Improve error messages when data is missing (#917)

* First attempt at a better error messages when data is missing

* Fix tests

* Fix codacy issues

* Refactor exception handling and fix tests

* Remove some codacy warnings

Author: Javier Vegas-Regidor

esmvalcore/_recipe.py

@@ -432,21 +432,18 @@ def _update_fx_files(step_name, settings, variable, config_user, fx_vars):
     if not fx_vars:
         return
 
-    fx_vars = [
-        _get_fx_file(variable, fxvar, config_user)
-        for fxvar in fx_vars
-    ]
+    fx_vars = [_get_fx_file(variable, fxvar, config_user) for fxvar in fx_vars]
 
     fx_dict = {fx_var[1]['short_name']: fx_var[0] for fx_var in fx_vars}
     settings['fx_variables'] = fx_dict
     logger.info('Using fx_files: %s for variable %s during step %s',
-                pformat(settings['fx_variables']),
-                variable['short_name'],
+                pformat(settings['fx_variables']), variable['short_name'],
                 step_name)
 
 
 def _update_fx_settings(settings, variable, config_user):
     """Update fx settings depending on the needed method."""
+
     # get fx variables either from user defined attribute or fixed
     def _get_fx_vars_from_attribute(step_settings, step_name):
         user_fx_vars = step_settings.get('fx_variables')
@@ -457,8 +454,8 @@ def _get_fx_vars_from_attribute(step_settings, step_name):
                     user_fx_vars.append('sftof')
             elif step_name == 'mask_landseaice':
                 user_fx_vars = ['sftgif']
-            elif step_name in ('area_statistics',
-                               'volume_statistics', 'zonal_statistics'):
+            elif step_name in ('area_statistics', 'volume_statistics',
+                               'zonal_statistics'):
                 user_fx_vars = []
         return user_fx_vars
 
@@ -470,8 +467,8 @@ def _get_fx_vars_from_attribute(step_settings, step_name):
     for step_name, step_settings in settings.items():
         if step_name in fx_steps:
             fx_vars = _get_fx_vars_from_attribute(step_settings, step_name)
-            _update_fx_files(step_name, step_settings,
-                             variable, config_user, fx_vars)
+            _update_fx_files(step_name, step_settings, variable, config_user,
+                             fx_vars)
 
 
 def _read_attributes(filename):
@@ -653,16 +650,12 @@ def get_matching(attributes):
     return grouped_products
 
 
-def _get_preprocessor_products(variables,
-                               profile,
-                               order,
-                               ancestor_products,
-                               config_user):
-    """
-    Get preprocessor product definitions for a set of datasets.
+def _get_preprocessor_products(variables, profile, order, ancestor_products,
+                               config_user, name):
+    """Get preprocessor product definitions for a set of datasets.
 
-    It updates recipe settings as needed by various preprocessors
-    and sets the correct ancestry.
+    It updates recipe settings as needed by various preprocessors and
+    sets the correct ancestry.
     """
     products = set()
     for variable in variables:
@@ -673,7 +666,7 @@ def _get_preprocessor_products(variables,
         grouped_ancestors = _match_products(ancestor_products, variables)
     else:
         grouped_ancestors = {}
-
+    missing_vars = set()
     for variable in variables:
         settings = _get_default_settings(
             variable,
@@ -682,29 +675,26 @@ def _get_preprocessor_products(variables,
         )
         _apply_preprocessor_profile(settings, profile)
         _update_multi_dataset_settings(variable, settings)
-        _update_target_levels(
-            variable=variable,
-            variables=variables,
-            settings=settings,
-            config_user=config_user,
-        )
-        _update_extract_shape(settings, config_user)
-        _update_weighting_settings(settings, variable)
-        _update_fx_settings(settings=settings,
-                            variable=variable,
-                            config_user=config_user)
-        _update_target_grid(
-            variable=variable,
-            variables=variables,
-            settings=settings,
-            config_user=config_user,
-        )
-        _update_regrid_time(variable, settings)
+        try:
+            _update_target_levels(
+                variable=variable,
+                variables=variables,
+                settings=settings,
+                config_user=config_user,
+            )
+        except RecipeError as ex:
+            missing_vars.add(ex.message)
+        _update_preproc_functions(settings, config_user, variable, variables,
+                                  missing_vars)
         ancestors = grouped_ancestors.get(variable['filename'])
         if not ancestors:
-            ancestors = _get_ancestors(variable, config_user)
-            if config_user.get('skip-nonexistent') and not ancestors:
-                logger.info("Skipping: no data found for %s", variable)
+            try:
+                ancestors = _get_ancestors(variable, config_user)
+            except RecipeError as ex:
+                if config_user.get('skip-nonexistent') and not ancestors:
+                    logger.info("Skipping: %s", ex.message)
+                else:
+                    missing_vars.add(ex.message)
                 continue
         product = PreprocessorFile(
             attributes=variable,
@@ -713,6 +703,11 @@ def _get_preprocessor_products(variables,
         )
         products.add(product)
 
+    if missing_vars:
+        separator = "\n- "
+        raise RecipeError(f'Missing data for preprocessor {name}:{separator}'
+                          f'{separator.join(sorted(missing_vars))}')
+
     _update_statistic_settings(products, order, config_user['preproc_dir'])
 
     for product in products:
@@ -721,6 +716,25 @@ def _get_preprocessor_products(variables,
     return products
 
 
+def _update_preproc_functions(settings, config_user, variable, variables,
+                              missing_vars):
+    _update_extract_shape(settings, config_user)
+    _update_weighting_settings(settings, variable)
+    _update_fx_settings(settings=settings,
+                        variable=variable,
+                        config_user=config_user)
+    try:
+        _update_target_grid(
+            variable=variable,
+            variables=variables,
+            settings=settings,
+            config_user=config_user,
+        )
+    except RecipeError as ex:
+        missing_vars.add(ex.message)
+    _update_regrid_time(variable, settings)
+
+
 def _get_single_preprocessor_task(variables,
                                   profile,
                                   config_user,
@@ -741,7 +755,9 @@ def _get_single_preprocessor_task(variables,
         profile=profile,
         order=order,
         ancestor_products=ancestor_products,
-        config_user=config_user)
+        config_user=config_user,
+        name=name,
+    )
 
     if not products:
         raise RecipeError(
@@ -911,7 +927,13 @@ def __init__(self,
             raw_recipe['diagnostics'], raw_recipe.get('datasets', []))
         self.entity = self._initialize_provenance(
             raw_recipe.get('documentation', {}))
-        self.tasks = self.initialize_tasks() if initialize_tasks else None
+        try:
+            self.tasks = self.initialize_tasks() if initialize_tasks else None
+        except RecipeError as ex:
+            logger.error(ex.message)
+            for task in ex.failed_tasks:
+                logger.error(task.message)
+            raise
 
     @staticmethod
     def _need_ncl(raw_diagnostics):
@@ -975,8 +997,7 @@ def _initialize_datasets(raw_datasets):
 
     @staticmethod
     def _expand_ensemble(variables):
-        """
-        Expand ensemble members to multiple datasets.
+        """Expand ensemble members to multiple datasets.
 
         Expansion only supports ensembles defined as strings, not lists.
         """
@@ -1267,24 +1288,29 @@ def initialize_tasks(self):
         tasknames_to_run = self._cfg.get('diagnostics')
 
         priority = 0
+        failed_tasks = []
         for diagnostic_name, diagnostic in self.diagnostics.items():
             logger.info("Creating tasks for diagnostic %s", diagnostic_name)
 
             # Create preprocessor tasks
             for variable_group in diagnostic['preprocessor_output']:
                 task_name = diagnostic_name + TASKSEP + variable_group
                 logger.info("Creating preprocessor task %s", task_name)
-                task = _get_preprocessor_task(
-                    variables=diagnostic['preprocessor_output']
-                    [variable_group],
-                    profiles=self._preprocessors,
-                    config_user=self._cfg,
-                    task_name=task_name,
-                )
-                for task0 in task.flatten():
-                    task0.priority = priority
-                tasks.add(task)
-                priority += 1
+                try:
+                    task = _get_preprocessor_task(
+                        variables=diagnostic['preprocessor_output']
+                        [variable_group],
+                        profiles=self._preprocessors,
+                        config_user=self._cfg,
+                        task_name=task_name,
+                    )
+                except RecipeError as ex:
+                    failed_tasks.append(ex)
+                else:
+                    for task0 in task.flatten():
+                        task0.priority = priority
+                    tasks.add(task)
+                    priority += 1
 
             # Create diagnostic tasks
             for script_name, script_cfg in diagnostic['scripts'].items():
@@ -1299,7 +1325,10 @@ def initialize_tasks(self):
                 task.priority = priority
                 tasks.add(task)
                 priority += 1
-
+        if failed_tasks:
+            ex = RecipeError('Could not create all tasks')
+            ex.failed_tasks.extend(failed_tasks)
+            raise ex
         check.tasks_valid(tasks)
 
         # Resolve diagnostic ancestors

esmvalcore/_recipe_checks.py

@@ -2,9 +2,9 @@
 import itertools
 import logging
 import os
+import re
 import subprocess
 from shutil import which
-import re
 
 import yamale
 
@@ -16,6 +16,14 @@
 
 class RecipeError(Exception):
     """Recipe contains an error."""
+    def __init__(self, msg):
+        super().__init__(self)
+        self.message = msg
+        self.failed_tasks = []
+
+    def __str__(self):
+        """Return message string."""
+        return self.message
 
 
 def ncl_version():
@@ -115,7 +123,8 @@ def data_availability(input_files, var, dirnames, filenames):
                 "Looked for files matching %s, but did not find any existing "
                 "input directory", filenames)
         logger.error("Set 'log_level' to 'debug' to get more information")
-        raise RecipeError("Missing data")
+        raise RecipeError(
+            f"Missing data for {var['alias']}: {var['short_name']}")
 
     # check time avail only for non-fx variables
     if var['frequency'] == 'fx':
@@ -184,10 +193,9 @@ def valid_multimodel_statistic(statistic):
     """Check that `statistic` is a valid argument for multimodel stats."""
     valid_names = ["mean", "median", "std", "min", "max"]
     valid_patterns = [r"^(p\d{1,2})(\.\d*)?$"]
-    if not (statistic in valid_names or
-            re.match(r'|'.join(valid_patterns), statistic)):
+    if not (statistic in valid_names
+            or re.match(r'|'.join(valid_patterns), statistic)):
         raise RecipeError(
             "Invalid value encountered for `statistic` in preprocessor "
             f"`multi_model_statistics`. Valid values are {valid_names} "
-            f"or patterns matching {valid_patterns}. Got '{statistic}.'"
-        )
+            f"or patterns matching {valid_patterns}. Got '{statistic}.'")