Ubuntu Manpage: collectd-unixsock - Documentation of collectd's "unixsock plugin"

Provided by: collectd-core_5.4.0-3ubuntu2.2_amd64

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 solutions, or submit externally collected values to collectd.

       For example, 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.

In general the plugin answers with a status line of the following form:

Status Message

If Status is greater than or equal to zero the message indicates success, if Status is
less than zero the message indicates failure. Message is a human-readable string that
further describes the return value.

On success, Status furthermore indicates the number of subsequent lines of output (not
including the status line). Each such lines usually contains a single return value. See
the description of each command for details.

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 list of name-value-pairs, each pair on its own line (the
number of lines is indicated by the status line - see above). Each name-value-pair 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 found
<- | 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. Each return value consists of the update time as an epoch
value and the identifier, separated by a space. The update time is the time of the
last value, as provided by the collecting instance and may be very different from the
time the server considers to be "now".

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 is a key-value-pair.
A list of currently understood options can be found below, all other options will be
ignored. Values that contain spaces must be quoted with double quotes.

Valuelist is a colon-separated list of the time and the values, each either an integer
if the data-source is a counter, or a double if the data-source is 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 command is 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. As with all
options: If the message includes spaces, it must be quoted with double quotes.
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

FLUSH [timeout=Timeout] [plugin=Plugin [...]] [identifier=Ident [...]]
Flushes all cached data older than Timeout seconds. If no timeout has been specified,
it defaults to -1 which causes all data to be flushed.

If the plugin option has been specified, only the Plugin plugin will be flushed. You
can have multiple plugin options to flush multiple plugins in one go. If the plugin
option is not given all plugins providing a flush callback will be flushed.

If the identifier option is given only the specified values will be flushed. This is
meant to be used by graphing or displaying frontends which want to have the latest
values for a specific graph. Again, you can specify the identifier option multiple
times to flush several values. If this option is not specified at all, all values will
be flushed.

Example:
-> | FLUSH plugin=rrdtool identifier=localhost/df/df-root
identifier=localhost/df/df-var
<- | 0 Done: 2 successful, 0 errors

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". If the identifier
includes spaces, it must be quoted using double quotes. 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
"myups/snmp/temperature-Outlet 1"

ABSTRACTION LAYER

       collectd ships the Perl-Module Collectd::Unixsock which provides an abstraction layer over
       the actual socket connection. It can be found in the directory bindings/perl/ in the
       source distribution or (usually) somewhere near /usr/share/perl5/ if you're using a
       package. If you want to use Perl to communicate with the daemon, you're encouraged to use
       and expand this module.

AUTHOR