github.com/axw/juju@v0.0.0-20161005053422-4bd6544d08d4/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  	"gopkg.in/juju/names.v2"
     9  
    10  	"github.com/juju/juju/apiserver/params"
    11  	"github.com/juju/juju/state"
    12  )
    13  
    14  // DeadEnsurer implements a common EnsureDead method for use by
    15  // various facades.
    16  type DeadEnsurer struct {
    17  	st           state.EntityFinder
    18  	getCanModify GetAuthFunc
    19  }
    20  
    21  // NewDeadEnsurer returns a new DeadEnsurer. The GetAuthFunc will be
    22  // used on each invocation of EnsureDead to determine current
    23  // permissions.
    24  func NewDeadEnsurer(st state.EntityFinder, getCanModify GetAuthFunc) *DeadEnsurer {
    25  	return &DeadEnsurer{
    26  		st:           st,
    27  		getCanModify: getCanModify,
    28  	}
    29  }
    30  
    31  func (d *DeadEnsurer) ensureEntityDead(tag names.Tag) error {
    32  	entity0, err := d.st.FindEntity(tag)
    33  	if err != nil {
    34  		return err
    35  	}
    36  	entity, ok := entity0.(state.EnsureDeader)
    37  	if !ok {
    38  		return NotSupportedError(tag, "ensuring death")
    39  	}
    40  	return entity.EnsureDead()
    41  }
    42  
    43  // EnsureDead calls EnsureDead on each given entity from state. It
    44  // will fail if the entity is not present. If it's Alive, nothing will
    45  // happen (see state/EnsureDead() for units or machines).
    46  func (d *DeadEnsurer) EnsureDead(args params.Entities) (params.ErrorResults, error) {
    47  	result := params.ErrorResults{
    48  		Results: make([]params.ErrorResult, len(args.Entities)),
    49  	}
    50  	if len(args.Entities) == 0 {
    51  		return result, nil
    52  	}
    53  	canModify, err := d.getCanModify()
    54  	if err != nil {
    55  		return params.ErrorResults{}, errors.Trace(err)
    56  	}
    57  	for i, entity := range args.Entities {
    58  		tag, err := names.ParseTag(entity.Tag)
    59  		if err != nil {
    60  			return params.ErrorResults{}, errors.Trace(err)
    61  		}
    62  
    63  		err = ErrPerm
    64  		if canModify(tag) {
    65  			err = d.ensureEntityDead(tag)
    66  		}
    67  		result.Results[i].Error = ServerError(err)
    68  	}
    69  	return result, nil
    70  }