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:
[+-]HH:MM (e.g. "+09:00")
[+-]HHMM (e.g. "+0900")
[+-]HH (e.g. "+09")
Region/Zone (e.g. "Asia/Tokyo")
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:
[+-]HH:MM (e.g. "+09:00")
[+-]HHMM (e.g. "+0900")
[+-]HH (e.g. "+09")
Region/Zone (e.g. "Asia/Tokyo")
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:
[+-]HH:MM (e.g. "+09:00")
[+-]HHMM (e.g. "+0900")
[+-]HH (e.g. "+09")
Region/Zone (e.g. "Asia/Tokyo")
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:
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:
[+-]HH:MM (e.g. "+09:00")
[+-]HHMM (e.g. "+0900")
[+-]HH (e.g. "+09")
Region/Zone (e.g. "Asia/Tokyo")
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'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:
[+-]HH:MM (e.g. "+09:00")
[+-]HHMM (e.g. "+0900")
[+-]HH (e.g. "+09")
Region/Zone (e.g. "Asia/Tokyo")
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:
[+-]HH:MM (e.g. "+09:00")
[+-]HHMM (e.g. "+0900")
[+-]HH (e.g. "+09")
Region/Zone (e.g. "Asia/Tokyo")
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 for further details.
Learn More
​Filter Plugin Overview​
If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is a open source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.
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