X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/54377a7bacc182ace0bb8b55a812e0a9fee5ced8..6fa7f9fbcf20aa866eed0618bd09e1ce2e109baa:/services/keep-web/handler.go

diff --git a/services/keep-web/handler.go b/services/keep-web/handler.go
index 12c2839f8c..b9250efec7 100644
--- a/services/keep-web/handler.go
+++ b/services/keep-web/handler.go
@@ -34,6 +34,7 @@ import (
 type handler struct {
 	Cache   cache
 	Cluster *arvados.Cluster
+	metrics *metrics
 
 	lockMtx    sync.Mutex
 	lock       map[string]*sync.RWMutex
@@ -177,7 +178,12 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
 		r.URL.Scheme = xfp
 	}
 
-	w := httpserver.WrapResponseWriter(wOrig)
+	wbuffer := newWriteBuffer(wOrig, int(h.Cluster.Collections.WebDAVOutputBuffer))
+	defer wbuffer.Close()
+	w := httpserver.WrapResponseWriter(responseWriter{
+		Writer:         wbuffer,
+		ResponseWriter: wOrig,
+	})
 
 	if r.Method == "OPTIONS" && ServeCORSPreflight(w, r.Header) {
 		return
@@ -424,11 +430,26 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
 			return
 		}
 		defer f.Close()
-		defer sess.Release()
 
 		collectionDir, sessionFS, session, tokenUser = f, fs, sess, user
 		break
 	}
+
+	// releaseSession() is equivalent to session.Release() except
+	// that it's a no-op if (1) session is nil, or (2) it has
+	// already been called.
+	//
+	// This way, we can do a defer call here to ensure it gets
+	// called in all code paths, and also call it inline (see
+	// below) in the cases where we want to release the lock
+	// before returning.
+	releaseSession := func() {}
+	if session != nil {
+		var releaseSessionOnce sync.Once
+		releaseSession = func() { releaseSessionOnce.Do(func() { session.Release() }) }
+	}
+	defer releaseSession()
+
 	if forceReload && collectionDir != nil {
 		err := collectionDir.Sync()
 		if err != nil {
@@ -516,6 +537,7 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
 	if r.Method == http.MethodGet || r.Method == http.MethodHead {
 		targetfnm := fsprefix + strings.Join(pathParts[stripParts:], "/")
 		if fi, err := sessionFS.Stat(targetfnm); err == nil && fi.IsDir() {
+			releaseSession() // because we won't be writing anything
 			if !strings.HasSuffix(r.URL.Path, "/") {
 				h.seeOtherWithCookie(w, r, r.URL.Path+"/", credentialsOK)
 			} else {
@@ -585,6 +607,15 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
 				collectionDir.Splice(snap)
 				return nil
 			}}
+	} else {
+		// When writing, we need to block session renewal
+		// until we're finished, in order to guarantee the
+		// effect of the write is visible in future responses.
+		// But if we're not writing, we can release the lock
+		// early.  This enables us to keep renewing sessions
+		// and processing more requests even if a slow client
+		// takes a long time to download a large file.
+		releaseSession()
 	}
 	if r.Method == http.MethodGet {
 		applyContentDispositionHdr(w, r, basename, attachment)
@@ -592,7 +623,7 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
 	if webdavPrefix == "" {
 		webdavPrefix = "/" + strings.Join(pathParts[:stripParts], "/")
 	}
-	wh := webdav.Handler{
+	wh := &webdav.Handler{
 		Prefix: webdavPrefix,
 		FileSystem: &webdavfs.FS{
 			FileSystem:    sessionFS,
@@ -607,7 +638,7 @@ func (h *handler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
 			}
 		},
 	}
-	wh.ServeHTTP(w, r)
+	h.metrics.track(wh, w, r)
 	if r.Method == http.MethodGet && w.WroteStatus() == http.StatusOK {
 		wrote := int64(w.WroteBodyBytes())
 		fnm := strings.Join(pathParts[stripParts:], "/")