state/apiserver: Relation ops for Uniter API

state/apiserver/uniter/uniter.go

Index: state/apiserver/uniter/uniter.go
=== modified file 'state/apiserver/uniter/uniter.go'
--- state/apiserver/uniter/uniter.go	2013-08-13 15:48:38 +0000
+++ state/apiserver/uniter/uniter.go	2013-08-16 08:49:10 +0000
@@ -6,6 +6,8 @@
 package uniter
 
 import (
+	"strconv"
+
 	"launchpad.net/juju-core/charm"
 	"launchpad.net/juju-core/errors"
 	"launchpad.net/juju-core/names"
@@ -22,12 +24,11 @@
 	*common.DeadEnsurer
 	*common.AgentEntityWatcher
 
-	st                        *state.State
-	auth                      common.Authorizer
-	resources                 *common.Resources
-	getCanAccessUnit          common.GetAuthFunc
-	getCanAccessService       common.GetAuthFunc
-	getCanAccessUnitOrService common.GetAuthFunc
+	st            *state.State
+	auth          common.Authorizer
+	resources     *common.Resources
+	accessUnit    common.GetAuthFunc
+	accessService common.GetAuthFunc
 }
 
 // NewUniterAPI creates a new instance of the Uniter API.
@@ -35,10 +36,10 @@
 	if !authorizer.AuthUnitAgent() {
 		return nil, common.ErrPerm
 	}
-	getCanAccessUnit := func() (common.AuthFunc, error) {
+	accessUnit := func() (common.AuthFunc, error) {
 		return authorizer.AuthOwner, nil
 	}
-	getCanAccessService := func() (common.AuthFunc, error) {
+	accessService := func() (common.AuthFunc, error) {
 		unit, ok := authorizer.GetAuthEntity().(*state.Unit)
 		if !ok {
 			panic("authenticated entity is not a unit")
@@ -47,25 +48,24 @@
 			return tag == names.ServiceTag(unit.ServiceName())
 		}, nil
 	}
-	getCanAccessUnitOrService := func() (common.AuthFunc, error) {
-		// These errors here are ignored: they're always nil.
-		canAccessService, _ := getCanAccessService()
-		canAccessUnit, _ := getCanAccessUnit()
+	accessRelation := func() (common.AuthFunc, error) {
 		return func(tag string) bool {
-			return canAccessService(tag) || canAccessUnit(tag)
+			_, _, err := names.ParseTag(tag, names.RelationTagKind)
+			return err == nil
 		}, nil
 	}
+	accessUnitOrService := common.AuthEither(accessUnit, accessService)
+	accessUnitServiceOrRelation := common.AuthEither(accessUnitOrService, accessRelation)
 	return &UniterAPI{
-		LifeGetter:                common.NewLifeGetter(st, getCanAccessUnitOrService),
-		StatusSetter:              common.NewStatusSetter(st, getCanAccessUnit),
-		DeadEnsurer:               common.NewDeadEnsurer(st, getCanAccessUnit),
-		AgentEntityWatcher:        common.NewAgentEntityWatcher(st, resources, getCanAccessUnitOrService),
-		st:                        st,
-		auth:                      authorizer,
-		resources:                 resources,
-		getCanAccessUnit:          getCanAccessUnit,
-		getCanAccessService:       getCanAccessService,
-		getCanAccessUnitOrService: getCanAccessUnitOrService,
+		LifeGetter:         common.NewLifeGetter(st, accessUnitServiceOrRelation),
+		StatusSetter:       common.NewStatusSetter(st, accessUnit),
+		DeadEnsurer:        common.NewDeadEnsurer(st, accessUnit),
+		AgentEntityWatcher: common.NewAgentEntityWatcher(st, resources, accessUnitOrService),
+		st:                 st,
+		auth:               authorizer,
+		resources:          resources,
+		accessUnit:         accessUnit,
+		accessService:      accessService,
 	}, nil
 }
 
@@ -91,7 +91,7 @@
 	result := params.StringBoolResults{
 		Results: make([]params.StringBoolResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.StringBoolResults{}, err
 	}
@@ -116,7 +116,7 @@
 	result := params.ErrorResults{
 		Results: make([]params.ErrorResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.ErrorResults{}, err
 	}
@@ -140,7 +140,7 @@
 	result := params.StringBoolResults{
 		Results: make([]params.StringBoolResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.StringBoolResults{}, err
 	}
@@ -165,7 +165,7 @@
 	result := params.ErrorResults{
 		Results: make([]params.ErrorResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.ErrorResults{}, err
 	}
@@ -188,7 +188,7 @@
 	result := params.ErrorResults{
 		Results: make([]params.ErrorResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.ErrorResults{}, err
 	}
@@ -211,7 +211,7 @@
 	result := params.StringBoolResults{
 		Results: make([]params.StringBoolResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.StringBoolResults{}, err
 	}
@@ -237,7 +237,7 @@
 	result := params.ErrorResults{
 		Results: make([]params.ErrorResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.ErrorResults{}, err
 	}
@@ -260,7 +260,7 @@
 	result := params.StringsResults{
 		Results: make([]params.StringsResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.StringsResults{}, err
 	}
@@ -283,7 +283,8 @@
 	result := params.StringBoolResults{
 		Results: make([]params.StringBoolResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnitOrService()
+	accessUnitOrService := common.AuthEither(u.accessUnit, u.accessService)
+	canAccess, err := accessUnitOrService()
 	if err != nil {
 		return params.StringBoolResults{}, err
 	}
@@ -312,7 +313,7 @@
 	result := params.ErrorResults{
 		Results: make([]params.ErrorResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.ErrorResults{}, err
 	}
@@ -340,7 +341,7 @@
 	result := params.ErrorResults{
 		Results: make([]params.ErrorResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.ErrorResults{}, err
 	}
@@ -364,7 +365,7 @@
 	result := params.ErrorResults{
 		Results: make([]params.ErrorResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.ErrorResults{}, err
 	}
@@ -408,7 +409,7 @@
 	result := params.NotifyWatchResults{
 		Results: make([]params.NotifyWatchResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.NotifyWatchResults{}, err
 	}
@@ -430,7 +431,7 @@
 	result := params.SettingsResults{
 		Results: make([]params.SettingsResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessUnit()
+	canAccess, err := u.accessUnit()
 	if err != nil {
 		return params.SettingsResults{}, err
 	}
@@ -476,7 +477,7 @@
 	result := params.StringsWatchResults{
 		Results: make([]params.StringsWatchResult, len(args.Entities)),
 	}
-	canAccess, err := u.getCanAccessService()
+	canAccess, err := u.accessService()
 	if err != nil {
 		return params.StringsWatchResults{}, err
 	}
@@ -540,15 +541,81 @@
 	return result, nil
 }
 
+func (u *UniterAPI) getOneRelation(canAccess common.AuthFunc, relTag, unitTag string) (params.RelationResult, error) {
+	nothing := params.RelationResult{}
+	_, id, err := names.ParseTag(relTag, names.RelationTagKind)
+	if err != nil {
+		return nothing, common.ErrPerm
+	}
+	// TODO(dimitern): Once the relation tags have a different format
+	// (e.g. "relation-service1@name1+service2@name2"), change the
+	// following code accordingly.
+	relId, err := strconv.Atoi(id)
+	if err != nil {
+		return nothing, common.ErrPerm
+	}
+	rel, err := u.st.Relation(relId)
+	if errors.IsNotFoundError(err) {
+		return nothing, common.ErrPerm
+	} else if err != nil {
+		return nothing, err
+	}
+	if !canAccess(unitTag) {
+		return nothing, common.ErrPerm
+	}
+	unit, err := u.getUnit(unitTag)
+	if err != nil {
+		return nothing, err
+	}
+	ep, err := rel.Endpoint(unit.ServiceName())
+	if err != nil {
+		return nothing, err
+	}
+	return params.RelationResult{
+		Id:  rel.Id(),
+		Key: rel.String(),
+		Endpoint: params.Endpoint{
+			ServiceName: ep.ServiceName,
+			Relation:    ep.Relation,
+		},
+	}, nil
+}
+
+// Relation returns information about all given relation/unit pairs,
+// including their id, key and the local endpoint.
+func (u *UniterAPI) Relation(args params.Relations) (params.RelationResults, error) {
+	result := params.RelationResults{
+		Results: make([]params.RelationResult, len(args.Relations)),
+	}
+	canAccess, err := u.accessUnit()
+	if err != nil {
+		return params.RelationResults{}, err
+	}
+	for i, rel := range args.Relations {
+		relParams, err := u.getOneRelation(canAccess, rel.Relation, rel.Unit)
+		if err == nil {
+			result.Results[i] = relParams
+		}
+		result.Results[i].Error = common.ServerError(err)
+	}
+	return result, nil
+}
+
+// EnvironUUID returns the UUID for the current juju environment.

[fwereade, 2013/08/16 09:38:07]

CurrentEnvironUUID

[dimitern, 2013/08/16 10:32:14]

Done in the follow-up branch.

+func (u *UniterAPI) CurrentEnvironUUID() (params.StringResult, error) {
+	result := params.StringResult{}
+	env, err := u.st.Environment()
+	if err == nil {
+		result.Result = env.UUID()
+	}
+	return result, err
+}
+
 // TODO(dimitern): Add the following needed calls:
-// RelationSetDying
-// RelationIsImplicit
-// RelationDestroy
-// RelationRelationUnit
-// RelationUnitRelation
-// RelationUnitSettings
-// RelationUnitEnterScope
-// RelationUnitLeaveScope
-// RelationUnitEndpoint
-// EndpointImplementedBy
-// EnvironUUID
+// EnterScope (rel-id, unit-tag)
+// LeaveScope (rel-id, unit-tag)
+// Settings (rel-id, unit-tag)
+// ReadSettings (rel-id, (remote)unit-tag)
+// WriteSettings (rel-id, unit-tag, settings)
+//
+// RelationUnitsWatcher