k3s/pkg/client/request.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 (
	"bytes"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"path"
	"time"

	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
)

// Server contains info locating a kubernetes api server.
// Example usage:
// auth, err := LoadAuth(filename)
// c := New(url, auth)
// resp, err := c.Verb("GET").
//	Path("pods").
//	Selector("area=staging").
//	Timeout(10*time.Second).
//	Do()
// list, ok := resp.(api.PodList)

// Begin a request with a verb (GET, POST, PUT, DELETE)
func (c *Client) Verb(verb string) *Request {
	return &Request{
		verb: verb,
		c:    c,
		path: "/api/v1beta1",
	}
}

// Begin a POST request.
func (c *Client) Post() *Request {
	return c.Verb("POST")
}

// Begin a PUT request.
func (c *Client) Put() *Request {
	return c.Verb("PUT")
}

// Begin a GET request.
func (c *Client) Get() *Request {
	return c.Verb("GET")
}

// Begin a DELETE request.
func (c *Client) Delete() *Request {
	return c.Verb("DELETE")
}

// Request allows for building up a request to a server in a chained fashion.
// Any errors are stored until the end of your call, so you only have to
// check once.
type Request struct {
	c        *Client
	err      error
	verb     string
	path     string
	body     io.Reader
	selector labels.Selector
	timeout  time.Duration
}

// Append an item to the request path. You must call Path at least once.
func (r *Request) Path(item string) *Request {
	if r.err != nil {
		return r
	}
	r.path = path.Join(r.path, item)
	return r
}

// Overwrite an existing path with the path parameter.
func (r *Request) AbsPath(path string) *Request {
	if r.err != nil {
		return r
	}
	r.path = path
	return r
}

// Parse the given string as a resource label selector. Optional.
func (r *Request) ParseSelector(item string) *Request {
	if r.err != nil {
		return r
	}
	r.selector, r.err = labels.ParseSelector(item)
	return r
}

// Use the given selector.
func (r *Request) Selector(s labels.Selector) *Request {
	if r.err != nil {
		return r
	}
	r.selector = s
	return r
}

// Use the given duration as a timeout. Optional.
func (r *Request) Timeout(d time.Duration) *Request {
	if r.err != nil {
		return r
	}
	r.timeout = d
	return r
}

// Use obj as the body of the request. Optional.
// If obj is a string, try to read a file of that name.
// If obj is a []byte, send it directly.
// Otherwise, assume obj is an api type and marshall it correctly.
func (r *Request) Body(obj interface{}) *Request {
	if r.err != nil {
		return r
	}
	switch t := obj.(type) {
	case string:
		data, err := ioutil.ReadFile(t)
		if err != nil {
			r.err = err
			return r
		}
		r.body = bytes.NewBuffer(data)
	case []byte:
		r.body = bytes.NewBuffer(t)
	case io.Reader:
		r.body = obj.(io.Reader)
	default:
		data, err := api.Encode(obj)
		if err != nil {
			r.err = err
			return r
		}
		r.body = bytes.NewBuffer(data)
	}
	return r
}

// Format and xecute the request. Returns the API object received, or an error.
func (r *Request) Do() Result {
	if r.err != nil {
		return Result{err: r.err}
	}
	finalUrl := r.c.host + r.path
	query := url.Values{}
	if r.selector != nil {
		query.Add("labels", r.selector.String())
	}
	if r.timeout != 0 {
		query.Add("timeout", r.timeout.String())
	}
	finalUrl += "?" + query.Encode()
	req, err := http.NewRequest(r.verb, finalUrl, r.body)
	if err != nil {
		return Result{err: err}
	}
	respBody, err := r.c.doRequest(req)
	if err != nil {
		if statusErr, ok := err.(*StatusErr); ok {
			// TODO: using the information in statusErr,
			// loop querying the server to wait and retrieve
			// the actual result.
			_ = statusErr
		}
	}
	return Result{respBody, err}
}

// Result contains the result of calling Request.Do().
type Result struct {
	body []byte
	err  error
}

// Raw returns the raw result.
func (r Result) Raw() ([]byte, error) {
	return r.body, r.err
}

// Get returns the result as an object.
func (r Result) Get() (interface{}, error) {
	if r.err != nil {
		return nil, r.err
	}
	return api.Decode(r.body)
}

// Into stores the result into obj, if possible..
func (r Result) Into(obj interface{}) error {
	if r.err != nil {
		return r.err
	}
	return api.DecodeInto(r.body, obj)
}

// Returns the error executing the request, nil if no error occurred.
func (r Result) Error() error {
	return r.err
}