metrics: Allocate metrics' titles dynamically

[cosmo0920]

However, still aded limitations over 1024 characters to prevent a waste of memory consumptions for title names.

Closes #8938

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

• Example configuration file for the change

$ fluent-bit -i fluentbit_metrics -o stdout -v

• Debug log output from testing the change

Fluent Bit v3.1.0
* Copyright (C) 2015-2024 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

___________.__                        __    __________.__  __          ________  
\_   _____/|  |  __ __   ____   _____/  |_  \______   \__|/  |_  ___  _\_____  \ 
 |    __)  |  | |  |  \_/ __ \ /    \   __\  |    |  _/  \   __\ \  \/ / _(__  < 
 |     \   |  |_|  |  /\  ___/|   |  \  |    |    |   \  ||  |    \   / /       \
 \___  /   |____/____/  \___  >___|  /__|    |______  /__||__|     \_/ /______  /
     \/                     \/     \/               \/                        \/ 

[2024/06/17 22:23:12] [ info] Configuration:
[2024/06/17 22:23:12] [ info]  flush time     | 1.000000 seconds
[2024/06/17 22:23:12] [ info]  grace          | 5 seconds
[2024/06/17 22:23:12] [ info]  daemon         | 0
[2024/06/17 22:23:12] [ info] ___________
[2024/06/17 22:23:12] [ info]  inputs:
[2024/06/17 22:23:12] [ info]      fluentbit_metrics
[2024/06/17 22:23:12] [ info] ___________
[2024/06/17 22:23:12] [ info]  filters:
[2024/06/17 22:23:12] [ info] ___________
[2024/06/17 22:23:12] [ info]  outputs:
[2024/06/17 22:23:12] [ info]      stdout.0
[2024/06/17 22:23:12] [ info] ___________
[2024/06/17 22:23:12] [ info]  collectors:
[2024/06/17 22:23:12] [ info] [fluent bit] version=3.1.0, commit=01ec4a8ede, pid=525311
[2024/06/17 22:23:12] [debug] [engine] coroutine stack size: 24576 bytes (24.0K)
[2024/06/17 22:23:12] [ info] [storage] ver=1.1.6, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2024/06/17 22:23:12] [ info] [cmetrics] version=0.9.1
[2024/06/17 22:23:12] [ info] [ctraces ] version=0.5.1
[2024/06/17 22:23:12] [ info] [input:fluentbit_metrics:fluentbit_metrics.0] initializing
[2024/06/17 22:23:12] [ info] [output:stdout:stdout.0] worker #0 started
[2024/06/17 22:23:12] [ info] [input:fluentbit_metrics:fluentbit_metrics.0] storage_strategy='memory' (memory only)
[2024/06/17 22:23:12] [debug] [fluentbit_metrics:fluentbit_metrics.0] created event channels: read=21 write=22
[2024/06/17 22:23:12] [debug] [stdout:stdout.0] created event channels: read=23 write=24
[2024/06/17 22:23:12] [ info] [sp] stream processor started
[2024/06/17 22:23:15] [debug] [task] created task=0x5f0c660 id=0 OK
[2024/06/17 22:23:15] [debug] [output:stdout:stdout.0] task_id=0 assigned to thread #0
2024-06-17T13:23:14.045002300Z fluentbit_uptime{hostname="cosmo-desktop2"} = 2
2024-06-17T13:23:12.721627690Z fluentbit_input_bytes_total{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_records_total{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:14.040403399Z fluentbit_input_metrics_scrapes_total{name="fluentbit_metrics.0"} = 1
2024-06-17T13:23:12.745225553Z fluentbit_output_proc_records_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_proc_bytes_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_errors_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_retries_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_retries_failed_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_dropped_records_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_retried_records_total{name="stdout.0"} = 0
2024-06-17T13:23:14.045002300Z fluentbit_process_start_time_seconds{hostname="cosmo-desktop2"} = 1718630592
2024-06-17T13:23:14.045002300Z fluentbit_build_info{hostname="cosmo-desktop2",version="3.1.0",os="linux"} = 1718630592
2024-06-17T13:23:14.045002300Z fluentbit_hot_reloaded_times{hostname="cosmo-desktop2"} = 0
2024-06-17T13:23:14.054781235Z fluentbit_storage_chunks = 0
2024-06-17T13:23:14.054781235Z fluentbit_storage_mem_chunks = 0
2024-06-17T13:23:14.054781235Z fluentbit_storage_fs_chunks = 0
2024-06-17T13:23:14.054781235Z fluentbit_storage_fs_chunks_up = 0
2024-06-17T13:23:14.054781235Z fluentbit_storage_fs_chunks_down = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_ingestion_paused{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_overlimit{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_memory_bytes{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks_up{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks_down{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks_busy{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks_busy_bytes{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_upstream_total_connections{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_upstream_busy_connections{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_chunk_available_capacity_percent{name="stdout.0"} = 100
[2024/06/17 22:23:15] [debug] [out flush] cb_destroy coro_id=0
[2024/06/17 22:23:15] [debug] [task] destroy task=0x5f0c660 (task_id=0)
^C[2024/06/17 22:23:16] [engine] caught signal (SIGINT)
[2024/06/17 22:23:16] [debug] [task] created task=0x5fd4930 id=0 OK
[2024/06/17 22:23:16] [debug] [output:stdout:stdout.0] task_id=0 assigned to thread #0
2024-06-17T13:23:16.038871114Z fluentbit_uptime{hostname="cosmo-desktop2"} = 4
2024-06-17T13:23:12.721627690Z fluentbit_input_bytes_total{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_records_total{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:16.038724569Z fluentbit_input_metrics_scrapes_total{name="fluentbit_metrics.0"} = 2
2024-06-17T13:23:15.079890779Z fluentbit_output_proc_records_total{name="stdout.0"} = 0
2024-06-17T13:23:15.079890779Z fluentbit_output_proc_bytes_total{name="stdout.0"} = 6005
2024-06-17T13:23:12.745225553Z fluentbit_output_errors_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_retries_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_retries_failed_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_dropped_records_total{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_retried_records_total{name="stdout.0"} = 0
2024-06-17T13:23:16.038871114Z fluentbit_process_start_time_seconds{hostname="cosmo-desktop2"} = 1718630592
2024-06-17T13:23:16.038871114Z fluentbit_build_info{hostname="cosmo-desktop2",version="3.1.0",os="linux"} = 1718630592
2024-06-17T13:23:16.038871114Z fluentbit_hot_reloaded_times{hostname="cosmo-desktop2"} = 0
2024-06-17T13:23:16.039507091Z fluentbit_storage_chunks = 0
2024-06-17T13:23:16.039507091Z fluentbit_storage_mem_chunks = 0
2024-06-17T13:23:16.039507091Z fluentbit_storage_fs_chunks = 0
2024-06-17T13:23:16.039507091Z fluentbit_storage_fs_chunks_up = 0
2024-06-17T13:23:16.039507091Z fluentbit_storage_fs_chunks_down = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_ingestion_paused{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_overlimit{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_memory_bytes{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks_up{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks_down{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks_busy{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.721627690Z fluentbit_input_storage_chunks_busy_bytes{name="fluentbit_metrics.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_upstream_total_connections{name="stdout.0"} = 0
2024-06-17T13:23:12.745225553Z fluentbit_output_upstream_busy_connections{name="stdout.0"} = 0
2024-06-17T13:23:15.079890779Z fluentbit_output_chunk_available_capacity_percent{name="stdout.0"} = 100
[2024/06/17 22:23:16] [ warn] [engine] service will shutdown in max 5 seconds
[2024/06/17 22:23:16] [ info] [input] pausing fluentbit_metrics.0
[2024/06/17 22:23:16] [debug] [out flush] cb_destroy coro_id=1
[2024/06/17 22:23:16] [debug] [task] destroy task=0x5fd4930 (task_id=0)
[2024/06/17 22:23:17] [ info] [engine] service has stopped (0 pending tasks)
[2024/06/17 22:23:17] [ info] [input] pausing fluentbit_metrics.0
[2024/06/17 22:23:17] [ info] [output:stdout:stdout.0] thread worker #0 stopping...
[2024/06/17 22:23:17] [ info] [output:stdout:stdout.0] thread worker #0 stopped

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

==525311== 
==525311== HEAP SUMMARY:
==525311==     in use at exit: 0 bytes in 0 blocks
==525311==   total heap usage: 5,894 allocs, 5,894 frees, 1,796,548 bytes allocated
==525311== 
==525311== All heap blocks were freed -- no leaks are possible
==525311== 
==525311== For lists of detected and suppressed errors, rerun with: -s
==525311== 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

Backporting

• Backport to latest stable release.

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