in_forward: Support empty_shared_key parameter

[cosmo0920]

This is unsupported case of the specification of classic format and yaml format of fluent-bit configuration.
In out_forward plugin, we already had supported empty_shared_key parameter.
However, in_forward plugin does not support such parameter in the current master.

I implemented empty_shared_key parameter in in_forward plugin.

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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

pipeline:
  inputs:
    - name: forward
      alias: Forward
      listen: 0.0.0.0
      port: "24225"
      empty_shared_key: on
      tls: on
      tls.verify: on
      tls.debug: "1"
      tls.crt_file: /path/to/ca_cert.pem
      tls.key_file: /path/to/ca_key.pem
      tls.key_passwd: fluentd
      tag: forwarded.from.fluentd
      processors:
         logs:
            - name: lua
              call: append_tag
              code: |
                     function append_tag(tag, timestamp, record)
                     new_record = record
                     new_record["tag"] = tag
                     return 1, timestamp, new_record
                     end
  outputs:
    - name: stdout
      format: json
      Match: '*'

• Debug log output from testing the change

Fluent Bit v3.2.3
* Copyright (C) 2015-2024 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

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


[2024/12/06 15:35:36] [ info] Configuration:
[2024/12/06 15:35:36] [ info]  flush time     | 1.000000 seconds
[2024/12/06 15:35:36] [ info]  grace          | 5 seconds
[2024/12/06 15:35:36] [ info]  daemon         | 0
[2024/12/06 15:35:36] [ info] ___________
[2024/12/06 15:35:36] [ info]  inputs:
[2024/12/06 15:35:36] [ info]      forward
[2024/12/06 15:35:36] [ info] ___________
[2024/12/06 15:35:36] [ info]  filters:
[2024/12/06 15:35:36] [ info] ___________
[2024/12/06 15:35:36] [ info]  outputs:
[2024/12/06 15:35:36] [ info]      stdout.0
[2024/12/06 15:35:36] [ info] ___________
[2024/12/06 15:35:36] [ info]  collectors:
[2024/12/06 15:35:36] [ info] [fluent bit] version=3.2.3, commit=48d52cc47c, pid=209374
[2024/12/06 15:35:36] [debug] [engine] coroutine stack size: 24576 bytes (24.0K)
[2024/12/06 15:35:36] [ info] [storage] ver=1.1.6, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2024/12/06 15:35:36] [ info] [simd    ] disabled
[2024/12/06 15:35:36] [ info] [cmetrics] version=0.9.9
[2024/12/06 15:35:36] [ info] [ctraces ] version=0.5.7
[2024/12/06 15:35:36] [ info] [input:forward:Forward] initializing
[2024/12/06 15:35:36] [ info] [input:forward:Forward] storage_strategy='memory' (memory only)
[2024/12/06 15:35:36] [debug] [forward:Forward] created event channels: read=25 write=26
[2024/12/06 15:35:36] [debug] [in_fw] Listen='0.0.0.0' TCP_Port=24224
[2024/12/06 15:35:36] [debug] [downstream] listening on 0.0.0.0:24224
[2024/12/06 15:35:36] [ info] [input:forward:Forward] listening on 0.0.0.0:24224
[2024/12/06 15:35:36] [debug] [stdout:stdout.0] created event channels: read=28 write=29
[2024/12/06 15:35:36] [ info] [sp] stream processor started
[2024/12/06 15:35:36] [ info] [output:stdout:stdout.0] worker #0 started
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: before SSL initialization
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: before SSL initialization
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS read client hello
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS write server hello
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS write certificate
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS write key exchange
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS write certificate request
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS write server done
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS write server done
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS read client certificate
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS read client key exchange
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS read change cipher spec
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS read finished
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS write session ticket
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS write change cipher spec
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL_accept: SSLv3/TLS write finished
[2024/12/06 15:35:44] [debug] [input:forward:Forward] protocol: sending HELO
[2024/12/06 15:35:44] [debug] [input:forward:Forward] protocol: checking PING
[2024/12/06 15:35:44] [debug] [input:forward:Forward] protocol: received PING
[2024/12/06 15:35:44] [debug] [input:forward:Forward] protocol: sending PONG
[2024/12/06 15:35:44] [debug] [input:forward:Forward] concatenated gzip payload count is 0
[2024/12/06 15:35:44] [debug] [tls] connection #48 SSL3 alert read:warning:close notify
[2024/12/06 15:35:44] [debug] [socket] could not validate socket status for #48 (don't worry)
[2024/12/06 15:35:45] [debug] [task] created task=0x7b3c9d0 id=0 OK
[{"date":1733466939.226009,"tailed_path":"./test.log","tag":"forward.raw","message":"Hi from FLuentd"}][2024/12/06 15:35:45] [debug] [output:stdout:stdout.0] task_id=0 assigned to thread #0

[2024/12/06 15:35:45] [debug] [out flush] cb_destroy coro_id=0
[2024/12/06 15:35:45] [debug] [task] destroy task=0x7b3c9d0 (task_id=0)
^C[2024/12/06 15:35:46] [engine] caught signal (SIGINT)
[2024/12/06 15:35:46] [ warn] [engine] service will shutdown in max 5 seconds
[2024/12/06 15:35:46] [ info] [input] pausing Forward
[2024/12/06 15:35:47] [ info] [engine] service has stopped (0 pending tasks)
[2024/12/06 15:35:47] [ info] [input] pausing Forward
[2024/12/06 15:35:47] [ info] [output:stdout:stdout.0] thread worker #0 stopping...
[2024/12/06 15:35:47] [ info] [output:stdout:stdout.0] thread worker #0 stopped

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

==209374== 
==209374== HEAP SUMMARY:
==209374==     in use at exit: 0 bytes in 0 blocks
==209374==   total heap usage: 17,764 allocs, 17,764 frees, 3,963,567 bytes allocated
==209374== 
==209374== All heap blocks were freed -- no leaks are possible
==209374== 
==209374== For lists of detected and suppressed errors, rerun with: -s
==209374== 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.

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

Documentation

• Documentation required for this feature

fluent/fluent-bit-docs#1525

Backporting

• Backport to latest stable release.

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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.

[RicardoAAD]

Tested the PR and it is working as expected.
Thanks @cosmo0920 Do we know when this can be merged/released?

[cosmo0920]

Thanks @cosmo0920 Do we know when this can be merged/released?

Currently, we don't have any ETA for the next release of Fluent Bit 3.2.
Maybe the middle of December or so?