kubernetes/pkg/registry/service/storage.go

/*
Copyright 2014 Google Inc. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package service

import (
	"fmt"
	"strconv"
	"strings"

	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/apiserver"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/cloudprovider"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/registry/minion"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
)

// RegistryStorage adapts a service registry into apiserver's RESTStorage model.
type RegistryStorage struct {
	registry Registry
	cloud    cloudprovider.Interface
	machines minion.Registry
}

// NewRegistryStorage returns a new RegistryStorage.
func NewRegistryStorage(registry Registry, cloud cloudprovider.Interface, machines minion.Registry) apiserver.RESTStorage {
	return &RegistryStorage{
		registry: registry,
		cloud:    cloud,
		machines: machines,
	}
}

func (rs *RegistryStorage) Create(obj interface{}) (<-chan interface{}, error) {
	srv := obj.(*api.Service)
	if errs := api.ValidateService(srv); len(errs) > 0 {
		return nil, fmt.Errorf("Validation errors: %v", errs)
	}
	return apiserver.MakeAsync(func() (interface{}, error) {
		// TODO: Consider moving this to a rectification loop, so that we make/remove external load balancers
		// correctly no matter what http operations happen.
		if srv.CreateExternalLoadBalancer {
			if rs.cloud == nil {
				return nil, fmt.Errorf("requested an external service, but no cloud provider supplied.")
			}
			balancer, ok := rs.cloud.TCPLoadBalancer()
			if !ok {
				return nil, fmt.Errorf("The cloud provider does not support external TCP load balancers.")
			}
			zones, ok := rs.cloud.Zones()
			if !ok {
				return nil, fmt.Errorf("The cloud provider does not support zone enumeration.")
			}
			hosts, err := rs.machines.List()
			if err != nil {
				return nil, err
			}
			zone, err := zones.GetZone()
			if err != nil {
				return nil, err
			}
			err = balancer.CreateTCPLoadBalancer(srv.ID, zone.Region, srv.Port, hosts)
			if err != nil {
				return nil, err
			}
		}
		// TODO actually wait for the object to be fully created here.
		err := rs.registry.CreateService(*srv)
		if err != nil {
			return nil, err
		}
		return rs.registry.GetService(srv.ID)
	}), nil
}

func (rs *RegistryStorage) Delete(id string) (<-chan interface{}, error) {
	service, err := rs.registry.GetService(id)
	if err != nil {
		return nil, err
	}
	return apiserver.MakeAsync(func() (interface{}, error) {
		rs.deleteExternalLoadBalancer(service)
		return api.Status{Status: api.StatusSuccess}, rs.registry.DeleteService(id)
	}), nil
}

func (rs *RegistryStorage) Get(id string) (interface{}, error) {
	s, err := rs.registry.GetService(id)
	if err != nil {
		return nil, err
	}
	return s, err
}

func (rs *RegistryStorage) List(selector labels.Selector) (interface{}, error) {
	list, err := rs.registry.ListServices()
	if err != nil {
		return nil, err
	}
	var filtered []api.Service
	for _, service := range list.Items {
		if selector.Matches(labels.Set(service.Labels)) {
			filtered = append(filtered, service)
		}
	}
	list.Items = filtered
	return list, err
}

func (rs RegistryStorage) New() interface{} {
	return &api.Service{}
}

// GetServiceEnvironmentVariables populates a list of environment variables that are use
// in the container environment to get access to services.
func GetServiceEnvironmentVariables(registry Registry, machine string) ([]api.EnvVar, error) {
	var result []api.EnvVar
	services, err := registry.ListServices()
	if err != nil {
		return result, err
	}
	for _, service := range services.Items {
		name := strings.ToUpper(service.ID) + "_SERVICE_PORT"
		value := strconv.Itoa(service.Port)
		result = append(result, api.EnvVar{Name: name, Value: value})
		result = append(result, makeLinkVariables(service, machine)...)
	}
	result = append(result, api.EnvVar{Name: "SERVICE_HOST", Value: machine})
	return result, nil
}

func (rs *RegistryStorage) Update(obj interface{}) (<-chan interface{}, error) {
	srv := obj.(*api.Service)
	if srv.ID == "" {
		return nil, fmt.Errorf("ID should not be empty: %#v", srv)
	}
	if errs := api.ValidateService(srv); len(errs) > 0 {
		return nil, fmt.Errorf("Validation errors: %v", errs)
	}
	return apiserver.MakeAsync(func() (interface{}, error) {
		// TODO: check to see if external load balancer status changed
		err := rs.registry.UpdateService(*srv)
		if err != nil {
			return nil, err
		}
		return rs.registry.GetService(srv.ID)
	}), nil
}

func (rs *RegistryStorage) deleteExternalLoadBalancer(service *api.Service) error {
	if !service.CreateExternalLoadBalancer || rs.cloud == nil {
		return nil
	}
	zones, ok := rs.cloud.Zones()
	if !ok {
		// We failed to get zone enumerator.
		// As this should have failed when we tried in "create" too,
		// assume external load balancer was never created.
		return nil
	}
	balancer, ok := rs.cloud.TCPLoadBalancer()
	if !ok {
		// See comment above.
		return nil
	}
	zone, err := zones.GetZone()
	if err != nil {
		return err
	}
	if err := balancer.DeleteTCPLoadBalancer(service.JSONBase.ID, zone.Region); err != nil {
		return err
	}
	return nil
}

func makeLinkVariables(service api.Service, machine string) []api.EnvVar {
	prefix := strings.ToUpper(service.ID)
	var port string
	if service.ContainerPort.Kind == util.IntstrString {
		port = service.ContainerPort.StrVal
	} else {
		port = strconv.Itoa(service.ContainerPort.IntVal)
	}
	portPrefix := prefix + "_PORT_" + strings.ToUpper(strings.Replace(port, "-", "_", -1)) + "_TCP"
	return []api.EnvVar{
		{
			Name:  prefix + "_PORT",
			Value: fmt.Sprintf("tcp://%s:%d", machine, service.Port),
		},
		{
			Name:  portPrefix,
			Value: fmt.Sprintf("tcp://%s:%d", machine, service.Port),
		},
		{
			Name:  portPrefix + "_PROTO",
			Value: "tcp",
		},
		{
			Name:  portPrefix + "_PORT",
			Value: strconv.Itoa(service.Port),
		},
		{
			Name:  portPrefix + "_ADDR",
			Value: machine,
		},
	}
}