github.com/niedbalski/juju@v0.0.0-20190215020005-8ff100488e47/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  	"gopkg.in/juju/names.v2"
    11  	"gopkg.in/juju/worker.v1"
    12  	"gopkg.in/juju/worker.v1/dependency"
    13  
    14  	"github.com/juju/juju/agent"
    15  	apiagent "github.com/juju/juju/api/agent"
    16  	"github.com/juju/juju/api/agenttools"
    17  	"github.com/juju/juju/api/base"
    18  	"github.com/juju/juju/cmd/jujud/agent/engine"
    19  	"github.com/juju/juju/state/multiwatcher"
    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, err := apiagent.NewState(apiCaller)
    34  	if err != nil {
    35  		return nil, errors.Trace(err)
    36  	}
    37  	isMM, err := isModelManager(a, st)
    38  	if err != nil {
    39  		return nil, errors.Trace(err)
    40  	}
    41  	if !isMM {
    42  		return nil, dependency.ErrMissing
    43  	}
    44  
    45  	// 4 times a day seems a decent enough amount of checks.
    46  	checkerParams := VersionCheckerParams{
    47  		CheckInterval: time.Hour * 6,
    48  	}
    49  	return New(agenttools.NewFacade(apiCaller), &checkerParams), nil
    50  }
    51  
    52  func isModelManager(a agent.Agent, st *apiagent.State) (bool, error) {
    53  	cfg := a.CurrentConfig()
    54  
    55  	// Grab the tag and ensure that it's for a machine.
    56  	tag, ok := cfg.Tag().(names.MachineTag)
    57  	if !ok {
    58  		return false, errors.New("this manifold may only be used inside a machine agent")
    59  	}
    60  
    61  	entity, err := st.Entity(tag)
    62  	if err != nil {
    63  		return false, err
    64  	}
    65  
    66  	for _, job := range entity.Jobs() {
    67  		if job == multiwatcher.JobManageModel {
    68  			return true, nil
    69  		}
    70  	}
    71  
    72  	return false, nil
    73  }