forked from sourcegraph/s3vfs
/
s3vfs.go
320 lines (277 loc) · 7.03 KB
/
s3vfs.go
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package s3vfs
import (
"bytes"
"encoding/xml"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"os"
pathpkg "path"
"path/filepath"
"time"
"golang.org/x/tools/godoc/vfs"
"strings"
"github.com/sqs/s3"
"github.com/sqs/s3/s3util"
"sourcegraph.com/sourcegraph/rwvfs"
)
var DefaultS3Config = s3util.Config{
Keys: &s3.Keys{
AccessKey: os.Getenv("AWS_ACCESS_KEY_ID"),
SecretKey: os.Getenv("AWS_SECRET_KEY"),
},
Service: s3.DefaultService,
}
// S3 returns an implementation of FileSystem using the specified S3 bucket and
// config. If config is nil, DefaultS3Config is used.
//
// The bucket URL is the full URL to the bucket on Amazon S3, including the
// bucket name and AWS region (e.g.,
// https://s3-us-west-2.amazonaws.com/mybucket).
func S3(bucket *url.URL, config *s3util.Config) rwvfs.FileSystem {
if config == nil {
config = &DefaultS3Config
}
return &S3FS{bucket, config}
}
type S3FS struct {
bucket *url.URL
config *s3util.Config
}
func (fs *S3FS) String() string {
return fmt.Sprintf("S3 filesystem at %s", fs.bucket)
}
func (fs *S3FS) url(path string) string {
path = pathpkg.Join(fs.bucket.Path, path)
return fs.bucket.ResolveReference(&url.URL{Path: path}).String()
}
func (fs *S3FS) Open(name string) (vfs.ReadSeekCloser, error) {
return fs.OpenRange(name, "")
}
type rangeTransport struct {
http.RoundTripper
rangeVal string
}
func (t rangeTransport) RoundTrip(req *http.Request) (*http.Response, error) {
req = cloneRequest(req)
req.Header.Set("range", t.rangeVal)
transport := t.RoundTripper
if transport == nil {
transport = http.DefaultTransport
}
resp, err := transport.RoundTrip(req)
return resp, err
}
// cloneRequest returns a clone of the provided *http.Request. The clone is a
// shallow copy of the struct and its Header map.
func cloneRequest(r *http.Request) *http.Request {
// shallow copy of the struct
r2 := new(http.Request)
*r2 = *r
// deep copy of the Header
r2.Header = make(http.Header)
for k, s := range r.Header {
r2.Header[k] = s
}
return r2
}
func (fs *S3FS) OpenRange(name string, rangeHeader string) (f vfs.ReadSeekCloser, err error) {
cfg := fs.config
if rangeHeader != "" {
tmp := *cfg
cfg = &tmp
var existingTransport http.RoundTripper
if cfg.Client != nil {
existingTransport = cfg.Client.Transport
}
cfg.Client = &http.Client{Transport: rangeTransport{RoundTripper: existingTransport, rangeVal: rangeHeader}}
}
rdr, err := s3util.Open(fs.url(name), cfg)
if err != nil {
return nil, &os.PathError{Op: "open", Path: fs.url(name), Err: err}
}
b, err := ioutil.ReadAll(rdr)
if err != nil {
return nil, err
}
defer func() {
err2 := rdr.Close()
if err == nil {
err = err2
}
}()
return nopCloser{bytes.NewReader(b)}, nil
}
func (fs *S3FS) OpenFetcher(name string) (vfs.ReadSeekCloser, error) {
return rwvfs.OpenFetcher(fs, name)
}
func (fs *S3FS) ReadDir(path string) ([]os.FileInfo, error) {
dir, err := s3util.NewFile(fs.url(path), fs.config)
if err != nil {
return nil, &os.PathError{Op: "readdir", Path: fs.url(path), Err: err}
}
fis, err := dir.Readdir(0)
if err != nil {
return nil, err
}
for i, fi := range fis {
fis[i] = &fileInfo{
name: pathpkg.Base(fi.Name()),
size: fi.Size(),
mode: fi.Mode(),
modTime: fi.ModTime(),
sys: fi.Sys(),
}
}
return fis, nil
}
func (fs *S3FS) Lstat(name string) (os.FileInfo, error) {
fi, err := fs.lstat(name)
if err != nil {
return nil, &os.PathError{Op: "lstat", Path: fs.url(name), Err: err}
}
return fi, nil
}
func (fs *S3FS) lstat(name string) (os.FileInfo, error) {
name = strings.TrimPrefix(filepath.Clean(name), "/")
if name == "." {
return &fileInfo{
name: ".",
size: 0,
mode: os.ModeDir,
modTime: time.Time{},
}, nil
}
client := fs.config.Client
if client == nil {
client = http.DefaultClient
}
q := make(url.Values)
q.Set("prefix", name+"/")
q.Set("max-keys", "1")
u := fs.bucket.ResolveReference(&url.URL{RawQuery: q.Encode()})
req, err := http.NewRequest("GET", u.String(), nil)
if err != nil {
return nil, err
}
req.Header.Set("Date", time.Now().UTC().Format(http.TimeFormat))
fs.config.Sign(req, *fs.config.Keys)
resp, err := client.Do(req)
if err != nil {
return nil, err
}
if resp.StatusCode != 200 {
resp.Body.Close()
return nil, newRespError(resp)
}
result := struct{ Contents []struct{ Key string } }{}
if err := xml.NewDecoder(resp.Body).Decode(&result); err != nil {
return nil, err
}
if err := resp.Body.Close(); err != nil {
return nil, err
}
// If Contents is non-empty, then this is a dir.
if len(result.Contents) == 1 {
return &fileInfo{
name: name,
size: 0,
mode: os.ModeDir,
}, nil
}
// Otherwise, see if a key exists here.
req, err = http.NewRequest("HEAD", fs.url(name), nil)
if err != nil {
return nil, err
}
req.Header.Set("Date", time.Now().UTC().Format(http.TimeFormat))
fs.config.Sign(req, *fs.config.Keys)
resp, err = client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode == http.StatusNotFound {
return nil, os.ErrNotExist
} else if resp.StatusCode != 200 {
return nil, newRespError(resp)
}
t, _ := time.Parse(http.TimeFormat, resp.Header.Get("last-modified"))
return &fileInfo{
name: name,
size: resp.ContentLength,
mode: 0, // file
modTime: t,
}, nil
}
func (fs *S3FS) Stat(name string) (os.FileInfo, error) {
return fs.Lstat(name)
}
// Create opens the file at path for writing, creating the file if it doesn't
// exist and truncating it otherwise.
func (fs *S3FS) Create(path string) (io.WriteCloser, error) {
wc, err := s3util.Create(fs.url(path), nil, fs.config)
if err != nil {
return nil, &os.PathError{Op: "create", Path: fs.url(path), Err: err}
}
return wc, nil
}
func (fs *S3FS) Mkdir(name string) error {
// S3 doesn't have directories.
return nil
}
// MkdirAll implements rwvfs.MkdirAllOverrider.
func (fs *S3FS) MkdirAll(name string) error {
// S3 doesn't have directories.
return nil
}
func (fs *S3FS) Remove(name string) (err error) {
var rdr io.ReadCloser
rdr, err = s3util.Delete(fs.url(name), fs.config)
defer func() {
if rdr != nil {
err2 := rdr.Close()
if err == nil {
err = err2
}
}
}()
return err
}
type nopCloser struct {
io.ReadSeeker
}
func (nc nopCloser) Close() error { return nil }
type fileInfo struct {
name string
size int64
mode os.FileMode
modTime time.Time
sys interface{}
}
func (f *fileInfo) Name() string { return f.name }
func (f *fileInfo) Size() int64 { return f.size }
func (f *fileInfo) Mode() os.FileMode { return f.mode }
func (f *fileInfo) ModTime() time.Time { return f.modTime }
func (f *fileInfo) IsDir() bool { return f.mode&os.ModeDir != 0 }
func (f *fileInfo) Sys() interface{} { return f.sys }
type respError struct {
r *http.Response
b bytes.Buffer
}
func newRespError(r *http.Response) *respError {
e := new(respError)
e.r = r
io.Copy(&e.b, r.Body)
r.Body.Close()
return e
}
func (e *respError) Error() string {
return fmt.Sprintf(
"unwanted http status %d: %q",
e.r.StatusCode,
e.b.String(),
)
}