JSON object in PostGIS function comment not generating the TileJSON as expected

[jjcfrancisco]

Hello,

I have a database function that pulls data from different tables and I've set it in the config.yaml. One column in such function is uid which I want to set as the primary id... I think in the tables sources in the config.yaml is known as id_column. As far as I can see, the only way to set the primary id in a function in martin is by adding a comment to the database function. The issue I have is that the comment does not get picked up by martin. As a test, I tried setting the description of the function but this does not seem to work either.

This is what I tried:

DO $do$ BEGIN
    EXECUTE 'COMMENT ON FUNCTION gis_functions.get_project(integer, integer, integer, json) IS $tj$' || $$
    {
        "description": "my test description"
        "id": "uid"
    }
    $$::json || '$tj$';
END $do$;

This is the generated tilejson

{
  "tiles": {
    "project": {
      "content_type": "application/x-protobuf",
      "description": "gis_functions.get_project"
    }
  },
  "sprites": {},
  "fonts": {}
}

[nyurik]

@jjcfrancisco I am not sure I understand the issue (we might need to improve documentation? If so, any suggestions are welcome):

• the json you posted is NOT tilejson. Its the catalog of all available sources, sprites, and fonts. You got it from /catalog URL. To get tilejson you should use /project instead (that's the name of your source).
• the feature ID (part of the MVT tile) is generated by your own function when it calls ST_AsMVT -- use the last variant bytea ST_AsMVT(anyelement row, text name, integer extent, text geom_name, text feature_id_name) -- the last parameter is the name of the column to use as a feature id.
• ID is not part of the tilejson afaik, so you don't need to specify that the internal uid table column is being used as the id.
• Note that if you were to let Martin auto-configure table sources (rather than a function source), you would specify that uid column of a table should be used as a feature id.

[jjcfrancisco]

Apologies, this is the tilejson:

{"tilejson":"3.0.0","tiles":["http://0.0.0.0:3001/test/{z}/{x}/{y}"],"description":"public.function_zxy_query","name":"test"}

As for version, just latest v0.11.1

[nyurik]

thx @jjcfrancisco , i would have to dig deeper into it. We have a test for this in https://github.com/maplibre/martin/blob/2aa736f8af01ca494420d1a8f75e879bc6d5a44f/tests/fixtures/functions/function_zxy_query.sql -- which has been working so far, so try to see if there is anything different with your usecase?

[jjcfrancisco]

Thanks @nyurik. I tried the example as well but does not work. For reference it was a PG15 + PostGIS 3.3. Thanks again for looking into, nothing to worry about as this is a minor thing in my opinion.

[nyurik]

Fixed in v0.11.3

[jjcfrancisco]

Thanks @nyurik so fast 🚀