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

     1  // Copyright 2016 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package toolsversionchecker
     5  
     6  import (
     7  	"time"
     8  
     9  	"github.com/juju/errors"
    10  
    11  	"github.com/juju/juju/agent"
    12  	apiagent "github.com/juju/juju/api/agent"
    13  	"github.com/juju/juju/api/agenttools"
    14  	"github.com/juju/juju/api/base"
    15  	"github.com/juju/juju/cmd/jujud/agent/engine"
    16  	"github.com/juju/juju/state/multiwatcher"
    17  	"github.com/juju/juju/worker"
    18  	"github.com/juju/juju/worker/dependency"
    19  	"gopkg.in/juju/names.v2"
    20  )
    21  
    22  // ManifoldConfig defines the names of the manifolds on which a Manifold will depend.
    23  type ManifoldConfig engine.AgentAPIManifoldConfig
    24  
    25  // Manifold returns a dependency manifold that runs a toolsversionchecker worker,
    26  // using the api connection resource named in the supplied config.
    27  func Manifold(config ManifoldConfig) dependency.Manifold {
    28  	typedConfig := engine.AgentAPIManifoldConfig(config)
    29  	return engine.AgentAPIManifold(typedConfig, newWorker)
    30  }
    31  
    32  func newWorker(a agent.Agent, apiCaller base.APICaller) (worker.Worker, error) {
    33  	st := apiagent.NewState(apiCaller)
    34  	isMM, err := isModelManager(a, st)
    35  	if err != nil {
    36  		return nil, errors.Trace(err)
    37  	}
    38  	if !isMM {
    39  		return nil, dependency.ErrMissing
    40  	}
    41  
    42  	// 4 times a day seems a decent enough amount of checks.
    43  	checkerParams := VersionCheckerParams{
    44  		CheckInterval: time.Hour * 6,
    45  	}
    46  	return New(agenttools.NewFacade(apiCaller), &checkerParams), nil
    47  }
    48  
    49  func isModelManager(a agent.Agent, st *apiagent.State) (bool, error) {
    50  	cfg := a.CurrentConfig()
    51  
    52  	// Grab the tag and ensure that it's for a machine.
    53  	tag, ok := cfg.Tag().(names.MachineTag)
    54  	if !ok {
    55  		return false, errors.New("this manifold may only be used inside a machine agent")
    56  	}
    57  
    58  	entity, err := st.Entity(tag)
    59  	if err != nil {
    60  		return false, err
    61  	}
    62  
    63  	for _, job := range entity.Jobs() {
    64  		if job == multiwatcher.JobManageModel {
    65  			return true, nil
    66  		}
    67  	}
    68  
    69  	return false, nil
    70  }