Skip to content

http: Handle missing but unambiguous ETags in response #1159

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
tiborvass merged 2 commits into from
Sep 5, 2019
Merged

http: Handle missing but unambiguous ETags in response #1159

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
c63c6f9
http: Handle missing but unambiguous ETags in response
rwe Sep 4, 2019
6ff0868
http: Response refers to requested ETag on 304, not 200
rwe Sep 5, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
22 changes: 22 additions & 0 deletions source/http/httpsource.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -144,6 +144,11 @@ func (hs *httpSourceHandler) CacheKey(ctx context.Context, index int) (string, b
req = req.WithContext(ctx)
m := map[string]*metadata.StorageItem{}

// If we request a single ETag in 'If-None-Match', some servers omit the
// unambiguous ETag in their response.
// See: https://github.com/moby/buildkit/issues/905
var onlyETag string

if len(sis) > 0 {
for _, si := range sis {
// if metaDigest := getMetaDigest(si); metaDigest == hs.formatCacheKey("") {
Expand All @@ -160,6 +165,10 @@ func (hs *httpSourceHandler) CacheKey(ctx context.Context, index int) (string, b
etags = append(etags, t)
}
req.Header.Add("If-None-Match", strings.Join(etags, ", "))

if len(etags) == 1 {
onlyETag = etags[0]
}
}
}

Expand All @@ -172,6 +181,12 @@ func (hs *httpSourceHandler) CacheKey(ctx context.Context, index int) (string, b
if err == nil {
if resp.StatusCode == http.StatusOK || resp.StatusCode == http.StatusNotModified {
respETag := resp.Header.Get("ETag")

// If a 304 is returned without an ETag and we had only sent one ETag,
// the response refers to the ETag we asked about.
if respETag == "" && onlyETag != "" && resp.StatusCode == http.StatusNotModified {
respETag = onlyETag
}
si, ok := m[respETag]
if ok {
hs.refID = si.ID()
Expand All @@ -197,6 +212,13 @@ func (hs *httpSourceHandler) CacheKey(ctx context.Context, index int) (string, b
}
if resp.StatusCode == http.StatusNotModified {
respETag := resp.Header.Get("ETag")
if respETag == "" && onlyETag != "" {
respETag = onlyETag

// Set the missing ETag header on the response so that it's available
// to .save()
resp.Header.Set("ETag", onlyETag)
}
si, ok := m[respETag]
if !ok {
return "", false, errors.Errorf("invalid not-modified ETag: %v", respETag)
Expand Down