github.com/cloudbase/juju-core@v0.0.0-20140504232958-a7271ac7912f/state/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  	"launchpad.net/juju-core/state"
     8  	"launchpad.net/juju-core/state/api/params"
     9  )
    10  
    11  // LifeGetter implements a common Life method for use by various facades.
    12  type LifeGetter struct {
    13  	st         state.EntityFinder
    14  	getCanRead GetAuthFunc
    15  }
    16  
    17  // NewLifeGetter returns a new LifeGetter. The GetAuthFunc will be used on
    18  // each invocation of Life to determine current permissions.
    19  func NewLifeGetter(st state.EntityFinder, getCanRead GetAuthFunc) *LifeGetter {
    20  	return &LifeGetter{
    21  		st:         st,
    22  		getCanRead: getCanRead,
    23  	}
    24  }
    25  
    26  func (lg *LifeGetter) oneLife(tag string) (params.Life, error) {
    27  	entity0, err := lg.st.FindEntity(tag)
    28  	if err != nil {
    29  		return "", err
    30  	}
    31  	entity, ok := entity0.(state.Lifer)
    32  	if !ok {
    33  		return "", NotSupportedError(tag, "life cycles")
    34  	}
    35  	return params.Life(entity.Life().String()), nil
    36  }
    37  
    38  // Life returns the life status of every supplied entity, where available.
    39  func (lg *LifeGetter) Life(args params.Entities) (params.LifeResults, error) {
    40  	result := params.LifeResults{
    41  		Results: make([]params.LifeResult, len(args.Entities)),
    42  	}
    43  	if len(args.Entities) == 0 {
    44  		return result, nil
    45  	}
    46  	canRead, err := lg.getCanRead()
    47  	if err != nil {
    48  		return params.LifeResults{}, err
    49  	}
    50  	for i, entity := range args.Entities {
    51  		err := ErrPerm
    52  		if canRead(entity.Tag) {
    53  			result.Results[i].Life, err = lg.oneLife(entity.Tag)
    54  		}
    55  		result.Results[i].Error = ServerError(err)
    56  	}
    57  	return result, nil
    58  }