api/uniter: Skeleton of remaining calls/objects

state/api/uniter/relation.go

Index: state/api/uniter/relation.go 
=== added file 'state/api/uniter/relation.go' 
--- state/api/uniter/relation.go	1970-01-01 00:00:00 +0000 
+++ state/api/uniter/relation.go	2013-08-19 15:08:17 +0000 
@@ -0,0 +1,70 @@ 
+// Copyright 2013 Canonical Ltd. 
+// Licensed under the AGPLv3, see LICENCE file for details. 
+ 
+package uniter 
+ 
+import ( 
+	"launchpad.net/juju-core/state/api/params" 
+) 
+ 
+// This module implements a subset of the interface provided by 
+// state.Relation, as needed by the uniter API. 
+ 
+// TODO: Only the required calls are added as placeholders, 
+// the actual implementation will come in a follow-up. 
+ 
+// TODO: Once the relation tags format change from "relation-<id>" to 
+// "relation-<key>", make the necessary changes here and at 
+// server-side. This affects the methods Relation() and KeyRelation() 
+// on uniter.State, as well Id() defined here, and any other method 
+// taking a relation tag as an argument. 
+ 
+// Relation represents a relation between one or two service 
+// endpoints. 
+type Relation struct { 
+	st *State 
+	tag string 
+	life params.Life 
+	// TODO: Add fields. 
+} 
+ 
+// Id returns the integer internal relation key. This is exposed 
+// because the unit agent needs to expose a value derived from this 
+// (as JUJU_RELATION_ID) to allow relation hooks to differentiate 
+// between relations with different services. 
+func (r *Relation) Id() int { 
+	// TODO: Convert the relation tag to id and return it. 
+	panic("not implemented") 
+} 
+ 
+// Life returns the relation's current life state. 
+func (r *Relation) Life() params.Life { 
+	return r.life 
+} 
+ 
+// Refresh refreshes the contents of the relation from the underlying 
+// state. It returns an error that satisfies IsNotFound if the relation has been 
+// removed. 
+func (r *Relation) Refresh() error { 
+	// TODO: Call Uniter.Life(), passing the relation tag as argument. 
+	// Update r.life accordingly after getting the result. 
+	panic("not implemented") 
+} 
+ 
+// Endpoint returns the endpoint of the relation for the service the 
+// uniter's managed unit belongs to. 
+func (r *Relation) Endpoint() Endpoint { 
+	// NOTE: This differs from state.Relation.Endpoint(), because when 
+	// talking to the API, there's already an authenticated entity - the 
+	// unit, and we can find out its service name. 
+	// TODO: Return an Endpoint initialized with the curret auth'ed unit's 
+	// service name and relevent info. 
+	panic("not implemented") 
+} 
+ 
+// Unit returns a RelationUnit for the supplied unit. 
+func (r *Relation) Unit(u *Unit) (*RelationUnit, error) { 
+	// TODO: Just create and return a uniter.RelationUnit initialized 
+	// properly and a nil error. 
+	panic("not implemented") 
+}