kubernetes/pkg/client/client.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 client

import (
	"crypto/tls"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"time"

	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/version"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
	"github.com/golang/glog"
)

// Interface holds the methods for clients of Kubernetes,
// an interface to allow mock testing.
// TODO: these should return/take pointers.
type Interface interface {
	PodInterface
	ReplicationControllerInterface
	ServiceInterface
	VersionInterface
	MinionInterface
}

// PodInterface has methods to work with Pod resources
type PodInterface interface {
	ListPods(selector labels.Selector) (api.PodList, error)
	GetPod(name string) (api.Pod, error)
	DeletePod(name string) error
	CreatePod(api.Pod) (api.Pod, error)
	UpdatePod(api.Pod) (api.Pod, error)
}

// ReplicationControllerInterface has methods to work with ReplicationController resources
type ReplicationControllerInterface interface {
	ListReplicationControllers(selector labels.Selector) (api.ReplicationControllerList, error)
	GetReplicationController(name string) (api.ReplicationController, error)
	CreateReplicationController(api.ReplicationController) (api.ReplicationController, error)
	UpdateReplicationController(api.ReplicationController) (api.ReplicationController, error)
	DeleteReplicationController(string) error
	WatchReplicationControllers(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error)
}

// ServiceInterface has methods to work with Service resources
type ServiceInterface interface {
	GetService(name string) (api.Service, error)
	CreateService(api.Service) (api.Service, error)
	UpdateService(api.Service) (api.Service, error)
	DeleteService(string) error
	WatchServices(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error)

	WatchEndpoints(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error)
}

// VersionInterface has a method to retrieve the server version
type VersionInterface interface {
	ServerVersion() (*version.Info, error)
}

type MinionInterface interface {
	ListMinions() (api.MinionList, error)
}

// Client is the actual implementation of a Kubernetes client.
type Client struct {
	*RESTClient
}

// StatusErr might get returned from an api call if your request is still being processed
// and hence the expected return data is not available yet.
type StatusErr struct {
	Status api.Status
}

func (s *StatusErr) Error() string {
	return fmt.Sprintf("Status: %v (%#v)", s.Status.Status, s.Status)
}

// AuthInfo is used to store authorization information
type AuthInfo struct {
	User     string
	Password string
}

// RESTClient holds common code used to work with API resources that follow the
// Kubernetes API pattern
// Host is the http://... base for the URL
type RESTClient struct {
	host       string
	auth       *AuthInfo
	httpClient *http.Client
	Sync       bool
	PollPeriod time.Duration
	Timeout    time.Duration
	Prefix     string
}

// NewRESTClient creates a new RESTClient. This client performs generic REST functions
// such as Get, Put, Post, and Delete on specified paths.
func NewRESTClient(host string, auth *AuthInfo, prefix string) *RESTClient {
	return &RESTClient{
		auth: auth,
		host: host,
		httpClient: &http.Client{
			Transport: &http.Transport{
				TLSClientConfig: &tls.Config{
					InsecureSkipVerify: true,
				},
			},
		},
		Sync:       false,
		PollPeriod: time.Second * 2,
		Timeout:    time.Second * 20,
		Prefix:     prefix,
	}

}

// New creates a Kubernetes client. This client works with pods, replication controllers
// and services. It allows operations such as list, get, update and delete on these objects.
func New(host string, auth *AuthInfo) *Client {
	return &Client{NewRESTClient(host, auth, "/api/v1beta1/")}
}

// Execute a request, adds authentication (if auth != nil), and HTTPS cert ignoring.
func (c *RESTClient) doRequest(request *http.Request) ([]byte, error) {
	if c.auth != nil {
		request.SetBasicAuth(c.auth.User, c.auth.Password)
	}
	response, err := c.httpClient.Do(request)
	if err != nil {
		return nil, err
	}
	defer response.Body.Close()
	body, err := ioutil.ReadAll(response.Body)
	if err != nil {
		return body, err
	}

	// Did the server give us a status response?
	isStatusResponse := false
	var status api.Status
	if err := api.DecodeInto(body, &status); err == nil && status.Status != "" {
		isStatusResponse = true
	}

	switch {
	case response.StatusCode == http.StatusConflict:
		// Return error given by server, if there was one.
		if isStatusResponse {
			return nil, &StatusErr{status}
		}
		fallthrough
	case response.StatusCode < http.StatusOK || response.StatusCode > http.StatusPartialContent:
		return nil, fmt.Errorf("request [%#v] failed (%d) %s: %s", request, response.StatusCode, response.Status, string(body))
	}

	// If the server gave us a status back, look at what it was.
	if isStatusResponse && status.Status != api.StatusSuccess {
		// "Working" requests need to be handled specially.
		// "Failed" requests are clearly just an error and it makes sense to return them as such.
		return nil, &StatusErr{status}
	}
	return body, err
}

// Underlying base implementation of performing a request.
// method is the HTTP method (e.g. "GET")
// path is the path on the host to hit
// requestBody is the body of the request. Can be nil.
// target the interface to marshal the JSON response into.  Can be nil.
func (c *RESTClient) rawRequest(method, path string, requestBody io.Reader, target interface{}) ([]byte, error) {
	reqUrl, err := c.makeURL(path)
	if err != nil {
		return nil, err
	}

	request, err := http.NewRequest(method, reqUrl, requestBody)
	if err != nil {
		return nil, err
	}
	body, err := c.doRequest(request)
	if err != nil {
		return body, err
	}
	if target != nil {
		err = api.DecodeInto(body, target)
	}
	if err != nil {
		glog.Infof("Failed to parse: %s\n", string(body))
		// FIXME: no need to return err here?
	}
	return body, err
}

func (c *RESTClient) makeURL(path string) (string, error) {
	base := c.host
	hostURL, err := url.Parse(base)
	if err != nil {
		return "", err
	}
	if hostURL.Scheme == "" {
		hostURL, err = url.Parse("http://" + base)
		if err != nil {
			return "", err
		}
		if hostURL.Path != "" && hostURL.Path != "/" {
			return "", fmt.Errorf("host must be a URL or a host:port pair: %s", base)
		}
	}
	hostURL.Path += c.Prefix + path

	return hostURL.String(), nil
}

// ListPods takes a selector, and returns the list of pods that match that selector
func (c *Client) ListPods(selector labels.Selector) (result api.PodList, err error) {
	err = c.Get().Path("pods").SelectorParam("labels", selector).Do().Into(&result)
	return
}

// GetPod takes the name of the pod, and returns the corresponding Pod object, and an error if it occurs
func (c *Client) GetPod(name string) (result api.Pod, err error) {
	err = c.Get().Path("pods").Path(name).Do().Into(&result)
	return
}

// DeletePod takes the name of the pod, and returns an error if one occurs
func (c *Client) DeletePod(name string) error {
	return c.Delete().Path("pods").Path(name).Do().Error()
}

// CreatePod takes the representation of a pod.  Returns the server's representation of the pod, and an error, if it occurs
func (c *Client) CreatePod(pod api.Pod) (result api.Pod, err error) {
	err = c.Post().Path("pods").Body(pod).Do().Into(&result)
	return
}

// UpdatePod takes the representation of a pod to update.  Returns the server's representation of the pod, and an error, if it occurs
func (c *Client) UpdatePod(pod api.Pod) (result api.Pod, err error) {
	if pod.ResourceVersion == 0 {
		err = fmt.Errorf("invalid update object, missing resource version: %v", pod)
		return
	}
	err = c.Put().Path("pods").Path(pod.ID).Body(pod).Do().Into(&result)
	return
}

// ListReplicationControllers takes a selector, and returns the list of replication controllers that match that selector
func (c *Client) ListReplicationControllers(selector labels.Selector) (result api.ReplicationControllerList, err error) {
	err = c.Get().Path("replicationControllers").SelectorParam("labels", selector).Do().Into(&result)
	return
}

// GetReplicationController returns information about a particular replication controller
func (c *Client) GetReplicationController(name string) (result api.ReplicationController, err error) {
	err = c.Get().Path("replicationControllers").Path(name).Do().Into(&result)
	return
}

// CreateReplicationController creates a new replication controller
func (c *Client) CreateReplicationController(controller api.ReplicationController) (result api.ReplicationController, err error) {
	err = c.Post().Path("replicationControllers").Body(controller).Do().Into(&result)
	return
}

// UpdateReplicationController updates an existing replication controller
func (c *Client) UpdateReplicationController(controller api.ReplicationController) (result api.ReplicationController, err error) {
	if controller.ResourceVersion == 0 {
		err = fmt.Errorf("invalid update object, missing resource version: %v", controller)
		return
	}
	err = c.Put().Path("replicationControllers").Path(controller.ID).Body(controller).Do().Into(&result)
	return
}

// DeleteReplicationController deletes an existing replication controller.
func (c *Client) DeleteReplicationController(name string) error {
	return c.Delete().Path("replicationControllers").Path(name).Do().Error()
}

// WatchReplicationControllers returns a watch.Interface that watches the requested controllers.
func (c *Client) WatchReplicationControllers(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error) {
	return c.Get().
		Path("watch").
		Path("replicationControllers").
		UintParam("resourceVersion", resourceVersion).
		SelectorParam("labels", label).
		SelectorParam("fields", field).
		Watch()
}

// GetService returns information about a particular service.
func (c *Client) GetService(name string) (result api.Service, err error) {
	err = c.Get().Path("services").Path(name).Do().Into(&result)
	return
}

// CreateService creates a new service.
func (c *Client) CreateService(svc api.Service) (result api.Service, err error) {
	err = c.Post().Path("services").Body(svc).Do().Into(&result)
	return
}

// UpdateService updates an existing service.
func (c *Client) UpdateService(svc api.Service) (result api.Service, err error) {
	if svc.ResourceVersion == 0 {
		err = fmt.Errorf("invalid update object, missing resource version: %v", svc)
		return
	}
	err = c.Put().Path("services").Path(svc.ID).Body(svc).Do().Into(&result)
	return
}

// DeleteService deletes an existing service.
func (c *Client) DeleteService(name string) error {
	return c.Delete().Path("services").Path(name).Do().Error()
}

// WatchService returns a watch.Interface that watches the requested services.
func (c *Client) WatchServices(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error) {
	return c.Get().
		Path("watch").
		Path("services").
		UintParam("resourceVersion", resourceVersion).
		SelectorParam("labels", label).
		SelectorParam("fields", field).
		Watch()
}

// WatchEndpoints returns a watch.Interface that watches the requested endpoints for a service.
func (c *Client) WatchEndpoints(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error) {
	return c.Get().
		Path("watch").
		Path("endpoints").
		UintParam("resourceVersion", resourceVersion).
		SelectorParam("labels", label).
		SelectorParam("fields", field).
		Watch()
}

// ServerVersion retrieves and parses the server's version.
func (c *Client) ServerVersion() (*version.Info, error) {
	body, err := c.Get().AbsPath("/version").Do().Raw()
	if err != nil {
		return nil, err
	}
	var info version.Info
	err = json.Unmarshal(body, &info)
	if err != nil {
		return nil, fmt.Errorf("Got '%s': %v", string(body), err)
	}
	return &info, nil
}

// Lists all the minions in the cluster.
func (c *Client) ListMinions() (minionList api.MinionList, err error) {
	err = c.Get().Path("minions").Do().Into(&minionList)
	return
}