3 collectd-unixsock - Documentation of collectd's C<unixsock plugin>
11 SocketFile "/path/to/socket"
12 SocketGroup "collectd"
18 The C<unixsock plugin> opens an UNIX-socket over which one can interact with
19 the daemon. This can be used to use the values collected by collectd in other
20 applications, such as monitoring solutions, or submit externally collected
23 For example, this plugin is used by L<collectd-nagios(1)> to check if some
24 value is in a certain range and exit with a Nagios-compatible exit code.
28 Upon start the C<unixsock plugin> opens a UNIX-socket and waits for
29 connections. Once a connection is established the client can send commands to
30 the daemon which it will answer, if it understand them.
32 In general the plugin answers with a status line of the following form:
36 If I<Status> is greater than or equal to zero the message indicates success,
37 if I<Status> is less than zero the message indicates failure. I<Message> is a
38 human-readable string that further describes the return value.
40 On success, I<Status> furthermore indicates the number of subsequent lines of
41 output (not including the status line). Each such lines usually contains a
42 single return value. See the description of each command for details.
44 The following commands are implemented:
48 =item B<GETVAL> I<Identifier>
50 If the value identified by I<Identifier> (see below) is found the complete
51 value-list is returned. The response is a list of name-value-pairs, each pair
52 on its own line (the number of lines is indicated by the status line - see
53 above). Each name-value-pair is of the form I<name>B<=>I<value>.
54 Counter-values are converted to a rate, e.E<nbsp>g. bytes per second.
55 Undefined values are returned as B<NaN>.
58 -> | GETVAL myhost/cpu-0/cpu-user
60 <- | value=1.260000e+00
64 Returns a list of the values available in the value cache together with the
65 time of the last update, so that querying applications can issue a B<GETVAL>
66 command for the values that have changed. Each return value consists of the
67 update time as an epoch value and the identifier, separated by a space. The
68 update time is the time of the last value, as provided by the collecting
69 instance and may be very different from the time the server considers to be
75 <- | 1182204284 myhost/cpu-0/cpu-idle
76 <- | 1182204284 myhost/cpu-0/cpu-nice
77 <- | 1182204284 myhost/cpu-0/cpu-system
78 <- | 1182204284 myhost/cpu-0/cpu-user
81 =item B<PUTVAL> I<Identifier> [I<OptionList>] I<Valuelist>
83 Submits one or more values (identified by I<Identifier>, see below) to the
84 daemon which will dispatch it to all it's write-plugins.
86 An I<Identifier> is of the form
87 C<I<host>B</>I<plugin>B<->I<instance>B</>I<type>B<->I<instance>> with both
88 I<instance>-parts being optional. If they're omitted the hyphen must be
89 omitted, too. I<plugin> and each I<instance>-part may be chosen freely as long
90 as the tuple (plugin, plugin instance, type instance) uniquely identifies the
91 plugin within collectd. I<type> identifies the type and number of values
92 (i.E<nbsp>e. data-set) passed to collectd. A large list of predefined
93 data-sets is available in the B<types.db> file.
95 The I<OptionList> is an optional list of I<Options>, where each option is a
96 key-value-pair. A list of currently understood options can be found below, all
97 other options will be ignored. Values that contain spaces must be quoted with
100 I<Valuelist> is a colon-separated list of the time and the values, each either
101 an integer if the data-source is a counter, or a double if the data-source is
102 of type "gauge". You can submit an undefined gauge-value by using B<U>. When
103 submitting B<U> to a counter the behavior is undefined. The time is given as
104 epoch (i.E<nbsp>e. standard UNIX time).
106 You can mix options and values, but the order is important: Options only
107 effect following values, so specifying an option as last field is allowed, but
108 useless. Also, an option applies to B<all> following values, so you don't need
109 to re-set an option over and over again.
111 The currently defined B<Options> are:
115 =item B<interval=>I<seconds>
117 Gives the interval in which the data identified by I<Identifier> is being
122 Please note that this is the same format as used in the B<exec plugin>, see
126 -> | PUTVAL testhost/interface/if_octets-test0 interval=10 1179574444:123:456
129 =item B<PUTNOTIF> [I<OptionList>] B<message=>I<Message>
131 Submits a notification to the daemon which will then dispatch it to all plugins
132 which have registered for receiving notifications.
134 The B<PUTNOTIF> command is followed by a list of options which further describe
135 the notification. The B<message> option is special in that it will consume the
136 rest of the line as its value. The B<message>, B<severity>, and B<time> options
143 =item B<message=>I<Message> (B<REQUIRED>)
145 Sets the message of the notification. This is the message that will be made
146 accessible to the user, so it should contain some useful information. As with
147 all options: If the message includes spaces, it must be quoted with double
148 quotes. This option is mandatory.
150 =item B<severity=failure>|B<warning>|B<okay> (B<REQUIRED>)
152 Sets the severity of the notification. This option is mandatory.
154 =item B<time=>I<Time> (B<REQUIRED>)
156 Sets the time of the notification. The time is given as "epoch", i.E<nbsp>e. as
157 seconds since January 1st, 1970, 00:00:00. This option is mandatory.
159 =item B<host=>I<Hostname>
161 =item B<plugin=>I<Plugin>
163 =item B<plugin_instance=>I<Plugin-Instance>
165 =item B<type=>I<Type>
167 =item B<type_instance=>I<Type-Instance>
169 These "associative" options establish a relation between this notification and
170 collected performance data. This connection is purely informal, i.E<nbsp>e. the
171 daemon itself doesn't do anything with this information. However, websites or
172 GUIs may use this information to place notifications near the affected graph or
173 table. All the options are optional, but B<plugin_instance> without B<plugin>
174 or B<type_instance> without B<type> doesn't make much sense and should be
177 Please note that this is the same format as used in the B<exec plugin>, see
183 -> | PUTNOTIF type=temperature severity=warning time=1201094702 message=The roof is on fire!
186 =item B<FLUSH> [B<timeout=>I<Timeout>] [B<plugin=>I<Plugin> [...]] [B<identifier=>I<Ident> [...]]
188 Flushes all cached data older than I<Timeout> seconds. If no timeout has been
189 specified, it defaults to -1 which causes all data to be flushed.
191 If the B<plugin> option has been specified, only the I<Plugin> plugin will be
192 flushed. You can have multiple B<plugin> options to flush multiple plugins in
193 one go. If the B<plugin> option is not given all plugins providing a flush
194 callback will be flushed.
196 If the B<identifier> option is given only the specified values will be flushed.
197 This is meant to be used by graphing or displaying frontends which want to have
198 the latest values for a specific graph. Again, you can specify the
199 B<identifier> option multiple times to flush several values. If this option is
200 not specified at all, all values will be flushed.
203 -> | FLUSH plugin=rrdtool identifier=localhost/df/df-root identifier=localhost/df/df-var
204 <- | 0 Done: 2 successful, 0 errors
210 Value or value-lists are identified in a uniform fashion:
212 I<Hostname>/I<Plugin>/I<Type>
214 Where I<Plugin> and I<Type> are both either of type "I<Name>" or
215 "I<Name>-I<Instance>". If the identifier includes spaces, it must be quoted
216 using double quotes. This sounds more complicated than it is, so here are
219 myhost/cpu-0/cpu-user
221 myhost/memory/memory-used
222 myhost/disk-sda/disk_octets
223 "myups/snmp/temperature-Outlet 1"
225 =head1 ABSTRACTION LAYER
227 B<collectd> ships the Perl-Module L<Collectd::Unixsock> which
228 provides an abstraction layer over the actual socket connection. It can be
229 found in the directory F<bindings/perl/> in the source distribution or
230 (usually) somewhere near F</usr/share/perl5/> if you're using a package. If
231 you want to use Perl to communicate with the daemon, you're encouraged to use
232 and expand this module.
238 L<collectd-nagios(1)>,
243 Florian Forster E<lt>octo@verplant.orgE<gt>