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package getter
import (
"encoding/xml"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"os"
"path/filepath"
"strings"
)
// HttpGetter is a Getter implementation that will download from an HTTP
// endpoint.
//
// For file downloads, HTTP is used directly.
//
// The protocol for downloading a directory from an HTTP endpoing is as follows:
//
// An HTTP GET request is made to the URL with the additional GET parameter
// "terraform-get=1". This lets you handle that scenario specially if you
// wish. The response must be a 2xx.
//
// First, a header is looked for "X-Terraform-Get" which should contain
// a source URL to download.
//
// If the header is not present, then a meta tag is searched for named
// "terraform-get" and the content should be a source URL.
//
// The source URL, whether from the header or meta tag, must be a fully
// formed URL. The shorthand syntax of "github.com/foo/bar" or relative
// paths are not allowed.
type HttpGetter struct {
// Netrc, if true, will lookup and use auth information found
// in the user's netrc file if available.
Netrc bool
}
func (g *HttpGetter) ClientMode(u *url.URL) (ClientMode, error) {
if strings.HasSuffix(u.Path, "/") {
return ClientModeDir, nil
}
return ClientModeFile, nil
}
func (g *HttpGetter) Get(dst string, u *url.URL) error {
// Copy the URL so we can modify it
var newU url.URL = *u
u = &newU
if g.Netrc {
// Add auth from netrc if we can
if err := addAuthFromNetrc(u); err != nil {
return err
}
}
// Add terraform-get to the parameter.
q := u.Query()
q.Add("terraform-get", "1")
u.RawQuery = q.Encode()
// Get the URL
resp, err := http.Get(u.String())
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode < 200 || resp.StatusCode >= 300 {
return fmt.Errorf("bad response code: %d", resp.StatusCode)
}
// Extract the source URL
var source string
if v := resp.Header.Get("X-Terraform-Get"); v != "" {
source = v
} else {
source, err = g.parseMeta(resp.Body)
if err != nil {
return err
}
}
if source == "" {
return fmt.Errorf("no source URL was returned")
}
// If there is a subdir component, then we download the root separately
// into a temporary directory, then copy over the proper subdir.
source, subDir := SourceDirSubdir(source)
if subDir == "" {
return Get(dst, source)
}
// We have a subdir, time to jump some hoops
return g.getSubdir(dst, source, subDir)
}
func (g *HttpGetter) GetFile(dst string, u *url.URL) error {
resp, err := http.Get(u.String())
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode != 200 {
return fmt.Errorf("bad response code: %d", resp.StatusCode)
}
// Create all the parent directories
if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
return err
}
f, err := os.Create(dst)
if err != nil {
return err
}
defer f.Close()
_, err = io.Copy(f, resp.Body)
return err
}
// getSubdir downloads the source into the destination, but with
// the proper subdir.
func (g *HttpGetter) getSubdir(dst, source, subDir string) error {
// Create a temporary directory to store the full source
td, err := ioutil.TempDir("", "tf")
if err != nil {
return err
}
defer os.RemoveAll(td)
// Download that into the given directory
if err := Get(td, source); err != nil {
return err
}
// Make sure the subdir path actually exists
sourcePath := filepath.Join(td, subDir)
if _, err := os.Stat(sourcePath); err != nil {
return fmt.Errorf(
"Error downloading %s: %s", source, err)
}
// Copy the subdirectory into our actual destination.
if err := os.RemoveAll(dst); err != nil {
return err
}
// Make the final destination
if err := os.MkdirAll(dst, 0755); err != nil {
return err
}
return copyDir(dst, sourcePath, false)
}
// parseMeta looks for the first meta tag in the given reader that
// will give us the source URL.
func (g *HttpGetter) parseMeta(r io.Reader) (string, error) {
d := xml.NewDecoder(r)
d.CharsetReader = charsetReader
d.Strict = false
var err error
var t xml.Token
for {
t, err = d.Token()
if err != nil {
if err == io.EOF {
err = nil
}
return "", err
}
if e, ok := t.(xml.StartElement); ok && strings.EqualFold(e.Name.Local, "body") {
return "", nil
}
if e, ok := t.(xml.EndElement); ok && strings.EqualFold(e.Name.Local, "head") {
return "", nil
}
e, ok := t.(xml.StartElement)
if !ok || !strings.EqualFold(e.Name.Local, "meta") {
continue
}
if attrValue(e.Attr, "name") != "terraform-get" {
continue
}
if f := attrValue(e.Attr, "content"); f != "" {
return f, nil
}
}
}
// attrValue returns the attribute value for the case-insensitive key
// `name', or the empty string if nothing is found.
func attrValue(attrs []xml.Attr, name string) string {
for _, a := range attrs {
if strings.EqualFold(a.Name.Local, name) {
return a.Value
}
}
return ""
}
// charsetReader returns a reader for the given charset. Currently
// it only supports UTF-8 and ASCII. Otherwise, it returns a meaningful
// error which is printed by go get, so the user can find why the package
// wasn't downloaded if the encoding is not supported. Note that, in
// order to reduce potential errors, ASCII is treated as UTF-8 (i.e. characters
// greater than 0x7f are not rejected).
func charsetReader(charset string, input io.Reader) (io.Reader, error) {
switch strings.ToLower(charset) {
case "ascii":
return input, nil
default:
return nil, fmt.Errorf("can't decode XML document using charset %q", charset)
}
}
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