Cannot load from vectortile source in XML

[amandasaurus]

I have a mapnik XML file which references a vectortile source, but it doesn't load any vector tiles.

You can see a demo of this by checking out the mapnik-source branch of the osm-carto-vector-tiles repo, and run make tessera. This will start a tessera server on http://localhost:8080/tiles/, and the entire map will be the blue colour of the map background, with no data. Rather than an OSM carto map. (You need a osm2pgsql imported DB in gis). tessera's http server prints to the console, and there's no record of it trying to access the tilejson index.js, nor any pbf vector tiles.

The <Parameters> of the XML file look like this:

<Parameters>
  <Parameter name="bounds">-180,-85.05112877980659,180,85.05112877980659</Parameter>
  <Parameter name="center">0,0,4</Parameter>
  <Parameter name="description"><![CDATA[A general-purpose OpenStreetMap mapnik style, in CartoCSS]]></Parameter>
  <Parameter name="format">png</Parameter>
  <Parameter name="maxzoom">22</Parameter>
  <Parameter name="metatile">2</Parameter>
  <Parameter name="minzoom">0</Parameter>
  <Parameter name="name"><![CDATA[OpenStreetMap Carto]]></Parameter>
  <Parameter name="scale">1</Parameter>
  <Parameter name="source"><![CDATA[tilejson+http://localhost:8080/pbfs/live/index.json]]></Parameter>
</Parameters>

The same style works as a tmstyle (that's the master branch of that repo), however osm-carto is complex, and some changes to support vectortiles cause carto to take 4 minutes to parse this file (cf. carto issue #470), and when using tmstyle this parsing occurs every time when starting the server. If I could use Mapnik XML, then I don't have to reparse the cartocss file every time, meaning a massive performance gain for me.

I thought that tilelive might not be loading things correctly, but I get the same outcome when I use this command: MAPNIK_FONT_PATH=$(find /usr/share/fonts/ -type f | sed 's|/[^/]*$||' | uniq | paste -s -d: -) ./node_modules/.bin/tessera -r tilelive-tilejson -r tilelive-vector -r tilejson -c tessera-serve-vector-tiles.json. But that's just a guess.

The pbf/tmsource endpoint works fine. If you run this command in another window MAPNIK_FONT_PATH=$(find /usr/share/fonts/ -type f | sed 's|/[^/]*$||' | uniq | paste -s -d: -) ./node_modules/.bin/tessera -p 8081 tmstyle://./osm-carto.tm2/ the map will correctly appear on http://localhost:8081/, and that uses the 8080 pbf source which the XML should be using.

I have hacked tilelive-tmstyle to print out the XML that carto renders (just before here), and it looks the same as what I have, with the same source and <Parameters>, which is what led me to think this raw XML would work. Is loading from vectortiles supported in tilelive-mapnik? Is there something obvious I'm missing? Is the source in the <Parameters> correct?

[amandasaurus]

Turns out I am using it wrong. If you use tilelive-vector, i.e. vector:, instead of mapnik:, then it does exactly this (Mapnik XML with vector tiles).