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Viewing changes to src/github.com/juju/juju/cmd/jujud/agent/machine/stateworkers.go

  • Committer: Martin Packman
  • Date: 2016-03-30 19:31:08 UTC
  • mfrom: (1.1.41)
  • Revision ID: martin.packman@canonical.com-20160330193108-h9iz3ak334uk0z5r
Merge new upstream source 2.0~beta3

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src/github.com/juju/juju/cmd/jujud/agent/machine/stateworkers.go
 
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// Copyright 2016 Canonical Ltd.
 
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// Licensed under the AGPLv3, see LICENCE file for details.
 
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package machine
 
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import (
 
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        "github.com/juju/errors"
 
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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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        workerstate "github.com/juju/juju/worker/state"
 
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)
 
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// StateWorkersConfig provides the dependencies for the
 
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// stateworkers manifold.
 
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type StateWorkersConfig struct {
 
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        StateName         string
 
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        StartStateWorkers func(*state.State) (worker.Worker, error)
 
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}
 
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// StateWorkersManifold starts workers that rely on a *state.State
 
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// using a function provided to it.
 
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//
 
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// This manifold exists to start State-using workers which have not
 
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// yet been ported to work directly with the dependency engine. Once
 
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// all state workers started by StartStateWorkers have been migrated
 
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// to the dependency engine, this manifold can be removed.
 
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func StateWorkersManifold(config StateWorkersConfig) dependency.Manifold {
 
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        return dependency.Manifold{
 
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                Inputs: []string{
 
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                        config.StateName,
 
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                },
 
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                Start: func(getResource dependency.GetResourceFunc) (worker.Worker, error) {
 
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                        if config.StartStateWorkers == nil {
 
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                                return nil, errors.New("StartStateWorkers not specified")
 
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                        }
 
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                        var stTracker workerstate.StateTracker
 
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                        if err := getResource(config.StateName, &stTracker); err != nil {
 
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                                return nil, err
 
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                        }
 
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                        st, err := stTracker.Use()
 
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                        if err != nil {
 
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                                return nil, errors.Annotate(err, "acquiring state")
 
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                        }
 
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                        w, err := config.StartStateWorkers(st)
 
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                        if err != nil {
 
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                                stTracker.Done()
 
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                                return nil, errors.Annotate(err, "worker startup")
 
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                        }
 
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                        // When the state workers are done, indicate that we no
 
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                        // longer need the State.
 
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                        go func() {
 
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                                w.Wait()
 
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                                stTracker.Done()
 
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                        }()
 
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                        return w, nil
 
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                },
 
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        }
 
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}