Decouple read chunk size from write chunk size

When using the copy_from option, readers and writers can have different
speeds to respectively read and write.
A reader timeout will happen if the writer is slow and the writer is
being asked to write a lot. This is currently happening when using
the VMware store and copying from an HTTP server. The reader is reading
16MB which takes too long to upload to vCenter which is causing a
timeout from the HTTP server. The writer should be able to control the
size of the chunks being read when using copy_from: this way the writer
will write fast enough to not make the reader timeout.

This patch addresses the issue by introducing the notion of read chunk
size and write chunk size. Each store can have its own value for read
and write. The write chunk size of the destination store will be used
as the read chunk size of the source store in case of an image-create
where the copy_from option is specified.

Closes-Bug: #1336168

Signed-off-by: Arnaud Legendre <[email protected]>
Signed-off-by: Zhi Yan Liu <[email protected]>

Change-Id: I4e0c563b8f3a5ced8f65fcca83d341a97729a5d4

Author: arnaudleg

glance/api/v1/images.py

@@ -447,9 +447,10 @@ def _external_source(self, image_meta, req):
         return Controller._validate_source(source, req)
 
     @staticmethod
-    def _get_from_store(context, where):
+    def _get_from_store(context, where, dest=None):
         try:
-            image_data, image_size = get_from_backend(context, where)
+            image_data, image_size = get_from_backend(
+                context, where, dest=dest)
         except exception.NotFound as e:
             raise HTTPNotFound(explanation=e.msg)
         image_size = int(image_size) if image_size else None
@@ -571,11 +572,15 @@ def _upload(self, req, image_meta):
         :retval The location where the image was stored
         """
 
+        scheme = req.headers.get('x-image-meta-store', CONF.default_store)
+        store = self.get_store_or_400(req, scheme)
+
         copy_from = self._copy_from(req)
         if copy_from:
             try:
                 image_data, image_size = self._get_from_store(req.context,
-                                                              copy_from)
+                                                              copy_from,
+                                                              dest=store)
             except Exception as e:
                 upload_utils.safe_kill(req, image_meta['id'])
                 msg = ("Copy from external source failed: %s" %
@@ -594,10 +599,6 @@ def _upload(self, req, image_meta):
 
             image_data = req.body_file
 
-        scheme = req.headers.get('x-image-meta-store', CONF.default_store)
-
-        store = self.get_store_or_400(req, scheme)
-
         image_id = image_meta['id']
         LOG.debug("Setting image %s to status 'saving'", image_id)
         registry.update_image_metadata(req.context, image_id,
@@ -1102,7 +1103,7 @@ def _deserialize(self, request):
         if image_size is None and data is not None:
             data = utils.LimitingReader(data, CONF.image_size_cap)
 
-            #NOTE(bcwaldon): this is a hack to make sure the downstream code
+            # NOTE(bcwaldon): this is a hack to make sure the downstream code
             # gets the correct image data
             request.body_file = data
 

glance/store/__init__.py

@@ -258,10 +258,12 @@ def get_from_backend(context, uri, **kwargs):
     """Yields chunks of data from backend specified by uri"""
 
     loc = location.get_location_from_uri(uri)
-    store = get_store_from_uri(context, uri, loc)
-
+    src_store = get_store_from_uri(context, uri, loc)
+    dest_store = kwargs.get('dest')
+    if dest_store is not None:
+        src_store.READ_CHUNKSIZE = dest_store.WRITE_CHUNKSIZE
     try:
-        return store.get(loc)
+        return src_store.get(loc)
     except NotImplementedError:
         raise exception.StoreGetNotSupported
 

glance/store/base.py

@@ -27,7 +27,8 @@
 
 class Store(object):
 
-    CHUNKSIZE = 16 * units.Mi  # 16M
+    READ_CHUNKSIZE = 16 * units.Mi  # 16M
+    WRITE_CHUNKSIZE = READ_CHUNKSIZE
 
     @staticmethod
     def _unconfigured(*args, **kwargs):

glance/store/filesystem.py

@@ -89,8 +89,6 @@ class ChunkedFile(object):
     something that can iterate over a large file
     """
 
-    CHUNKSIZE = 65536
-
     def __init__(self, filepath):
         self.filepath = filepath
         self.fp = open(self.filepath, 'rb')
@@ -100,7 +98,7 @@ def __iter__(self):
         try:
             if self.fp:
                 while True:
-                    chunk = self.fp.read(ChunkedFile.CHUNKSIZE)
+                    chunk = self.fp.read(Store.READ_CHUNKSIZE)
                     if chunk:
                         yield chunk
                     else:
@@ -117,6 +115,9 @@ def close(self):
 
 class Store(glance.store.base.Store):
 
+    READ_CHUNKSIZE = 64 * units.Ki
+    WRITE_CHUNKSIZE = READ_CHUNKSIZE
+
     def get_schemes(self):
         return ('file', 'filesystem')
 
@@ -431,7 +432,7 @@ def add(self, image_id, image_file, image_size):
         try:
             with open(filepath, 'wb') as f:
                 for buf in utils.chunkreadable(image_file,
-                                               ChunkedFile.CHUNKSIZE):
+                                               self.WRITE_CHUNKSIZE):
                     bytes_written += len(buf)
                     checksum.update(buf)
                     f.write(buf)

glance/store/http.py

@@ -122,7 +122,7 @@ def get(self, location):
         """
         conn, resp, content_length = self._query(location, 'GET')
 
-        iterator = http_response_iterator(conn, resp, self.CHUNKSIZE)
+        iterator = http_response_iterator(conn, resp, self.READ_CHUNKSIZE)
 
         class ResponseIndexable(glance.store.Indexable):
             def another(self):

glance/store/rbd.py

@@ -188,7 +188,8 @@ def configure_add(self):
         itself, it should raise `exception.BadStoreConfiguration`
         """
         try:
-            self.chunk_size = CONF.rbd_store_chunk_size * units.Mi
+            self.READ_CHUNKSIZE = CONF.rbd_store_chunk_size * units.Mi
+            self.WRITE_CHUNKSIZE = self.READ_CHUNKSIZE
 
             # these must not be unicode since they will be passed to a
             # non-unicode-aware C library
@@ -323,7 +324,7 @@ def add(self, image_id, image_file, image_size):
             if hasattr(conn, 'get_fsid'):
                 fsid = conn.get_fsid()
             with conn.open_ioctx(self.pool) as ioctx:
-                order = int(math.log(self.chunk_size, 2))
+                order = int(math.log(self.WRITE_CHUNKSIZE, 2))
                 LOG.debug('creating image %(name)s with order %(order)d and '
                           'size %(size)d',
                           {'name': text_type(image_name),
@@ -345,7 +346,7 @@ def add(self, image_id, image_file, image_size):
                         bytes_written = 0
                         offset = 0
                         chunks = utils.chunkreadable(image_file,
-                                                     self.chunk_size)
+                                                     self.WRITE_CHUNKSIZE)
                         for chunk in chunks:
                             # If the image size provided is zero we need to do
                             # a resize for the amount we are writing. This will

glance/store/s3.py

@@ -257,8 +257,6 @@ class ChunkedFile(object):
     something that can iterate over a ``boto.s3.key.Key``
     """
 
-    CHUNKSIZE = 65536
-
     def __init__(self, fp):
         self.fp = fp
 
@@ -267,7 +265,7 @@ def __iter__(self):
         try:
             if self.fp:
                 while True:
-                    chunk = self.fp.read(ChunkedFile.CHUNKSIZE)
+                    chunk = self.fp.read(Store.READ_CHUNKSIZE)
                     if chunk:
                         yield chunk
                     else:
@@ -295,6 +293,9 @@ def close(self):
 class Store(glance.store.base.Store):
     """An implementation of the s3 adapter."""
 
+    READ_CHUNKSIZE = 64 * units.Ki
+    WRITE_CHUNKSIZE = READ_CHUNKSIZE
+
     EXAMPLE_URL = "s3://<ACCESS_KEY>:<SECRET_KEY>@<S3_URL>/<BUCKET>/<OBJ>"
 
     def get_schemes(self):
@@ -372,11 +373,11 @@ def get(self, location):
         """
         key = self._retrieve_key(location)
 
-        key.BufferSize = self.CHUNKSIZE
+        key.BufferSize = self.READ_CHUNKSIZE
 
         class ChunkedIndexable(glance.store.Indexable):
             def another(self):
-                return (self.wrapped.fp.read(ChunkedFile.CHUNKSIZE)
+                return (self.wrapped.fp.read(self.READ_CHUNKSIZE)
                         if self.wrapped.fp else None)
 
         return (ChunkedIndexable(ChunkedFile(key), key.size), key.size)
@@ -504,7 +505,7 @@ def _sanitize(uri):
             tmpdir = self.s3_store_object_buffer_dir
             temp_file = tempfile.NamedTemporaryFile(dir=tmpdir)
             checksum = hashlib.md5()
-            for chunk in utils.chunkreadable(image_file, self.CHUNKSIZE):
+            for chunk in utils.chunkreadable(image_file, self.WRITE_CHUNKSIZE):
                 checksum.update(chunk)
                 temp_file.write(chunk)
             temp_file.flush()

glance/store/sheepdog.py

@@ -191,7 +191,8 @@ def configure(self):
         """
 
         try:
-            self.chunk_size = CONF.sheepdog_store_chunk_size * units.Mi
+            self.READ_CHUNKSIZE = CONF.sheepdog_store_chunk_size * units.Mi
+            self.WRITE_CHUNKSIZE = self.READ_CHUNKSIZE
             self.addr = CONF.sheepdog_store_address.strip()
             self.port = CONF.sheepdog_store_port
         except cfg.ConfigFileValueError as e:
@@ -231,7 +232,7 @@ def get(self, location):
 
         loc = location.store_location
         image = SheepdogImage(self.addr, self.port, loc.image,
-                              self.chunk_size)
+                              self.READ_CHUNKSIZE)
         if not image.exist():
             raise exception.NotFound(_("Sheepdog image %s does not exist")
                                      % image.name)
@@ -250,7 +251,7 @@ def get_size(self, location):
 
         loc = location.store_location
         image = SheepdogImage(self.addr, self.port, loc.image,
-                              self.chunk_size)
+                              self.READ_CHUNKSIZE)
         if not image.exist():
             raise exception.NotFound(_("Sheepdog image %s does not exist")
                                      % image.name)
@@ -272,7 +273,7 @@ def add(self, image_id, image_file, image_size):
         """
 
         image = SheepdogImage(self.addr, self.port, image_id,
-                              self.chunk_size)
+                              self.WRITE_CHUNKSIZE)
         if image.exist():
             raise exception.Duplicate(_("Sheepdog image %s already exists")
                                       % image_id)
@@ -285,7 +286,7 @@ def add(self, image_id, image_file, image_size):
         try:
             total = left = image_size
             while left > 0:
-                length = min(self.chunk_size, left)
+                length = min(self.WRITE_CHUNKSIZE, left)
                 data = image_file.read(length)
                 image.write(data, total - left, length)
                 left -= length
@@ -311,7 +312,7 @@ def delete(self, location):
 
         loc = location.store_location
         image = SheepdogImage(self.addr, self.port, loc.image,
-                              self.chunk_size)
+                              self.WRITe_CHUNKSIZE)
         if not image.exist():
             raise exception.NotFound(_("Sheepdog image %s does not exist") %
                                      loc.image)

glance/store/swift.py

@@ -31,6 +31,7 @@
 from glance import i18n
 from glance.openstack.common import excutils
 import glance.openstack.common.log as logging
+from glance.openstack.common import units
 import glance.store
 import glance.store.base
 import glance.store.location
@@ -350,7 +351,7 @@ def Store(context=None, loc=None, configure=True):
 
 
 class BaseStore(glance.store.base.Store):
-    CHUNKSIZE = 65536
+    READ_CHUNKSIZE = 64 * units.Ki
 
     def get_schemes(self):
         return ('swift+https', 'swift', 'swift+http', 'swift+config')
@@ -379,7 +380,7 @@ def _get_object(self, location, connection=None, start=None):
         try:
             resp_headers, resp_body = connection.get_object(
                 container=location.container, obj=location.obj,
-                resp_chunk_size=self.CHUNKSIZE, headers=headers)
+                resp_chunk_size=self.READ_CHUNKSIZE, headers=headers)
         except swiftclient.ClientException as e:
             if e.http_status == httplib.NOT_FOUND:
                 msg = _("Swift could not find object %s.") % location.obj

glance/store/vmware_datastore.py

@@ -30,6 +30,7 @@
 from glance.openstack.common import excutils
 from glance.openstack.common import gettextutils
 import glance.openstack.common.log as logging
+from glance.openstack.common import units
 import glance.store
 import glance.store.base
 import glance.store.location
@@ -221,6 +222,8 @@ def parse_uri(self, uri):
 class Store(glance.store.base.Store):
     """An implementation of the VMware datastore adapter."""
 
+    WRITE_CHUNKSIZE = units.Mi
+
     def get_schemes(self):
         return (STORE_SCHEME,)
 
@@ -366,7 +369,7 @@ def get(self, location):
                         from glance.store.location.get_location_from_uri()
         """
         conn, resp, content_length = self._query(location, 'GET')
-        iterator = http_response_iterator(conn, resp, self.CHUNKSIZE)
+        iterator = http_response_iterator(conn, resp, self.READ_CHUNKSIZE)
 
         class ResponseIndexable(glance.store.Indexable):