github.com/mattyw/juju@v0.0.0-20140610034352-732aecd63861/state/apiserver/firewaller/firewaller.go

// Copyright 2012, 2013 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.
package firewaller

import (
	"github.com/juju/names"

	"github.com/juju/juju/state"
	"github.com/juju/juju/state/api/params"
	"github.com/juju/juju/state/apiserver/common"
)

// FirewallerAPI provides access to the Firewaller API facade.
type FirewallerAPI struct {
	*common.LifeGetter
	*common.EnvironWatcher
	*common.AgentEntityWatcher
	*common.UnitsWatcher
	*common.EnvironMachinesWatcher
	*common.InstanceIdGetter

	st            *state.State
	resources     *common.Resources
	authorizer    common.Authorizer
	accessUnit    common.GetAuthFunc
	accessService common.GetAuthFunc
}

// NewFirewallerAPI creates a new server-side FirewallerAPI facade.
func NewFirewallerAPI(
	st *state.State,
	resources *common.Resources,
	authorizer common.Authorizer,
) (*FirewallerAPI, error) {
	if !authorizer.AuthEnvironManager() {
		// Firewaller must run as environment manager.
		return nil, common.ErrPerm
	}
	// Set up the various authorization checkers.
	accessUnit := getAuthFuncForTagKind(names.UnitTagKind)
	accessService := getAuthFuncForTagKind(names.ServiceTagKind)
	accessMachine := getAuthFuncForTagKind(names.MachineTagKind)
	accessEnviron := getAuthFuncForTagKind("")
	accessUnitOrService := common.AuthEither(accessUnit, accessService)
	accessUnitServiceOrMachine := common.AuthEither(accessUnitOrService, accessMachine)

	// Life() is supported for units, services or machines.
	lifeGetter := common.NewLifeGetter(
		st,
		accessUnitServiceOrMachine,
	)
	// EnvironConfig() and WatchForEnvironConfigChanges() are allowed
	// with unrestriced access.
	environWatcher := common.NewEnvironWatcher(
		st,
		resources,
		accessEnviron,
		accessEnviron,
	)
	// Watch() is supported for units or services.
	entityWatcher := common.NewAgentEntityWatcher(
		st,
		resources,
		accessUnitOrService,
	)
	// WatchUnits() is supported for machines.
	unitsWatcher := common.NewUnitsWatcher(st,
		resources,
		accessMachine,
	)
	// WatchEnvironMachines() is allowed with unrestricted access.
	machinesWatcher := common.NewEnvironMachinesWatcher(
		st,
		resources,
		accessEnviron,
	)
	// InstanceId() is supported for machines.
	instanceIdGetter := common.NewInstanceIdGetter(
		st,
		accessMachine,
	)
	return &FirewallerAPI{
		LifeGetter:             lifeGetter,
		EnvironWatcher:         environWatcher,
		AgentEntityWatcher:     entityWatcher,
		UnitsWatcher:           unitsWatcher,
		EnvironMachinesWatcher: machinesWatcher,
		InstanceIdGetter:       instanceIdGetter,
		st:                     st,
		resources:              resources,
		authorizer:             authorizer,
		accessUnit:             accessUnit,
		accessService:          accessService,
	}, nil
}

// OpenedPorts returns the list of opened ports for each given unit.
func (f *FirewallerAPI) OpenedPorts(args params.Entities) (params.PortsResults, error) {
	result := params.PortsResults{
		Results: make([]params.PortsResult, len(args.Entities)),
	}
	canAccess, err := f.accessUnit()
	if err != nil {
		return params.PortsResults{}, err
	}
	for i, entity := range args.Entities {
		var unit *state.Unit
		unit, err = f.getUnit(canAccess, entity.Tag)
		if err == nil {
			result.Results[i].Ports = unit.OpenedPorts()
		}
		result.Results[i].Error = common.ServerError(err)
	}
	return result, nil
}

// GetExposed returns the exposed flag value for each given service.
func (f *FirewallerAPI) GetExposed(args params.Entities) (params.BoolResults, error) {
	result := params.BoolResults{
		Results: make([]params.BoolResult, len(args.Entities)),
	}
	canAccess, err := f.accessService()
	if err != nil {
		return params.BoolResults{}, err
	}
	for i, entity := range args.Entities {
		var service *state.Service
		service, err = f.getService(canAccess, entity.Tag)
		if err == nil {
			result.Results[i].Result = service.IsExposed()
		}
		result.Results[i].Error = common.ServerError(err)
	}
	return result, nil
}

// GetAssignedMachine returns the assigned machine tag (if any) for
// each given unit.
func (f *FirewallerAPI) GetAssignedMachine(args params.Entities) (params.StringResults, error) {
	result := params.StringResults{
		Results: make([]params.StringResult, len(args.Entities)),
	}
	canAccess, err := f.accessUnit()
	if err != nil {
		return params.StringResults{}, err
	}
	for i, entity := range args.Entities {
		var unit *state.Unit
		unit, err = f.getUnit(canAccess, entity.Tag)
		if err == nil {
			var machineId string
			machineId, err = unit.AssignedMachineId()
			if err == nil {
				result.Results[i].Result = names.MachineTag(machineId)
			}
		}
		result.Results[i].Error = common.ServerError(err)
	}
	return result, nil
}

func (f *FirewallerAPI) getEntity(canAccess common.AuthFunc, tag string) (state.Entity, error) {
	if !canAccess(tag) {
		return nil, common.ErrPerm
	}
	return f.st.FindEntity(tag)
}

func (f *FirewallerAPI) getUnit(canAccess common.AuthFunc, tag string) (*state.Unit, error) {
	entity, err := f.getEntity(canAccess, tag)
	if err != nil {
		return nil, err
	}
	// The authorization function guarantees that the tag represents a
	// unit.
	return entity.(*state.Unit), nil
}

func (f *FirewallerAPI) getService(canAccess common.AuthFunc, tag string) (*state.Service, error) {
	entity, err := f.getEntity(canAccess, tag)
	if err != nil {
		return nil, err
	}
	// The authorization function guarantees that the tag represents a
	// service.
	return entity.(*state.Service), nil
}

// getAuthFuncForTagKind returns a GetAuthFunc which creates an
// AuthFunc allowing only the given tag kind and denies all
// others. In the special case where a single empty string is given,
// it's assumed only environment tags are allowed, but not specified
// (for now).
func getAuthFuncForTagKind(kind string) common.GetAuthFunc {
	return func() (common.AuthFunc, error) {
		return func(tag string) bool {
			if tag == "" {
				// Assume an empty tag means a missing environment tag.
				return kind == ""
			}
			// Allow only the given tag kind.
			_, _, err := names.ParseTag(tag, kind)
			if err != nil {
				return false
			}
			return true
		}, nil
	}
}