[metrics] standardize/simplify export pipeline setup

[matej-g]

This PR implements a method for simplified export pipeline setup for stdout exporter.

Resolves #343

Co-authored-by: Liz Fong-Jones [email protected]

[jmacd]

How about two methods, one InstallNewPipeline and one NewPipeline. The Install form calls NewPipeline and then sets the global provider.

pipeline, err := stdout.InstallNewPipeline(stdout.Options{...})
if err != nil {
 ...
}
defer pipeline.Stop()
// ... Done

[lizthegrey]

I've done as you asked on behalf of the original pull submitter, PTAL.

[jmacd]

I think this is an unrelated remark.

I thought we had moved toward the practice of using "Config" as the structure name, and Option as a functional argument (func(*Config)), and Options as a []Option. See api/trace StartConfig and StartOption, for example.

That's why I prefer this struct be called Config.

[jmacd]

See #369

[lizthegrey]

The goal of this was to standardize the patterns for all Exporter options/config. Prometheus and stdout were using options, statsd was using config...

[jmacd]

I like the new simplified exporter setup. I would prefer to keep a Config struct.

[lizthegrey]

I like the new simplified exporter setup. I would prefer to keep a Config struct.

Alright. Let's merge this as is (to make the one case that's Config go to Options for consistency), and then I'll do a quick followup to rename all the Options systematically to Config.

[lizthegrey]

@paivagustavo want to take a look before we merge?