# fluent-plugin-concat

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Fluentd Filter plugin to concatenate multiline log separated in multiple events.

## Requirements

| fluent-plugin-concat | fluentd    | ruby   |
|----------------------|------------|--------|
| >= 2.0.0             | >= v0.14.0 | >= 2.1 |
| < 2.0.0              | >= v0.12.0 | >= 1.9 |

## Installation

Add this line to your application's Gemfile:

```ruby
gem 'fluent-plugin-concat'
```

And then execute:

    $ bundle

Or install it yourself as:

    $ gem install fluent-plugin-concat

## Configuration

**key** (required)

The key for part of multiline log.

**separator**

The separator of lines.
Default value is `"\n"`.

**n\_lines**

The number of lines.
This is exclusive with `multiline_start_regex`.

**multiline\_start\_regexp**

The regexp to match beginning of multiline.
This is exclusive with `n_lines.`

**multiline\_end\_regexp**

The regexp to match ending of multiline.

**continuous\_line_\_regexp**

The regexp to match continuous lines.

**stream\_identity\_key**

The key to determine which stream an event belongs to.

**flush\_interval**

The number of seconds after which the last received event log will be flushed.
If specified 0, wait for next line forever.

**use\_first\_timestamp**

Use timestamp of first record when buffer is flushed.

## Usage

Every 10 events will be concatenated into one event.

```aconf
<filter docker.log>
  @type concat
  key message
  n_lines 10
</filter>
```

Specify first line of multiline by regular expression.

```aconf
<filter docker.log>
  @type concat
  key message
  multiline_start_regexp /^Start/
</filter>
```

You can handle timeout events and remaining buffers on shutdown this plugin.

```aconf
<label @ERROR>
  <match docker.log>
    @type file
    path /path/to/error.log
  </match>
</label>
```

Handle timeout log lines the same as normal logs.

```aconf
<filter **>
  @type concat
  key message
  multiline_start_regexp /^Start/
  flush_interval 5
  timeout_label @NORMAL
</filter>

<match **>
  @type relabel
  @label @NORMAL
</match>

<label @NORMAL>
  <match **>
    @type stdout
  </match>
</label>
```

## Contributing

1. Fork it
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create new Pull Request

## License

The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).