# format

Specifies which output format impstats uses for emitted statistics records.

This parameter applies to impstats: Generate Periodic Statistics of Internal Counters.

Name:

  format

Scope:

  module

Type:

  word

Default:

  module=legacy

Required?:

  no

Introduced:

  8.16.0

## Description

Added in version 8.16.0.

Specifies the format of emitted stats messages. The default of `legacy` is compatible with pre v6-rsyslog. The other options provide support for structured formats (note that `cee` is actually “project lumberjack” logging).

The `json-elasticsearch` format supports the broken ElasticSearch JSON implementation. ES 2.0 no longer supports valid JSON and disallows dots inside names. The `json-elasticsearch` format option replaces those dots by the bang (“!”) character. So `discarded.full` becomes `discarded!full`.

Options:

- `json`

- `json-elasticsearch`

- `cee`

- `legacy`

- `prometheus`

Note

The `prometheus` option is available in builds that include the 2025-07-15 enhancement noted in the `ChangeLog`.

## Module usage

    module(load="impstats" format="json")

## See also

See also impstats: Generate Periodic Statistics of Internal Counters.

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