1COLLECTD-EXEC(5)                   collectd                   COLLECTD-EXEC(5)
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NAME

6       collectd-exec - Documentation of collectd's "exec plugin"
7

SYNOPSIS

9         # See collectd.conf(5)
10         LoadPlugin exec
11         # ...
12         <Plugin exec>
13           Exec "myuser:mygroup" "myprog"
14           Exec "otheruser" "/path/to/another/binary" "arg0" "arg1"
15           NotificationExec "user" "/usr/lib/collectd/exec/handle_notification"
16         </Plugin>
17

DESCRIPTION

19       The "exec plugin" forks off an executable either to receive values or
20       to dispatch notifications to the outside world. The syntax of the
21       configuration is explained in collectd.conf(5) but summarized in the
22       above synopsis.
23
24       If you want/need better performance or more functionality you should
25       take a long look at the "perl plugin", collectd-perl(5).
26

EXECUTABLE TYPES

28       There are currently two types of executables that can be executed by
29       the "exec plugin":
30
31       "Exec"
32           These programs are forked and values that it writes to "STDOUT" are
33           read back.  The executable is forked in a fashion similar to init:
34           It is forked once and not again until it exits. If it exited, it
35           will be forked again after at most Interval seconds. It is
36           perfectly legal for the executable to run for a long time and
37           continuously write values to "STDOUT".
38
39           See "EXEC DATA FORMAT" below for a description of the output format
40           expected from these programs.
41
42           Warning: If the executable only writes one value and then exits it
43           will be executed every Interval seconds. If Interval is short (the
44           default is 10 seconds) this may result in serious system load.
45
46       "NotificationExec"
47           The program is forked once for each notification that is handled by
48           the daemon.  The notification is passed to the program on "STDIN"
49           in a fashion similar to HTTP-headers. In contrast to programs
50           specified with "Exec" the execution of this program is not
51           serialized, so that several instances of this program may run at
52           once if multiple notifications are received.
53
54           See "NOTIFICATION DATA FORMAT" below for a description of the data
55           passed to these programs.
56

EXEC DATA FORMAT

58       The forked executable is expected to print values to "STDOUT". The
59       expected format is as follows:
60
61       Comments
62           Each line beginning with a "#" (hash mark) is ignored.
63
64       PUTVAL Identifier [OptionList] Valuelist
65           Submits one or more values (identified by Identifier, see below) to
66           the daemon which will dispatch it to all its write-plugins.
67
68           An Identifier is of the form "host/plugin-instance/type-instance"
69           with both instance-parts being optional. If they're omitted the
70           hyphen must be omitted, too. plugin and each instance-part may be
71           chosen freely as long as the tuple (plugin, plugin instance, type
72           instance) uniquely identifies the plugin within collectd. type
73           identifies the type and number of values (i. e. data-set) passed to
74           collectd. A large list of predefined data-sets is available in the
75           types.db file. See types.db(5) for a description of the format of
76           this file.
77
78           The OptionList is an optional list of Options, where each option is
79           a key-value-pair. A list of currently understood options can be
80           found below, all other options will be ignored. Values that contain
81           spaces must be quoted with double quotes.
82
83           Valuelist is a colon-separated list of the time and the values,
84           each either an integer if the data-source is a counter, or a double
85           if the data-source is of type "gauge". You can submit an undefined
86           gauge-value by using U. When submitting U to a counter the behavior
87           is undefined. The time is given as epoch (i. e. standard UNIX time)
88           or N to use the current time.
89
90           You can mix options and values, but the order is important: Options
91           only effect following values, so specifying an option as last field
92           is allowed, but useless. Also, an option applies to all following
93           values, so you don't need to re-set an option over and over again.
94
95           The currently defined Options are:
96
97           interval=seconds
98               Gives the interval in which the data identified by Identifier
99               is being collected.
100
101           meta:key=value
102               Add meta data with the key key and the value value.
103
104           Please note that this is the same format as used in the unixsock
105           plugin, see collectd-unixsock(5). There's also a bit more
106           information on identifiers in case you're confused.
107
108           Since examples usually let one understand a lot better, here are
109           some:
110
111             PUTVAL leeloo/cpu-0/cpu-idle N:2299366
112             PUTVAL alice/interface/if_octets-eth0 interval=10 1180647081:421465:479194
113
114       PUTNOTIF [OptionList] message=Message
115           Submits a notification to the daemon which will then dispatch it to
116           all plugins which have registered for receiving notifications.
117
118           The PUTNOTIF if followed by a list of options which further
119           describe the notification. The message option is special in that it
120           will consume the rest of the line as its value. The message,
121           severity, and time options are mandatory.
122
123           Valid options are:
124
125           message=Message (REQUIRED)
126               Sets the message of the notification. This is the message that
127               will be made accessible to the user, so it should contain some
128               useful information. As with all options: If the message
129               includes spaces, it must be quoted with double quotes. This
130               option is mandatory.
131
132           severity=failure|warning|okay (REQUIRED)
133               Sets the severity of the notification. This option is
134               mandatory.
135
136           time=Time (REQUIRED)
137               Sets the time of the notification. The time is given as
138               "epoch", i. e. as seconds since January 1st, 1970, 00:00:00.
139               This option is mandatory.
140
141           host=Hostname
142           plugin=Plugin
143           plugin_instance=Plugin-Instance
144           type=Type
145           type_instance=Type-Instance
146               These "associative" options establish a relation between this
147               notification and collected performance data. This connection is
148               purely informal, i. e. the daemon itself doesn't do anything
149               with this information. However, websites or GUIs may use this
150               information to place notifications near the affected graph or
151               table. All the options are optional, but plugin_instance
152               without plugin or type_instance without type doesn't make much
153               sense and should be avoided.
154
155           type:key=value
156               Sets user defined meta information. The type key is a single
157               character defining the type of the meta information.
158
159               The current supported types are:
160
161               s A string passed as-is.
162
163       Please note that this is the same format as used in the unixsock
164       plugin, see collectd-unixsock(5).
165
166       When collectd exits it sends a SIGTERM to all still running child-
167       processes upon which they have to quit.
168

NOTIFICATION DATA FORMAT

170       The notification executables receive values rather than providing them.
171       In fact, after the program is started "STDOUT" is connected to
172       "/dev/null".
173
174       The data is passed to the executables over "STDIN" in a format very
175       similar to HTTP: At first there is a "header" with one line per field.
176       Every line consists of a field name, ended by a colon, and the
177       associated value until end-of-line.  The "header" is ended by two
178       newlines immediately following another, i.e. an empty line. The rest,
179       basically the "body", is the message of the notification.
180
181       The following is an example notification passed to a program:
182
183         Severity: FAILURE
184         Time: 1200928930.515
185         Host: myhost.mydomain.org
186         \n
187         This is a test notification to demonstrate the format
188
189       The following header files are currently used. Please note, however,
190       that you should ignore unknown header files to be as forward-compatible
191       as possible.
192
193       Severity
194           Severity of the notification. May either be FAILURE, WARNING, or
195           OKAY.
196
197       Time
198           The time in epoch, i.e. as seconds since 1970-01-01 00:00:00 UTC.
199           The value currently has millisecond precision (i.e. three decimal
200           places), but scripts should accept arbitrary numbers of decimal
201           places, including no decimal places.
202
203       Host
204       Plugin
205       PluginInstance
206       Type
207       TypeInstance
208           Identification of the performance data this notification is
209           associated with.  All of these fields are optional because
210           notifications do not need to be associated with a certain value.
211

ENVIRONMENT

213       The following environment variables are set by the plugin before
214       calling exec:
215
216       COLLECTD_INTERVAL
217           Value of the global interval setting.
218
219       COLLECTD_HOSTNAME
220           Hostname used by collectd to dispatch local values.
221

USING NAGIOS PLUGINS

223       Though the interface is far from perfect, there are tons of plugins for
224       Nagios.  You can use these plugins with collectd by using a simple
225       transition layer, "exec-nagios.px", which is shipped with the collectd
226       distribution in the "contrib/" directory. It is a simple Perl script
227       that comes with embedded documentation. To see it, run the following
228       command:
229
230         perldoc exec-nagios.px
231
232       This script expects a configuration file, "exec-nagios.conf". You can
233       find an example in the "contrib/" directory, too.
234
235       Even a simple mechanism to submit "performance data" to collectd is
236       implemented. If you need a more sophisticated setup, please rewrite the
237       plugin to make use of collectd's more powerful interface.
238

CAVEATS

240       ·   The user, the binary is executed as, may not have root privileges,
241           i. e.  must have an UID that is non-zero. This is for your own
242           good.
243
244       ·   Early versions of the plugin did not use a command but treated all
245           lines as if they were arguments to the PUTVAL command. When the
246           PUTNOTIF command was implemented, this behavior was kept for lines
247           which start with an unknown command for backwards compatibility.
248           This compatibility code has been removed in collectd 5.
249

SEE ALSO

251       collectd(1), collectd.conf(5), collectd-perl(5), collectd-unixsock(5),
252       fork(2), exec(3)
253

AUTHOR

255       Florian Forster <octo@collectd.org>
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2595.9.1.599.gbb5cfbc                2020-03-08                  COLLECTD-EXEC(5)
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