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  • Committer: Nicholas Skaggs
  • Date: 2016-10-24 20:56:05 UTC
  • Revision ID: nicholas.skaggs@canonical.com-20161024205605-z8lta0uvuhtxwzwl
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src/github.com/juju/juju/worker/upgradesteps/manifold.go
 
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// Copyright 2015 Canonical Ltd.
 
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// Licensed under the AGPLv3, see LICENCE file for details.
 
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package upgradesteps
 
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import (
 
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        "github.com/juju/errors"
 
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        "gopkg.in/juju/names.v2"
 
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        "github.com/juju/juju/agent"
 
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        "github.com/juju/juju/api"
 
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        apiagent "github.com/juju/juju/api/agent"
 
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        apimachiner "github.com/juju/juju/api/machiner"
 
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        "github.com/juju/juju/state"
 
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        "github.com/juju/juju/worker"
 
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        "github.com/juju/juju/worker/dependency"
 
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        "github.com/juju/juju/worker/gate"
 
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)
 
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// ManifoldConfig defines the names of the manifolds on which a
 
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// Manifold will depend.
 
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type ManifoldConfig struct {
 
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        AgentName            string
 
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        APICallerName        string
 
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        UpgradeStepsGateName string
 
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        OpenStateForUpgrade  func() (*state.State, error)
 
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        PreUpgradeSteps      func(*state.State, agent.Config, bool, bool) error
 
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}
 
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// Manifold returns a dependency manifold that runs an upgrader
 
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// worker, using the resource names defined in the supplied config.
 
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func Manifold(config ManifoldConfig) dependency.Manifold {
 
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        return dependency.Manifold{
 
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                Inputs: []string{
 
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                        config.AgentName,
 
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                        config.APICallerName,
 
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                        config.UpgradeStepsGateName,
 
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                },
 
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                Start: func(context dependency.Context) (worker.Worker, error) {
 
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                        // Sanity checks
 
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                        if config.OpenStateForUpgrade == nil {
 
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                                return nil, errors.New("missing OpenStateForUpgrade in config")
 
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                        }
 
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                        if config.PreUpgradeSteps == nil {
 
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                                return nil, errors.New("missing PreUpgradeSteps in config")
 
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                        }
 
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                        // Get machine agent.
 
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                        var agent agent.Agent
 
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                        if err := context.Get(config.AgentName, &agent); err != nil {
 
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                                return nil, err
 
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                        }
 
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                        // Grab the tag and ensure that it's for a machine.
 
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                        tag, ok := agent.CurrentConfig().Tag().(names.MachineTag)
 
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                        if !ok {
 
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                                return nil, errors.New("agent's tag is not a machine tag")
 
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                        }
 
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                        // Get API connection.
 
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                        // TODO(fwereade): can we make the worker use an
 
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                        // APICaller instead? should be able to depend on
 
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                        // the Engine to abort us when conn is closed...
 
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                        var apiConn api.Connection
 
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                        if err := context.Get(config.APICallerName, &apiConn); err != nil {
 
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                                return nil, err
 
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                        }
 
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                        // Get the machine agent's jobs.
 
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                        // TODO(fwereade): use appropriate facade!
 
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                        agentFacade := apiagent.NewState(apiConn)
 
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                        entity, err := agentFacade.Entity(tag)
 
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                        if err != nil {
 
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                                return nil, err
 
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                        }
 
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                        jobs := entity.Jobs()
 
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                        // Get machine instance for setting status on.
 
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                        // TODO(fwereade): use appropriate facade!
 
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                        machinerFacade := apimachiner.NewState(apiConn)
 
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                        machine, err := machinerFacade.Machine(tag)
 
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                        if err != nil {
 
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                                return nil, err
 
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                        }
 
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                        // Get upgradesteps completed lock.
 
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                        var upgradeStepsLock gate.Lock
 
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                        if err := context.Get(config.UpgradeStepsGateName, &upgradeStepsLock); err != nil {
 
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                                return nil, err
 
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                        }
 
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                        return NewWorker(
 
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                                upgradeStepsLock,
 
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                                agent,
 
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                                apiConn,
 
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                                jobs,
 
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                                config.OpenStateForUpgrade,
 
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                                config.PreUpgradeSteps,
 
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                                machine,
 
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                        )
 
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                },
 
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        }
 
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}