FIX blank internal pages (#164) (#292)

Hello 👋

since it affected my deployment of the pages server I started to look into the problem of the blank pages and think I found a solution for it:

1. There is no check if the file response is empty, neither in cache retrieval nor in writing of a cache. Also the provided method for checking for empty responses had a bug.
2. I identified the redirect response to be the issue here. There is a cache write with the full cache key (e. g. rawContent/user/repo|branch|route/index.html) happening in the handling of the redirect response. But the written body here is empty. In the triggered request from the redirect response the server then finds a cache item to the key and serves the empty body. A quick fix is the check for empty file responses mentioned in 1.
3. The decision to redirect the user comes quite far down in the upstream function. Before that happens a lot of stuff that may not be important since after the redirect response comes a new request anyway. Also, I suspect that this causes the caching problem because there is a request to the forge server and its error handling with some recursions happening before. I propose to move two of the redirects before "Preparing"
4. The recursion in the upstream function makes it difficult to understand what is actually happening. I added some more logging to have an easier time with that.
5. I changed the default behaviour to append a trailing slash to the path to true. In my tested scenarios it happened anyway. This way there is no recursion happening before the redirect.

I am not developing in go frequently and rarely contribute to open source -> so feedback of all kind is appreciated

closes #164

Reviewed-on: https://codeberg.org/Codeberg/pages-server/pulls/292
Reviewed-by: 6543 <6543@obermui.de>
Reviewed-by: crapStone <codeberg@crapstone.dev>
Co-authored-by: Hoernschen <julian.hoernschemeyer@mailbox.org>
Co-committed-by: Hoernschen <julian.hoernschemeyer@mailbox.org>
This commit is contained in:
Hoernschen 2024-02-26 22:21:42 +00:00 committed by crapStone
parent 7e80ade24b
commit a6e9510c07
4 changed files with 41 additions and 16 deletions

View file

@ -39,7 +39,7 @@ type FileResponse struct {
}
func (f FileResponse) IsEmpty() bool {
return len(f.Body) != 0
return len(f.Body) == 0
}
func (f FileResponse) createHttpResponse(cacheKey string) (header http.Header, statusCode int) {
@ -72,13 +72,14 @@ type BranchTimestamp struct {
type writeCacheReader struct {
originalReader io.ReadCloser
buffer *bytes.Buffer
rileResponse *FileResponse
fileResponse *FileResponse
cacheKey string
cache cache.ICache
hasError bool
}
func (t *writeCacheReader) Read(p []byte) (n int, err error) {
log.Trace().Msgf("[cache] read %q", t.cacheKey)
n, err = t.originalReader.Read(p)
if err != nil && err != io.EOF {
log.Trace().Err(err).Msgf("[cache] original reader for %q has returned an error", t.cacheKey)
@ -90,12 +91,20 @@ func (t *writeCacheReader) Read(p []byte) (n int, err error) {
}
func (t *writeCacheReader) Close() error {
if !t.hasError {
fc := *t.rileResponse
fc.Body = t.buffer.Bytes()
_ = t.cache.Set(t.cacheKey, fc, fileCacheTimeout)
doWrite := !t.hasError
fc := *t.fileResponse
fc.Body = t.buffer.Bytes()
if fc.IsEmpty() {
log.Trace().Msg("[cache] file response is empty")
doWrite = false
}
log.Trace().Msgf("cacheReader for %q saved=%t closed", t.cacheKey, !t.hasError)
if doWrite {
err := t.cache.Set(t.cacheKey, fc, fileCacheTimeout)
if err != nil {
log.Trace().Err(err).Msgf("[cache] writer for %q has returned an error", t.cacheKey)
}
}
log.Trace().Msgf("cacheReader for %q saved=%t closed", t.cacheKey, doWrite)
return t.originalReader.Close()
}
@ -108,7 +117,7 @@ func (f FileResponse) CreateCacheReader(r io.ReadCloser, cache cache.ICache, cac
return &writeCacheReader{
originalReader: r,
buffer: bytes.NewBuffer(make([]byte, 0)),
rileResponse: &f,
fileResponse: &f,
cache: cache,
cacheKey: cacheKey,
}

View file

@ -112,26 +112,27 @@ func (client *Client) GiteaRawContent(targetOwner, targetRepo, ref, resource str
func (client *Client) ServeRawContent(targetOwner, targetRepo, ref, resource string) (io.ReadCloser, http.Header, int, error) {
cacheKey := fmt.Sprintf("%s/%s/%s|%s|%s", rawContentCacheKeyPrefix, targetOwner, targetRepo, ref, resource)
log := log.With().Str("cache_key", cacheKey).Logger()
log.Trace().Msg("try file in cache")
// handle if cache entry exist
if cache, ok := client.responseCache.Get(cacheKey); ok {
cache := cache.(FileResponse)
cachedHeader, cachedStatusCode := cache.createHttpResponse(cacheKey)
// TODO: check against some timestamp mismatch?!?
if cache.Exists {
log.Debug().Msg("[cache] exists")
if cache.IsSymlink {
linkDest := string(cache.Body)
log.Debug().Msgf("[cache] follow symlink from %q to %q", resource, linkDest)
return client.ServeRawContent(targetOwner, targetRepo, ref, linkDest)
} else {
log.Debug().Msg("[cache] return bytes")
} else if !cache.IsEmpty() {
log.Debug().Msgf("[cache] return %d bytes", len(cache.Body))
return io.NopCloser(bytes.NewReader(cache.Body)), cachedHeader, cachedStatusCode, nil
} else if cache.IsEmpty() {
log.Debug().Msg("[cache] is empty")
}
} else {
return nil, cachedHeader, cachedStatusCode, ErrorNotFound
}
}
log.Trace().Msg("file not in cache")
// not in cache, open reader via gitea api
reader, resp, err := client.sdkClient.GetFileReader(targetOwner, targetRepo, ref, resource, client.supportLFS)
if resp != nil {
@ -155,12 +156,14 @@ func (client *Client) ServeRawContent(targetOwner, targetRepo, ref, resource str
linkDest = path.Join(path.Dir(resource), linkDest)
// we store symlink not content to reduce duplicates in cache
if err := client.responseCache.Set(cacheKey, FileResponse{
fileResponse := FileResponse{
Exists: true,
IsSymlink: true,
Body: []byte(linkDest),
ETag: resp.Header.Get(ETagHeader),
}, fileCacheTimeout); err != nil {
}
log.Trace().Msgf("file response has %d bytes", len(fileResponse.Body))
if err := client.responseCache.Set(cacheKey, fileResponse, fileCacheTimeout); err != nil {
log.Error().Err(err).Msg("[cache] error on cache write")
}

View file

@ -26,6 +26,7 @@ func Handler(
dnsLookupCache, canonicalDomainCache, redirectsCache cache.ICache,
) http.HandlerFunc {
return func(w http.ResponseWriter, req *http.Request) {
log.Debug().Msg("\n----------------------------------------------------------")
log := log.With().Strs("Handler", []string{req.Host, req.RequestURI}).Logger()
ctx := context.New(w, req)

View file

@ -56,6 +56,8 @@ type Options struct {
func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client, redirectsCache cache.ICache) bool {
log := log.With().Strs("upstream", []string{o.TargetOwner, o.TargetRepo, o.TargetBranch, o.TargetPath}).Logger()
log.Debug().Msg("Start")
if o.TargetOwner == "" || o.TargetRepo == "" {
html.ReturnErrorPage(ctx, "forge client: either repo owner or name info is missing", http.StatusBadRequest)
return true
@ -104,13 +106,16 @@ func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client, redi
// Handle not found error
if err != nil && errors.Is(err, gitea.ErrorNotFound) {
log.Debug().Msg("Handling not found error")
// Get and match redirects
redirects := o.getRedirects(giteaClient, redirectsCache)
if o.matchRedirects(ctx, giteaClient, redirects, redirectsCache) {
log.Trace().Msg("redirect")
return true
}
if o.TryIndexPages {
log.Trace().Msg("try index page")
// copy the o struct & try if an index page exists
optionsForIndexPages := *o
optionsForIndexPages.TryIndexPages = false
@ -121,6 +126,7 @@ func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client, redi
return true
}
}
log.Trace().Msg("try html file with path name")
// compatibility fix for GitHub Pages (/example → /example.html)
optionsForIndexPages.appendTrailingSlash = false
optionsForIndexPages.redirectIfExists = strings.TrimSuffix(ctx.Path(), "/") + ".html"
@ -130,8 +136,11 @@ func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client, redi
}
}
log.Trace().Msg("not found")
ctx.StatusCode = http.StatusNotFound
if o.TryIndexPages {
log.Trace().Msg("try not found page")
// copy the o struct & try if a not found page exists
optionsForNotFoundPages := *o
optionsForNotFoundPages.TryIndexPages = false
@ -142,6 +151,7 @@ func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client, redi
return true
}
}
log.Trace().Msg("not found page missing")
}
return false
@ -173,10 +183,12 @@ func (o *Options) Upstream(ctx *context.Context, giteaClient *gitea.Client, redi
// Append trailing slash if missing (for index files), and redirect to fix filenames in general
// o.appendTrailingSlash is only true when looking for index pages
if o.appendTrailingSlash && !strings.HasSuffix(ctx.Path(), "/") {
log.Trace().Msg("append trailing slash and redirect")
ctx.Redirect(ctx.Path()+"/", http.StatusTemporaryRedirect)
return true
}
if strings.HasSuffix(ctx.Path(), "/index.html") && !o.ServeRaw {
log.Trace().Msg("remove index.html from path and redirect")
ctx.Redirect(strings.TrimSuffix(ctx.Path(), "index.html"), http.StatusTemporaryRedirect)
return true
}