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

datacube_ows/config_utils.py

@@ -625,6 +625,7 @@ class OWSFlagBandStandalone:
     """
     def __init__(self, band: str) -> None:
         self.pq_band = band
+        self.canonical_band_name = band
         self.pq_names: List["datacube.model.DatasetType"] = []
         self.pq_ignore_time = False
         self.pq_manual_merge = False
@@ -649,7 +650,9 @@ 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.main_products = pq_names["main_products"]
         self.pq_band = cfg["band"]
+        self.canonical_band_name = self.pq_band # Update for aliasing on make_ready
         if "fuse_func" in cfg:
             self.pq_fuse_func: Optional[FunctionWrapper] = FunctionWrapper(self.product, cast(Mapping[str, Any], cfg["fuse_func"]))
         else:
@@ -685,12 +688,19 @@ 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)
 
-        # pyre-ignore[16]
+        # Resolve band alias if necessary.
+        if self.main_products:
+            try:
+                self.canonical_band_name = self.product.band_idx.band(self.pq_band)
+            except ConfigException:
+                pass
+
+    # pyre-ignore[16]
         self.info_mask: int = ~0
         # A (hopefully) representative product
         product = self.pq_products[0]
         try:
-            meas = product.lookup_measurements([self.pq_band])[self.pq_band]
+            meas = product.lookup_measurements([self.canonical_band_name])[self.canonical_band_name]
         except KeyError:
             raise ConfigException(
                 f"Band {self.pq_band} does not exist in product {product.name} - cannot be used as a flag band for layer {self.product.name}.")
@@ -723,7 +733,7 @@ def __init__(self, flag_band: FlagBand,
         super().__init__({})
         self.layer = layer
         self.bands: Set[str] = set()
-        self.bands.add(flag_band.pq_band)
+        self.bands.add(flag_band.canonical_band_name)
         self.flag_bands = {flag_band.pq_band: flag_band}
         self.product_names = tuple(flag_band.pq_names)
         self.ignore_time = flag_band.pq_ignore_time

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):

docs/cfg_layers.rst

@@ -1003,8 +1003,12 @@ The name of the measurement band to be used for style-based masking.
 Pixel-quality bitmask bands or enumeration flag bands can be used, although
 bitmask bands are better supported and are recommended where possible.
 
+If the flag product(s) is/are the same as the main data product(s), then
+an alias from the `bands dictionary <#bands-dictionary-bands>`_ may be used.
+
 Note that it is not possible to combine flag bands from separate products
-if they have the same band name.
+if they have the same band name (unless one of the products is the main product
+and a band alias is used.)
 
 Required.
 

integration_tests/cfg/ows_test_cfg.py

@@ -62,15 +62,15 @@
     "nbart_nir_2": ["nbar_nir_2", "nir2", "nbart_nir_2"],
     "nbart_swir_2": ["nbar_swir_2", "swir_2", "nbart_swir_2"],
     "nbart_swir_3": ["nbar_swir_3", "swir_3", "nbart_swir_3"],
-    "fmask": ["fmask"],
+    "fmask": ["fmask", "fmask_alias"],
 }
 
 
 # REUSABLE CONFIG FRAGMENTS - Style definitions
 
 s2_nrt_fmask = [
     {
-        "band": "fmask",
+        "band": "fmask_alias",
         "values": [0, 2, 3],
         "invert": True,
     },
@@ -807,7 +807,7 @@
                     },
                     "flags": [
                         {
-                            "band": "fmask",
+                            "band": "fmask_alias",
                             "products": ["s2a_ard_granule", "s2b_ard_granule"],
                             "ignore_time": False,
                             "ignore_info_flags": []

integration_tests/cfg/translations/en/LC_MESSAGES/ows_cfg.po

@@ -6,7 +6,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: Over-ridden: aardvark 2022-03-24T23:29:57.407805\n"
 "Report-Msgid-Bugs-To: [email protected]\n"
-"POT-Creation-Date: 2022-08-26 13:23+1000\n"
+"POT-Creation-Date: 2022-10-18 13:28+1100\n"
 "PO-Revision-Date: 2022-03-24 23:33+0000\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language: en\n"

tests/test_styles.py

@@ -44,6 +44,7 @@ def __init__(self, pq_name, band):
             self.pq_products = [FakeODCProduct(pq_name)]
             self.pq_low_res_products = None
             self.pq_band = band
+            self.canonical_band_name = band
             self.pq_names = [pq_name]
             self.pq_ignore_time = False
             self.pq_manual_merge = False