1nbdkit-streaming-plugin(1)          NBDKIT          nbdkit-streaming-plugin(1)
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NAME

6       nbdkit-streaming-plugin - nbdkit streaming plugin
7

SYNOPSIS

9        nbdkit streaming pipe=FILENAME [size=SIZE]
10

DESCRIPTION

12       "nbdkit-streaming-plugin" is a plugin for nbdkit(1) that can turn
13       certain kinds of input into a stream.
14
15       If the NBD client opens the NBD port, and writes from the start to the
16       end of the disk without seeking backwards, then this plugin will turn
17       the resulting disk image into a stream of data which is written to the
18       named "pipe" parameter.
19
20                      ┌───────────┐
21        client        │ nbdkit    │        plugin streams
22        writes ──────▶│ streaming │──────▶ data to pipe
23                      │ plugin    │
24                      └───────────┘
25
26       Typical usage is with qemu tools.  The following command will not work
27       because the output is a pipe or socket:
28
29        qemu-img convert input -O raw pipe
30
31       However this will work:
32
33        nbdkit -U - streaming pipe=pipe --run '
34          qemu-img convert -n input -O raw $nbd
35        '
36
37                     ┌───────────┐       ┌───────────┐
38        reads        │ qemu-img  │       │ nbdkit    │        plugin streams
39        input ──────▶│ convert   │──────▶│ streaming │──────▶ data to pipe
40        file         │ command   │       │ plugin    │
41                     └───────────┘      ↑└───────────┘
42                                     Unix domain socket (-U -)
43
44       For use of the --run and -U - options, see nbdkit-captive(1).
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PARAMETERS

47       pipe=FILENAME
48           Write to the named pipe or socket.  If the pipe or socket does not
49           exist, then it is created (as a named FIFO), otherwise the existing
50           pipe or socket is opened and used.
51
52           This parameter is required.
53
54       size=SIZE
55           Specify the virtual size of the stream.
56
57           This parameter is optional.  If not specified, then the virtual
58           disk appears to the client to be very large (effectively infinite).
59           Whether you need to specify this parameter depends on the client.
60           Some clients don't check the size and just write/stream, others do
61           checks or calculations based on the apparent size.
62

SEE ALSO

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

67       Richard W.M. Jones
68
70       Copyright (C) 2014 Red Hat Inc.
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LICENSE

73       Redistribution and use in source and binary forms, with or without
74       modification, are permitted provided that the following conditions are
75       met:
76
77       ·   Redistributions of source code must retain the above copyright
78           notice, this list of conditions and the following disclaimer.
79
80       ·   Redistributions in binary form must reproduce the above copyright
81           notice, this list of conditions and the following disclaimer in the
82           documentation and/or other materials provided with the
83           distribution.
84
85       ·   Neither the name of Red Hat nor the names of its contributors may
86           be used to endorse or promote products derived from this software
87           without specific prior written permission.
88
89       THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY
90       EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
91       IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
92       PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE
93       LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
94       CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
95       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
96       BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
97       WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
98       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
99       ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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103nbdkit-1.12.3                     2019-05-22        nbdkit-streaming-plugin(1)
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