"regexp"
"runtime"
"strconv"
+ "strings"
"sync"
"time"
)
// Replace the current trash queue.
rest.HandleFunc(`/trash`, TrashHandler).Methods("PUT")
+ // Untrash moves blocks from trash back into store
+ rest.HandleFunc(`/untrash/{hash:[0-9a-f]{32}}`, UntrashHandler).Methods("PUT")
+
// Any request which does not match any of these routes gets
// 400 Bad Request.
rest.NotFoundHandler = http.HandlerFunc(BadRequestHandler)
}
}
- block, err := GetBlock(mux.Vars(req)["hash"])
+ // TODO: Probe volumes to check whether the block _might_
+ // exist. Some volumes/types could support a quick existence
+ // check without causing other operations to suffer. If all
+ // volumes support that, and assure us the block definitely
+ // isn't here, we can return 404 now instead of waiting for a
+ // buffer.
+
+ buf, err := getBufferForResponseWriter(resp, bufs, BlockSize)
if err != nil {
- // This type assertion is safe because the only errors
- // GetBlock can return are DiskHashError or NotFoundError.
- http.Error(resp, err.Error(), err.(*KeepError).HTTPCode)
+ http.Error(resp, err.Error(), http.StatusServiceUnavailable)
return
}
- defer bufs.Put(block)
+ defer bufs.Put(buf)
- resp.Header().Set("Content-Length", strconv.Itoa(len(block)))
+ size, err := GetBlock(mux.Vars(req)["hash"], buf, resp)
+ if err != nil {
+ code := http.StatusInternalServerError
+ if err, ok := err.(*KeepError); ok {
+ code = err.HTTPCode
+ }
+ http.Error(resp, err.Error(), code)
+ return
+ }
+
+ resp.Header().Set("Content-Length", strconv.Itoa(size))
resp.Header().Set("Content-Type", "application/octet-stream")
- resp.Write(block)
+ resp.Write(buf[:size])
+}
+
+// Get a buffer from the pool -- but give up and return a non-nil
+// error if resp implements http.CloseNotifier and tells us that the
+// client has disconnected before we get a buffer.
+func getBufferForResponseWriter(resp http.ResponseWriter, bufs *bufferPool, bufSize int) ([]byte, error) {
+ var closeNotifier <-chan bool
+ if resp, ok := resp.(http.CloseNotifier); ok {
+ closeNotifier = resp.CloseNotify()
+ }
+ var buf []byte
+ bufReady := make(chan []byte)
+ go func() {
+ bufReady <- bufs.Get(bufSize)
+ close(bufReady)
+ }()
+ select {
+ case buf = <-bufReady:
+ return buf, nil
+ case <-closeNotifier:
+ go func() {
+ // Even if closeNotifier happened first, we
+ // need to keep waiting for our buf so we can
+ // return it to the pool.
+ bufs.Put(<-bufReady)
+ }()
+ return nil, ErrClientDisconnect
+ }
}
// PutBlockHandler is a HandleFunc to address Put block requests.
return
}
- buf := bufs.Get(int(req.ContentLength))
- _, err := io.ReadFull(req.Body, buf)
+ buf, err := getBufferForResponseWriter(resp, bufs, int(req.ContentLength))
+ if err != nil {
+ http.Error(resp, err.Error(), http.StatusServiceUnavailable)
+ return
+ }
+
+ _, err = io.ReadFull(req.Body, buf)
if err != nil {
http.Error(resp, err.Error(), 500)
bufs.Put(buf)
Failed int `json:"copies_failed"`
}
for _, vol := range KeepVM.AllWritable() {
- if err := vol.Delete(hash); err == nil {
+ if err := vol.Trash(hash); err == nil {
result.Deleted++
} else if os.IsNotExist(err) {
continue
trashq.ReplaceQueue(tlist)
}
-// ==============================
+// UntrashHandler processes "PUT /untrash/{hash:[0-9a-f]{32}}" requests for the data manager.
+func UntrashHandler(resp http.ResponseWriter, req *http.Request) {
+ // Reject unauthorized requests.
+ if !IsDataManagerToken(GetApiToken(req)) {
+ http.Error(resp, UnauthorizedError.Error(), UnauthorizedError.HTTPCode)
+ return
+ }
+
+ hash := mux.Vars(req)["hash"]
+
+ if len(KeepVM.AllWritable()) == 0 {
+ http.Error(resp, "No writable volumes", http.StatusNotFound)
+ return
+ }
+
+ var untrashedOn, failedOn []string
+ var numNotFound int
+ for _, vol := range KeepVM.AllWritable() {
+ err := vol.Untrash(hash)
+
+ if os.IsNotExist(err) {
+ numNotFound++
+ } else if err != nil {
+ log.Printf("Error untrashing %v on volume %v", hash, vol.String())
+ failedOn = append(failedOn, vol.String())
+ } else {
+ log.Printf("Untrashed %v on volume %v", hash, vol.String())
+ untrashedOn = append(untrashedOn, vol.String())
+ }
+ }
+
+ if numNotFound == len(KeepVM.AllWritable()) {
+ http.Error(resp, "Block not found on any of the writable volumes", http.StatusNotFound)
+ return
+ }
+
+ if len(failedOn) == len(KeepVM.AllWritable()) {
+ http.Error(resp, "Failed to untrash on all writable volumes", http.StatusInternalServerError)
+ } else {
+ respBody := "Successfully untrashed on: " + strings.Join(untrashedOn, ",")
+ if len(failedOn) > 0 {
+ respBody += "; Failed to untrash on: " + strings.Join(failedOn, ",")
+ }
+ resp.Write([]byte(respBody))
+ }
+}
+
// GetBlock and PutBlock implement lower-level code for handling
// blocks by rooting through volumes connected to the local machine.
// Once the handler has determined that system policy permits the
// should be the only part of the code that cares about which volume a
// block is stored on, so it should be responsible for figuring out
// which volume to check for fetching blocks, storing blocks, etc.
-// ==============================
-// GetBlock fetches and returns the block identified by "hash".
-//
-// On success, GetBlock returns a byte slice with the block data, and
-// a nil error.
+// GetBlock fetches the block identified by "hash" into the provided
+// buf, and returns the data size.
//
// If the block cannot be found on any volume, returns NotFoundError.
//
// If the block found does not have the correct MD5 hash, returns
// DiskHashError.
//
-func GetBlock(hash string) ([]byte, error) {
+func GetBlock(hash string, buf []byte, resp http.ResponseWriter) (int, error) {
// Attempt to read the requested hash from a keep volume.
errorToCaller := NotFoundError
for _, vol := range KeepVM.AllReadable() {
- buf, err := vol.Get(hash)
+ size, err := vol.Get(hash, buf)
if err != nil {
// IsNotExist is an expected error and may be
// ignored. All other errors are logged. In
}
// Check the file checksum.
//
- filehash := fmt.Sprintf("%x", md5.Sum(buf))
+ filehash := fmt.Sprintf("%x", md5.Sum(buf[:size]))
if filehash != hash {
// TODO: Try harder to tell a sysadmin about
// this.
log.Printf("%s: checksum mismatch for request %s (actual %s)",
vol, hash, filehash)
errorToCaller = DiskHashError
- bufs.Put(buf)
continue
}
if errorToCaller == DiskHashError {
log.Printf("%s: checksum mismatch for request %s but a good copy was found on another volume and returned",
vol, hash)
}
- return buf, nil
+ return size, nil
}
- return nil, errorToCaller
+ return 0, errorToCaller
}
// PutBlock Stores the BLOCK (identified by the content id HASH) in Keep.
// If we already have this data, it's intact on disk, and we
// can update its timestamp, return success. If we have
// different data with the same hash, return failure.
- if err := CompareAndTouch(hash, block); err == nil || err == CollisionError {
- return 0, err
+ if n, err := CompareAndTouch(hash, block); err == nil || err == CollisionError {
+ return n, err
}
// Choose a Keep volume to write to.
return 0, GenericError
}
-// CompareAndTouch returns nil if one of the volumes already has the
-// given content and it successfully updates the relevant block's
-// modification time in order to protect it from premature garbage
-// collection.
-func CompareAndTouch(hash string, buf []byte) error {
+// CompareAndTouch returns the current replication level if one of the
+// volumes already has the given content and it successfully updates
+// the relevant block's modification time in order to protect it from
+// premature garbage collection. Otherwise, it returns a non-nil
+// error.
+func CompareAndTouch(hash string, buf []byte) (int, error) {
var bestErr error = NotFoundError
for _, vol := range KeepVM.AllWritable() {
if err := vol.Compare(hash, buf); err == CollisionError {
// both, so there's no point writing it even
// on a different volume.)
log.Printf("%s: Compare(%s): %s", vol, hash, err)
- return err
+ return 0, err
} else if os.IsNotExist(err) {
// Block does not exist. This is the only
// "normal" error: we don't log anything.
continue
}
// Compare and Touch both worked --> done.
- return nil
+ return vol.Replication(), nil
}
- return bestErr
+ return 0, bestErr
}
var validLocatorRe = regexp.MustCompile(`^[0-9a-f]{32}$`)
projects / arvados.git / blobdiff