github.com/mwhudson/juju@v0.0.0-20160512215208-90ff01f3497f/worker/uniter/manifold.go (about)

     1  // Copyright 2015 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package uniter
     5  
     6  import (
     7  	"github.com/juju/errors"
     8  	"github.com/juju/names"
     9  	"github.com/juju/utils/clock"
    10  	"github.com/juju/utils/fslock"
    11  
    12  	"github.com/juju/juju/agent"
    13  	"github.com/juju/juju/api"
    14  	"github.com/juju/juju/api/uniter"
    15  	"github.com/juju/juju/apiserver/params"
    16  	"github.com/juju/juju/core/leadership"
    17  	"github.com/juju/juju/worker"
    18  	"github.com/juju/juju/worker/dependency"
    19  	"github.com/juju/juju/worker/fortress"
    20  	"github.com/juju/juju/worker/uniter/operation"
    21  )
    22  
    23  // ManifoldConfig defines the names of the manifolds on which a
    24  // Manifold will depend.
    25  type ManifoldConfig struct {
    26  	AgentName             string
    27  	APICallerName         string
    28  	MachineLockName       string
    29  	LeadershipTrackerName string
    30  	CharmDirName          string
    31  	HookRetryStrategyName string
    32  }
    33  
    34  // Manifold returns a dependency manifold that runs a uniter worker,
    35  // using the resource names defined in the supplied config.
    36  func Manifold(config ManifoldConfig) dependency.Manifold {
    37  	return dependency.Manifold{
    38  		Inputs: []string{
    39  			config.AgentName,
    40  			config.APICallerName,
    41  			config.LeadershipTrackerName,
    42  			config.MachineLockName,
    43  			config.CharmDirName,
    44  			config.HookRetryStrategyName,
    45  		},
    46  		Start: func(context dependency.Context) (worker.Worker, error) {
    47  
    48  			// Collect all required resources.
    49  			var agent agent.Agent
    50  			if err := context.Get(config.AgentName, &agent); err != nil {
    51  				return nil, err
    52  			}
    53  			var apiConn api.Connection
    54  			if err := context.Get(config.APICallerName, &apiConn); err != nil {
    55  				// TODO(fwereade): absence of an APICaller shouldn't be the end of
    56  				// the world -- we ought to return a type that can at least run the
    57  				// leader-deposed hook -- but that's not done yet.
    58  				return nil, err
    59  			}
    60  			var machineLock *fslock.Lock
    61  			if err := context.Get(config.MachineLockName, &machineLock); err != nil {
    62  				return nil, err
    63  			}
    64  			var leadershipTracker leadership.Tracker
    65  			if err := context.Get(config.LeadershipTrackerName, &leadershipTracker); err != nil {
    66  				return nil, err
    67  			}
    68  			var charmDirGuard fortress.Guard
    69  			if err := context.Get(config.CharmDirName, &charmDirGuard); err != nil {
    70  				return nil, err
    71  			}
    72  
    73  			var hookRetryStrategy params.RetryStrategy
    74  			if err := context.Get(config.HookRetryStrategyName, &hookRetryStrategy); err != nil {
    75  				return nil, err
    76  			}
    77  
    78  			downloader := api.NewCharmDownloader(apiConn.Client())
    79  
    80  			// Configure and start the uniter.
    81  			config := agent.CurrentConfig()
    82  			tag := config.Tag()
    83  			unitTag, ok := tag.(names.UnitTag)
    84  			if !ok {
    85  				return nil, errors.Errorf("expected a unit tag, got %v", tag)
    86  			}
    87  			uniterFacade := uniter.NewState(apiConn, unitTag)
    88  			uniter, err := NewUniter(&UniterParams{
    89  				UniterFacade:         uniterFacade,
    90  				UnitTag:              unitTag,
    91  				LeadershipTracker:    leadershipTracker,
    92  				DataDir:              config.DataDir(),
    93  				Downloader:           downloader,
    94  				MachineLock:          machineLock,
    95  				CharmDirGuard:        charmDirGuard,
    96  				UpdateStatusSignal:   NewUpdateStatusTimer(),
    97  				HookRetryStrategy:    hookRetryStrategy,
    98  				NewOperationExecutor: operation.NewExecutor,
    99  				Clock:                clock.WallClock,
   100  			})
   101  			if err != nil {
   102  				return nil, errors.Trace(err)
   103  			}
   104  			return uniter, nil
   105  		},
   106  	}
   107  }