in_tcp: add source address even when format is none

[jadeKim1993]

Modify to add source_address even when input format is none instead of JSON

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Enter [N/A] in the box, if an item is not applicable to your change.

Testing
Before we can approve your change; please submit the following in a comment:

• Example configuration file for the change

[INPUT]
    Name        tcp
    Listen      0.0.0.0
    Port        55555
    Format      none
    Source_Address_Key source_address

[OUTPUT]
    Name        stdout
    Match       *

• Debug log output from testing the change

[2026/01/08 14:42:27] [ info] Configuration:
[2026/01/08 14:42:27] [ info]  flush time     | 1.000000 seconds
[2026/01/08 14:42:27] [ info]  grace          | 5 seconds
[2026/01/08 14:42:27] [ info]  daemon         | 0
[2026/01/08 14:42:27] [ info] ___________
[2026/01/08 14:42:27] [ info]  inputs:
[2026/01/08 14:42:27] [ info]      tcp
[2026/01/08 14:42:27] [ info] ___________
[2026/01/08 14:42:27] [ info]  filters:
[2026/01/08 14:42:27] [ info] ___________
[2026/01/08 14:42:27] [ info]  outputs:
[2026/01/08 14:42:27] [ info]      stdout.0
[2026/01/08 14:42:27] [ info] ___________
[2026/01/08 14:42:27] [ info]  collectors:
[2026/01/08 14:42:27] [ info] [fluent bit] version=4.0.2, commit=3a17947d29, pid=63465
[2026/01/08 14:42:27] [debug] [engine] coroutine stack size: 24576 bytes (24.0K)
[2026/01/08 14:42:27] [ info] [storage] ver=1.5.3, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2026/01/08 14:42:27] [ info] [simd    ] disabled
[2026/01/08 14:42:27] [ info] [cmetrics] version=1.0.0
[2026/01/08 14:42:27] [ info] [ctraces ] version=0.6.4
[2026/01/08 14:42:27] [ info] [input:tcp:tcp.0] initializing
[2026/01/08 14:42:27] [ info] [input:tcp:tcp.0] storage_strategy='memory' (memory only)
[2026/01/08 14:42:27] [debug] [tcp:tcp.0] created event channels: read=25 write=26
[2026/01/08 14:42:27] [debug] [downstream] listening on 0.0.0.0:55555
[2026/01/08 14:42:27] [debug] [stdout:stdout.0] created event channels: read=28 write=29
[2026/01/08 14:42:27] [ info] [sp] stream processor started
[2026/01/08 14:42:27] [ info] [output:stdout:stdout.0] worker #0 started
[2026/01/08 14:42:31] [debug] [task] created task=0x7fde14029420 id=0 OK
[2026/01/08 14:42:31] [debug] [output:stdout:stdout.0] task_id=0 assigned to thread #0
[0] tcp.0: [[1767850950.628888995, {}], {"log"=>"Hello TCP", "source_address"=>"tcp://127.0.0.1:60994"}]
[2026/01/08 14:42:31] [debug] [out flush] cb_destroy coro_id=0
[2026/01/08 14:42:31] [debug] [task] destroy task=0x7fde14029420 (task_id=0)

• Attached Valgrind output that shows no leaks or memory corruption was found

==63490== Memcheck, a memory error detector
==63490== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==63490== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==63490== Command: ./fluent-bit -c test.conf
==63490==
Fluent Bit v4.0.2
* Copyright (C) 2015-2025 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

______ _                  _    ______ _ _             ___  _____
|  ___| |                | |   | ___ (_) |           /   ||  _  |
| |_  | |_   _  ___ _ __ | |_  | |_/ /_| |_  __   __/ /| || |/' |
|  _| | | | | |/ _ \ '_ \| __| | ___ \ | __| \ \ / / /_| ||  /| |
| |   | | |_| |  __/ | | | |_  | |_/ / | |_   \ V /\___  |\ |_/ /
\_|   |_|\__,_|\___|_| |_|\__| \____/|_|\__|   \_/     |_(_)___/


[2026/01/08 14:54:08] [ info] Configuration:
[2026/01/08 14:54:08] [ info]  flush time     | 1.000000 seconds
[2026/01/08 14:54:08] [ info]  grace          | 5 seconds
[2026/01/08 14:54:08] [ info]  daemon         | 0
[2026/01/08 14:54:08] [ info] ___________
[2026/01/08 14:54:08] [ info]  inputs:
[2026/01/08 14:54:08] [ info]      tcp
[2026/01/08 14:54:08] [ info] ___________
[2026/01/08 14:54:08] [ info]  filters:
[2026/01/08 14:54:08] [ info] ___________
[2026/01/08 14:54:08] [ info]  outputs:
[2026/01/08 14:54:08] [ info]      stdout.0
[2026/01/08 14:54:08] [ info] ___________
[2026/01/08 14:54:08] [ info]  collectors:
[2026/01/08 14:54:08] [ info] [fluent bit] version=4.0.2, commit=3a17947d29, pid=63490
[2026/01/08 14:54:08] [debug] [engine] coroutine stack size: 24576 bytes (24.0K)
[2026/01/08 14:54:08] [ info] [storage] ver=1.5.3, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2026/01/08 14:54:08] [ info] [simd    ] disabled
[2026/01/08 14:54:08] [ info] [cmetrics] version=1.0.0
[2026/01/08 14:54:08] [ info] [output:stdout:stdout.0] worker #0 started
[2026/01/08 14:54:08] [ info] [ctraces ] version=0.6.4
[2026/01/08 14:54:08] [ info] [input:tcp:tcp.0] initializing
[2026/01/08 14:54:08] [ info] [input:tcp:tcp.0] storage_strategy='memory' (memory only)
[2026/01/08 14:54:08] [debug] [tcp:tcp.0] created event channels: read=25 write=26
[2026/01/08 14:54:08] [debug] [downstream] listening on 0.0.0.0:55555
[2026/01/08 14:54:08] [debug] [stdout:stdout.0] created event channels: read=28 write=29
[2026/01/08 14:54:08] [ info] [sp] stream processor started
[0] tcp.0: [[1767851652.262490636, {}], {"log"=>"Hello TCP", "source_address"=>"tcp://127.0.0.1:59940"}]
[2026/01/08 14:54:12] [debug] [task] created task=0x54af260 id=0 OK
[2026/01/08 14:54:12] [debug] [output:stdout:stdout.0] task_id=0 assigned to thread #0
[2026/01/08 14:54:12] [debug] [out flush] cb_destroy coro_id=0
[2026/01/08 14:54:12] [debug] [task] destroy task=0x54af260 (task_id=0)
^C[2026/01/08 14:54:15] [engine] caught signal (SIGINT)
[2026/01/08 14:54:15] [ warn] [engine] service will shutdown in max 5 seconds
[2026/01/08 14:54:15] [ info] [engine] service has stopped (0 pending tasks)
[2026/01/08 14:54:15] [ info] [output:stdout:stdout.0] thread worker #0 stopping...
[2026/01/08 14:54:15] [ info] [output:stdout:stdout.0] thread worker #0 stopped
==63490==
==63490== HEAP SUMMARY:
==63490==     in use at exit: 0 bytes in 0 blocks
==63490==   total heap usage: 1,701 allocs, 1,701 frees, 900,312 bytes allocated
==63490==
==63490== All heap blocks were freed -- no leaks are possible
==63490==
==63490== For lists of detected and suppressed errors, rerun with: -s
==63490== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• [N/A] Run local packaging test showing all targets (including any new ones) build.
• [N/A] Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• Documentation required for this feature

Please refer to the official documentation at the following link
(https://github.com/fluent/fluent-bit-docs/blob/master/pipeline/inputs/tcp.md)

Backporting

• [N/A] Backport to latest stable release.

---

Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[github-actions]

This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 10 days.

[jadeKim1993]

I have updated the PR description. Please review it at your convenience.
thank you.

[leonardo-albertovich]

@edsiper this PR is pretty simple and it's covered by a test case, it's ready for the next merge window.