github.com/altoros/juju-vmware@v0.0.0-20150312064031-f19ae857ccca/apiserver/common/ensuredead.go (about)

     1  // Copyright 2013 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package common
     5  
     6  import (
     7  	"github.com/juju/errors"
     8  	"github.com/juju/juju/apiserver/params"
     9  	"github.com/juju/juju/state"
    10  	"github.com/juju/names"
    11  )
    12  
    13  // DeadEnsurer implements a common EnsureDead method for use by
    14  // various facades.
    15  type DeadEnsurer struct {
    16  	st           state.EntityFinder
    17  	getCanModify GetAuthFunc
    18  }
    19  
    20  // NewDeadEnsurer returns a new DeadEnsurer. The GetAuthFunc will be
    21  // used on each invocation of EnsureDead to determine current
    22  // permissions.
    23  func NewDeadEnsurer(st state.EntityFinder, getCanModify GetAuthFunc) *DeadEnsurer {
    24  	return &DeadEnsurer{
    25  		st:           st,
    26  		getCanModify: getCanModify,
    27  	}
    28  }
    29  
    30  func (d *DeadEnsurer) ensureEntityDead(tag names.Tag) error {
    31  	entity0, err := d.st.FindEntity(tag)
    32  	if err != nil {
    33  		return err
    34  	}
    35  	entity, ok := entity0.(state.EnsureDeader)
    36  	if !ok {
    37  		return NotSupportedError(tag, "ensuring death")
    38  	}
    39  	return entity.EnsureDead()
    40  }
    41  
    42  // EnsureDead calls EnsureDead on each given entity from state. It
    43  // will fail if the entity is not present. If it's Alive, nothing will
    44  // happen (see state/EnsureDead() for units or machines).
    45  func (d *DeadEnsurer) EnsureDead(args params.Entities) (params.ErrorResults, error) {
    46  	result := params.ErrorResults{
    47  		Results: make([]params.ErrorResult, len(args.Entities)),
    48  	}
    49  	if len(args.Entities) == 0 {
    50  		return result, nil
    51  	}
    52  	canModify, err := d.getCanModify()
    53  	if err != nil {
    54  		return params.ErrorResults{}, errors.Trace(err)
    55  	}
    56  	for i, entity := range args.Entities {
    57  		tag, err := names.ParseTag(entity.Tag)
    58  		if err != nil {
    59  			return params.ErrorResults{}, errors.Trace(err)
    60  		}
    61  
    62  		err = ErrPerm
    63  		if canModify(tag) {
    64  			err = d.ensureEntityDead(tag)
    65  		}
    66  		result.Results[i].Error = ServerError(err)
    67  	}
    68  	return result, nil
    69  }