JSONL, or JSON Lines, serializes JSON so that each value occupies a separate line. In Fluent Bit, the stdout output plugin selects this behavior with format json_lines, making console output easier to inspect as a sequence of individual log events. section 5.4 section 2.1.3
Use JSONL output when record boundaries matter in a stream:
- Set format json_lines on an stdout output to emit each matching event on its own line. section 5.4
- Route events to that output with match; * acts as a wildcard for tags. section 5.4
- Add a received timestamp with json_date_key, then choose json_date_format such as iso8601, epoch, or epoch_ms. section 5.4
- Choose json_lines rather than json_stream when each record must be line-delimited; both produce syntactically correct JSON output. section 2.1.3
Console output with ISO 8601 timestamps
Configure an HTTP input and route all tags to stdout. Setting format json_lines keeps each received log event on one line; json_date_key received-date and json_date_format iso8601 add a received-date field in ISO 8601 form. section 5.4
Listing 5.4 Formatting output: std-output.conf
[SERVICE] flush 1 log_level error #1 [INPUT] name http listen 0.0.0.0 port 9881 tag http-in [OUTPUT] match * #2 name stdout #3 format json_lines #4 json_date_key received-date #5 json_date_format iso8601 #6
This configuration shows the operational core: stdout, wildcard matching, JSONL formatting, and an ISO 8601 received-date field. section 5.4
