Increasing the metric buffer

[M0rdecay]

Required for all PRs:

• Signed CLA.
• Associated README.md updated.
• Has appropriate unit tests.

Closes #8142
Also related with #8121

[ssoroka]

this is actually the buffer size used for storing a single metric, not multiple metrics.

[ssoroka]

I'm still not sure I like that it's configurable. we should just do the right thing. Too many knobs and dials to configure is just confusing.

This could literally be a two line change that works for 100% of people. No configuration options.

[M0rdecay]

I'm still not sure I like that it's configurable. we should just do the right thing. Too many knobs and dials to configure is just confusing.

This could literally be a two line change that works for 100% of people. No configuration options.

What about these values?
Hope this will be enough (unfortunately i don't really know how large metrics i have yet to see)...

	scanner := bufio.NewScanner(out)
	scanBuf := make([]byte, 4096) // default size
	scanner.Buffer(scanBuf, 262144) // max size

[ssoroka]

Looks good.

[ssoroka]

You may run into size issues in other places, but at least this won't be one of them.

[M0rdecay]

You may run into size issues in other places, but at least this won't be one of them.

Yes, I understand, but for now we prefer to use an external processor for working with XML - until a built-in parser appears in the telegraf.

I tested processing larger documents (10-12 thousand lines), everything is fine with the new buffer.
Also, there are no errors when processing such metrics when using an assembly with the parser inside the agent.

Many thanks for the help!

[meseeif]

its the same when execd used as inputs plugin？