Libguestfs - May 2020 - ANNOUNCE: nbdkit 1.20 - high performance NBD server

I'm pleased to announce the release of nbdkit 1.20, a high performance
plugin-based Network Block Device (NBD) server.
https://en.wikipedia.org/wiki/Network_block_device

Key features of nbdkit:

 * Multithreaded NBD server written in C with good performance.
 * Minimal dependencies for the basic server.
 * Liberal license (BSD) allows nbdkit to be linked to proprietary
   libraries or included in proprietary code.
 * Well-documented, simple plugin API with a stable ABI guarantee.
   Lets you export “unconventional” block devices easily.
 * You can write plugins in C, [new!] Go, Lua, Perl, Python, OCaml,
   Ruby, Rust, shell script or Tcl.
 * Filters can be stacked in front of plugins to transform the output.

Git: https://github.com/libguestfs/nbdkit
Download: http://download.libguestfs.org/nbdkit/1.20-stable/
Fedora: https://koji.fedoraproject.org/koji/packageinfo?packageID=16469

Release notes (http://libguestfs.org/nbdkit-release-notes-1.20.1.html)

       These are the release notes for nbdkit stable release 1.20.  This
       describes the major changes since 1.18.

       nbdkit 1.20.0 was released on 2nd May 2020.

   Security
       There were no security issues found.  All past security issues and
       information about how to report new ones can be found in
       nbdkit-security(1).

   Plugins
       New nbdkit-tmpdisk-plugin(1) is a scriptable “remote tmpfs” for
       creating temporary filesystems (eg. for thin clients), and also for
       blank or prepopulated temporary disks.

       nbdkit-data-plugin(1) now has support for prepopulating disks with more
       complex test patterns such as repeated sequences of bytes.

       nbdkit-curl-plugin(1) now supports setting a proxy, enabling TCP
       keepalives, and disabling Nagle’s algorithm.

       nbdkit-perl-plugin(1) now supports API version 2.  In particular the
       full NBD client flags are visible to plugins, along with support for
       the ".get_ready" callback.  Also there is a new function
       "Nbdkit::debug" which is a wrapper around the
"nbdkit_debug" API.

       nbdkit-vddk-plugin(1) drops support for VDDK 5.1.1.  This version was
       last updated in 2014 and is no longer supported by VMware.  Since this
       was the last version of VDDK to support i686, 32-bit support is also
       dropped (Eric Blake).

   Language bindings
       Plugins may now be written in Golang, see nbdkit-golang-plugin(3)
       (thanks Dan Berrangé, James Shubin).

       OCaml plugins can now access "nbdkit_realpath",
"nbdkit_nanosleep",
       "nbdkit_export_name" and "nbdkit_shutdown".

       Python plugins now transparently support fail-fast zero (Eric Blake).

   Filters
       New nbdkit-exitlast-filter(1) causes nbdkit to exit after the last
       client connection.

       New nbdkit-limit-filter(1) allows you to limit the number of clients
       which can simultaneously connect to any plugin.

   Server
       The --run option now waits for the nbdkit plugin and nbdkit to exit
       before returning to the caller.  This allows for more predictable clean
       up in shell scripts using this feature.

       nbdkit --dump-config output now includes separate lines for
       "version_major" and "version_minor", making it easier
to find out from
       shell scripts which version of nbdkit is installed.

       nbdkit -s option (which connects to the client over stdin/stdout) now
       rejects various options that would also try to read from or write to
       stdin/stdout, for example --dump-plugin or "password=-" (Eric
Blake).

   API
       New "nbdkit_shutdown" call which allows plugins to ask for
nbdkit to
       exit.  This is used to implement the new "exitlast" filter.

       New "nbdkit_stdio_safe" call allows plugins to check if reading
from
       stdin or writing to stdout is safe, eg. if it is safe to read passwords
       interactively (Eric Blake).

       "can_*" callbacks which return booleans can return any value ≥
1 to
       mean true.  Previous versions of nbdkit had inconsistent behaviour if
       plugins returned anything other than 1 for true (Eric Blake).

   Bug fixes
       nbdkit-tar-plugin(1) now works and there is a regression test for it.

       nbdkit-curl-plugin(1) "-D curl.version=1" option now works.

       Fixed a rare hang when closing a connection in nbdkit-nbd-plugin(1)
       (Eric Blake).

       Fix compilation on certain platforms with clang (Khem Raj).

       Don’t leak $tmpdir from nbdkit-sh-plugin(1) into the --run subcommand.

       nbdkit now correctly sets "FD_CLOEXEC" when using systemd
socket
       activation (Eric Blake).

   Documentation
       The nbdkit-plugin(3) man page has been overhauled completely to make it
       easier to follow.  Also we now have documentation for how to compile
       plugins in various environments which was missing before.

   Tests
       All valgrind tests now pass.

       “Old plugin” tests were added for v1.18.2 on x86-64, and a variety of
       old plugins compiled on i686.  The i686 plugins will allow us to test
       for regressions in 32 bit support.

       Tests of the nbd plugin should now be stable (Eric Blake).

       There is an additional test combining the offset and truncate filters,
       which tests several corner cases as well as providing tests of error
       handling between layers.

   Build
       nbdkit-nbd-plugin(1) now requires libnbd.  (If libnbd is not present at
       build time then this plugin is not built).  The fallback code in this
       plugin which made NBD connections by constructing NBD command packets
       without using libnbd has been removed (Eric Blake).

       scripts/git.orderfile has been improved so that commands like
       "git diff" and "git show" display OCaml sources in a
natural order with
       interface first followed by implementation.

       Various fixes for MinGW.  Note MinGW / MSYS support is a work in
       progress and not finished yet (Frank Gu).

       Multiple fixes to Haiku build.

       awk(1) is no longer required to run the tests.  It was a “hidden”
       required dependency, but all use of it has now been eliminated.

   Internals
       There is now an internal utility library for creating vectors/lists of
       objects, for example lists of strings (common/utils/vector.h).  It is
       widely used by the server, plugins and filters.

       README discusses how to use lcov(1) for code coverage reports.

SEE ALSO
       nbdkit(1).

AUTHORS
       Authors of nbdkit 1.20:

       Eric Blake
           (33 commits)

       Khem Raj
           (1 commit)

       Richard W.M. Jones
           (134 commits)

       Frank Gu
           (6 commits)

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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