This requires some discussion of how we will handle errors due to network problems
and after further changes in that direction some more stress testing. There is also an
upcomming commit implementing zero fill on WriteStream when offset is greater than
the current size of the file.
Requires all paths in the inmemory and filesystem drivers to begin with
a slash, and then contain only valid path components (2+ alphanumeric
characters with optional period, hyphen, and underscore separators)
delimited by slashes.
Also updates the storage driver test suites to construct paths of this
format, and causes the suite to abort if files are not cleaned up after
the test run.
We are change the the rpc call for WriteStream to not require the size
argument, opting to drive the process with io.Reader. The main issue was that
io.Reader may return io.EOF before reaching size, making the error handling
around this condition for callers more complex. To complement this, WriteStream
now returns the number of successfully written bytes.
The method no longer requires an io.ReadCloser, opting to require just an
io.Reader. This keeps the reader under the control of the caller, which
provides more flexibility.
This also begins to address some of the problems described in #791.
To support single-flight Size and ModTime queries against backend storage file,
we are replacing the CurrentSize call with a Stat call. A FileInfo interface is
provided for backends to provide a type, with a default implementation called
FileInfoInternal, for use by driver implementations.
More work needs to follow this change to update all the driver implementations.
This change brings the storagedriver API in line with the Go standard library's
use of int64 for offsets. The main benefit is simplicity in interfacing with
the io library reducing the number of type conversions in simple code.
The registry currently only accepts storage driver versions with the
same major version and an equal or lower minor version as its own
current storage driver api version, but this may be changed in the
future if we decide to implement specific version cross-compatibility.
Custom storage drivers can register a factory to create the driver by
name, similar to the database/sql package's Register and Open
factory.Create returns an in-process driver if registered or an IPC
driver if one can be found, erroring otherwise
This standardizes parameter passing for creation of storage drivers
Also adds documentation for storagedriver package and children
