feat: Support to exclude default metrics and other options

[yorch]

• Adds httpMetricsPrefix option to optionally add a prefix to HTTP metrics.
• Adds excludeDefaultMetricLabels option to exclude all or certain metrics that are added by default.
• Adds useCountersForRequestSizeMetric option to expose two counters for Request Size (_sum and _count) instead of Histogram.
• Adds useCountersForResponseSizeMetric option to expose two counters for Response Size (_sum and _count) instead of Histogram.

[yorch]

@kobik This is another PR for changes I've made for my company's use case, I'm fixing tests and making sure the build passes, but if you could start taking a look and let me know your feedback please. Thanks

[kobik]

@yorch can you please rebase from master so we'll have the circleci running on your branch?

[yorch]

@kobik this is ready for review please

[kobik]

@kobik this is ready for review please

Will do

[kobik]

Hi @yorch , sorry for the delay it's been busy time + holidays here.

I started reviewing you PR and I have a question regarding httpMetricsPrefix, can you share your use-case?

[yorch]

@kobik The use case for the prefix is that depending on your infrastructure, you may want to avoid having multiple different NodeJS services exposing the same metrics. Like in our case, we have a big variety of NodeJS services, so we only want similar services to share metric names.

[kobik]

ok, so i have a little different idea in mind.

how about adding excludeDefaultMetricLabels as you did in order not break anything and on top of that add the option to selectively pick the metrics you'd like to expose?

and on the next breaking version we can change the default behavior to make it more consistent, making excludeDefaultMetricLabels false by default and httpRequestMetrics and httpResponseMetrics to be required.

this way the developer will be aware of the metrics he's adding.

i.e

{
   excludeDefaultMetricLabels: true,
   httpRequestMetrics: ["sum", "count", "histogram"],
   httpResponseMetrics: ["sum", "count", "histogram"]
}

let me know what you think.

[pragmaticivan]

Are there plans to merge this PR?

[kobik]

never got a response from @yorch regarding my latest comment.

i don't want to introduce a breaking change if we can avoid that.