Supporting key-value pairs for amp-analytics to work with Google Analytics

[jlaurito]

(note: while this sounds similar to #1701 it is a different issue)

amp-experiments supports human-readable experiment and variable names. Unfortunately, most A/B testing frameworks, including Google Experiments/Google Analytics, don't allow for human readable experiment & variable names.

Specifically, Google Experiments requires a 0-indexed integer as an experiment id (xvar). So to get amp-experiments to pass events to Google Experiments, each variant needs to be named a 0-indexed integer instead of human-readable names. So instead of

"variants": { "yellow": 50, "green": 50 }

I need

"variants": { "0": 50, "1": 50 }

If amp-analytics supported some mapping, ie {"yellow":0,"green":0} in extraUrlParams, we could retain human-readability in experiments and pass machine-readable params to Google Experiments.

[lannka]

This is a tricky problem.

Say if a page wants to incorporate 2 analytics platforms that have contradictory naming constraints:
A needs a number but B needs alphabetic string. Obviously no matter how you name your variants, one of them will fail.

@rudygalfi do you have any idea? We have to introduce a mapping, but I don't know where.

[rudygalfi]

Since we haven't acted on this in awhile, I'm going to close.

Please re-open if anyone is interested to continue discuss adding this.