feat(inputs.net): Add speed metric

[DStrand1]

Summary

Adds a speed metric, reading /sys/class/net/*/speed as documented here in the kernel documentation. Currently only implemented for Linux. There is a PR to gopsutil, shirou/gopsutil#1473, which implements this metric as part of its interface and supports more platforms, but we decided to move forward with implementing this ourselves for the time being.

Checklist

• No AI generated code was used in this PR

Related issues

resolves #4658

[powersj]

Thanks for the quick PR! Question about the -1.

[Hipska]

I agree to have a test for the -1 value.

Also, wouldn't it be better to already be on-par with the upstream gopsutil and have a separate field for in and out? Like speed_in and speed_out? (Seems to be only supported by Windows to have different values)

[powersj]

Also, wouldn't it be better to already be on-par with the upstream gopsutil and have a separate field for in and out? Like speed_in and speed_out? (Seems to be only supported by Windows to have different values)

The net plugin only supports linux. If someone eventually gets gopsutil support enabled for other distros, then that could be re-evaluted down the road for Windows users.

[telegraf-tiger]

Download PR build artifacts for linux_amd64.tar.gz, darwin_arm64.tar.gz, and windows_amd64.zip.
Downloads for additional architectures and packages are available below.

☺️ This pull request doesn't significantly change the Telegraf binary size (less than 1%)

📦 Click here to get additional PR build artifacts

Artifact URLs

DEB	RPM	TAR GZ	ZIP
amd64.deb	aarch64.rpm	darwin_amd64.tar.gz	windows_amd64.zip
arm64.deb	armel.rpm	darwin_arm64.tar.gz	windows_arm64.zip
armel.deb	armv6hl.rpm	freebsd_amd64.tar.gz	windows_i386.zip
armhf.deb	i386.rpm	freebsd_armv7.tar.gz
i386.deb	ppc64le.rpm	freebsd_i386.tar.gz
mips.deb	riscv64.rpm	linux_amd64.tar.gz
mipsel.deb	s390x.rpm	linux_arm64.tar.gz
ppc64el.deb	x86_64.rpm	linux_armel.tar.gz
riscv64.deb		linux_armhf.tar.gz
s390x.deb		linux_i386.tar.gz
		linux_mips.tar.gz
		linux_mipsel.tar.gz
		linux_ppc64le.tar.gz
		linux_riscv64.tar.gz
		linux_s390x.tar.gz

[Hipska]

The net plugin only supports linux.

Oh sorry, didn’t check that. Never mind my remark then.

[srebhan]

@DStrand1 thanks for the clean PR! Just one question about the return value...