tests: runtime: processor_content_modifier: add test code

[nokute78]

This patch is to

• Add test code for "logs" using processor_content_modifier
• Fix not freed memory issue for processor_content_modifier

Note: Test code for metrics and traces are not implemented.

Memory issue is

==66962== HEAP SUMMARY:
==66962==     in use at exit: 105 bytes in 2 blocks
==66962==   total heap usage: 12,619 allocs, 12,617 frees, 4,267,696 bytes allocated
==66962== 
==66962== 105 (24 direct, 81 indirect) bytes in 1 blocks are definitely lost in loss record 2 of 2
==66962==    at 0x484DA83: calloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==66962==    by 0x96CE2F: cfl_variant_create (cfl_variant.c:242)
==66962==    by 0x96CB1A: cfl_variant_create_from_string_s (cfl_variant.c:94)
==66962==    by 0x53D9A7: cfl_variant_convert (cm_logs.c:182)
==66962==    by 0x53D6AB: hash_transformer (cm_logs.c:79)
==66962==    by 0x53E234: run_action_hash (cm_logs.c:449)
==66962==    by 0x53E6A9: cm_logs_process (cm_logs.c:584)
==66962==    by 0x534BE2: cb_process_logs (cm.c:78)
==66962==    by 0x214BC4: flb_processor_run (flb_processor.c:570)
==66962==    by 0x28F7EC: input_log_append (flb_input_log.c:51)
==66962==    by 0x28F909: flb_input_log_append (flb_input_log.c:90)
==66962==    by 0x51511D: in_lib_collect (in_lib.c:162)
==66962== 
==66962== LEAK SUMMARY:
==66962==    definitely lost: 24 bytes in 1 blocks
==66962==    indirectly lost: 81 bytes in 1 blocks
==66962==      possibly lost: 0 bytes in 0 blocks
==66962==    still reachable: 0 bytes in 0 blocks
==66962==         suppressed: 0 bytes in 0 blocks
==66962== 

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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:

• [N/A] Example configuration file for the change
• Debug log output from testing the change

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

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

• [N/A] Documentation required for this feature

Backporting

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

Debug/Valgrind output

$ valgrind --leak-check=full bin/flb-rt-processor_content_modifier 
==32959== Memcheck, a memory error detector
==32959== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==32959== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==32959== Command: bin/flb-rt-processor_content_modifier
==32959== 
Test logs.action.insert...                      [ OK ]
Test logs.action.delete...                      [ OK ]
Test logs.action.rename...                      [ OK ]
Test logs.action.upsert...                      [ OK ]
Test logs.action.hash...                        [ OK ]
Test logs.action.extract...                     [ OK ]
Test logs.action.convert_from_string_to_int...  [ OK ]
Test logs.action.convert_from_int_to_string...  [ OK ]
Test logs.action.convert_from_string_to_double... [ OK ]
Test logs.action.convert_from_double_to_string... [ OK ]
Test logs.action.convert_from_string_to_boolean... [ OK ]
SUCCESS: All unit tests have passed.
==32959== 
==32959== HEAP SUMMARY:
==32959==     in use at exit: 0 bytes in 0 blocks
==32959==   total heap usage: 21,979 allocs, 21,979 frees, 8,949,295 bytes allocated
==32959== 
==32959== All heap blocks were freed -- no leaks are possible
==32959== 
==32959== For lists of detected and suppressed errors, rerun with: -s
==32959== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

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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.

[nokute78]

Hmm processor_content_modifier doesn't support some conversion rules and can't test them now.
e.g. boolean -> string , positive integer -> string.

I think it is better to use/enhance flb_typecast.c to unify conversion rules.

I raised an issue #8592

[edsiper]

thank you