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Net::Statsd is a Perl client for Etsy's statsd metric collection daemon

branch: master
README.pod

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
    );

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.

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).

FUNCTIONS

timing($stat, $time, $sample_rate = 1)

Log timing information. Time is assumed to be in milliseconds (ms).

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

increment($stats, $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 pass an array reference:

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

You can also use "inc()" instead of "increment()" to type less.

decrement($stats, $sample_rate=1)

Same as increment, but decrements. Yay.

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

You can also use "dec()" instead of "decrement()" to type less.

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).

_sample_data(\%data, $sample_rate = 1)

This method is used internally, it's not part of the public interface.

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.

gauge($stat, $gauge)

Log arbitrary values.

    Net::Statsd::gauge('some.thing', 15);

send(\%data, $sample_rate = 1)

Squirt the metrics over UDP.

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