github.com/niedbalski/juju@v0.0.0-20190215020005-8ff100488e47/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  	"gopkg.in/juju/names.v2"
     9  
    10  	"github.com/juju/juju/apiserver/params"
    11  	"github.com/juju/juju/state"
    12  )
    13  
    14  // LifeGetter implements a common Life method for use by various facades.
    15  type LifeGetter struct {
    16  	st         state.EntityFinder
    17  	getCanRead GetAuthFunc
    18  }
    19  
    20  // NewLifeGetter returns a new LifeGetter. The GetAuthFunc will be used on
    21  // each invocation of Life to determine current permissions.
    22  func NewLifeGetter(st state.EntityFinder, getCanRead GetAuthFunc) *LifeGetter {
    23  	return &LifeGetter{
    24  		st:         st,
    25  		getCanRead: getCanRead,
    26  	}
    27  }
    28  
    29  func (lg *LifeGetter) oneLife(tag names.Tag) (params.Life, error) {
    30  	entity0, err := lg.st.FindEntity(tag)
    31  	if err != nil {
    32  		return "", err
    33  	}
    34  	entity, ok := entity0.(state.Lifer)
    35  	if !ok {
    36  		return "", NotSupportedError(tag, "life cycles")
    37  	}
    38  	return params.Life(entity.Life().String()), nil
    39  }
    40  
    41  // Life returns the life status of every supplied entity, where available.
    42  func (lg *LifeGetter) Life(args params.Entities) (params.LifeResults, error) {
    43  	result := params.LifeResults{
    44  		Results: make([]params.LifeResult, len(args.Entities)),
    45  	}
    46  	if len(args.Entities) == 0 {
    47  		return result, nil
    48  	}
    49  	canRead, err := lg.getCanRead()
    50  	if err != nil {
    51  		return params.LifeResults{}, errors.Trace(err)
    52  	}
    53  	for i, entity := range args.Entities {
    54  		tag, err := names.ParseTag(entity.Tag)
    55  		if err != nil {
    56  			result.Results[i].Error = ServerError(ErrPerm)
    57  			continue
    58  		}
    59  		err = ErrPerm
    60  		if canRead(tag) {
    61  			result.Results[i].Life, err = lg.oneLife(tag)
    62  		}
    63  		result.Results[i].Error = ServerError(err)
    64  	}
    65  	return result, nil
    66  }