To make the definition of supported digests more clear, we have refactored the
digest package to have a special Algorithm type. This represents the digest's
prefix and we associated various supported hash implementations through
function calls.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Remote md5 and sha1 hashes which are not supported by distribution.
Add more secure hashes sha384 and sha512.
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
Several API tests were added to ensure correct acceptance of zero-size and
empty tar files. This led to several changes in the storage backend around the
guarantees of remote file reading, which backs the layer and layer upload type.
In support of these changes, zero-length and empty checks have been added to
the digest package. These provide a sanity check against upstream tarsum
changes. The fileReader has been modified to be more robust when reading and
seeking on zero-length or non-existent files. The file no longer needs to exist
for the reader to be created. Seeks can now move beyond the end of the file,
causing reads to issue an io.EOF. This eliminates errors during certain race
conditions for reading files which should be detected by stat calls. As a part
of this, a few error types were factored out and the read buffer size was
increased to something more reasonable.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
The Digest type will be fairly central for blob and layer management. The type
presented in this package provides a number of core features that should enable
reliable use within the registry. This commit will be followed by others that
convert the storage layer and webapp to use this type as the primary layer/blob
CAS identifier.
