DRAFT: Change /locations logic

[lukas-phaf]

This PR is just to discuss an idea.

Change /locations to first get all unique parameters, and then the actual stations, making the connection only by parameter_name.

Advantage is that it there is less data to transfer. For the KNMI test data set:
Before: One request of 220 KB
After: One request of 4 KB followed by request of 132 KB.

Disadvantage is that we can no longer check for inconsistent parameter definitions (i.e. different parameters that have the same parameter_name).

I think a better way of doing this would be to do this approach in the store directly, which means the filtering is done in the store, and significantly less data would be send to the API.

[github-actions]

API Unit Test Coverage Report

File	Stmts	Miss	Cover	Missing
\_\_init\_\_.py	0	0	100%
datastore_pb2.py	58	46	21%	24–69
datastore_pb2_grpc.py	43	23	47%	37–52, 85–87, 92–94, 99–101, 106–108, 112–136, 174, 191, 208, 225
grpc_getter.py	20	11	45%	15–16, 20–23, 27–29, 33–35
locustfile.py	15	15	0%	1–31
main.py	34	5	85%	41, 51–52, 62–63
metadata_endpoints.py	55	25	55%	42–51, 55, 72–151, 155
utilities.py	68	32	53%	15, 33, 40, 62–65, 73–80, 85–92, 104–123
custom_geo_json
edr_feature_collection.py	6	0	100%
formatters
\_\_init\_\_.py	11	0	100%
covjson.py	53	1	98%	75
geojson.py	15	1	93%	42
routers
\_\_init\_\_.py	0	0	100%
edr.py	111	28	75%	68–140, 225–226, 270–271
feature.py	45	19	58%	70–103, 113–118, 124–146
TOTAL	534	206	61%

API Unit Test Coverage Summary

Tests	Skipped	Failures	Errors	Time
17	0 💤	0 ❌	0 🔥	2.015s ⏱️

[Jeffrey-Vervoort-KNMI]

Is it possible that there is a duplicate parameter name? If so should then an exception be raised that it already exists?

[lukas-phaf]

Yes, that is probably the right way/place to do it.

[Teddy-1000]

I don't think it is possible. make_parameter creates the definition from variables used for parameter_name.

[Jeffrey-Vervoort-KNMI]

Is this possible to do on lines 76-79? Because if a parameter_name exists that is not unique, it is likely impossible to distinguish between them for stations.

[Jeffrey-Vervoort-KNMI]

I think it is an improvement that we can request more data. I am curious how it impacts the API performance. Especially now that is less likely that we hit the gRPC limit.

[jo-asplin-met-no]

FYI: Based on discussions I added this issue. Feel free to comment!