tiles: skip layers without data when combining vector tiles

xtraplatform-tiles/src/main/java/de/ii/xtraplatform/tiles/app/TileEncoderMvt.java

@@ -7,6 +7,10 @@
  */
 package de.ii.xtraplatform.tiles.app;
 
+import de.ii.xtraplatform.crs.domain.BoundingBox;
+import de.ii.xtraplatform.crs.domain.CrsTransformationException;
+import de.ii.xtraplatform.crs.domain.CrsTransformerFactory;
+import de.ii.xtraplatform.crs.domain.OgcCrs;
 import de.ii.xtraplatform.tiles.domain.ChainedTileProvider;
 import de.ii.xtraplatform.tiles.domain.ImmutableTileQuery;
 import de.ii.xtraplatform.tiles.domain.TileEncoder;
@@ -21,6 +25,7 @@
 import java.util.Map.Entry;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import no.ecc.vectortile.VectorTileDecoder;
@@ -32,7 +37,15 @@ public class TileEncoderMvt implements TileEncoder {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(TileEncoderMvt.class);
 
-  public TileEncoderMvt() {}
+  private final Function<String, Optional<BoundingBox>> tilesetBounds;
+  private final CrsTransformerFactory crsTransformerFactory;
+
+  public TileEncoderMvt(
+      Function<String, Optional<BoundingBox>> tilesetBounds,
+      CrsTransformerFactory crsTransformerFactory) {
+    this.tilesetBounds = tilesetBounds;
+    this.crsTransformerFactory = crsTransformerFactory;
+  }
 
   @Override
   public byte[] empty(TileMatrixSetBase tms) {
@@ -48,8 +61,15 @@ public byte[] combine(
         getLayerTilesets(data, combinedTileset, tile.getGenerationParametersTransient());
     VectorTileEncoder encoder = new VectorTileEncoder(tile.getTileMatrixSet().getTileExtent());
     VectorTileDecoder decoder = new VectorTileDecoder();
+    Optional<BoundingBox> tileBounds = getTileBounds(tile);
 
     for (String tileset : tilesets) {
+      // a tileset without data in the area of the tile cannot contribute a layer; without this
+      // check, a tile that is not in the cache, because it was not seeded, would be generated
+      if (isOutsideBounds(tileset, tileBounds)) {
+        continue;
+      }
+
       TileQuery tileQuery = ImmutableTileQuery.builder().from(tile).tileset(tileset).build();
       TileResult layer = tileProvider.get(tileQuery);
 
@@ -90,6 +110,26 @@ public byte[] combine(
     return encoder.encode();
   }
 
+  private Optional<BoundingBox> getTileBounds(TileQuery tile) {
+    try {
+      return Optional.of(tile.getBoundingBox(OgcCrs.CRS84, crsTransformerFactory));
+    } catch (CrsTransformationException e) {
+      // ignore, assume that all tilesets may have data
+      return Optional.empty();
+    }
+  }
+
+  private boolean isOutsideBounds(String tileset, Optional<BoundingBox> tileBounds) {
+    if (tileBounds.isEmpty()) {
+      return false;
+    }
+
+    return tilesetBounds
+        .apply(tileset)
+        .filter(bounds -> !BoundingBox.intersects(bounds, tileBounds.get()))
+        .isPresent();
+  }
+
   private List<String> getLayerTilesets(
       TileProviderFeaturesData data,
       TilesetFeatures combinedTileset,

xtraplatform-tiles/src/main/java/de/ii/xtraplatform/tiles/app/TileEncoders.java

@@ -9,6 +9,8 @@
 
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Range;
+import de.ii.xtraplatform.crs.domain.BoundingBox;
+import de.ii.xtraplatform.crs.domain.CrsTransformerFactory;
 import de.ii.xtraplatform.tiles.domain.ChainedTileProvider;
 import de.ii.xtraplatform.tiles.domain.TileEncoder;
 import de.ii.xtraplatform.tiles.domain.TileMatrixSetBase;
@@ -18,16 +20,24 @@
 import jakarta.ws.rs.core.MediaType;
 import java.io.IOException;
 import java.util.Map;
+import java.util.Optional;
+import java.util.function.Function;
 
 public class TileEncoders implements ChainedTileProvider {
-  private static final Map<MediaType, TileEncoder> ENCODERS =
-      ImmutableMap.of(FeatureEncoderMVT.FORMAT, new TileEncoderMvt());
+  private final Map<MediaType, TileEncoder> encoders;
   private final TileProviderFeaturesData data;
   private final ChainedTileProvider generatorProviderChain;
 
-  public TileEncoders(TileProviderFeaturesData data, ChainedTileProvider generatorProviderChain) {
+  public TileEncoders(
+      TileProviderFeaturesData data,
+      ChainedTileProvider generatorProviderChain,
+      Function<String, Optional<BoundingBox>> tilesetBounds,
+      CrsTransformerFactory crsTransformerFactory) {
     this.data = data;
     this.generatorProviderChain = generatorProviderChain;
+    this.encoders =
+        ImmutableMap.of(
+            FeatureEncoderMVT.FORMAT, new TileEncoderMvt(tilesetBounds, crsTransformerFactory));
   }
 
   @Override
@@ -48,14 +58,14 @@ public TileResult getTile(TileQuery tile) throws IOException {
   }
 
   public boolean canEncode(MediaType mediaType) {
-    return ENCODERS.containsKey(mediaType);
+    return encoders.containsKey(mediaType);
   }
 
   public byte[] empty(MediaType mediaType, TileMatrixSetBase tms) {
-    return ENCODERS.get(mediaType).empty(tms);
+    return encoders.get(mediaType).empty(tms);
   }
 
   public byte[] combine(TileQuery tile) throws IOException {
-    return ENCODERS.get(tile.getMediaType()).combine(tile, data, generatorProviderChain);
+    return encoders.get(tile.getMediaType()).combine(tile, data, generatorProviderChain);
   }
 }

xtraplatform-tiles/src/main/java/de/ii/xtraplatform/tiles/app/TileProviderFeatures.java

@@ -115,6 +115,7 @@ public class TileProviderFeatures extends AbstractTileProvider<TileProviderFeatu
   static final String TILES_DIR_NAME = "tiles";
 
   private final TileGenerator tileGenerator;
+  private final CrsTransformerFactory crsTransformerFactory;
   private final Map<Type, Map<Storage, TileStore>> tileStores;
   private final List<TileCache> generatorCaches;
   private final List<TileCache> combinerCaches;
@@ -149,6 +150,7 @@ public TileProviderFeatures(
     this.asyncStartup = appContext.getConfiguration().getModules().isStartupAsync();
     this.tileMatrixSetRepository = Optional.of(tileMatrixSetRepository);
     this.dataDir = appContext.getDataDir().toString();
+    this.crsTransformerFactory = crsTransformerFactory;
     this.tileGenerator =
         new TileGeneratorFeatures(
             data,
@@ -226,7 +228,9 @@ private void init() {
 
     this.generatorProviderChain = current;
 
-    this.tileEncoders = new TileEncoders(getData(), generatorProviderChain);
+    this.tileEncoders =
+        new TileEncoders(
+            getData(), generatorProviderChain, this::getTilesetBounds, crsTransformerFactory);
     current = tileEncoders;
 
     for (int i = 0; i < getData().getCaches().size(); i++) {
@@ -547,6 +551,14 @@ public Optional<TilesetMetadata> getMetadata(String tilesetId) {
     return Optional.ofNullable(metadata.get(tilesetId));
   }
 
+  /**
+   * The area in which the tileset may have data, that is the spatial extent of the feature types of
+   * its layers. Empty, if the extent is unknown.
+   */
+  private Optional<BoundingBox> getTilesetBounds(String tileset) {
+    return getMetadata(tileset).flatMap(TilesetMetadata::getBounds);
+  }
+
   @Override
   public Optional<TilesetMetadata> getMetadata(String vectorTilesetId, String mapStyleId) {
     return Optional.ofNullable(metadata.get(getMapStyleTileset(vectorTilesetId, mapStyleId)));

xtraplatform-tiles/src/main/java/de/ii/xtraplatform/tiles/app/TileSeedingJobCreator.java

@@ -244,6 +244,11 @@ public JobResult process(Job job, JobSet jobSet, JobQueueMin jobQueue) {
               });
         }
 
+        // when no tileset of the job set has tiles to seed, no job was added and the total is still
+        // unknown; a total of zero makes the job set complete instead of leaving it in the queue,
+        // where it would never reach 100% and suppress every following seeding run
+        jobSet.getTotal().compareAndSet(-1, 0);
+
         if (jobSet.isDone()) {
           jobSet.getCleanup().ifPresent(jobQueue::push);
           return JobResult.success(); // early return