MUL-132: Populate the (e)ORCA UID cache without reading the grids

Author: Razvan Aguridan

src/multio/action/encode/GridDownloader.cc

@@ -12,6 +12,7 @@
 
 #include "GribEncoder.h"
 
+#include "atlas/grid/SpecRegistry.h"
 #include "atlas/grid/Grid.h"
 #include "atlas/grid/Iterator.h"
 #include "atlas/library.h"
@@ -79,6 +80,10 @@ AtlasInstance& AtlasInstance::instance() {
 GridDownloader::GridDownloader(const config::ComponentConfiguration& compConf) :
     encoder_(createEncoder(compConf)), templateMetadata_(), gridCoordinatesCache_(), gridUIDCache_() {
 
+    ScopedAtlasInstance scopedAtlasInstance;
+
+    populateUIDCache(compConf);
+
     if (encoder_ != nullptr) {
         initTemplateMetadata();
 
@@ -109,6 +114,23 @@ std::optional<GridCoordinates> GridDownloader::getGridCoords(const GridDownloade
     return GridCoordinates{encodedLat, encodedLon};
 }
 
+void GridDownloader::populateUIDCache(const config::ComponentConfiguration& compConf) {
+    if (compConf.parsedConfig().has("unstructured-grid-type")) {
+        atlas::mpi::Scope mpi_scope("self");
+
+        const auto baseGridName = compConf.parsedConfig().getString("unstructured-grid-type");
+        for (auto const& unstructuredGridSubtype : {"T", "U", "V", "W", "F"}) {
+            const auto completeGridName = baseGridName + "_" + unstructuredGridSubtype;
+
+            const auto gridSpec = atlas::grid::SpecRegistry::get(completeGridName);
+            const auto gridUID = gridSpec.getString("uid");
+
+            gridUIDCache_.emplace(std::piecewise_construct, std::tuple(std::string(unstructuredGridSubtype) + " grid"),
+                std::tuple(gridUID));
+        }
+    }
+}
+
 void GridDownloader::initTemplateMetadata() {
     templateMetadata_.set("step", 0);
     templateMetadata_.set("typeOfLevel", "oceanSurface");
@@ -133,8 +155,6 @@ multio::message::Metadata GridDownloader::createMetadataFromCoordsData(size_t gr
 }
 
 void GridDownloader::downloadOrcaGridCoordinates(const config::ComponentConfiguration& compConf) {
-    ScopedAtlasInstance scopedAtlasInstance;
-
     const auto baseGridName = compConf.parsedConfig().getString("unstructured-grid-type");
     for (auto const& unstructuredGridSubtype : {"T", "U", "V", "W", "F"}) {
         const auto completeGridName = baseGridName + "_" + unstructuredGridSubtype;
@@ -147,9 +167,6 @@ void GridDownloader::downloadOrcaGridCoordinates(const config::ComponentConfigur
 
         const auto gridUID = grid.uid();
 
-        gridUIDCache_.emplace(std::piecewise_construct, std::tuple(std::string(unstructuredGridSubtype) + " grid"),
-                              std::tuple(gridUID));
-
         if (encoder_ != nullptr) {
             const auto gridSize = grid.size();
 

src/multio/action/encode/GridDownloader.h

@@ -76,6 +76,8 @@ class GridDownloader : eckit::NonCopyable {
     using GridCoordinateCache = std::unordered_map<DomainType, GridCoordinates>;
     using GridUIDCache = std::unordered_map<DomainType, GridUIDType>;
 
+    void populateUIDCache(const config::ComponentConfiguration& compConf);
+
     void initTemplateMetadata();
     multio::message::Metadata createMetadataFromCoordsData(size_t gridSize, const std::string& unstructuredGridSubtype,
                                                            const std::string& gridUID, int paramId);