eb1d14fc44ca0a324af4610d2e0fe67c22659685
1 =encoding UTF-8
3 =head1 NAME
5 collectd-unixsock - Documentation of collectd's C<unixsock plugin>
7 =head1 SYNOPSIS
9 # See collectd.conf(5)
10 LoadPlugin unixsock
11 # ...
12 <Plugin unixsock>
13 SocketFile "/path/to/socket"
14 SocketGroup "collectd"
15 SocketPerms "0770"
16 </Plugin>
18 =head1 DESCRIPTION
20 The C<unixsock plugin> opens an UNIX-socket over which one can interact with
21 the daemon. This can be used to use the values collected by collectd in other
22 applications, such as monitoring solutions, or submit externally collected
23 values to collectd.
25 For example, this plugin is used by L<collectd-nagios(1)> to check if some
26 value is in a certain range and exit with a Nagios-compatible exit code.
28 =head1 COMMANDS
30 Upon start the C<unixsock plugin> opens a UNIX-socket and waits for
31 connections. Once a connection is established the client can send commands to
32 the daemon which it will answer, if it understand them.
34 In general the plugin answers with a status line of the following form:
36 I<Status> I<Message>
38 If I<Status> is greater than or equal to zero the message indicates success,
39 if I<Status> is less than zero the message indicates failure. I<Message> is a
40 human-readable string that further describes the return value.
42 On success, I<Status> furthermore indicates the number of subsequent lines of
43 output (not including the status line). Each such lines usually contains a
44 single return value. See the description of each command for details.
46 The following commands are implemented:
48 =over 4
50 =item B<GETVAL> I<Identifier>
52 If the value identified by I<Identifier> (see below) is found the complete
53 value-list is returned. The response is a list of name-value-pairs, each pair
54 on its own line (the number of lines is indicated by the status line - see
55 above). Each name-value-pair is of the form I<name>B<=>I<value>.
56 Counter-values are converted to a rate, e.E<nbsp>g. bytes per second.
57 Undefined values are returned as B<NaN>.
59 Example:
60 -> | GETVAL myhost/cpu-0/cpu-user
61 <- | 1 Value found
62 <- | value=1.260000e+00
64 =item B<LISTVAL>
66 Returns a list of the values available in the value cache together with the
67 time of the last update, so that querying applications can issue a B<GETVAL>
68 command for the values that have changed. Each return value consists of the
69 update time as an epoch value and the identifier, separated by a space. The
70 update time is the time of the last value, as provided by the collecting
71 instance and may be very different from the time the server considers to be
72 "now".
74 Example:
75 -> | LISTVAL
76 <- | 69 Values found
77 <- | 1182204284 myhost/cpu-0/cpu-idle
78 <- | 1182204284 myhost/cpu-0/cpu-nice
79 <- | 1182204284 myhost/cpu-0/cpu-system
80 <- | 1182204284 myhost/cpu-0/cpu-user
81 ...
83 =item B<PUTVAL> I<Identifier> [I<OptionList>] I<Valuelist>
85 Submits one or more values (identified by I<Identifier>, see below) to the
86 daemon which will dispatch it to all it's write-plugins.
88 An I<Identifier> is of the form
89 C<I<host>B</>I<plugin>B<->I<instance>B</>I<type>B<->I<instance>> with both
90 I<instance>-parts being optional. If they're omitted the hyphen must be
91 omitted, too. I<plugin> and each I<instance>-part may be chosen freely as long
92 as the tuple (plugin, plugin instance, type instance) uniquely identifies the
93 plugin within collectd. I<type> identifies the type and number of values
94 (i.E<nbsp>e. data-set) passed to collectd. A large list of predefined
95 data-sets is available in the B<types.db> file.
97 The I<OptionList> is an optional list of I<Options>, where each option is a
98 key-value-pair. A list of currently understood options can be found below, all
99 other options will be ignored. Values that contain spaces must be quoted with
100 double quotes.
102 I<Valuelist> is a colon-separated list of the time and the values, each either
103 an integer if the data-source is a counter, or a double if the data-source is
104 of type "gauge". You can submit an undefined gauge-value by using B<U>. When
105 submitting B<U> to a counter the behavior is undefined. The time is given as
106 epoch (i.E<nbsp>e. standard UNIX time).
108 You can mix options and values, but the order is important: Options only
109 effect following values, so specifying an option as last field is allowed, but
110 useless. Also, an option applies to B<all> following values, so you don't need
111 to re-set an option over and over again.
113 The currently defined B<Options> are:
115 =over 4
117 =item B<interval=>I<seconds>
119 Gives the interval in which the data identified by I<Identifier> is being
120 collected.
122 =back
124 Please note that this is the same format as used in the B<exec plugin>, see
125 L<collectd-exec(5)>.
127 Example:
128 -> | PUTVAL testhost/interface/if_octets-test0 interval=10 1179574444:123:456
129 <- | 0 Success
131 =item B<PUTNOTIF> [I<OptionList>] B<message=>I<Message>
133 Submits a notification to the daemon which will then dispatch it to all plugins
134 which have registered for receiving notifications.
136 The B<PUTNOTIF> command is followed by a list of options which further describe
137 the notification. The B<message> option is special in that it will consume the
138 rest of the line as its value. The B<message>, B<severity>, and B<time> options
139 are mandatory.
141 Valid options are:
143 =over 4
145 =item B<message=>I<Message> (B<REQUIRED>)
147 Sets the message of the notification. This is the message that will be made
148 accessible to the user, so it should contain some useful information. As with
149 all options: If the message includes spaces, it must be quoted with double
150 quotes. This option is mandatory.
152 =item B<severity=failure>|B<warning>|B<okay> (B<REQUIRED>)
154 Sets the severity of the notification. This option is mandatory.
156 =item B<time=>I<Time> (B<REQUIRED>)
158 Sets the time of the notification. The time is given as "epoch", i.E<nbsp>e. as
159 seconds since January 1st, 1970, 00:00:00. This option is mandatory.
161 =item B<host=>I<Hostname>
163 =item B<plugin=>I<Plugin>
165 =item B<plugin_instance=>I<Plugin-Instance>
167 =item B<type=>I<Type>
169 =item B<type_instance=>I<Type-Instance>
171 These "associative" options establish a relation between this notification and
172 collected performance data. This connection is purely informal, i.E<nbsp>e. the
173 daemon itself doesn't do anything with this information. However, websites or
174 GUIs may use this information to place notifications near the affected graph or
175 table. All the options are optional, but B<plugin_instance> without B<plugin>
176 or B<type_instance> without B<type> doesn't make much sense and should be
177 avoided.
179 =item B<type:key=>I<value>
181 Sets user defined meta information. The B<type> key is a single character
182 defining the type of the meta information.
184 The current supported types are:
186 =over 8
188 =item B<s> A string passed as-is.
190 =back
192 =back
194 Please note that this is the same format as used in the B<exec plugin>, see
195 L<collectd-exec(5)>.
197 Example:
198 -> | PUTNOTIF type=temperature severity=warning time=1201094702 message=The roof is on fire!
199 <- | 0 Success
201 =item B<FLUSH> [B<timeout=>I<Timeout>] [B<plugin=>I<Plugin> [...]] [B<identifier=>I<Ident> [...]]
203 Flushes all cached data older than I<Timeout> seconds. If no timeout has been
204 specified, it defaults to -1 which causes all data to be flushed.
206 If the B<plugin> option has been specified, only the I<Plugin> plugin will be
207 flushed. You can have multiple B<plugin> options to flush multiple plugins in
208 one go. If the B<plugin> option is not given all plugins providing a flush
209 callback will be flushed.
211 If the B<identifier> option is given only the specified values will be flushed.
212 This is meant to be used by graphing or displaying frontends which want to have
213 the latest values for a specific graph. Again, you can specify the
214 B<identifier> option multiple times to flush several values. If this option is
215 not specified at all, all values will be flushed.
217 Example:
218 -> | FLUSH plugin=rrdtool identifier=localhost/df/df-root identifier=localhost/df/df-var
219 <- | 0 Done: 2 successful, 0 errors
221 =back
223 =head2 Identifiers
225 Value or value-lists are identified in a uniform fashion:
227 I<Hostname>/I<Plugin>/I<Type>
229 Where I<Plugin> and I<Type> are both either of type "I<Name>" or
230 "I<Name>-I<Instance>". If the identifier includes spaces, it must be quoted
231 using double quotes. This sounds more complicated than it is, so here are
232 some examples:
234 myhost/cpu-0/cpu-user
235 myhost/load/load
236 myhost/memory/memory-used
237 myhost/disk-sda/disk_octets
238 "myups/snmp/temperature-Outlet 1"
240 =head1 ABSTRACTION LAYER
242 B<collectd> ships the Perl-Module L<Collectd::Unixsock> which
243 provides an abstraction layer over the actual socket connection. It can be
244 found in the directory F<bindings/perl/> in the source distribution or
245 (usually) somewhere near F</usr/share/perl5/> if you're using a package. If
246 you want to use Perl to communicate with the daemon, you're encouraged to use
247 and expand this module.
249 =head1 SEE ALSO
251 L<collectd(1)>,
252 L<collectd.conf(5)>,
253 L<collectd-nagios(1)>,
254 L<unix(7)>
256 =head1 AUTHOR
258 Florian Forster E<lt>octo@collectd.orgE<gt>
260 =cut