# NAME

Plack::Middleware::Statsd - send statistics to statsd

# SYNOPSIS

```perl
use Plack::Builder;
use Net::Statsd::Tiny;

builder {

  enable "Statsd",
    client      => Net::Statsd::Tiny->new( ... ),
    sample_rate => 1.0;

  ...

  sub {
    my ($env) = @_;

    # Send statistics via other middleware

    if (my $stats = $env->{'psgix.monitor.statsd'}) {

      $stats->increment('myapp.wibble');

    }

    # Securely count the number of unique session ids

    if (my $secure_set_add = $env->{'psgix.monitor.statsd_secure_set_add'}) {

      my $options = $c->req->env->{'psgix.session.options'};
      $secure_set_add->( 'myapp.sessions', $options->{id} );

    }

  };

};
```

# DESCRIPTION

This middleware gathers metrics from the application send sends them
to a statsd server.

# RECENT CHANGES

Changes for version v0.9.0 (2026-05-09)

- Security
    - The psgi.request.remote\_addr metric is no longer logged unless the secure\_set\_key is specified in the constructor. This is to avoid leaking personally identifiable information if the connection to the statsd client is not secure, CVE-2026-45179.
- Enhancements
    - Added psgix.monitor.statsd\_secure\_set\_add to the environment with a method for securely logging set data.
- Documentation
    - Added a SECURITY CONSIDERATIONS section.
    - Updated copyright year.
    - Updated author email due to issues with cpan.org email forwarding.
    - Removed CONTRIBUTING.md due to re-evaluation about some AI-assisted issue reporting.
    - Fixed spelling errors.
- Tests
    - Added author tests for POD spelling.
- Toolchain
    - Stopped signing distributions, since Module::Signature is deprecated.
    - Added doap.xml to the distribution.

See the `Changes` file for more details.

# REQUIREMENTS

This module lists the following modules as runtime dependencies:

- [Crypt::Mac::HMAC](https://metacpan.org/pod/Crypt%3A%3AMac%3A%3AHMAC) version 0.088 or later
- [List::Util](https://metacpan.org/pod/List%3A%3AUtil)
- [Plack::Middleware](https://metacpan.org/pod/Plack%3A%3AMiddleware)
- [Ref::Util](https://metacpan.org/pod/Ref%3A%3AUtil)
- [Time::HiRes](https://metacpan.org/pod/Time%3A%3AHiRes)
- [Try::Tiny](https://metacpan.org/pod/Try%3A%3ATiny)
- [experimental](https://metacpan.org/pod/experimental)
- [parent](https://metacpan.org/pod/parent)
- [perl](https://metacpan.org/pod/perl) version v5.20.0 or later
- [warnings](https://metacpan.org/pod/warnings)

See the `cpanfile` file for the full list of prerequisites.

# INSTALLATION

The latest version of this module (along with any dependencies) can be installed from [CPAN](https://www.cpan.org) with the `cpan` tool that is included with Perl:

```
cpan Plack::Middleware::Statsd
```

You can also extract the distribution archive and install this module (along with any dependencies):

```
cpan .
```

You can also install this module manually using the following commands:

```
perl Makefile.PL
make
make test
make install
```

If you are working with the source repository, then it may not have a `Makefile.PL` file.  But you can use the [Dist::Zilla](https://dzil.org/) tool in anger to build and install this module:

```
dzil build
dzil test
dzil install --install-command="cpan ."
```

For more information, see [How to install CPAN modules](https://www.cpan.org/modules/INSTALL.html).

# SECURITY CONSIDERATIONS

If the ["client"](#client) does not have a secure communications channel to the
statsd server, then there is the risk that information such as IP
addresses or session ids will be leaked.

Other middleware or frameworks that make use of the `psgix.monitor.statsd` client
should use the `psgix.monitor.statsd_secure_set_add` method when adding set data
that contains personally identifiable information, authentication tokens or other
sensitive data.

# SUPPORT

Only the latest version of this module will be supported.

This module requires Perl v5.20 or later.
Future releases may only support Perl versions released in the last ten (10) years.

## Reporting Bugs and Submitting Feature Requests

Please report any bugs or feature requests on the bugtracker website
[https://github.com/robrwo/Plack-Middleware-Statsd/issues](https://github.com/robrwo/Plack-Middleware-Statsd/issues)

When submitting a bug or request, please include a test-file or a
patch to an existing test-file that illustrates the bug or desired
feature.

If the bug you are reporting has security implications which make it inappropriate to send to a public issue tracker,
then see `SECURITY.md` for instructions how to report security vulnerabilities.

# SOURCE

The development version is on github at [https://github.com/robrwo/Plack-Middleware-Statsd](https://github.com/robrwo/Plack-Middleware-Statsd)
and may be cloned from [https://github.com/robrwo/Plack-Middleware-Statsd.git](https://github.com/robrwo/Plack-Middleware-Statsd.git)

# AUTHOR

Robert Rothenberg <perl@rhizomnic.com>

The initial development of this module was sponsored by Science Photo
Library [https://www.sciencephoto.com](https://www.sciencephoto.com).

# COPYRIGHT AND LICENSE

This software is Copyright (c) 2018-2026 by Robert Rothenberg.

This is free software, licensed under:

```
The Artistic License 2.0 (GPL Compatible)
```

# SEE ALSO

[Net::Statsd::Client](https://metacpan.org/pod/Net%3A%3AStatsd%3A%3AClient)

[Net::Statsd::Tiny](https://metacpan.org/pod/Net%3A%3AStatsd%3A%3ATiny)

[PSGI](https://metacpan.org/pod/PSGI)