Upload tools uses simplestreams

provider/ec2/httpstorage/httpstorage.go

Index: provider/ec2/httpstorage/httpstorage.go
=== added file 'provider/ec2/httpstorage/httpstorage.go'
--- provider/ec2/httpstorage/httpstorage.go	1970-01-01 00:00:00 +0000
+++ provider/ec2/httpstorage/httpstorage.go	2013-09-16 04:44:39 +0000
@@ -0,0 +1,108 @@
+// Copyright 2013 Canonical Ltd.
+// Licensed under the AGPLv3, see LICENCE file for details.
+
+package httpstorage
+
+import (
+	"encoding/xml"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"sort"
+	"strings"
+	"time"
+
+	"launchpad.net/juju-core/environs"
+	"launchpad.net/juju-core/errors"
+	"launchpad.net/juju-core/utils"
+)
+
+var storageAttempt = utils.AttemptStrategy{
+	Total: 5 * time.Second,
+	Delay: 200 * time.Millisecond,
+}
+
+// httpStorageReader implements the environs.StorageReader interface
+// to access an EC2 storage via HTTP.
+
+type httpStorageReader struct {
+	url string
+}
+
+// NewHTTPStorageReader creates a storage reader for the HTTP
+// access to an EC2 storage like the juju-dist storage.
+func NewHTTPStorageReader(url string) environs.StorageReader {
+	return &httpStorageReader{url}
+}
+
+// Get implements environs.StorageReader.Get.
+func (h *httpStorageReader) Get(name string) (io.ReadCloser, error) {
+	nameURL, err := h.URL(name)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := http.Get(nameURL)
+	if err != nil || resp.StatusCode == http.StatusNotFound {
+		return nil, errors.NewNotFoundError(err, "")
+	}
+	return resp.Body, nil
+}
+
+// List implements environs.StorageReader.List.
+func (h *httpStorageReader) List(prefix string) ([]string, error) {
+	lbr, err := h.getListResult()
+	if err != nil {
+		return nil, err
+	}
+	var names []string
+	for _, c := range lbr.Contents {
+		if strings.HasPrefix(c.Key, prefix) {
+			names = append(names, c.Key)
+		}
+	}
+	sort.Strings(names)
+	return names, nil
+}
+
+// URL implements environs.StorageReader.URL.
+func (h *httpStorageReader) URL(name string) (string, error) {
+	if strings.HasSuffix(h.url, "/") {
+		return h.url + name, nil
+	}
+	return h.url + "/" + name, nil
+}
+
+// ConsistencyStrategy is specified in the StorageReader interface.
+func (s *httpStorageReader) ConsistencyStrategy() utils.AttemptStrategy {
+	return storageAttempt
+}
+
+// getListResult retrieves the index of the storage,
+func (h *httpStorageReader) getListResult() (*listResult, error) {
+	resp, err := http.Get(h.url)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	buf, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	var lbr listResult
+	err = xml.Unmarshal(buf, &lbr)
+	if err != nil {
+		return nil, err
+	}
+	return &lbr, nil
+}
+
+// listResult is the top level XML element of the storage index.
+// We only need the contents.
+type listResult struct {
+	Contents []*contents
+}
+
+// contents describes one entry of the storage index.
+type contents struct {
+	Key string
+}