github.com/niedbalski/juju@v0.0.0-20190215020005-8ff100488e47/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  	"gopkg.in/juju/names.v2"
    11  
    12  	"github.com/juju/juju/apiserver/params"
    13  	"github.com/juju/juju/state"
    14  )
    15  
    16  // Remover implements a common Remove method for use by various facades.
    17  type Remover struct {
    18  	st             state.EntityFinder
    19  	callEnsureDead bool
    20  	getCanModify   GetAuthFunc
    21  }
    22  
    23  // NewRemover returns a new Remover. The callEnsureDead flag specifies
    24  // whether EnsureDead should be called on an entity before
    25  // removing. The GetAuthFunc will be used on each invocation of Remove
    26  // to determine current permissions.
    27  func NewRemover(st state.EntityFinder, callEnsureDead bool, getCanModify GetAuthFunc) *Remover {
    28  	return &Remover{
    29  		st:             st,
    30  		callEnsureDead: callEnsureDead,
    31  		getCanModify:   getCanModify,
    32  	}
    33  }
    34  
    35  func (r *Remover) removeEntity(tag names.Tag) error {
    36  	entity, err := r.st.FindEntity(tag)
    37  	if err != nil {
    38  		return err
    39  	}
    40  	remover, ok := entity.(interface {
    41  		state.Lifer
    42  		state.Remover
    43  		state.EnsureDeader
    44  	})
    45  	if !ok {
    46  		return NotSupportedError(tag, "removal")
    47  	}
    48  	// Only remove entites that are not Alive.
    49  	if life := remover.Life(); life == state.Alive {
    50  		return fmt.Errorf("cannot remove entity %q: still alive", tag.String())
    51  	}
    52  	if r.callEnsureDead {
    53  		if err := remover.EnsureDead(); err != nil {
    54  			return err
    55  		}
    56  	}
    57  	return remover.Remove()
    58  }
    59  
    60  // Remove removes every given entity from state, calling EnsureDead
    61  // first, then Remove. It will fail if the entity is not present.
    62  func (r *Remover) Remove(args params.Entities) (params.ErrorResults, error) {
    63  	result := params.ErrorResults{
    64  		Results: make([]params.ErrorResult, len(args.Entities)),
    65  	}
    66  	if len(args.Entities) == 0 {
    67  		return result, nil
    68  	}
    69  	canModify, err := r.getCanModify()
    70  	if err != nil {
    71  		return params.ErrorResults{}, errors.Trace(err)
    72  	}
    73  	for i, entity := range args.Entities {
    74  		tag, err := names.ParseTag(entity.Tag)
    75  		if err != nil {
    76  			result.Results[i].Error = ServerError(ErrPerm)
    77  			continue
    78  		}
    79  		err = ErrPerm
    80  		if canModify(tag) {
    81  			err = r.removeEntity(tag)
    82  		}
    83  		result.Results[i].Error = ServerError(err)
    84  	}
    85  	return result, nil
    86  }