move coreos-cloudinit into config/cloudinit

Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au>

config/cloudinit/pkg/http_client.go

@@ -0,0 +1,165 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// 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 pkg
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	neturl "net/url"
+	"strings"
+	"time"
+)
+
+const (
+	HTTP_2xx = 2
+	HTTP_4xx = 4
+)
+
+type Err error
+
+type ErrTimeout struct {
+	Err
+}
+
+type ErrNotFound struct {
+	Err
+}
+
+type ErrInvalid struct {
+	Err
+}
+
+type ErrServer struct {
+	Err
+}
+
+type ErrNetwork struct {
+	Err
+}
+
+type HttpClient struct {
+	// Initial backoff duration. Defaults to 50 milliseconds
+	InitialBackoff time.Duration
+
+	// Maximum exp backoff duration. Defaults to 5 seconds
+	MaxBackoff time.Duration
+
+	// Maximum number of connection retries. Defaults to 15
+	MaxRetries int
+
+	// Headers to add to the request.
+	Header http.Header
+
+	client *http.Client
+}
+
+type Getter interface {
+	Get(string) ([]byte, error)
+	GetRetry(string) ([]byte, error)
+}
+
+func NewHttpClient() *HttpClient {
+	return NewHttpClientHeader(nil)
+}
+
+func NewHttpClientHeader(header http.Header) *HttpClient {
+	hc := &HttpClient{
+		InitialBackoff: 50 * time.Millisecond,
+		MaxBackoff:     time.Second * 5,
+		MaxRetries:     15,
+		Header:         header,
+		client: &http.Client{
+			Timeout: 10 * time.Second,
+		},
+	}
+
+	return hc
+}
+
+func ExpBackoff(interval, max time.Duration) time.Duration {
+	interval = interval * 2
+	if interval > max {
+		interval = max
+	}
+	return interval
+}
+
+// GetRetry fetches a given URL with support for exponential backoff and maximum retries
+func (h *HttpClient) GetRetry(rawurl string) ([]byte, error) {
+	if rawurl == "" {
+		return nil, ErrInvalid{errors.New("URL is empty. Skipping.")}
+	}
+
+	url, err := neturl.Parse(rawurl)
+	if err != nil {
+		return nil, ErrInvalid{err}
+	}
+
+	// Unfortunately, url.Parse is too generic to throw errors if a URL does not
+	// have a valid HTTP scheme. So, we have to do this extra validation
+	if !strings.HasPrefix(url.Scheme, "http") {
+		return nil, ErrInvalid{fmt.Errorf("URL %s does not have a valid HTTP scheme. Skipping.", rawurl)}
+	}
+
+	dataURL := url.String()
+
+	duration := h.InitialBackoff
+	for retry := 1; retry <= h.MaxRetries; retry++ {
+		log.Printf("Fetching data from %s. Attempt #%d", dataURL, retry)
+
+		data, err := h.Get(dataURL)
+		switch err.(type) {
+		case ErrNetwork:
+			log.Printf(err.Error())
+		case ErrServer:
+			log.Printf(err.Error())
+		case ErrNotFound:
+			return data, err
+		default:
+			return data, err
+		}
+
+		duration = ExpBackoff(duration, h.MaxBackoff)
+		log.Printf("Sleeping for %v...", duration)
+		time.Sleep(duration)
+	}
+
+	return nil, ErrTimeout{fmt.Errorf("Unable to fetch data. Maximum retries reached: %d", h.MaxRetries)}
+}
+
+func (h *HttpClient) Get(dataURL string) ([]byte, error) {
+	request, err := http.NewRequest("GET", dataURL, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	request.Header = h.Header
+	if resp, err := h.client.Do(request); err == nil {
+		defer resp.Body.Close()
+		switch resp.StatusCode / 100 {
+		case HTTP_2xx:
+			return ioutil.ReadAll(resp.Body)
+		case HTTP_4xx:
+			return nil, ErrNotFound{fmt.Errorf("Not found. HTTP status code: %d", resp.StatusCode)}
+		default:
+			return nil, ErrServer{fmt.Errorf("Server error. HTTP status code: %d", resp.StatusCode)}
+		}
+	} else {
+		return nil, ErrNetwork{fmt.Errorf("Unable to fetch data: %s", err.Error())}
+	}
+}