github.com/mwhudson/juju@v0.0.0-20160512215208-90ff01f3497f/worker/uniter/operation/deploy.go (about)

     1  // Copyright 2014-2015 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package operation
     5  
     6  import (
     7  	"fmt"
     8  
     9  	"github.com/juju/errors"
    10  	corecharm "gopkg.in/juju/charm.v6-unstable"
    11  	"gopkg.in/juju/charm.v6-unstable/hooks"
    12  
    13  	"github.com/juju/juju/worker/uniter/charm"
    14  	"github.com/juju/juju/worker/uniter/hook"
    15  )
    16  
    17  // deploy implements charm install and charm upgrade operations.
    18  type deploy struct {
    19  	DoesNotRequireMachineLock
    20  
    21  	kind     Kind
    22  	charmURL *corecharm.URL
    23  	revert   bool
    24  	resolved bool
    25  
    26  	callbacks Callbacks
    27  	deployer  charm.Deployer
    28  	abort     <-chan struct{}
    29  }
    30  
    31  // String is part of the Operation interface.
    32  func (d *deploy) String() string {
    33  	verb := "upgrade to"
    34  	prefix := ""
    35  	switch {
    36  	case d.kind == Install:
    37  		verb = "install"
    38  	case d.revert:
    39  		prefix = "switch "
    40  	case d.resolved:
    41  		prefix = "continue "
    42  	}
    43  	return fmt.Sprintf("%s%s %s", prefix, verb, d.charmURL)
    44  }
    45  
    46  // Prepare downloads and verifies the charm, and informs the controller
    47  // that the unit will be using it. If the supplied state indicates that a
    48  // hook was pending, that hook is recorded in the returned state.
    49  // Prepare is part of the Operation interface.
    50  func (d *deploy) Prepare(state State) (*State, error) {
    51  	if err := d.checkAlreadyDone(state); err != nil {
    52  		return nil, errors.Trace(err)
    53  	}
    54  	if d.revert {
    55  		if err := d.deployer.NotifyRevert(); err != nil {
    56  			return nil, errors.Trace(err)
    57  		}
    58  	}
    59  	if d.resolved {
    60  		if err := d.deployer.NotifyResolved(); err != nil {
    61  			return nil, errors.Trace(err)
    62  		}
    63  	}
    64  	info, err := d.callbacks.GetArchiveInfo(d.charmURL)
    65  	if err != nil {
    66  		return nil, errors.Trace(err)
    67  	}
    68  	if err := d.deployer.Stage(info, d.abort); err != nil {
    69  		return nil, errors.Trace(err)
    70  	}
    71  	// note: yes, this *should* be in Prepare, not Execute. Before we can safely
    72  	// write out local state referencing the charm url (by returning the new
    73  	// State to the Executor, below), we have to register our interest in that
    74  	// charm on the controller. If we neglected to do so, the operation could
    75  	// race with a new service-charm-url change on the controller, and lead to
    76  	// failures on resume in which we try to obtain archive info for a charm that
    77  	// has already been removed from the controller.
    78  	if err := d.callbacks.SetCurrentCharm(d.charmURL); err != nil {
    79  		return nil, errors.Trace(err)
    80  	}
    81  	return d.getState(state, Pending), nil
    82  }
    83  
    84  // Execute installs or upgrades the prepared charm, and preserves any hook
    85  // recorded in the supplied state.
    86  // Execute is part of the Operation interface.
    87  func (d *deploy) Execute(state State) (*State, error) {
    88  	if err := d.deployer.Deploy(); err == charm.ErrConflict {
    89  		return nil, NewDeployConflictError(d.charmURL)
    90  	} else if err != nil {
    91  		return nil, errors.Trace(err)
    92  	}
    93  	return d.getState(state, Done), nil
    94  }
    95  
    96  // Commit restores state for any interrupted hook, or queues an install or
    97  // upgrade-charm hook if no hook was interrupted.
    98  func (d *deploy) Commit(state State) (*State, error) {
    99  	change := &stateChange{
   100  		Kind: RunHook,
   101  	}
   102  	if hookInfo := d.interruptedHook(state); hookInfo != nil {
   103  		change.Hook = hookInfo
   104  		change.Step = Pending
   105  	} else {
   106  		change.Hook = &hook.Info{Kind: deployHookKinds[d.kind]}
   107  		change.Step = Queued
   108  	}
   109  	return change.apply(state), nil
   110  }
   111  
   112  func (d *deploy) checkAlreadyDone(state State) error {
   113  	if state.Kind != d.kind {
   114  		return nil
   115  	}
   116  	if *state.CharmURL != *d.charmURL {
   117  		return nil
   118  	}
   119  	if state.Step == Done {
   120  		return ErrSkipExecute
   121  	}
   122  	return nil
   123  }
   124  
   125  func (d *deploy) getState(state State, step Step) *State {
   126  	return stateChange{
   127  		Kind:     d.kind,
   128  		Step:     step,
   129  		CharmURL: d.charmURL,
   130  		Hook:     d.interruptedHook(state),
   131  	}.apply(state)
   132  }
   133  
   134  func (d *deploy) interruptedHook(state State) *hook.Info {
   135  	switch state.Kind {
   136  	case RunHook, Upgrade:
   137  		return state.Hook
   138  	}
   139  	return nil
   140  }
   141  
   142  // deployHookKinds determines what kind of hook should be queued after a
   143  // given deployment operation.
   144  var deployHookKinds = map[Kind]hooks.Kind{
   145  	Install: hooks.Install,
   146  	Upgrade: hooks.UpgradeCharm,
   147  }