1nbdkit-probing(1)                   NBDKIT                   nbdkit-probing(1)
2
3
4

NAME

6       nbdkit-probing - how to probe for nbdkit configuration and plugins
7

SYNOPSIS

9        nbdkit --dump-config
10
11        nbdkit PLUGIN --dump-plugin
12

DESCRIPTION

14       You can query information about nbdkit and available plugins from the
15       nbdkit binary.
16
17   Query basic configuration
18        nbdkit --dump-config
19
20       lists information about how nbdkit was configured.  The most important
21       fields in the output are the name of the directory where nbdkit looks
22       for plugins and the version of nbdkit, eg:
23
24        plugindir=/usr/lib64/nbdkit/plugins
25        version=1.2.3
26
27   Query information about a particular plugin
28        nbdkit pluginname --dump-plugin
29
30       (where pluginname is the name or full path of a plugin) will dump
31       information about that plugin, eg:
32
33        $ nbdkit file --dump-plugin
34        path=/usr/lib64/nbdkit/plugins/nbdkit-file-plugin.so
35        name=file
36        version=1.2.3
37        api_version=1
38        struct_size=176
39        thread_model=serialize_requests
40        [etc]
41
42       Plugins which ship with nbdkit usually have the same version as the
43       corresponding nbdkit binary.  The nbdkit binary will always be able to
44       utilize plugins compiled against an older version of the header;
45       however, newer plugins may not be fully supported by an older nbdkit
46       binary (for example, a plugin compiled with "NBDKIT_API_VERSION" of 2
47       fails to load with an older nbdkit that only knows "NBDKIT_API_VERSION"
48       1).
49
50   Detect if a plugin is installed
51       To find out if a plugin is installed (and working) in the plugin
52       directory, use --dump-plugin as above:
53
54        $ nbdkit foo --dump-plugin
55        nbdkit: error: cannot open plugin 'foo': /usr/lib64/nbdkit/plugins/nbdkit-foo-plugin.so: cannot open shared object file: No such file or directory
56        Use 'nbdkit --help' or read the nbdkit(1) manual page for documentation.
57
58       Note it is better to test for the existence of plugins this way rather
59       than just seeing if the .so file exists, because nbdkit will load the
60       plugin and check that all its dependencies can be satisfied, and also
61       that plugin registration works.
62
63   List all plugins in the plugin directory
64       You could simply get the plugin directory (from --dump-config) and list
65       all files in this directory called nbdkit-*-plugin.so.
66
67       However a better test is to run --dump-plugin (see above) on each one
68       to check that it is working and all of its dependencies are installed.
69       A complete shell script which does this is:
70
71        #!/bin/sh -
72        plugindir=`nbdkit --dump-config | grep ^plugindir= | sed 's/[^=]*=//'`
73        for f in $plugindir/nbdkit-*-plugin.so; do
74            if nbdkit "$f" --dump-plugin >/dev/null 2>&1; then
75                b=`echo "$f" | sed 's,.*/nbdkit-\(.*\)-plugin.so$,\1,'`
76                echo "$b ($f)"
77            fi
78        done
79
80   Detect if a filter is installed
81       To find out if a filter is installed (and working) use --dump-plugin
82       with the "null" plugin and the name of the filter to test:
83
84        nbdkit --dump-plugin --filter=foo null
85
86       This will fail with an error and non-zero exit code if the "foo" filter
87       cannot be loaded.
88

SEE ALSO

90       nbdkit(1).
91

AUTHORS

93       Eric Blake
94
95       Richard W.M. Jones
96
97       Pino Toscano
98

100       Copyright (C) 2013-2018 Red Hat Inc.
101

LICENSE

103       Redistribution and use in source and binary forms, with or without
104       modification, are permitted provided that the following conditions are
105       met:
106
107       ·   Redistributions of source code must retain the above copyright
108           notice, this list of conditions and the following disclaimer.
109
110       ·   Redistributions in binary form must reproduce the above copyright
111           notice, this list of conditions and the following disclaimer in the
112           documentation and/or other materials provided with the
113           distribution.
114
115       ·   Neither the name of Red Hat nor the names of its contributors may
116           be used to endorse or promote products derived from this software
117           without specific prior written permission.
118
119       THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY
120       EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
121       IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
122       PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE
123       LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
124       CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
125       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
126       BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
127       WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
128       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
129       ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
130
131
132
133nbdkit-1.16.1                     2019-12-03                 nbdkit-probing(1)
Impressum