launchpad.net/~rogpeppe/juju-core/500-errgo-fix@v0.0.0-20140213181702-000000002356/worker/uniter/jujuc/relation-list.go (about)

     1  // Copyright 2012, 2013 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package jujuc
     5  
     6  import (
     7  	"launchpad.net/errgo/errors"
     8  	"launchpad.net/gnuflag"
     9  
    10  	"launchpad.net/juju-core/cmd"
    11  )
    12  
    13  // RelationListCommand implements the relation-list command.
    14  type RelationListCommand struct {
    15  	cmd.CommandBase
    16  	ctx        Context
    17  	RelationId int
    18  	out        cmd.Output
    19  }
    20  
    21  func NewRelationListCommand(ctx Context) cmd.Command {
    22  	return &RelationListCommand{ctx: ctx}
    23  }
    24  
    25  func (c *RelationListCommand) Info() *cmd.Info {
    26  	doc := "-r must be specified when not in a relation hook"
    27  	if _, found := c.ctx.HookRelation(); found {
    28  		doc = ""
    29  	}
    30  	return &cmd.Info{
    31  		Name:    "relation-list",
    32  		Purpose: "list relation units",
    33  		Doc:     doc,
    34  	}
    35  }
    36  
    37  func (c *RelationListCommand) SetFlags(f *gnuflag.FlagSet) {
    38  	c.out.AddFlags(f, "smart", cmd.DefaultFormatters)
    39  	f.Var(newRelationIdValue(c.ctx, &c.RelationId), "r", "specify a relation by id")
    40  }
    41  
    42  func (c *RelationListCommand) Init(args []string) (err error) {
    43  	if c.RelationId == -1 {
    44  		return errors.Newf("no relation id specified")
    45  	}
    46  	return cmd.CheckEmpty(args)
    47  }
    48  
    49  func (c *RelationListCommand) Run(ctx *cmd.Context) error {
    50  	r, found := c.ctx.Relation(c.RelationId)
    51  	if !found {
    52  		return errors.Newf("unknown relation id")
    53  	}
    54  	unitNames := r.UnitNames()
    55  	if unitNames == nil {
    56  		unitNames = []string{}
    57  	}
    58  	return c.out.Write(ctx, unitNames)
    59  }