launchpad.net/~rogpeppe/juju-core/500-errgo-fix@v0.0.0-20140213181702-000000002356/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/errors"
     8  	"launchpad.net/juju-core/state"
     9  	"launchpad.net/juju-core/state/api/params"
    10  )
    11  
    12  // LifeGetter implements a common Life method for use by various facades.
    13  type LifeGetter struct {
    14  	st         state.EntityFinder
    15  	getCanRead GetAuthFunc
    16  }
    17  
    18  // NewLifeGetter returns a new LifeGetter. The GetAuthFunc will be used on
    19  // each invocation of Life to determine current permissions.
    20  func NewLifeGetter(st state.EntityFinder, getCanRead GetAuthFunc) *LifeGetter {
    21  	return &LifeGetter{
    22  		st:         st,
    23  		getCanRead: getCanRead,
    24  	}
    25  }
    26  
    27  func (lg *LifeGetter) oneLife(tag string) (params.Life, error) {
    28  	entity0, err := lg.st.FindEntity(tag)
    29  	if err != nil {
    30  		return "", mask(err, errors.IsNotFoundError)
    31  	}
    32  	entity, ok := entity0.(state.Lifer)
    33  	if !ok {
    34  		return "", NotSupportedError(tag, "life cycles")
    35  	}
    36  	return params.Life(entity.Life().String()), nil
    37  }
    38  
    39  // Life returns the life status of every supplied entity, where available.
    40  func (lg *LifeGetter) Life(args params.Entities) (params.LifeResults, error) {
    41  	result := params.LifeResults{
    42  		Results: make([]params.LifeResult, len(args.Entities)),
    43  	}
    44  	if len(args.Entities) == 0 {
    45  		return result, nil
    46  	}
    47  	canRead, err := lg.getCanRead()
    48  	if err != nil {
    49  		return params.LifeResults{}, mask(err)
    50  	}
    51  	for i, entity := range args.Entities {
    52  		err := ErrPerm
    53  		if canRead(entity.Tag) {
    54  			result.Results[i].Life, err = lg.oneLife(entity.Tag)
    55  		}
    56  		result.Results[i].Error = ServerError(err)
    57  	}
    58  	return result, nil
    59  }