NAME

       nbdkit-streaming-plugin - nbdkit streaming plugin

SYNOPSIS

        nbdkit streaming pipe=FILENAME [size=SIZE]

DESCRIPTION

       "nbdkit-streaming-plugin" is a plugin for nbdkit(1) that can turn certain kinds of input into a stream.

       If the NBD client opens the NBD port, and writes from the start to the end of the disk without seeking
       backwards, then this plugin will turn the resulting disk image into a stream of data which is written to
       the named "pipe" parameter.

                      ┌───────────┐
        client        │ nbdkit    │        plugin streams
        writes ──────▶│ streaming │──────▶ data to pipe
                      │ plugin    │
                      └───────────┘

       Typical usage is with qemu tools.  The following command will not work because the output is a pipe or
       socket:

        qemu-img convert input -O raw pipe

       However this will work:

        nbdkit -U - streaming pipe=pipe --run '
          qemu-img convert -n input -O raw $nbd
        '

                     ┌───────────┐       ┌───────────┐
        reads        │ qemu-img  │       │ nbdkit    │        plugin streams
        input ──────▶│ convert   │──────▶│ streaming │──────▶ data to pipe
        file         │ command   │       │ plugin    │
                     └───────────┘      ↑└───────────┘
                                     Unix domain socket (-U -)

       For use of the --run and -U - options, see nbdkit-captive(1).

PARAMETERS

       pipe=FILENAME
           Write  to  the  named pipe or socket.  If the pipe or socket does not exist, then it is created (as a
           named FIFO), otherwise the existing pipe or socket is opened and used.

           This parameter is required.

       size=SIZE
           Specify the virtual size of the stream.

           This parameter is optional.  If not specified, then the virtual disk appears to the client to be very
           large (effectively infinite).  Whether you need to specify this  parameter  depends  on  the  client.
           Some  clients  don't  check the size and just write/stream, others do checks or calculations based on
           the apparent size.

FILES

       $plugindir/nbdkit-streaming-plugin.so
           The plugin.

           Use "nbdkit --dump-config" to find the location of $plugindir.

VERSION

       "nbdkit-streaming-plugin" first appeared in nbdkit 1.2.

SEE ALSO

       nbdkit(1), nbdkit-plugin(3).

AUTHORS

       Richard W.M. Jones

COPYRIGHT

       Copyright (C) 2014 Red Hat Inc.

LICENSE

       Redistribution and use in source and binary forms, with or without modification, are  permitted  provided
       that the following conditions are met:

       •   Redistributions  of  source  code must retain the above copyright notice, this list of conditions and
           the following disclaimer.

       •   Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
           the following disclaimer in the documentation and/or other materials provided with the distribution.

       •   Neither the name of Red Hat nor the names of its contributors may  be  used  to  endorse  or  promote
           products derived from this software without specific prior written permission.

       THIS  SOFTWARE  IS  PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
       INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND  FITNESS  FOR  A  PARTICULAR
       PURPOSE  ARE  DISCLAIMED.  IN  NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
       INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,  PROCUREMENT  OF
       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
       ON  ANY  THEORY  OF  LIABILITY,  WHETHER  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
       DAMAGE.

nbdkit-1.16.2                                      2020-01-28                         nbdkit-streaming-plugin(1)