in_node_exporter_metrics: fix referencing wrong interval between cpu and cpufreq

[nokute78]

This patch is to fix referencing wrong intervals.

Following configuration doesn't output metrics.
We expect that fluent-bit output cpu metrics.

[INPUT]
    Name node_exporter_metrics
    Metrics cpu
    collector.cpufreq.scrape_interval 1

[OUTPUT]
    Name stdout
    Match *

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

• 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.
• 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.

Configuration

[INPUT]
    Name node_exporter_metrics
    Metrics cpu
    collector.cpufreq.scrape_interval 1

[OUTPUT]
    Name stdout
    Match *

Debug/Valgrind output

$ valgrind --leak-check=full bin/fluent-bit -c a.conf 
==39545== Memcheck, a memory error detector
==39545== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==39545== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==39545== Command: bin/fluent-bit -c a.conf
==39545== 
Fluent Bit v2.2.0
* Copyright (C) 2015-2022 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

[2023/10/09 09:42:37] [ info] [fluent bit] version=2.2.0, commit=a397936438, pid=39545
[2023/10/09 09:42:37] [ info] [storage] ver=1.2.0, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2023/10/09 09:42:37] [ info] [cmetrics] version=0.6.3
[2023/10/09 09:42:37] [ info] [ctraces ] version=0.3.1
[2023/10/09 09:42:37] [ info] [input:node_exporter_metrics:node_exporter_metrics.0] initializing
[2023/10/09 09:42:37] [ info] [input:node_exporter_metrics:node_exporter_metrics.0] storage_strategy='memory' (memory only)
[2023/10/09 09:42:37] [ info] [input:node_exporter_metrics:node_exporter_metrics.0] path.procfs = /proc
[2023/10/09 09:42:37] [ info] [input:node_exporter_metrics:node_exporter_metrics.0] path.sysfs  = /sys
[2023/10/09 09:42:37] [ info] [input:node_exporter_metrics:node_exporter_metrics.0] thread instance initialized
[2023/10/09 09:42:37] [ info] [output:stdout:stdout.0] worker #0 started
[2023/10/09 09:42:37] [ info] [sp] stream processor started
2023-10-09T00:42:42.447867583Z node_cpu_seconds_total{cpu="0",mode="idle"} = 19827.23
2023-10-09T00:42:42.447867583Z node_cpu_seconds_total{cpu="0",mode="iowait"} = 48.670000000000002
2023-10-09T00:42:42.447867583Z node_cpu_seconds_total{cpu="0",mode="irq"} = 0
2023-10-09T00:42:42.447867583Z node_cpu_seconds_total{cpu="0",mode="nice"} = 14.25
2023-10-09T00:42:42.447867583Z node_cpu_seconds_total{cpu="0",mode="softirq"} = 0.53000000000000003
2023-10-09T00:42:42.447867583Z node_cpu_seconds_total{cpu="0",mode="steal"} = 0
2023-10-09T00:42:42.447867583Z node_cpu_seconds_total{cpu="0",mode="system"} = 745.08000000000004
2023-10-09T00:42:42.447867583Z node_cpu_seconds_total{cpu="0",mode="user"} = 3141.9899999999998
2023-10-09T00:42:42.447867583Z node_cpu_guest_seconds_total{cpu="0",mode="user"} = 0
2023-10-09T00:42:42.447867583Z node_cpu_guest_seconds_total{cpu="0",mode="nice"} = 0
^C[2023/10/09 09:42:44] [engine] caught signal (SIGINT)
[2023/10/09 09:42:44] [ warn] [engine] service will shutdown in max 5 seconds
[2023/10/09 09:42:44] [ info] [engine] service has stopped (0 pending tasks)
[2023/10/09 09:42:44] [ info] [output:stdout:stdout.0] thread worker #0 stopping...
[2023/10/09 09:42:44] [ info] [output:stdout:stdout.0] thread worker #0 stopped
==39545== 
==39545== HEAP SUMMARY:
==39545==     in use at exit: 0 bytes in 0 blocks
==39545==   total heap usage: 2,148 allocs, 2,148 frees, 810,625 bytes allocated
==39545== 
==39545== All heap blocks were freed -- no leaks are possible
==39545== 
==39545== For lists of detected and suppressed errors, rerun with: -s
==39545== 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.

[edsiper]

assigned to @cosmo0920

[cosmo0920]

Ah, we made a mistake. Good catch. 👍