Merge pull request #506 from MetOffice/fix-tutorial-um-database

Fix UM database tutorial example

forest/drivers/unified_model.py

@@ -90,6 +90,27 @@ def full_path(self, name):
             return os.path.join(self.directory, name)
 
 
+class Facade:
+    """Translation layer between dataset labels and file system patterns
+    """
+
+    def __init__(self, pattern, database):
+        self.pattern = pattern
+        self.database = database
+
+    def variables(self, _label):
+        return self.database.variables(self.pattern)
+
+    def initial_times(self, _label, variable):
+        return self.database.initial_times(self.pattern, variable)
+
+    def valid_times(self, _label, variable, initial_time):
+        return self.database.valid_times(self.pattern, variable, initial_time)
+
+    def pressures(self, _label, variable, initial_time):
+        return self.database.pressures(self.pattern, variable, initial_time)
+
+
 class Dataset:
     def __init__(
         self,
@@ -114,7 +135,7 @@ def __init__(
 
     def navigator(self):
         if self.use_database:
-            return self.database
+            return Facade(self.pattern, self.database)
         else:
             return Navigator(self.pattern)
 

forest/tutorial/core.py

@@ -111,9 +111,9 @@ def build_um_config(build_dir):
          pattern: "*{}"
          directory: {}
          locator: database
-         database_path: database.db
+         database_path: {}
 """.format(
-        UM_FILE, build_dir
+        UM_FILE, build_dir, db_path(build_dir)
     )
     print("writing: {}".format(path))
     with open(path, "w") as stream:
@@ -181,13 +181,15 @@ def build_um(build_dir):
         var[1] = Z_1.T
 
 
+def db_path(build_dir):
+    return os.path.join(build_dir, DB_FILE)
+
 def build_database(build_dir):
-    db_path = os.path.join(build_dir, DB_FILE)
     um_path = os.path.join(build_dir, UM_FILE)
     if not os.path.exists(um_path):
         build_um(build_dir)
-    print("building: {}".format(db_path))
-    database = forest.db.database.Database.connect(db_path)
+    print("building: {}".format(db_path(build_dir)))
+    database = forest.db.database.Database.connect(db_path(build_dir))
     database.insert_netcdf(um_path)
     database.close()
 

test/test_drivers_unified_model.py

@@ -49,7 +49,10 @@ def test_navigator_use_database(tmpdir):
     }
     dataset = forest.drivers.get_dataset("unified_model", settings)
     navigator = dataset.navigator()
-    assert isinstance(navigator, forest.db.database.Database)
+    assert hasattr(navigator, "variables")
+    assert hasattr(navigator, "initial_times")
+    assert hasattr(navigator, "valid_times")
+    assert hasattr(navigator, "pressures")
 
 
 def test_loader_use_database(tmpdir):

test/test_tutorial.py

@@ -101,7 +101,7 @@ def test_build_all_builds_um_config_file(build_dir):
                         "pattern": "*" + forest.tutorial.core.UM_FILE,
                         "directory": build_dir,
                         "locator": "database",
-                        "database_path": "database.db",
+                        "database_path": f"{build_dir}/database.db",
                     },
                 },
             }