juju/api/base"
    13  	"github.com/juju/juju/migration"
    14  	"github.com/juju/juju/worker"
    15  	"github.com/juju/juju/worker/dependency"
    16  	"github.com/juju/juju/worker/fortress"
    17  )
    18  
    19  // ManifoldConfig defines the names of the manifolds on which a
    20  // Worker manifold will depend.
    21  type ManifoldConfig struct {
    22  	AgentName     string
    23  	APICallerName string
    24  	FortressName  string
    25  
    26  	Clock     clock.Clock
    27  	NewFacade func(base.APICaller) (Facade, error)
    28  	NewWorker func(Config) (worker.Worker, error)
    29  }
    30  
    31  // Validate is called by start to check for bad configuration.
    32  func (config ManifoldConfig) Validate() error {
    33  	if config.AgentName == "" {
    34  		return errors.NotValidf("empty AgentName")
    35  	}
    36  	if config.APICallerName == "" {
    37  		return errors.NotValidf("empty APICallerName")
    38  	}
    39  	if config.FortressName == "" {
    40  		return errors.NotValidf("empty FortressName")
    41  	}
    42  	if config.NewFacade == nil {
    43  		return errors.NotValidf("nil NewFacade")
    44  	}
    45  	if config.NewWorker == nil {
    46  		return errors.NotValidf("nil NewWorker")
    47  	}
    48  	if config.Clock == nil {
    49  		return errors.NotValidf("nil Clock")
    50  	}
    51  	return nil
    52  }
    53  
    54  // start is a StartFunc for a Worker manifold.
    55  func (config ManifoldConfig) start(context dependency.Context) (worker.Worker, error) {
    56  	if err := config.Validate(); err != nil {
    57  		return nil, errors.Trace(err)
    58  	}
    59  
    60  	var agent agent.Agent
    61  	if err := context.Get(config.AgentName, &agent); err != nil {
    62  		return nil, errors.Trace(err)
    63  	}
    64  	var apiConn api.Connection
    65  	if err := context.Get(config.APICallerName, &apiConn); err != nil {
    66  		return nil, errors.Trace(err)
    67  	}
    68  	var guard fortress.Guard
    69  	if err := context.Get(config.FortressName, &guard); err != nil {
    70  		return nil, errors.Trace(err)
    71  	}
    72  	facade, err := config.NewFacade(apiConn)
    73  	if err != nil {
    74  		return nil, errors.Trace(err)
    75  	}
    76  	apiClient := apiConn.Client()
    77  	worker, err := config.NewWorker(Config{
    78  		ModelUUID:       agent.CurrentConfig().Model().Id(),
    79  		Facade:          facade,
    80  		Guard:           guard,
    81  		APIOpen:         api.Open,
    82  		UploadBinaries:  migration.UploadBinaries,
    83  		CharmDownloader: apiClient,
    84  		ToolsDownloader: apiClient,
    85  		Clock:           config.Clock,
    86  	})
    87  	if err != nil {
    88  		return nil, errors.Trace(err)
    89  	}
    90  	return worker, nil
    91  }
    92  
    93  func errorFilter(err error) error {
    94  	switch err {
    95  	case ErrMigrated:
    96  		// If the model has migrated, the migrationmaster should no
    97  		// longer be running.
    98  		return dependency.ErrUninstall
    99  	case ErrInactive:
   100  		// If the migration is no longer active, restart the
   101  		// migrationmaster immediately so it can wait for the next
   102  		// attempt.
   103  		return dependency.ErrBounce
   104  	default:
   105  		return err
   106  	}
   107  }
   108  
   109  // Manifold packages a Worker for use in a dependency.Engine.
   110  func Manifold(config ManifoldConfig) dependency.Manifold {
   111  	return dependency.Manifold{
   112  		Inputs: []string{
   113  			config.AgentName,
   114  			config.APICallerName,
   115  			config.FortressName,
   116  		},
   117  		Start:  config.start,
   118  		Filter: errorFilter,
   119  	}
   120  }