github.com/altoros/juju-vmware@v0.0.0-20150312064031-f19ae857ccca/apiserver/common/remove.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  	"fmt"
     8  
     9  	"github.com/juju/errors"
    10  	"github.com/juju/juju/apiserver/params"
    11  	"github.com/juju/juju/state"
    12  	"github.com/juju/names"
    13  )
    14  
    15  // Remover implements a common Remove method for use by various facades.
    16  type Remover struct {
    17  	st             state.EntityFinder
    18  	callEnsureDead bool
    19  	getCanModify   GetAuthFunc
    20  }
    21  
    22  // NewRemover returns a new Remover. The callEnsureDead flag specifies
    23  // whether EnsureDead should be called on an entity before
    24  // removing. The GetAuthFunc will be used on each invocation of Remove
    25  // to determine current permissions.
    26  func NewRemover(st state.EntityFinder, callEnsureDead bool, getCanModify GetAuthFunc) *Remover {
    27  	return &Remover{
    28  		st:             st,
    29  		callEnsureDead: callEnsureDead,
    30  		getCanModify:   getCanModify,
    31  	}
    32  }
    33  
    34  func (r *Remover) removeEntity(tag names.Tag) error {
    35  	entity, err := r.st.FindEntity(tag)
    36  	if err != nil {
    37  		return err
    38  	}
    39  	remover, ok := entity.(interface {
    40  		state.Lifer
    41  		state.Remover
    42  		state.EnsureDeader
    43  	})
    44  	if !ok {
    45  		return NotSupportedError(tag, "removal")
    46  	}
    47  	// Only remove entites that are not Alive.
    48  	if life := remover.Life(); life == state.Alive {
    49  		return fmt.Errorf("cannot remove entity %q: still alive", tag.String())
    50  	}
    51  	if r.callEnsureDead {
    52  		if err := remover.EnsureDead(); err != nil {
    53  			return err
    54  		}
    55  	}
    56  	return remover.Remove()
    57  }
    58  
    59  // Remove removes every given entity from state, calling EnsureDead
    60  // first, then Remove. It will fail if the entity is not present.
    61  func (r *Remover) Remove(args params.Entities) (params.ErrorResults, error) {
    62  	result := params.ErrorResults{
    63  		Results: make([]params.ErrorResult, len(args.Entities)),
    64  	}
    65  	if len(args.Entities) == 0 {
    66  		return result, nil
    67  	}
    68  	canModify, err := r.getCanModify()
    69  	if err != nil {
    70  		return params.ErrorResults{}, errors.Trace(err)
    71  	}
    72  	for i, entity := range args.Entities {
    73  		tag, err := names.ParseTag(entity.Tag)
    74  		if err != nil {
    75  			result.Results[i].Error = ServerError(ErrPerm)
    76  			continue
    77  		}
    78  		err = ErrPerm
    79  		if canModify(tag) {
    80  			err = r.removeEntity(tag)
    81  		}
    82  		result.Results[i].Error = ServerError(err)
    83  	}
    84  	return result, nil
    85  }