Provided by:
collectd_4.3.0-1_i386 
NAME
collectd-unixsock - Documentation of collectd’s "unixsock plugin"
SYNOPSIS
# See collectd.conf(5)
LoadPlugin unixsock
# ...
<Plugin unixsock>
SocketFile "/path/to/socket"
SocketGroup "collectd"
SocketPerms "0770"
</Plugin>
DESCRIPTION
The "unixsock plugin" opens an UNIX-socket over which one can interact
with the daemon. This can be used to use the values collected by
collectd in other applications, such as monitoring, or submit
externally collected values to collectd.
This plugin is used by collectd-nagios(1) to check if some value is in
a certain range and exit with a Nagios-compatible exit code.
COMMANDS
Upon start the "unixsock plugin" opens a UNIX-socket and waits for
connections. Once a connection is established the client can send
commands to the daemon which it will answer, if it understand them.
The following commands are implemented:
GETVAL Identifier
If the value identified by Identifier (see below) is found the
complete value-list is returned. The response is a space separated
list of name-value-pairs:
num name=value[ name=value[ ...]]
If num is less then zero, an error occurred. Otherwise it contains
the number of values that follow. Each value is of the form
name=value. Counter-values are converted to a rate, e. g. bytes
per second. Undefined values are returned as NaN.
Example:
-> | GETVAL myhost/cpu-0/cpu-user
<- | 1 value=1.260000e+00
LISTVAL
Returns a list of the values available in the value cache together
with the time of the last update, so that querying applications can
issue a GETVAL command for the values that have changed.
The first line’s status number is the number of identifiers
returned or less than zero if an error occurred. Each of the
following lines contains the update time as an epoch value and the
identifier, separated by a space.
Example:
-> | LISTVAL
<- | 69 Values found
<- | 1182204284 leeloo/cpu-0/cpu-idle
<- | 1182204284 leeloo/cpu-0/cpu-nice
<- | 1182204284 leeloo/cpu-0/cpu-system
<- | 1182204284 leeloo/cpu-0/cpu-user
...
PUTVAL Identifier [OptionList] Valuelist
Submits one or more values (identified by Identifier, see below) to
the daemon which will dispatch it to all it’s write-plugins.
An Identifier is of the form "host/plugin-instance/type-instance"
with both instance-parts being optional. If they’re omitted the
hyphen must be omitted, too. plugin and each instance-part may be
chosen freely as long as the tuple (plugin, plugin instance, type
instance) uniquely identifies the plugin within collectd. type
identifies the type and number of values (i. e. data-set) passed to
collectd. A large list of predefined data-sets is available in the
types.db file.
The OptionList is an optional list of Options, where each option if
a key-value-pair. A list of currently understood options can be
found below, all other options will be ignored.
Valuelist is a colon-separated list of the time and the values,
each either an integer if the data-source is a counter, of a double
if the data-source if of type "gauge". You can submit an undefined
gauge-value by using U. When submitting U to a counter the behavior
is undefined. The time is given as epoch (i. e. standard UNIX
time).
You can mix options and values, but the order is important: Options
only effect following values, so specifying an option as last field
is allowed, but useless. Also, an option applies to all following
values, so you don’t need to re-set an option over and over again.
The currently defined Options are:
interval=seconds
Gives the interval in which the data identified by Identifier
is being collected.
Please note that this is the same format as used in the exec
plugin, see collectd-exec(5).
Example:
-> | PUTVAL testhost/interface/if_octets-test0 interval=10
1179574444:123:456
<- | 0 Success
PUTNOTIF [OptionList] message=Message
Submits a notification to the daemon which will then dispatch it to
all plugins which have registered for receiving notifications.
The PUTNOTIF if followed by a list of options which further
describe the notification. The message option is special in that it
will consume the rest of the line as its value. The message,
severity, and time options are mandatory.
Valid options are:
message=Message (REQUIRED)
Sets the message of the notification. This is the message that
will be made accessible to the user, so it should contain some
useful information. This option must be the last option because
the rest of the line will be its value, even if there are
spaces and equal-signs following it! This option is mandatory.
severity=failure|warning|okay (REQUIRED)
Sets the severity of the notification. This option is
mandatory.
time=Time (REQUIRED)
Sets the time of the notification. The time is given as
"epoch", i. e. as seconds since January 1st, 1970, 00:00:00.
This option is mandatory.
host=Hostname
plugin=Plugin
plugin_instance=Plugin-Instance
type=Type
type_instance=Type-Instance
These "associative" options establish a relation between this
notification and collected performance data. This connection is
purely informal, i. e. the daemon itself doesn’t do anything
with this information. However, websites or GUIs may use this
information to place notifications near the affected graph or
table. All the options are optional, but plugin_instance
without plugin or type_instance without type doesn’t make much
sense and should be avoided.
Please note that this is the same format as used in the exec
plugin, see collectd-exec(5).
Example:
-> | PUTNOTIF type=temperature severity=warning time=1201094702
message=The roof is on fire!
<- | 0 Success
Identifiers
Value or value-lists are identified in a uniform fashion:
Hostname/Plugin/Type
Where Plugin and Type are both either of type "Name" or
"Name-Instance". This sounds more complicated than it is, so here are
some examples:
myhost/cpu-0/cpu-user
myhost/load/load
myhost/memory/memory-used
myhost/disk-sda/disk_octets
Return values
Unless otherwise noted the plugin answers with a line of the following
form:
Num Message
If Num is zero the message indicates success, if Num is non-zero the
message indicates failure. Message is a human-readable string that
describes the return value further.
Commands that return values may use Num to return the number of values
that follow, such as the GETVAL command. These commands usually return
a negative value on failure and never return zero.
ABSTRACTION LAYER
Shipped with the sourcecode comes the Perl-Module Collectd::Unixsock
which provides an abstraction layer over the actual socket connection.
It can be found in the directory contrib/PerlLib. If you want to use
Perl to communicate with the daemon, you’re encouraged to use and
expand this module.
SEE ALSO
collectd(1), collectd.conf(5), collectd-nagios(1), unix(7)
AUTHOR
Florian Forster <octo@verplant.org>