github.com/altoros/juju-vmware@v0.0.0-20150312064031-f19ae857ccca/apiserver/common/life.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  // LifeGetter implements a common Life method for use by various facades.
    14  type LifeGetter struct {
    15  	st         state.EntityFinder
    16  	getCanRead GetAuthFunc
    17  }
    18  
    19  // NewLifeGetter returns a new LifeGetter. The GetAuthFunc will be used on
    20  // each invocation of Life to determine current permissions.
    21  func NewLifeGetter(st state.EntityFinder, getCanRead GetAuthFunc) *LifeGetter {
    22  	return &LifeGetter{
    23  		st:         st,
    24  		getCanRead: getCanRead,
    25  	}
    26  }
    27  
    28  func (lg *LifeGetter) oneLife(tag names.Tag) (params.Life, error) {
    29  	entity0, err := lg.st.FindEntity(tag)
    30  	if err != nil {
    31  		return "", err
    32  	}
    33  	entity, ok := entity0.(state.Lifer)
    34  	if !ok {
    35  		return "", NotSupportedError(tag, "life cycles")
    36  	}
    37  	return params.Life(entity.Life().String()), nil
    38  }
    39  
    40  // Life returns the life status of every supplied entity, where available.
    41  func (lg *LifeGetter) Life(args params.Entities) (params.LifeResults, error) {
    42  	result := params.LifeResults{
    43  		Results: make([]params.LifeResult, len(args.Entities)),
    44  	}
    45  	if len(args.Entities) == 0 {
    46  		return result, nil
    47  	}
    48  	canRead, err := lg.getCanRead()
    49  	if err != nil {
    50  		return params.LifeResults{}, errors.Trace(err)
    51  	}
    52  	for i, entity := range args.Entities {
    53  		tag, err := names.ParseTag(entity.Tag)
    54  		if err != nil {
    55  			result.Results[i].Error = ServerError(ErrPerm)
    56  			continue
    57  		}
    58  		err = ErrPerm
    59  		if canRead(tag) {
    60  			result.Results[i].Life, err = lg.oneLife(tag)
    61  		}
    62  		result.Results[i].Error = ServerError(err)
    63  	}
    64  	return result, nil
    65  }