- return nil, err
- }
-
- // rewriting signatures will make manifest text 5-10% bigger so calculate
- // capacity accordingly
- updatedManifest := bytes.NewBuffer(make([]byte, 0, int(float64(len(col.ManifestText))*1.1)))
-
- hasher := md5.New()
- mw := io.MultiWriter(hasher, updatedManifest)
- sz := 0
-
- scanner := bufio.NewScanner(strings.NewReader(col.ManifestText))
- scanner.Buffer(make([]byte, 1048576), len(col.ManifestText))
- for scanner.Scan() {
- line := scanner.Text()
- tokens := strings.Split(line, " ")
- if len(tokens) < 3 {
- return nil, fmt.Errorf("Invalid stream (<3 tokens): %q", line)
- }
-
- n, err := mw.Write([]byte(tokens[0]))
- if err != nil {
- return nil, fmt.Errorf("Error updating manifest: %v", err)
- }
- sz += n
- for _, token := range tokens[1:] {
- n, err = mw.Write([]byte(" "))
- if err != nil {
- return nil, fmt.Errorf("Error updating manifest: %v", err)
- }
- sz += n
-
- m := keepclient.SignedLocatorRe.FindStringSubmatch(token)
- if m != nil {
- // Rewrite the block signature to be a remote signature
- _, err = fmt.Fprintf(updatedManifest, "%s%s%s+R%s-%s%s", m[1], m[2], m[3], rw.clusterID, m[5][2:], m[8])
- if err != nil {
- return nil, fmt.Errorf("Error updating manifest: %v", err)
- }
-
- // for hash checking, ignore signatures
- n, err = fmt.Fprintf(hasher, "%s%s", m[1], m[2])
- if err != nil {
- return nil, fmt.Errorf("Error updating manifest: %v", err)
- }
- sz += n
- } else {
- n, err = mw.Write([]byte(token))
- if err != nil {
- return nil, fmt.Errorf("Error updating manifest: %v", err)
- }
- sz += n
- }
- }
- n, err = mw.Write([]byte("\n"))
- if err != nil {
- return nil, fmt.Errorf("Error updating manifest: %v", err)
- }
- sz += n
- }
-
- // Check that expected hash is consistent with
- // portable_data_hash field of the returned record
- if rw.expectHash == "" {
- rw.expectHash = col.PortableDataHash
- } else if rw.expectHash != col.PortableDataHash {
- return nil, fmt.Errorf("portable_data_hash %q on returned record did not match expected hash %q ", rw.expectHash, col.PortableDataHash)
- }
-
- // Certify that the computed hash of the manifest_text matches our expectation
- sum := hasher.Sum(nil)
- computedHash := fmt.Sprintf("%x+%v", sum, sz)
- if computedHash != rw.expectHash {
- return nil, fmt.Errorf("Computed manifest_text hash %q did not match expected hash %q", computedHash, rw.expectHash)
- }
-
- col.ManifestText = updatedManifest.String()
-
- newbody, err := json.Marshal(col)
- if err != nil {
- return nil, err
- }
-
- buf := bytes.NewBuffer(newbody)
- resp.Body = ioutil.NopCloser(buf)
- resp.ContentLength = int64(buf.Len())
- resp.Header.Set("Content-Length", fmt.Sprintf("%v", buf.Len()))
-
- return resp, nil
-}
-
-func filterLocalClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
- if requestError != nil {
- return resp, requestError
- }
-
- if resp.StatusCode == 404 {
- // Suppress returning this result, because we want to
- // search the federation.
- return nil, nil
- }
- return resp, nil
-}
-
-type searchRemoteClusterForPDH struct {
- pdh string
- remoteID string
- mtx *sync.Mutex
- sentResponse *bool
- sharedContext *context.Context
- cancelFunc func()
- errors *[]string
- statusCode *int
-}
-
-func (s *searchRemoteClusterForPDH) filterRemoteClusterResponse(resp *http.Response, requestError error) (newResponse *http.Response, err error) {
- s.mtx.Lock()
- defer s.mtx.Unlock()
-
- if *s.sentResponse {
- // Another request already returned a response
- return nil, nil
- }
-
- if requestError != nil {
- *s.errors = append(*s.errors, fmt.Sprintf("Request error contacting %q: %v", s.remoteID, requestError))
- // Record the error and suppress response
- return nil, nil
- }
-
- if resp.StatusCode != 200 {
- // Suppress returning unsuccessful result. Maybe
- // another request will find it.
- // TODO collect and return error responses.
- *s.errors = append(*s.errors, fmt.Sprintf("Response from %q: %v", s.remoteID, resp.Status))
- if resp.StatusCode != 404 {
- // Got a non-404 error response, convert into BadGateway
- *s.statusCode = http.StatusBadGateway
- }
- return nil, nil
- }
-
- s.mtx.Unlock()
-
- // This reads the response body. We don't want to hold the
- // lock while doing this because other remote requests could
- // also have made it to this point, and we don't want a
- // slow response holding the lock to block a faster response
- // that is waiting on the lock.
- newResponse, err = rewriteSignaturesClusterId{s.remoteID, s.pdh}.rewriteSignatures(resp, nil)
-
- s.mtx.Lock()
-
- if *s.sentResponse {
- // Another request already returned a response
- return nil, nil
- }
-
- if err != nil {
- // Suppress returning unsuccessful result. Maybe
- // another request will be successful.
- *s.errors = append(*s.errors, fmt.Sprintf("Error parsing response from %q: %v", s.remoteID, err))
- return nil, nil
- }
-
- // We have a successful response. Suppress/cancel all the
- // other requests/responses.
- *s.sentResponse = true
- s.cancelFunc()
-
- return newResponse, nil
-}
-
-func (h *collectionFederatedRequestHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
- if req.Method != "GET" {
- // Only handle GET requests right now
- h.next.ServeHTTP(w, req)
- return
- }
-
- m := collectionByPDHRe.FindStringSubmatch(req.URL.Path)
- if len(m) != 2 {
- // Not a collection PDH GET request
- m = collectionRe.FindStringSubmatch(req.URL.Path)
- clusterId := ""
-
- if len(m) > 0 {
- clusterId = m[2]
- }
-
- if clusterId != "" && clusterId != h.handler.Cluster.ClusterID {
- // request for remote collection by uuid
- h.handler.remoteClusterRequest(clusterId, w, req,
- rewriteSignaturesClusterId{clusterId, ""}.rewriteSignatures)
- return
- }
- // not a collection UUID request, or it is a request
- // for a local UUID, either way, continue down the
- // handler stack.
- h.next.ServeHTTP(w, req)
- return
- }
-
- // Request for collection by PDH. Search the federation.
-
- // First, query the local cluster.
- if h.handler.localClusterRequest(w, req, filterLocalClusterResponse) {
- return
- }
-
- sharedContext, cancelFunc := context.WithCancel(req.Context())
- defer cancelFunc()
- req = req.WithContext(sharedContext)
-
- // Create a goroutine for each cluster in the
- // RemoteClusters map. The first valid result gets
- // returned to the client. When that happens, all
- // other outstanding requests are cancelled or
- // suppressed.
- sentResponse := false
- mtx := sync.Mutex{}
- wg := sync.WaitGroup{}
- var errors []string
- var errorCode int = 404
-
- // use channel as a semaphore to limit the number of parallel
- // requests at a time
- sem := make(chan bool, h.handler.Cluster.ParallelRemoteRequests)
- defer close(sem)
- for remoteID := range h.handler.Cluster.RemoteClusters {
- // blocks until it can put a value into the
- // channel (which has a max queue capacity)
- sem <- true
- if sentResponse {
- break
- }
- search := &searchRemoteClusterForPDH{m[1], remoteID, &mtx, &sentResponse,
- &sharedContext, cancelFunc, &errors, &errorCode}
- wg.Add(1)
- go func() {
- h.handler.remoteClusterRequest(search.remoteID, w, req, search.filterRemoteClusterResponse)
- wg.Done()
- <-sem
- }()