[dev] move meter status state to the controller

api/common/unitstate.go

@@ -18,8 +18,8 @@ type UnitStateAPI struct {
 	tag    names.UnitTag
 }
 
-// NewUpgradeSeriesAPI creates a UpgradeSeriesAPI on the specified facade,
-// and uses this name when calling through the caller.
+// NewUniterStateAPI creates a UnitStateAPI that uses the provided FacadeCaller
+// for making calls.
 func NewUniterStateAPI(facade base.FacadeCaller, tag names.UnitTag) *UnitStateAPI {
 	return &UnitStateAPI{facade: facade, tag: tag}
 }

apiserver/common/unitstate.go

@@ -80,7 +80,6 @@ func NewUnitStateAPI(
 	accessUnit GetAuthFunc,
 	logger loggo.Logger,
 ) *UnitStateAPI {
-	logger.Tracef("NewUnitStateAPI called with %s", authorizer.GetAuthTag())
 	return &UnitStateAPI{
 		backend:    backend,
 		resources:  resources,
@@ -120,14 +119,11 @@ func (u *UnitStateAPI) State(args params.Entities) (params.UnitStateResults, err
 			res[i].Error = ServerError(err)
 			continue
 		}
-		uState, _ := unitState.State()
-		res[i].State = uState
-		uUState, _ := unitState.UniterState()
-		res[i].UniterState = uUState
-		rState, _ := unitState.RelationState()
-		res[i].RelationState = rState
-		sState, _ := unitState.StorageState()
-		res[i].StorageState = sState
+		res[i].State, _ = unitState.State()
+		res[i].UniterState, _ = unitState.UniterState()
+		res[i].RelationState, _ = unitState.RelationState()
+		res[i].StorageState, _ = unitState.StorageState()
+		res[i].MeterStatusState, _ = unitState.MeterStatusState()
 	}
 
 	return params.UnitStateResults{Results: res}, nil
@@ -178,6 +174,9 @@ func (u *UnitStateAPI) SetState(args params.SetUnitStateArgs) (params.ErrorResul
 		if arg.StorageState != nil {
 			unitState.SetStorageState(*arg.StorageState)
 		}
+		if arg.MeterStatusState != nil {
+			unitState.SetMeterStatusState(*arg.MeterStatusState)
+		}
 
 		ops := unit.SetStateOperation(
 			unitState,

apiserver/facades/agent/meterstatus/meterstatus.go

@@ -8,13 +8,18 @@ import (
 	"gopkg.in/juju/names.v3"
 
 	"github.com/juju/errors"
+	"github.com/juju/loggo"
+
 	"github.com/juju/juju/apiserver/common"
 	"github.com/juju/juju/apiserver/facade"
 	"github.com/juju/juju/apiserver/params"
+	"github.com/juju/juju/controller"
 	"github.com/juju/juju/state"
 	"github.com/juju/juju/state/watcher"
 )
 
+var logger = loggo.GetLogger("juju.apiserver.meterstatus")
+
 // MeterStatus defines the methods exported by the meter status API facade.
 type MeterStatus interface {
 	GetMeterStatus(args params.Entities) (params.MeterStatusResults, error)
@@ -24,6 +29,8 @@ type MeterStatus interface {
 // MeterStatusState represents the state of an model required by the MeterStatus.
 //go:generate mockgen -package mocks -destination mocks/meterstatus_mock.go github.com/juju/juju/apiserver/facades/agent/meterstatus MeterStatusState
 type MeterStatusState interface {
+	ApplyOperation(state.ModelOperation) error
+	ControllerConfig() (controller.Config, error)
 
 	// Application returns a application state by name.
 	Application(name string) (*state.Application, error)
@@ -35,6 +42,8 @@ type MeterStatusState interface {
 // MeterStatusAPI implements the MeterStatus interface and is the concrete implementation
 // of the API endpoint.
 type MeterStatusAPI struct {
+	*common.UnitStateAPI
+
 	state      MeterStatusState
 	accessUnit common.GetAuthFunc
 	resources  facade.Resources
@@ -56,38 +65,48 @@ func NewMeterStatusAPI(
 	if !authorizer.AuthUnitAgent() && !authorizer.AuthApplicationAgent() {
 		return nil, common.ErrPerm
 	}
-	return &MeterStatusAPI{
-		state: st,
-		accessUnit: func() (common.AuthFunc, error) {
-			switch tag := authorizer.GetAuthTag().(type) {
-			case names.ApplicationTag:
-				// If called by an application agent, any of the units
-				// belonging to that application can be accessed.
-				app, err := st.Application(tag.Name)
-				if err != nil {
-					return nil, errors.Trace(err)
-				}
-				allUnits, err := app.AllUnits()
-				if err != nil {
-					return nil, errors.Trace(err)
-				}
-				return func(tag names.Tag) bool {
-					for _, u := range allUnits {
-						if u.Tag() == tag {
-							return true
-						}
-					}
-					return false
-				}, nil
-			case names.UnitTag:
-				return func(tag names.Tag) bool {
-					return authorizer.AuthOwner(tag)
-				}, nil
-			default:
-				return nil, errors.Errorf("expected names.UnitTag or names.ApplicationTag, got %T", tag)
+
+	var accessCheckerFn = func() (common.AuthFunc, error) {
+		switch tag := authorizer.GetAuthTag().(type) {
+		case names.ApplicationTag:
+			// If called by an application agent, any of the units
+			// belonging to that application can be accessed.
+			app, err := st.Application(tag.Name)
+			if err != nil {
+				return nil, errors.Trace(err)
+			}
+			allUnits, err := app.AllUnits()
+			if err != nil {
+				return nil, errors.Trace(err)
 			}
-		},
-		resources: resources,
+			return func(tag names.Tag) bool {
+				for _, u := range allUnits {
+					if u.Tag() == tag {
+						return true
+					}
+				}
+				return false
+			}, nil
+		case names.UnitTag:
+			return func(tag names.Tag) bool {
+				return authorizer.AuthOwner(tag)
+			}, nil
+		default:
+			return nil, errors.Errorf("expected names.UnitTag or names.ApplicationTag, got %T", tag)
+		}
+	}
+
+	return &MeterStatusAPI{
+		state:      st,
+		accessUnit: accessCheckerFn,
+		resources:  resources,
+		UnitStateAPI: common.NewUnitStateAPI(
+			unitStateShim{st},
+			resources,
+			authorizer,
+			accessCheckerFn,
+			logger,
+		),
 	}, nil
 }
 
@@ -160,3 +179,21 @@ func (m *MeterStatusAPI) GetMeterStatus(args params.Entities) (params.MeterStatu
 	}
 	return result, nil
 }
+
+// unitStateShim adapts the state backend for this facade to make it compatible
+// with common.UnitStateAPI.
+type unitStateShim struct {
+	st MeterStatusState
+}
+
+func (s unitStateShim) ApplyOperation(op state.ModelOperation) error {
+	return s.st.ApplyOperation(op)
+}
+
+func (s unitStateShim) ControllerConfig() (controller.Config, error) {
+	return s.st.ControllerConfig()
+}
+
+func (s unitStateShim) Unit(name string) (common.UnitStateUnit, error) {
+	return s.st.Unit(name)
+}

apiserver/facades/agent/uniter/uniter.go

@@ -3420,18 +3420,38 @@ func (u *UniterAPI) commitHookChangesForOneUnit(unitTag names.UnitTag, changes p
 		if changes.SetUnitState.Tag != changes.Tag {
 			return common.ErrPerm
 		}
+
+		newUS := state.NewUnitState()
 		if changes.SetUnitState.State != nil {
-			newUS := state.NewUnitState()
 			newUS.SetState(*changes.SetUnitState.State)
-			modelOp := unit.SetStateOperation(
-				newUS,
-				state.UnitStateSizeLimits{
-					MaxCharmStateSize: ctrlCfg.MaxCharmStateSize(),
-					MaxAgentStateSize: ctrlCfg.MaxAgentStateSize(),
-				},
-			)
-			modelOps = append(modelOps, modelOp)
 		}
+
+		// NOTE(achilleasa): The following state fields are not
+		// presently populated by the uniter calls to this API as they
+		// get persisted after the hook changes get committed. However,
+		// they are still checked here for future use and for ensuring
+		// symmetry with the SetState call (see apiserver/common).
+		if changes.SetUnitState.UniterState != nil {
+			newUS.SetUniterState(*changes.SetUnitState.UniterState)
+		}
+		if changes.SetUnitState.RelationState != nil {
+			newUS.SetRelationState(*changes.SetUnitState.RelationState)
+		}
+		if changes.SetUnitState.StorageState != nil {
+			newUS.SetStorageState(*changes.SetUnitState.StorageState)
+		}
+		if changes.SetUnitState.MeterStatusState != nil {
+			newUS.SetMeterStatusState(*changes.SetUnitState.MeterStatusState)
+		}
+
+		modelOp := unit.SetStateOperation(
+			newUS,
+			state.UnitStateSizeLimits{
+				MaxCharmStateSize: ctrlCfg.MaxCharmStateSize(),
+				MaxAgentStateSize: ctrlCfg.MaxAgentStateSize(),
+			},
+		)
+		modelOps = append(modelOps, modelOp)
 	}
 
 	for _, addParams := range changes.AddStorage {