# Perl

The [`Fluent::Logger`](https://github.com/fluent/fluent-logger-perl) library is used to post records from Perl applications to Fluentd.

This article explains how to use it.

## Prerequisites

* Basic knowledge of Perl
* Basic knowledge of Fluentd
* Perl 5.10 or higher

## Installing Fluentd

Please refer to the following document to install Fluentd:

* [Installation](../installation/)

## Modifying the Config File

Configure Fluentd to use the [`forward`](../input/forward.md) input plugin as its data source:

```text
<source>
  @type forward
  port 24224
</source>
<match fluentd.test.**>
  @type stdout
</match>
```

Restart agent after configuring.

```text
# for rpm/deb only
$ sudo /etc/init.d/td-agent restart

# or systemd
$ sudo systemctl restart td-agent.service
```

## Using `Fluent::Logger`

Install [`Fluent::Logger`](https://search.cpan.org/dist/Fluent-Logger/) library via CPAN:

```text
$ cpan
cpan[1]> install Fluent::Logger
```

Create a script to post the records:

```text
# test.pl
use Fluent::Logger;
my $logger = Fluent::Logger->new(
    host => '127.0.0.1',
    port => 24224,
    tag_prefix => 'fluentd.test',
);
$logger->post("follow", { "entry1" => "value1", "entry2" => 2 });
```

Executing the script will send the logs to Fluentd:

```text
$ perl test.pl
```

The logs should be output to `/var/log/td-agent/td-agent.log` or the standard output of the Fluentd process via [`stdout`](../output/stdout.md) output plugin.

## Production Deployments

### Output Plugins

Various [output plugins](../output/) are available for writing records to other destinations:

* Examples
  * [Store Apache Logs into Amazon S3](../how-to-guides/apache-to-s3.md)
  * [Store Apache Logs into MongoDB](../how-to-guides/apache-to-mongodb.md)
  * [Data Collection into HDFS](../how-to-guides/http-to-hdfs.md)
* List of Plugin References
  * [Output to Another Fluentd](../output/forward.md)
  * [Output to MongoDB](../output/mongo.md) or [MongoDB ReplicaSet](../output/mongo_replset.md)
  * [Output to Hadoop](../output/webhdfs.md)
  * [Output to File](../output/file.md)
  * [etc...](https://www.fluentd.org/plugins/)

### High-Availability Configurations of Fluentd

For high-traffic websites \(more than 5 application nodes\), we recommend using the high-availability configuration for `td-agent`. This will improve the reliability of data transfer and query performance.

* [High-Availability Configurations of Fluentd](../deployment/high-availability.md)

### Monitoring

Monitoring Fluentd itself is also important. The article below describes the general monitoring methods for `td-agent`.

* [Monitoring Fluentd](../monitoring-fluentd/overview.md)