# Perl

The [`Fluent::Logger`](http://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](https://docs.fluentd.org/installation)

## Modifying the Config File

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

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

Restart agent after configuring.

```
# 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`](http://search.cpan.org/dist/Fluent-Logger/) library via CPAN:

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

Create a script to post the records:

```
# 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:

```
$ 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`](https://docs.fluentd.org/output/stdout) output plugin.

## Production Deployments

### Output Plugins

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

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

### 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](https://docs.fluentd.org/deployment/high-availability)

### Monitoring

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

* [Monitoring Fluentd](https://docs.fluentd.org/monitoring-fluentd/overview)

If this article is incorrect or outdated, or omits critical information, please [let us know](https://github.com/fluent/fluentd-docs-gitbook/issues?state=open). [Fluentd](http://www.fluentd.org/) is an open-source project under [Cloud Native Computing Foundation (CNCF)](https://cncf.io/). All components are available under the Apache 2 License.


---

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```
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