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Net::Statsd - Perl client for Etsy's statsd daemon

About Sampling

       A note about sample rate: A sample rate of < 1 instructs this library to send only the specified
       percentage of the samples to the server. As such, the application code should call this module for every
       occurence of each metric and allow this library to determine which specific measurements to deliver,
       based on the sample_rate value. (e.g. a sample rate of 0.5 would indicate that approximately only half of
       the metrics given to this module would actually be sent to statsd).

Author

       Cosimo Streppone <cosimo@cpan.org>

Description

       This module implement a UDP client for the statsd statistics collector daemon in use at Etsy.com.

       You want to use this module to track statistics in your Perl application, such as how many times a
       certain event occurs (user logins in a web application, or database queries issued), or you want to time
       and then graph how long certain events take, like database queries execution time or time to download a
       certain file, etc...

       If you're uncertain whether you'd want to use this module or statsd, then you can read some background
       information here:

           http://codeascraft.etsy.com/2011/02/15/measure-anything-measure-everything/

       The github repository for statsd is:

           http://github.com/etsy/statsd

       By default the client will try to send statistic metrics to "localhost:8125", but you can change the
       default hostname and port with:

           $Net::Statsd::HOST = 'your.statsd.hostname.net';
           $Net::Statsd::PORT = 9999;

       just after including the "Net::Statsd" module.

Functions

"timing($name,$time,$sample_rate=1)"
       Log timing information.  Timeisassumedtobeinmilliseconds(ms).

           Net::Statsd::timing('some.timer', 500);

   "increment($counter,$sample_rate=1)""increment(\@counter,$sample_rate=1)"
       Increments one or more stats counters

           # +1 on 'some.int'
           Net::Statsd::increment('some.int');

           # 0.5 = 50% sampling
           Net::Statsd::increment('some.int', 0.5);

       To increment more than one counter at a time, you can passanarrayreference:

           Net::Statsd::increment(['grue.dinners', 'room.lamps'], 1);

       Youcanalsouse"inc()"insteadof"increment()"totypeless.

   "decrement($counter,$sample_rate=1)"
       Same as increment, but decrements. Yay.

           Net::Statsd::decrement('some.int')

       Youcanalsouse"dec()"insteadof"decrement()"totypeless.

   "update_stats($stats,$delta=1,$sample_rate=1)"
       Updates one or more stats counters by arbitrary amounts

           Net::Statsd::update_stats('some.int', 10)

       equivalent to:

           Net::Statsd::update_stats('some.int', 10, 1)

       A sampling rate less than 1 means only update the stats every x number of times (0.1 = 10% of the times).

   "gauge($name,$value)"
       Log arbitrary values, as a temperature, or server load.

           Net::Statsd::gauge('core.temperature', 55);

       Statsd interprets gauge values with "+" or "-" sign as increment/decrement.  Therefore, to explicitly set
       a gauge to a negative number it has to be set to zero first.

       However, if either the zero or the actual negative value is lost in UDP transport to statsd server
       because of e.g. network congestion or packet loss, your gauge will become skewed.

       To ensure network problems will not skew your data, Net::Statsd::gauge() supports packing multiple values
       in single UDP packet sent to statsd:

           Net::Statsd::gauge(
               'core.temperature' => 55,
               'freezer.temperature' => -18
           );

       Make sure you don't supply too many values, or you might risk exceeding the MTU of the network interface
       and cause the resulting UDP packet to be dropped.

       In general, a safe limit should be 512 bytes. Related to the example above, "core.temperature" of 55 will
       be likely packed as a string:

           core.temperature:55|g

       which is 21 characters, plus a newline used as delimiter (22).  Using this example, you can pack at least
       20 distinct gauge values without problems. That will result in a UDP message of 440 bytes (22 times 20),
       which is well below the safe threshold of 512.

       In reality, if the communication happens on a local interface, or over a 10G link, you are allowed much
       more than that.

   "send(\%data,$sample_rate=1)"
       Squirt the metrics over UDP.

           Net::Statsd::send({ 'some.int' => 1 });

   "_sample_data(\%data,$sample_rate=1)"Thismethodisusedinternally,it'snotpartofthepublicinterface.

       Takes care of transforming a hash of metrics data into a sampled hash of metrics data, according to the
       given $sample_rate.

       If "$sample_rate == 1", then sampled data is exactly the incoming data.

       If "$sample_rate = 0.2", then every metric value will be marked with the given sample rate, so the Statsd
       server will automatically scale it. For example, with a sample rate of 0.2, the metric values will be
       multiplied by 5.

Name

       Net::Statsd - Perl client for Etsy's statsd daemon

Synopsis

           # Configure where to send events
           # That's where your statsd daemon is listening.
           $Net::Statsd::HOST = 'localhost';    # Default
           $Net::Statsd::PORT = 8125;           # Default

           #
           # Keep track of events as counters
           #
           Net::Statsd::increment('site.logins');
           Net::Statsd::increment('database.connects');

           #
           # Log timing of events, ex. db queries
           #
           use Time::HiRes;
           my $start_time = [ Time::HiRes::gettimeofday ];

           # do the complex database query
           # note: time value sent to timing should
           # be in milliseconds.
           Net::Statsd::timing(
               'database.complexquery',
               Time::HiRes::tv_interval($start_time) * 1000
           );

           #
           # Log metric values
           #
           Net::Statsd::gauge('core.temperature' => 55);

Version

       version 0.12

See Also