# stdout

The `filter_stdout` filter plugin prints events to stdout (or logs if launched with daemon mode). This filter plugin is useful for debugging purposes.

## Example Configurations

`filter_stdout` is included in Fluentd's core. No installation required.

```
<filter pattern>
  @type stdout
</filter>
```

A sample output is as follows:

```
2015-05-02 12:12:17 +0900 tag: {"field1":"value1","field2":"value2"}
```

where the first part shows the output time, the second part shows the tag, and the third part shows the record. The first part shows the \*\*output\*\* time, not the time attribute of message event structure as \`out\_stdout\` does.

## Parameters

### type (required)

The value must be `stdout`.

### format

The format of the output. The default is `stdout`.

### output\_type

This is the option of `stdout` format. Configure the format of record (third part). Any formatter plugins can be specified. The default is `json`.

### out\_file

Output time, tag and json record separated by a delimiter:

```
time[delimiter]tag[delimiter]record\n
```

Example:

```
2014-06-08T23:59:40[TAB]file.server.logs[TAB]{"field1":"value1","field2":"value2"}\n
```

`out_file` format has several options to customize the format.

```
delimiter SPACE   # Optional, SPACE or COMMA. "\t"(TAB) is used by default
output_tag false  # Optional, defaults to true. Output the tag field if true.
output_time true  # Optional, defaults to true. Output the time field if true.
```

For this format, the following common parameters are also supported.

* **include\_time\_key** (Boolean, Optional, defaults to false) If

  true, the time field (as specified by the `time_key` parameter) is

  kept in the record.
* **time\_key** (String, Optional, defaults to "time") The field name

  for the time key.
* **time\_format** (String. Optional) By default, the output format is

  iso8601 (e.g. "2008-02-01T21:41:49"). One can specify their own

  format with this parameter.
* **include\_tag\_key** (Boolean. Optional, defaults to false) If

  true, the tag field (as specified by the `tag_key` parameter) is

  kept in the record.
* **tag\_key** (String, Optional, defaults to "tag") The field name

  for the tag key.
* **localtime** (Boolean. Optional, defaults to true) If true, use

  local time. Otherwise, UTC is used. This parameter is overwritten by

  the `utc` parameter.
* **timezone** (String. Optional) By setting this parameter, one can parse the time value in the specified timezone. The following formats are accepted:

  1. \[+-]HH:MM (e.g. "+09:00")
  2. \[+-]HHMM (e.g. "+0900")
  3. \[+-]HH (e.g. "+09")
  4. Region/Zone (e.g. "Asia/Tokyo")
  5. Region/Zone/Zone (e.g. "America/Argentina/Buenos\_Aires")

  **The timezone set in this parameter takes precedence over `localtime`**, e.g., if `localtime` is set to `true` but `timezone` is set to `+0000`, UTC would be used.

### json

Output a json record without the time or tag field:

```
{"field1":"value1","field2":"value2"}\n
```

For this format, the following common parameters are also supported.

* **include\_time\_key** (Boolean, Optional, defaults to false) If

  true, the time field (as specified by the `time_key` parameter) is

  kept in the record.
* **time\_key** (String, Optional, defaults to "time") The field name

  for the time key.
* **time\_format** (String. Optional) By default, the output format is

  iso8601 (e.g. "2008-02-01T21:41:49"). One can specify their own

  format with this parameter.
* **include\_tag\_key** (Boolean. Optional, defaults to false) If

  true, the tag field (as specified by the `tag_key` parameter) is

  kept in the record.
* **tag\_key** (String, Optional, defaults to "tag") The field name

  for the tag key.
* **localtime** (Boolean. Optional, defaults to true) If true, use

  local time. Otherwise, UTC is used. This parameter is overwritten by

  the `utc` parameter.
* **timezone** (String. Optional) By setting this parameter, one can parse the time value in the specified timezone. The following formats are accepted:

  1. \[+-]HH:MM (e.g. "+09:00")
  2. \[+-]HHMM (e.g. "+0900")
  3. \[+-]HH (e.g. "+09")
  4. Region/Zone (e.g. "Asia/Tokyo")
  5. Region/Zone/Zone (e.g. "America/Argentina/Buenos\_Aires")

  **The timezone set in this parameter takes precedence over `localtime`**, e.g., if `localtime` is set to `true` but `timezone` is set to `+0000`, UTC would be used.

### hash

Output a record as ruby hash without the time or tag field:

```
{"field1"=>"value1","field2"=>"value2"}\n
```

For this format, the following common parameters are also supported.

* **include\_time\_key** (Boolean, Optional, defaults to false) If

  true, the time field (as specified by the `time_key` parameter) is

  kept in the record.
* **time\_key** (String, Optional, defaults to "time") The field name

  for the time key.
* **time\_format** (String. Optional) By default, the output format is

  iso8601 (e.g. "2008-02-01T21:41:49"). One can specify their own

  format with this parameter.
* **include\_tag\_key** (Boolean. Optional, defaults to false) If

  true, the tag field (as specified by the `tag_key` parameter) is

  kept in the record.
* **tag\_key** (String, Optional, defaults to "tag") The field name

  for the tag key.
* **localtime** (Boolean. Optional, defaults to true) If true, use

  local time. Otherwise, UTC is used. This parameter is overwritten by

  the `utc` parameter.
* **timezone** (String. Optional) By setting this parameter, one can parse the time value in the specified timezone. The following formats are accepted:

  1. \[+-]HH:MM (e.g. "+09:00")
  2. \[+-]HHMM (e.g. "+0900")
  3. \[+-]HH (e.g. "+09")
  4. Region/Zone (e.g. "Asia/Tokyo")
  5. Region/Zone/Zone (e.g. "America/Argentina/Buenos\_Aires")

  **The timezone set in this parameter takes precedence over `localtime`**, e.g., if `localtime` is set to `true` but `timezone` is set to `+0000`, UTC would be used.

### ltsv

Output the record as [LTSV](http://ltsv.org):

```
field1[label_delimiter]value1[delimiter]field2[label_delimiter]value2\n
```

`ltsv` format supports `delimiter` and `label_delimiter` options.

```
format ltsv
delimiter SPACE   # Optional. "\t"(TAB) is used by default
label_delimiter = # Optional. ":" is used by default
```

For this format, the following common parameters are also supported.

* **include\_time\_key** (Boolean, Optional, defaults to false) If

  true, the time field (as specified by the `time_key` parameter) is

  kept in the record.
* **time\_key** (String, Optional, defaults to "time") The field name

  for the time key.
* **time\_format** (String. Optional) By default, the output format is

  iso8601 (e.g. "2008-02-01T21:41:49"). One can specify their own

  format with this parameter.
* **include\_tag\_key** (Boolean. Optional, defaults to false) If

  true, the tag field (as specified by the `tag_key` parameter) is

  kept in the record.
* **tag\_key** (String, Optional, defaults to "tag") The field name

  for the tag key.
* **localtime** (Boolean. Optional, defaults to true) If true, use

  local time. Otherwise, UTC is used. This parameter is overwritten by

  the `utc` parameter.
* **timezone** (String. Optional) By setting this parameter, one can parse the time value in the specified timezone. The following formats are accepted:

  1. \[+-]HH:MM (e.g. "+09:00")
  2. \[+-]HHMM (e.g. "+0900")
  3. \[+-]HH (e.g. "+09")
  4. Region/Zone (e.g. "Asia/Tokyo")
  5. Region/Zone/Zone (e.g. "America/Argentina/Buenos\_Aires")

  **The timezone set in this parameter takes precedence over `localtime`**, e.g., if `localtime` is set to `true` but `timezone` is set to `+0000`, UTC would be used.

### single\_value

Output the value of a single field instead of the whole record. Often used in conjunction with [in\_tail](https://docs.fluentd.org/0.12/input/tail)'s `format none`.

```
value1\n
```

`single_value` format supports the `add_newline` and `message_key` options.

```
add_newline false # Optional, defaults to true. If there is a trailing "\n" already, set it "false"
message_key my_field # Optional, defaults to "message". The value of this field is outputted.
```

### csv

Output the record as CSV/TSV:

```
"value1"[delimiter]"value2"[delimiter]"value3"\n
```

`csv` format supports the `delimiter` and `force_quotes` options.

```
format csv
fields field1,field2,field3
delimiter \t   # Optional. "," is used by default.
force_quotes false # Optional. true is used by default. If false, value won't be framed by quotes.
```

For this format, the following common parameters are also supported.

* **include\_time\_key** (Boolean, Optional, defaults to false) If

  true, the time field (as specified by the `time_key` parameter) is

  kept in the record.
* **time\_key** (String, Optional, defaults to "time") The field name

  for the time key.
* **time\_format** (String. Optional) By default, the output format is

  iso8601 (e.g. "2008-02-01T21:41:49"). One can specify their own

  format with this parameter.
* **include\_tag\_key** (Boolean. Optional, defaults to false) If

  true, the tag field (as specified by the `tag_key` parameter) is

  kept in the record.
* **tag\_key** (String, Optional, defaults to "tag") The field name

  for the tag key.
* **localtime** (Boolean. Optional, defaults to true) If true, use

  local time. Otherwise, UTC is used. This parameter is overwritten by

  the `utc` parameter.
* **timezone** (String. Optional) By setting this parameter, one can parse the time value in the specified timezone. The following formats are accepted:

  1. \[+-]HH:MM (e.g. "+09:00")
  2. \[+-]HHMM (e.g. "+0900")
  3. \[+-]HH (e.g. "+09")
  4. Region/Zone (e.g. "Asia/Tokyo")
  5. Region/Zone/Zone (e.g. "America/Argentina/Buenos\_Aires")

  **The timezone set in this parameter takes precedence over `localtime`**, e.g., if `localtime` is set to `true` but `timezone` is set to `+0000`, UTC would be used.

### stdout

This format is aimed to be used by stdout plugins.

Output time, tag and formatted record as follows:

```
time tag: formatted_record\n
```

Example:

```
2015-05-02 12:12:17 +0900 tag: {"field1":"value1","field2":"value2"}\n
```

`stdout` format has a following option to customize the format of the record part.

```
output_type format # Optional, defaults to "json". The format of
`formatted_record`. Any formatter plugins can be specified.
```

For this format, the following common parameters are also supported.

* **include\_time\_key** (Boolean, Optional, defaults to false) If

  true, the time field (as specified by the `time_key` parameter) is

  kept in the record.
* **time\_key** (String, Optional, defaults to "time") The field name

  for the time key.
* **time\_format** (String. Optional) By default, the output format is

  iso8601 (e.g. "2008-02-01T21:41:49"). One can specify their own

  format with this parameter.
* **include\_tag\_key** (Boolean. Optional, defaults to false) If

  true, the tag field (as specified by the `tag_key` parameter) is

  kept in the record.
* **tag\_key** (String, Optional, defaults to "tag") The field name

  for the tag key.
* **localtime** (Boolean. Optional, defaults to true) If true, use

  local time. Otherwise, UTC is used. This parameter is overwritten by

  the `utc` parameter.
* **timezone** (String. Optional) By setting this parameter, one can parse the time value in the specified timezone. The following formats are accepted:

  1. \[+-]HH:MM (e.g. "+09:00")
  2. \[+-]HHMM (e.g. "+0900")
  3. \[+-]HH (e.g. "+09")
  4. Region/Zone (e.g. "Asia/Tokyo")
  5. Region/Zone/Zone (e.g. "America/Argentina/Buenos\_Aires")

  **The timezone set in this parameter takes precedence over `localtime`**, e.g., if `localtime` is set to `true` but `timezone` is set to `+0000`, UTC would be used.

### log\_level option

The `log_level` option allows the user to set different levels of logging for each plugin. The supported log levels are: `fatal`, `error`, `warn`, `info`, `debug`, and `trace`.

Please see the [logging article](https://docs.fluentd.org/0.12/deployment/logging) for further details.

## Learn More

* [Filter Plugin Overview](https://docs.fluentd.org/0.12/filter)

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 a open source project under [Cloud Native Computing Foundation (CNCF)](https://cncf.io/). All components are available under the Apache 2 License.