github.com/makyo/juju@v0.0.0-20160425123129-2608902037e9/worker/resumer/manifold.go (about)

     1  // Copyright 2016 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package resumer
     5  
     6  import (
     7  	"github.com/juju/errors"
     8  	"github.com/juju/names"
     9  
    10  	"github.com/juju/juju/agent"
    11  	apiagent "github.com/juju/juju/api/agent"
    12  	"github.com/juju/juju/api/base"
    13  	apiresumer "github.com/juju/juju/api/resumer"
    14  	"github.com/juju/juju/cmd/jujud/agent/util"
    15  	"github.com/juju/juju/state/multiwatcher"
    16  	"github.com/juju/juju/worker"
    17  	"github.com/juju/juju/worker/dependency"
    18  )
    19  
    20  // ManifoldConfig defines the names of the manifolds on which a Manifold will depend.
    21  type ManifoldConfig util.AgentApiManifoldConfig
    22  
    23  // Manifold returns a dependency manifold that runs a resumer worker,
    24  // using the api connection resource named in the supplied config.
    25  func Manifold(config ManifoldConfig) dependency.Manifold {
    26  	typedConfig := util.AgentApiManifoldConfig(config)
    27  	return util.AgentApiManifold(typedConfig, newWorker)
    28  }
    29  
    30  func newWorker(a agent.Agent, apiCaller base.APICaller) (worker.Worker, error) {
    31  	cfg := a.CurrentConfig()
    32  	// Grab the tag and ensure that it's for a machine.
    33  	tag, ok := cfg.Tag().(names.MachineTag)
    34  	if !ok {
    35  		return nil, errors.New("this manifold may only be used inside a machine agent")
    36  	}
    37  
    38  	// Get the machine agent's jobs.
    39  	// TODO(fwereade): this functionality should be on the
    40  	// deployer facade instead.
    41  	agentFacade := apiagent.NewState(apiCaller)
    42  	entity, err := agentFacade.Entity(tag)
    43  	if err != nil {
    44  		return nil, err
    45  	}
    46  
    47  	var isModelManager bool
    48  	for _, job := range entity.Jobs() {
    49  		if job == multiwatcher.JobManageModel {
    50  			isModelManager = true
    51  			break
    52  		}
    53  	}
    54  	if !isModelManager {
    55  		return nil, dependency.ErrMissing
    56  	}
    57  
    58  	return NewResumer(apiresumer.NewAPI(apiCaller)), nil
    59  }