Make FlagBands aware of band aliases on the main product(s).

datacube_ows/config_utils.py

@@ -649,7 +649,8 @@ def __init__(self, cfg: CFG_DICT, product_cfg: "datacube_ows.ows_configuration.O
         pq_names = self.product.parse_pq_names(cfg)
         self.pq_names = pq_names["pq_names"]
         self.pq_low_res_names = pq_names["pq_low_res_names"]
-        self.pq_band = cfg["band"]
+        self.main_products = pq_names["main_products"]
+        self.pq_band = cfg["band"]  # N.B. May be an alias if on main_products
         if "fuse_func" in cfg:
             self.pq_fuse_func: Optional[FunctionWrapper] = FunctionWrapper(self.product, cast(Mapping[str, Any], cfg["fuse_func"]))
         else:
@@ -685,6 +686,12 @@ def make_ready(self, dc: "datacube.Datacube", *args, **kwargs) -> None:
                     raise ConfigException(f"Could not find flags low_res product {pqn} for layer {self.product.name} in datacube")
                 self.pq_low_res_products.append(pq_product)
 
+        # Resolve band alias if necessary.
+        if self.main_products:
+            canonical_band = self.product.band_idx.band(self.pq_band)
+            if canonical_band and canonical_band != self.pq_band:
+                self.pq_band = canonical_band
+
         # pyre-ignore[16]
         self.info_mask: int = ~0
         # A (hopefully) representative product

datacube_ows/ows_configuration.py

@@ -921,24 +921,30 @@ def parse_product_names(self, cfg):
             raise ConfigException(f"'low_res_product_names' entry in non-multi-product layer {self.name} - use 'low_res_product_name' only")
 
     def parse_pq_names(self, cfg):
+        main_product = False
         if "dataset" in cfg:
             raise ConfigException(f"The 'dataset' entry in the flags section is no longer supported.  Please refer to the documentation for the correct format (layer {self.name})")
         if "product" in cfg:
             pq_names = (cfg["product"],)
         else:
             pq_names = (self.product_name,)
+            main_product = (pq_names[0] == self.product_name)
 
         if "low_res_product" in cfg:
             pq_low_res_names = (cfg.get("low_res_product"),)
-        else:
+        elif main_product:
             pq_low_res_names = self.low_res_product_names
+        else:
+            pq_low_res_names = pq_names
+
         if "products" in cfg:
             raise ConfigException(f"'products' entry in flags section of non-multi-product layer {self.name} - use 'product' only")
         if "low_res_products" in cfg:
             raise ConfigException(f"'low_res_products' entry in flags section of non-multi-product layer {self.name}- use 'low_res_product' only")
         return {
             "pq_names": pq_names,
             "pq_low_res_names": pq_low_res_names,
+            "main_products": main_product
         }
 
 
@@ -959,11 +965,14 @@ def parse_product_names(self, cfg):
             raise ConfigException(f"'low_res_product_name' entry in multi-product layer {self.name} - use 'low_res_product_names' only")
 
     def parse_pq_names(self, cfg):
+        main_products = False
         if "datasets" in cfg:
             raise ConfigException(f"The 'datasets' entry in the flags section is no longer supported. Please refer to the documentation for the correct format (layer {self.name})")
         if "products" in cfg:
             pq_names = tuple(cfg["products"])
+            main_products = pq_names == self.product_names
         else:
+            main_products = True
             pq_names = self.product_names
 
         if "low_res_products" in cfg:
@@ -977,6 +986,7 @@ def parse_pq_names(self, cfg):
         return {
             "pq_names": pq_names,
             "pq_low_res_names": pq_low_res_names,
+            "main_products": main_products,
         }
 
     def dataset_groupby(self):