/
manifold.go
79 lines (68 loc) · 2.39 KB
/
manifold.go
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// Copyright 2015 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.
package charmrevisionmanifold
import (
"time"
"github.com/juju/errors"
"github.com/juju/utils/clock"
"github.com/juju/juju/api/base"
"github.com/juju/juju/api/charmrevisionupdater"
"github.com/juju/juju/worker"
"github.com/juju/juju/worker/charmrevision"
"github.com/juju/juju/worker/dependency"
)
// ManifoldConfig describes how to create a worker that checks for updates
// available to deployed charms in an environment.
type ManifoldConfig struct {
// The named dependencies will be exposed to the start func as resources.
APICallerName string
ClockName string
// The remaining dependencies will be used with the resources to configure
// and create the worker. The period must be greater than 0; the NewFacade
// and NewWorker fields must not be nil. charmrevision.NewWorker, and
// NewAPIFacade, are suitable implementations for most clients.
Period time.Duration
NewFacade func(base.APICaller) (Facade, error)
NewWorker func(charmrevision.Config) (worker.Worker, error)
}
// Manifold returns a dependency.Manifold that runs a charm revision worker
// according to the supplied configuration.
func Manifold(config ManifoldConfig) dependency.Manifold {
return dependency.Manifold{
Inputs: []string{
config.APICallerName,
config.ClockName,
},
Start: func(context dependency.Context) (worker.Worker, error) {
var clock clock.Clock
if err := context.Get(config.ClockName, &clock); err != nil {
return nil, errors.Trace(err)
}
var apiCaller base.APICaller
if err := context.Get(config.APICallerName, &apiCaller); err != nil {
return nil, errors.Trace(err)
}
facade, err := config.NewFacade(apiCaller)
if err != nil {
return nil, errors.Annotatef(err, "cannot create facade")
}
worker, err := config.NewWorker(charmrevision.Config{
RevisionUpdater: facade,
Clock: clock,
Period: config.Period,
})
if err != nil {
return nil, errors.Annotatef(err, "cannot create worker")
}
return worker, nil
},
}
}
// NewAPIFacade returns a Facade backed by the supplied APICaller.
func NewAPIFacade(apiCaller base.APICaller) (Facade, error) {
return charmrevisionupdater.NewState(apiCaller), nil
}
// Facade has all the controller methods used by the charm revision worker.
type Facade interface {
charmrevision.RevisionUpdater
}