feat(export): add variant and price filters

[PhilippSpo]

@emmenko @hajoeichler @mmoelli
This is not the most beautiful solution, but it works for the moment.
We can now filter variants by attributes and we can filter the variants prices.
If a variant has no prices left, after the price filter was applied to it, it gets removed from the export. This gives use the possibility to export for certain countries only.
What do you think about this approach?

[hajoeichler]

How do those 2 filter and the queryString options interfere with each other. Can they all be chosen independent?

[PhilippSpo]

The 2 filters are not added to the query, but are applied to the result. So yes they can be chosen independently.

[hajoeichler]

Thanks for the explanation. Makes sense ;)

[emmenko]

@PhilippSpo btw: we should prevent using the search endpoint for exports.

[PhilippSpo]

@emmenko so how about getting rid of the queryType option and default to query?

[hajoeichler]

Sound reasonable for me to remove the search option.

[butenkor]

Why not using search endpoint for exports? Is it some common rule or just currently bad practice?

[PhilippSpo]

@butenkor I just asked @agourlay on this and he gave me a great response:

1. the search endpoint is eventually consistent
2. the search endpoint is meant for "search" not for dumping large amount of data efficiently.

We would need to expose the scan/scroll api from ES for that https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-scroll.html
I guess you can use ES for dumping large amount of data right now, I am just not sure you will like the performance you will get

Thanks for clarifying @agourlay 👍

[butenkor]

Thanks for info.

[PhilippSpo]

OK I fixed the tests locally. We are experiencing some coveralls issues here...