1nbdkit-probing(1) NBDKIT nbdkit-probing(1)
2
6 nbdkit-probing - how to probe for nbdkit configuration and plugins
7
9 nbdkit --dump-config
10 nbdkit PLUGIN --dump-plugin
12 nbdkit --version
14 nbdkit PLUGIN --version
16 nbdkit --filter=FILTER null --version
18
20 You can query information about nbdkit and available plugins and
21 filters using the nbdkit binary. This can include whether nbdkit is
22 installed, and whether plugins or filters and installed.
23 Query if nbdkit is installed
25 Use this command to see if the nbdkit program is installed:
26 nbdkit --version
28 This will fail with an error and non-zero exit code if nbdkit is not
30 installed or not working.
31 Query basic configuration
33 nbdkit --dump-config
34 lists information about how nbdkit was configured. The most important
36 fields in the output are the name of the directory where nbdkit looks
37 for plugins and the version of nbdkit, eg:
38 plugindir=/usr/lib64/nbdkit/plugins
40 version=1.20.1
41 version_major=1
42 version_minor=20
43 Test nbdkit ≥ version
45 To test if nbdkit ≥ a particular version is installed, use the
46 --dump-config option and look for the "version_major" and
47 "version_minor" fields:
48 $ nbdkit --dump-config | grep ^version_minor
50 version_minor=20
51 $ major=$( nbdkit --dump-config | grep ^version_major | cut -d= -f2 )
52 $ minor=$( nbdkit --dump-config | grep ^version_minor | cut -d= -f2 )
53 $ if [ $major -eq 1 ] && [ $minor -lt 12 ]
54 then echo 'nbdkit >= 1.12 is required'; exit 1; fi
55 These fields were first added in nbdkit 1.16.5 and were not present in
57 earlier versions.
58 You can also probe the minimum version using pkg-config(1). See
60 "PKG-CONFIG/PKGCONF" in nbdkit-plugin(3).
61 Query information about a particular plugin
63 nbdkit pluginname --dump-plugin
64 (where pluginname is the name or full path of a plugin) will dump
66 information about that plugin, eg:
67 $ nbdkit file --dump-plugin
69 path=/usr/lib64/nbdkit/plugins/nbdkit-file-plugin.so
70 name=file
71 version=1.20.1
72 api_version=1
73 struct_size=176
74 thread_model=serialize_requests
75 [etc]
76 Plugins which ship with nbdkit usually have the same version as the
78 corresponding nbdkit binary. The nbdkit binary will always be able to
79 utilize plugins compiled against an older version of the header;
80 however, newer plugins may not be fully supported by an older nbdkit
81 binary (for example, a plugin compiled with "NBDKIT_API_VERSION" of 2
82 fails to load with an older nbdkit that only knows "NBDKIT_API_VERSION"
83 1).
84 Detect if a plugin is installed
86 To find out if a plugin is installed (and working) in the plugin
87 directory, use:
88 $ nbdkit foo --version
90 nbdkit: error: cannot open plugin 'foo': /usr/lib64/nbdkit/plugins/nbdkit-foo-plugin.so: cannot open shared object file: No such file or directory
91 Use 'nbdkit --help' or read the nbdkit(1) manual page for documentation.
92 This will fail with an error and non-zero exit code if the "foo" plugin
94 cannot be loaded.
95 Note it is better to test for the existence of plugins this way rather
97 than just seeing if the .so file exists, because nbdkit will load the
98 plugin and check that all its dependencies can be satisfied, and also
99 that plugin registration works.
100 List all plugins in the plugin directory
102 You could simply get the plugin directory (from --dump-config) and list
103 all files in this directory called nbdkit-*-plugin.so.
104 However a better test is to run --dump-plugin (see above) on each one
106 to check that it is working and all of its dependencies are installed.
107 A complete shell script which does this is:
108 #!/bin/sh -
110 plugindir=`nbdkit --dump-config | grep ^plugindir= | sed 's/[^=]*=//'`
111 for f in $plugindir/nbdkit-*-plugin.so; do
112 if nbdkit "$f" --version >/dev/null 2>&1; then
113 b=`echo "$f" | sed 's,.*/nbdkit-\(.*\)-plugin.so$,\1,'`
114 echo "$b ($f)"
115 fi
116 done
117 Detect if a filter is installed
119 To find out if a filter is installed (and working) use --version with
120 the "null" plugin and the name of the filter to test:
121 nbdkit --version --filter=foo null
123 This will fail with an error and non-zero exit code if the "foo" filter
125 cannot be loaded.
126
128 nbdkit(1).
129
131 Eric Blake
132 Richard W.M. Jones
134 Pino Toscano
136
138 Copyright (C) 2013-2020 Red Hat Inc.
139
141 Redistribution and use in source and binary forms, with or without
142 modification, are permitted provided that the following conditions are
143 met:
144 · Redistributions of source code must retain the above copyright
146 notice, this list of conditions and the following disclaimer.
147 · Redistributions in binary form must reproduce the above copyright
149 notice, this list of conditions and the following disclaimer in the
150 documentation and/or other materials provided with the
151 distribution.
152 · Neither the name of Red Hat nor the names of its contributors may
154 be used to endorse or promote products derived from this software
155 without specific prior written permission.
156 THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY
158 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
159 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
160 PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE
161 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
162 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
163 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
164 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
165 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
166 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
167 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
168nbdkit-1.24.2 2021-03-02 nbdkit-probing(1)